Assessment of composition and spatial dynamics of weed communities in agroecosystem under varying edaphic factors.

Weeds are important components of the agroecosystems due to their role as primary producers within the farming systems, yet they are considered as major constraints to crop production. A phytosociological study was conducted to assess the composition and spatial distribution of existing weed species under the influence of various edaphic factors in the 15 wheat fields. Quadrat method was applied and different phytosociological attributes including abundance, density, and frequency were estimated by randomly laying down 10 square-shaped quadrats of size 1m2 in each wheat field. A total of 34 weed species belonging to 17 families and 30 genera were explored from 150 quadrats. Fabaceae and Asteraceae were ubiquitous plant families. Various edaphic factors such as; soil texture, electrical conductivity, soil pH, total dissolved solids, nitrogen, calcium carbonate, organic matter, NaCl, calcium, phosphorous, potassium, sodium, and zinc were determined. Pearson's correlation was employed to correlate weeds and the potential edaphic variables. The results depicted that most of these weed pairs' associations correlated positively. Simultaneously, the abundant weed species including Trifolium repens, Coronopus didymus, and Urtica dioica showed a positive correlation with most of the investigated ecological variables.

Introduction

Wheat (Triticum aestivum L.) is an annual, autogamous crop that is grown on an area of about 237 million hectares across the globe, constituting a yield of 749 million tonnes [1]. This crop is a main dietary component for approximately one-third of the total global population. Wheat is acclimated to the latitudes of 30° and 60°N, and 27° and 40°S on the globe. It grows at an optimum temperature of 25° C with precipitation varying between 250 to 1750 millimeters. Practically, 1/6 of the total world’s fertile land is under wheat cultivation, making it a major product in the global food market. It is a mostly-consumed agricultural product in Pakistan cultivated on an area of around 9 million hectares which is roughly 40% of the country’s total fertile land [2].

Weeds as an integral component of a dynamic ecosystem, often emerge as pioneer plants in secondary succession and ultimately expand as an obtrusive participant with food crops [3]. The notion of weed as an undesirable plant was originally realized when humans begin to establish plants for their nutritional benefits. Holm et al., [4], classified 250 substantial weed species for agricultural uses across the world. In agro-ecosystems, weeds have been remained a persisting impediment to crop yield, owing to the ideal features they possess that includes its active transpiration rate, allelopathy, ecological flexibility, effective stomatal conductance, efficient seed dispersal method, fast reproduction rate, higher photosynthetic activity, rapid seed development, short life cycle and higher resilience to ecological stresses [5, 6].

Weeds pose a global threat to crops as their populations vary both spatially and temporally which induce substantial crop damage in arable fields with an estimated yield loss of about 10 to 80% [7, 8]. Weeds are perceived as the most significant adversary of the wheat crop as they induce delays in wheat harvest, reduce its kernel quality, and inflate the operational expenses for cleaning and threshing. Globally, the reduction in wheat yield brought about by the weeds is approximated to be 13.1% [9]. In Pakistan, the rampant growth of weeds causes an estimated yield loss of 20 to 40% of the wheat crop adding up to more than 28 billion rupees at the national scale [10].

Weeds compete with crops for limited natural resources such as minerals, light, and dampness. Moreover, they are highly adaptable to new weed control and management strategies. The variations in the spatial pattern of weeds mainly depend on various anthropogenic and ecological factors such as no-tillage practices, herbicide application, and crop rotation which cause significant variations in weed densities [11, 12]. Rew and Cousens [13], observed that a site-specific weed species composition related to spatial soil heterogeneity often occurs within arable fields. Various soil properties including soil organic carbon, nutrient status of the soil, and soil texture primarily influence weed growth and its composition in a rather complex way, therefore, one must consider different inter-relations [6, 14].

Currently, various advanced approaches are being employed to accurately predict weed occurrence in the fields. But until now, the precise weed data correlated to various soil properties is limited, even though soil sensing approaches ensure soil data evaluations at high spatial resolution. Variability in the weed community structure and its distribution is chiefly influenced by various ecological drivers including crop type and its sustainability, farm management practices, physico-chemistry of the soil, seasonality, and urbanization [15].

The scope of the current investigation was to document and correlate weed data with soil properties to determine the influence of edaphic variants on the composition and spatial distribution of weed species of wheat crop of Sialkot, Pakistan. A prerequisite for the research was to employ a multivariate statistical approach that would further aid in developing a sustainable interminable plan for effective weed control management.

Materials and methods

Study area

The current research was conducted during the Rabbi season (December 2019 –April 2020) to investigate the weed ecology of 15 different fields of Sialkot, where the wheat crop has sporadically been cultivated. Sialkot is situated at an altitude of 256 meters above sea level, between 32°30’ North latitude and 74°31’ East longitude, in the North-East of the Punjab Province, Pakistan (Fig 1). It features a humid subtropical climate and expands on an area of around 1900 hectares which comprises about 637 villages. Approximately, 169.32 acres (4.2%) of Sialkot’s total land is utilized for agriculture purposes. The grains were sown during late November 2019, followed by the irrigation and plowing of the fields which were frequently visited to explore the weed flora. The quantitative ecological approach i.e., the quadrat method was applied after Clements [16]. And phytosociological attributes such as density, frequency, and abundance of weed species were estimated by establishing 10 square-shaped quadrats on each of the 15 wheat fields (a total of 150 quadrats) having a size of 1m2 in each projected area. Sub-tropical deciduous vegetation such as Acacia nilotica, Albizzia lebbek, Azadirachta indica, Bombax ceiba, Cassia fistula, Dalbergia sissoo, Eucalyptus camaldulensis, Melia azedarach, Morus alba, Pongamia pinata, and Vaccinium myrtillus inhabited the land. Furthermore, herbicides are seldom sprayed by native farmers, hence weeds are thriving abundantly.

Fig 1

Study area along with sites in district Sialkot, Pakistan.

Weed identification

Weed species were identified by reviewing accessible literature [17-22].

Phytosociological attributes

Community attributes such as abundance, density and frequency of each weed species were recorded following Odum [23].

Acquired data was put in a tabulated form to correlate it with the soil properties of the investigated area.

Soil sampling

Three soil samples (a total of 45 samples) were collected at 15cm to 20cm depths from each of the 15 wheat fields during the survey conducted in 2019–2020 during the Rabbi season. In each field, 3 random areas were marked and dug with a blunt knife to retrieve 500g of soil. Each soil sample was put in a polythene bag accompanying a tag on which sample number, date and place of the collection were specified. A set of 45 soil samples were then brought to the laboratory for further analysis to discover the inherent fertility and textural class of the observed soil.

During physico-chemical analysis, various parameters including calcium carbonate, concentration of Ca+, K+, Na+, P+, Zn and total nitrogen, electrical conductivity (EC), NaCl%, organic matter, soil pH, total dissolved solids (TDS), and texture were recorded using conventional laboratory techniques. A flame photometer (Flame photometer 410, Corning) was used to record K+ and Na+ ions whereas, an Atomic Absorption Spectrophotometer (Perkin Elmer Analyst 100) was utilized to determine the concentrations of Ca+2, P, Zn and N in the observed soil samples. Soil texture was demonstrated by the feel method. To determine the lime content of these soil samples, acid neutralization method was employed. Approximately, 5g of soil was initially treated with 0.5N hydrochloric acid and then titrated with 0.025N sodium hydroxide while using phenolphthalein as an acid-base indicator. Meanwhile, the standard sequential LOI (Loss on ignition) method was applied for soil OM (organic matter) measurement [24]. The investigated samples were air dried and mixed homogeneously followed by grounding. 2g of each pulverized sample was passed through a 60 μm mesh. These samples were later measured in 20 ml crucibles and were placed overnight inside an oven at 105°C. Subsequently, cooled in desiccators, the air-dried samples were again weighed to find the residual moisture content. Loss on ignition of the organic matter was estimated by the equation:

In a flask, 25g of each sample was taken and supplemented up to 100ml by distilled water for demonstrating the soil pH, TDS, EC and NaCl%. The mixture was stirred by manual shaking for about 10 minutes straight and then was properly stirred for 6 hours on a shaking machine in order to segregate the suspended matter from the solution. A Whatman filter paper No.1 was used to filter the aforementioned solution. Afterwards, soil pH, NaCl% and EC were measured by pH meter and conductivity meter, respectively [25]. While, soil TDS was recorded by TDS meter (Hanna HI 83141).

Data analysis

Multivariate ordination techniques are successfully applied in soil-plant research to analyze multi-dimensional data viz., edaphic factors and population [26]. The collective data of 150 quadrats was organized in MS excel and PC-ORD version 5 was adopted to perform Principal Component Analysis (PCA) in order to demonstrate the influence of various edaphic factors on spatial heterogeneity of weed species [27]. Ordination diagrams (attribute biplots) were derived through Canoco version 4.5 to display the relationship between weed communities of the observed localities and various attributes. Also, Pearson Correlation was used to correlate different weed species as well as with other ecological variables. Pearson correlation is a linear correlation, where positive correlation suggests that two weed species representing mutualism or weak parasitism and have similar requirements for environmental factors are likely to emerge simultaneously. Whereas, a negative correlation indicates the exclusive appearance of two weed species in the plots primarily on account of definite ecological requirements, interference and competition among them. Species richness, Shannon index of α-diversity, and species evenness were carried out to identify similarity. While, Non-metric multidimensional scaling (NMDS) based on Bray-Curtis dissimilarity matrices, including analysis of similarity (ANOSIM) was carried out to test dissimilarity among existing weed species at different sites.

Results

Density (m-2)

The recorded weed data exhibits that 34 weed species were documented in 15 wheat fields of Sialkot, Pakistan (Fig 2). Salehpur (80.5), Ajuwali (70.3), and Kala Khambra (65.7) were identified as the most intensely weed infested locations, whereas the weed density was relatively low in Pindi Panjoran (13). The investigated area of Sialkot was mostly dominated by Trifolium repens (108.4), Coronopus didymus (83.6) along with Urtica dioica (73.3) and Anagallis arvensis (70). Meanwhile, Portulaca oleraceae (0.7), Oxalis corniculata (0.6) and Malva parviflora (0.4) emerged as minor weeds in only one or two locations of studied area.

Fig 2

Chord diagram representing the density of recorded weed species in fifteen different wheat fields of Sialkot.

After the weed community composition data were transformed for chord distance, the relationship between densities of weed communities from various wheat fields was then explored via principal component analysis (PCA). Most weed assemblages in the wheat fields of Khambranwala, Salehpur, and Kapurowaali were characterized by positive values along the PC1 (first principal component). The weed associations in the aforementioned fields were significantly different from rest of the wheat fields as evident in the PCA biplot (Fig 3). Overall, all 34 weed species contributed strongly to the first two principal components as displayed by the labelled vectors (Fig 3). Twenty one (21 out of 34) of the weed species contributed to a larger %age in Khambranwala, Salehpur and Kapurowaali wheat fields whereas 13 (13 out of 34) of them were relatively more abundant in the rest of the wheat fields in Sialkot.

Fig 3

PCA biplot for analyzing relationship between weed communities’ density in different wheat fields.

Principal component analysis was performed for analyzing weed frequency from fifteen surveyed wheat fields in Sialkot. First principal component axis was mostly represented by 19 (19 out of 34) weed species of Khambranwala, Ajuwali, Salehpur, Sagarpur, and Kapurowaali while the remaining 15 (15 out of 34) of them represent the rest of the wheat fields. The weed species were relatively more frequent in Ajuwali as denoted by labelled vectors in first principal component of the PCA biplot. T. repens was the most frequent weed species as shown in the PCA biplot. Melilotus indicus was mostly associated with Salehpur fields (Fig 4).

Fig 4

PCA biplot for analyzing relationship between weed communities’ frequency in different wheat fields.

Correlation among different weed species

Correlation data (Fig 5) on different weed species indicates that at 99% confidence level, Cynodon dactylon-T. repens and M. indicus-T. repens correlate strongly negative with each other. Meanwhile, weed species pairs: A. arvensis-E. helioscopia, Centella asiatica-Sonchus oleraceus, C. arvense-O. corniculata, C. arvense-Parthenium hysterophorus, C. arvense-Plantago lanceolata, Convolvulus arvensis-Lathyrus aphaca, C. arvensis-Medicago polymorpha, C. arvensis-P. repense, L. aphaca-P. repense, M. polymorpha-P. repense, O. corniculata-P. hysterophorus, O. corniculata-P. lanceolata, and P. hysterophorus-P. lanceolata show a strong positive correlation.

Fig 5

Correlation matrix of different weed species.

Asterisk (*) sign denotes significant relationship (p ≤ 0.05).

Furthermore, moderately positive correlated weed species are: A. arvensis-M. denticulata, A. arvensis-Melilotus alba, B. napus-M. polymorpha, B. napus-M. indicus, C. sativa-R. obtusifolius, C. sativa-S. oleraceus, C. asiatica-C. album, C. arvense-M. indicus, C. arvense-P. plebeium, C. arvense-R. obtusifolius, C. arvensis-Glechoma hyderaceae, C. arvensis-V. sativa, C. didymus-P. oleraceae, C. dactylon-M. indicus, C. dactylon-P. plebeium, Digitaria sanguinallis-Festuca rubra, E. helioscopia-M. polymorpha, E. helioscopia-P. repense, G. hyderaceae-L. aphaca, G. hyderaceae-M. polymorpha, G. hyderaceae-P. repense, G. hyderaceae-V. sativa, L. aphaca-M. polymorpha, M. denticulata-M. alba, M. polymorpha-M. indicus, M. polymorpha-V. sativa, M. indicus-P. plebeium, O. corniculata-P. plebeium, O. corniculata-R. obtusifolius, P. repense-V. sativa, P. hysterophorus-P. plebeium, P. hysterophorus-R. obtusifolius, P. lanceolata-P. plebeium, P. lanceolata-R. obtusifolius, P. plebeium-R. obtusifolius and R. dentatus-S. marianum.

Correlation among different edaphic factors

A correlation analysis of the data of different edaphic factors demonstrates some significant negative and positive relations among them (Fig 6). EC and TDS show significant positive correlation with each other. Whereas, Zn has shown a significant negative correlation with N. Other than this, we could not find a strong positive or strong negative correlation among edaphic factors generally.

Fig 6

Correlation among various edaphic factors.

Abbreviations used are TDS (total dissolved solids); OM (organic matter); EC (electrical conductivity).

Correlation between weed species and different edaphic factors

Composition and distribution of different weed species varies spatially due to the influence of various edaphic variables. Pearson correlation data on different edaphic factors and weed species demonstrates the positive and negative relationship between them (Fig 7). It was indicated that pH correlates negatively with S. oleraceus, C. album, and C. asiatica, while it correlates positively with M. polymorpha and C. arvensis. Whereas, TDS shows a negative correlation with M. indicus and C. dactylon and positive correlation with T. repens, P. oleraceae, and C. asiatica. EC, K, and Ca correlate positively with C. asiatica, M. parviflora, and C. sativa, respectively. Na shows a negative relationship with D. sanguinallis and C. sativa, simultaneously, P correlates negatively with M. alba, M. denticulata, E. helioscopia, and A. arvensis. It was also observed that Zn showed a positive correlation with M. neglecta. Meanwhile, CaCO3 correlates positively with R. dentatus and negatively with P. plebeium, M. indicus, and C. dactylon. Furthermore, NaCl correlates positively with L. aphaca, D. sanguinallis, and C. arvensis and nitrogen correlates negatively with M. neglecta.

Fig 7

Correlation data on weed species and different edaphic factors.

Abbreviations used are TDS (total dissolved solids); OM (organic matter); EC (electrical conductivity). * denotes significant interaction at p ≤ 0.05, and ** denotes significant interaction at p ≤ 0.01.

Relative abundance

The weed species abundance data (Fig 8) displayed that wheat fields of Salehpur, Ajuwali, Kapurowaali, Sagarpur, and Khambranwala exhibited highest abundance of different weed species. While, Bhagwal Awanan site showed fewer number of respective weed species compared to other fields. T. repens was the most abundant weed species that was found abundantly in ten out of fifteen wheat fields followed by C. didymus (9 fields) and U. dioica (5 fields). On the other hand, O. corniculata, P. repense and M. parviflora were rare weed species that were present in only one or two of the 15 investigated wheat fields.

Fig 8

Relative abundance of 34 weed species in 15 different wheat fields of Sialkot.

Diversity indices

According to Shannon index, the α-diversity of plant species found to be greatest at Ajuwali, followed by Salehpur and Sagarpur sites (Fig 9a). Of all the sites studied, the median value of α- diversity was noted at Ballanwala. However, the lowest α-diversity based on Shannon’s index, was recorded at Saidpur site. Taking into consideration the species richness and evenness, Kapurowaali site had the highest species evenness (Fig 9b), species richness was, however, found to be highest at Ajuwali (Fig 9c).

Fig 9

Alpha diversity (Shannon index) (a), Species evenness (b), and species richness (c) of weeds at various study sites.

* shows significance at p ≤ 0.05, ** shows significance at p ≤ 0.01, *** indicate significance at p ≤ 0.001, and **** indicate significance at p ≤ 0.0001.

Moreover, NMDS ordination, based on Bray-Curtis dissimilarity matrices, explained significantly (ANOSIM, R = -0.301, P = 0.7593, Stress = 0171265) distinct variation among different sites. Beta-diversity using NMDS ordination revealed that weed communities in studied sites had different pattern, and provided distinct clustering of weed communities related to sites (Fig 10).

Fig 10

Non-metric multidimensional scaling (NMDS) based on Bray-Curtis dissimilarity matrices showing beta-diversity among different studied sites.

AW: Ajuwali; BA: Bhagwal Awanan; BW: Ballanwala; CM: Chak Mandhaar; JK: Jorian Kalan; KB: Kotli Bhutta; KK: Kala Khambra; KP: Kapurowaali; KW: Khambranwala; LP: Lalpur; MK: Machi Khokhar; PP: Pindi Panjoran; SG: Sagarpur; SL: Salehpur; SP: Saidpur.

Discussion

The present investigation is demonstrated on the culmination of the survey carried out in wheat fields of Sialkot, Punjab, Pakistan. The survey was conducted during winter season (December 2019 to April 2020) to appraise the floristic spectrum of weed species in wheat crops of Sialkot. The current research established 34 weed species belonging to 17 families and 30 genera assorted in about 150 quadrats. About 30 of them (88.23%) were dicotyledonous whereas the rest of 4 weed species (11.76%) were monocotyledonous. The eudicot families; Fabaceae (7 weed species) and Asteraceae (5 weed species) were the predominant lineages of the 17 families recorded in the research area, followed by the monocot family Poaceae (4 weed species) and eudicot family Polygonaceae (3 weed species).

In terms of weed species richness, the order of families found in Sialkot region was as follow: Fabaceae, Asteraceae, Poaceae, Polygonaceae, Brassicaceae, Malvaceae, Amaranthaceae, Apiaceae, Cannabaceae, Convolvulaceae, Euphorbiaceae, Lamiaceae, Oxalidaceae, Plantaginaceae, Portulaceae, Primulaceae and Urticaceae. Khattak et al., [28] reported a total of 43 weed species associated with 17 families. Among them, Asteraceae was the predominant family which was also observed in the current investigation. Poaceae was also reported as the most prominent weed family in the PMAS Arid Agriculture University, Rawalpindi campus during a survey supervised from 2007 to 2008 [29]. The current study also complies with the works of [30-33], who also recorded Fabaceae and Poaceae as the most substantial families.

The floristic spectrum of surveyed fields also depicts that the wheat crop has its suite of selective weed species [8, 34]. The current findings also reciprocate the works of Hyvönen et al., [11] and Marwat et al., [8] who observed the higher number of weeds species particularly dicotyledonous species in wheat fields mainly due to cultivation inputs inadequacy. The most predominant weed species in the studied fields were T. repens, C. didymus along with U. dioica and A. arvensis. Gupta et al., [35] recorded A. arvensis and C. album as the most abundant weeds species that actively compete with wheat crop for light, space, and moisture.

Physico-chemical properties of soil, crop rotation, and diverse farming practices greatly affects the diversity and richness of weed species [13]. Weed composition data on the wheat fields of Sialkot disclosed that the estimated densities and spatial patterns of studied weed species were distributed heterogeneously throughout the region. Ritter and Gerhards [12] evaluated the additional modification of species composition owing to the weed density competition with the investigated crop. To explicate the multifaceted impacts of these edaphic factors on weed data variability, PCA was performed and these diverse soil features were correlated with weed species density. PCA bi-plot analysis signifies the specific composition and distribution patterns of investigated weed species in relation to edaphic factors.

Density and variability of weed species also depend on the inconstancy of both anthropogenic and ecological variables [15]. The essential properties of soil i.e., its pH, fertility, structure, and texture as well as crop rotation, farming practices and availability of moisture strongly impact the weed count and its heterogeneity. Soil analysis of the surveyed fields exhibited that the soil texture varied between sandy clay loam to loam, silty clay loam, silt loam and clay loam (Table 1).

Table 1

Physicochemical properties of the soil at 30°C of wheat fields of Sialkot.

Sr No.	Field Name	Texture	pH	TDS	EC	OM	K (ppm)	Na (ppm)	Ca (ppm)	P (ppm)	Zn (ppm)	CaCo3 (%)	NaCl (%)	N (%)
1	Chak Mandhaar	Silty clay loam	8.3±0.05	244±21.2	0.3±0.03	1.4	333.6±5.7	412.3±7.2	0.14±0.01	15±1.1	1.4±0.05	19.3±0.6	1.2±0.06	0.8±0.03
2	Ballanwala	Silty clay loam	8.3±0.03	229±4.8	0.3±0.02	3.1	438±19.5	458±3.5	0.11±0.002	13.6±1.4	2.2±0.01	18.4±0.3	0.6±0.04	0.8±0.04
3	Saidpur	Clay loam	8.4±0.01	272±30.3	0.4±0.04	1.4	308.3±4.1	742.6±18.6	0.18±0.008	12.3±1.8	0.8±0.05	18.2±1.1	0.5±0.03	0.7±0.01
4	Kala Khambra	Sandy clay loam	8.2±0.21	311±37.4	0.4±0.05	1.7	362.6±6.3	660.6±2.4	0.09±0.01	16±1.1	2.3±0.05	14.1±0.6	0.7±0.2	0.8±0.01
5	Pindi Panjoran	Clay loam	8.3±0.08	222±10.7	0.3±0.02	2.3	379±11.5	526±8.3	0.07±0.006	13.3±2.02	2.3±0.05	15.6±0.3	0.8±0.06	0.55±0.01
6	Lalpur	Sandy clay loam	8.1±0.33	305±35.3	0.4±0.05	2.4	274.3±8.4	339±3.2	0.17±0.002	12±1.5	2.09±0.02	15.6±0.8	1.03±0.06	0.8±0.01
7	Machi Khokhar	Sandy clay loam	8.4±0.04	263±32.6	0.4±0.04	1.6	222.3±13.8	226.3±14.1	0.16±0.002	17.3±1.1	1.9±0.03	13.3±1.4	1±0.5	0.7±0.02
8	Kotli Bhutta	Silt loam	8.2±0.17	234±5.2	0.3±0.01	1.2	155.3±4.7	338±4.5	0.11±0.001	7.7±0.8	4.2±0.08	11.2±0.3	0.5±0.04	0.5±0.01
9	Bhagwal Awanan	Silty clay loam	8.5±0.06	281±28.4	0.4±0.04	2.6	364.6±4.6	710±7.6	0.18±0.02	17.4±1.7	3.4±0.01	18.5±0.9	0.4±0.03	0.6±0.03
10	Jorian Kalan	Silty clay loam	8.3±0.12	217±11.2	0.3±0.01	2.1	750±22.6	522.6±6.3	0.13±0.002	19.09±1.04	3.2±0.1	15.3±0.4	0.7±0.1	0.5±0.01
11	Khambranwala	Loam	8.4±0.01	215±4.6	0.3±0.005	1.65	336.6±26.6	616.6±19.09	0.11±0.001	17.4±0.8	1.1±0.005	7.3±0.4	1.13±0.06	0.8±0.003
12	Ajuwali	Silt loam	8.5±0.01	241±19.9	0.3±0.03	1.2	332±5.7	418±11.1	0.07±0.001	13.1±0.6	2.2±0.03	14.9±1.07	1.23±0.06	0.5±0.01
13	Salehpur	Clay loam	8.3±0.003	197±8.2	0.3±0.01	2.1	367.3±8.9	471±3.2	0.19±0.003	4.7±0.7	2.4±0.03	16.6±0.3	1.29±0.01	0.7±0.005
14	Sagarpur	Silty clay loam	8.3±0.11	203±11.9	0.3±0.01	2.6	301.6±1.2	405±2.8	0.18±0.003	16.9±1.1	2.07±0.01	11.8±0.6	0.6±0.06	0.8±0.01
15	Kapurowaali	Silty clay loam	8.3±0.02	220±15.2	0.3±0.02	1.6	151.6±13.01	695±3.6	0.13±0.002	10.2±0.3	2.01±0.01	12.1±1.4	0.5±0.01	0.8±0.003

Abbreviations used are TDS (total dissolved solids); OM (organic matter); EC (electrical conductivity).

The estimated soil pH differed from 8.1 to 8.5. EC and TDS ranged from 0.3 to 0.4 mS/cm and 197ppm to 311ppm, respectively. The calcium carbonate %age fluctuated between 6.5 to 20%. NaCl was in the range of 0.0–0.4%, while Nitrogen varied between 0.49 to 0.89%. Meanwhile, the inorganic salts were found as: calcium (0.068ppm to 0.199ppm), sodium (218ppm to 770ppm), phosphorous (3.38ppm to 20.27ppm), potassium (130ppm to 777ppm), and zinc (0.79ppm to 3.44ppm).

Hoveizeh [36] stated that soil properties directly impact weed growth and its distribution. Sperry and Hacke [37] declared that soil texture plays a key role in the maintenance and regulation of infiltration rate and water holding capacity of the soil. Various other investigations also revealed the significance of soil texture and its properties in molding vegetation structure. Passioura [38] demonstrated that the spatial arrangement of soil particles, aggregates and pores is a primary variable that governs vegetation performance. Zhang et al., [39] noted that soil topography and organic matter essentially influence weed composition patterns. It is also hypothesized that soil texture may control nutrient and water availability. Normally, fine-textured soils are rich in organic matter and thus have a greater number of nutrients than coarse-textured soils. Whereas, precipitation percolates to a greater extent through coarse-textured soils in contrast to fine-textured soils [26, 40, 41]. The culmination of current research also acknowledges that divergence of weed species composition was greatly spatially assembled due to specific soil type and its properties.

The present research also correlated various weed species of the wheat fields in Sialkot with each other and various edaphic factors via Pearson’s correlation. Most of these weed species associations were positive. Therefore, the competition and interference between these positively correlated weed species were fairly insignificant. Zhang et al., [42] also demonstrated the succession of weed communities in the rice fields in Pearl River Delta, China, via Spearman rank correlation, Pearson correlation, and point correlation. The current results were in alignment with his work which also indicated that most of the weed species/families showed positive correlation with each other.

In the present study, it was also observed that soil pH was negatively correlated with C. asiatica, C. album, and S. oleraceus. Similarly, Malva neglecta showed negative correlation with available nitrogen. A negative relationship was also found among sodium, C. sativa and D. sanguinallis. Phosphorous correlated negatively with A. arvensis, E. helioscopia, M. denticulata and M. alba. Also, weed species including C. dactylon and M. indicus showed a negative correlation with soil TDS and calcium carbonate content. The aforementioned results depict that various edaphic factor including soil pH, TDS, nitrogen, CaCo3, and inorganic salts (Na and P) substantially influenced weed growth and composition in the investigated wheat fields of Sialkot, Pakistan. Schuster and Diekmann [43] and Stevens et al., [14] also found that pH harms species density whereas, the weed species dominating the USC and UPA correlated positively with clay content, phosphorous and potassium. In inter-correlation of edaphic factors, only EC and TDS were appeared to be having positive correlation with each other. Mostly, the edaphic factors in this study did not show any specific agreement in their existence. This was inconsistence with previous studies as most edaphic factors remained unresponsive to themselves and certain climatic factors such as in Madagascar [44].

Plant species diversity can be commendably estimated using species richness and evenness, however, it is not necessarily true that these components have some relation with each other [41, 45, 46]. But, taking into consideration richness or evenness alone is not a true measure of species diversity. In conformity with previous studies, our sites also varied for their species richness and evenness [47, 48]. However, species richness, and α-diversity were highest at the same sites which are usually the same measure of diversity (S1 Table).

Conclusions

A quantitative comparison of the prevalent weed species in wheat fields of Sialkot is presented in the current investigation. About 34 weed species associated with 17 families were discovered from 150 quadrats in 15 wheat fields, indicating that the wheat crop of the investigated area is highly susceptible to weed infestation. Most of these weed associations were positive. Also most soil factors were positively correlated with weeds, therefore, the competition and niche separation among these weed species was negligible. However, the edaphic factors significantly influenced the weed density and diversity of the study area. It is also noteworthy that the order of significance of the impact of the evaluated environmental variables is only realistic for the present area of the study and is not an absolute standard. These edaphic variables may act as the vegetation structure determinant in a definite area and a co-factor in others considering the feasible natural resources. The research presents a relevant report to the scientific society regarding the weed flora flourishing in the wheat fields of Sialkot. Thus, the narratives of the current investigation would be valuable in forging a substantial weed management plan as well as in making an insightful discernment in selecting herbicides. However, such survey results from other cereal crops would give a comprehensive picture of the weeds invading the area.

Different diversity indices of weed communities.

(DOCX)

Click here for additional data file.

(XLSX)

Click here for additional data file.

3 Feb 2022

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Ansar Hussain

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. We note that the grant information you provided in the ‘Funding Information’ and ‘Financial Disclosure’ sections do not match.

When you resubmit, please ensure that you provide the correct grant numbers for the awards you received for your study in the ‘Funding Information’ section.

3. Thank you for stating the following in the Acknowledgments Section of your manuscript:

"The authors extend their appreciation to the Government College Women University, Sialkot, Pakistan for providing lab facilities. Authors also extend their appreciation to the Deanship of Scientific Research, King Khalid University for funding this publication work through research groups program under grant number R.G.P. 1/241/41."

We note that you have provided funding information that is not currently declared in your Funding Statement. However, funding information should not appear in the Acknowledgments section or other areas of your manuscript. We will only publish funding information present in the Funding Statement section of the online submission form.

Please remove any funding-related text from the manuscript and let us know how you would like to update your Funding Statement. Currently, your Funding Statement reads as follows:

"yes"

Please include your amended statements within your cover letter; we will change the online submission form on your behalf.

4. In your Data Availability statement, you have not specified where the minimal data set underlying the results described in your manuscript can be found. PLOS defines a study's minimal data set as the underlying data used to reach the conclusions drawn in the manuscript and any additional data required to replicate the reported study findings in their entirety. All PLOS journals require that the minimal data set be made fully available. For more information about our data policy, please see http://journals.plos.org/plosone/s/data-availability.

Upon re-submitting your revised manuscript, please upload your study’s minimal underlying data set as either Supporting Information files or to a stable, public repository and include the relevant URLs, DOIs, or accession numbers within your revised cover letter. For a list of acceptable repositories, please see http://journals.plos.org/plosone/s/data-availability#loc-recommended-repositories. Any potentially identifying patient information must be fully anonymized.

Important: If there are ethical or legal restrictions to sharing your data publicly, please explain these restrictions in detail. Please see our guidelines for more information on what we consider unacceptable restrictions to publicly sharing data: http://journals.plos.org/plosone/s/data-availability#loc-unacceptable-data-access-restrictions. Note that it is not acceptable for the authors to be the sole named individuals responsible for ensuring data access.

We will update your Data Availability statement to reflect the information you provide in your cover letter.

5. Please include your full ethics statement in the ‘Methods’ section of your manuscript file. In your statement, please include the full name of the IRB or ethics committee who approved or waived your study, as well as whether or not you obtained informed written or verbal consent. If consent was waived for your study, please include this information in your statement as well.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Dear Authors,

The article submitted for review: Assessment of Composition and Spatial Dynamics of Weed Communities in Agroecosystem under Varying Edaphic Factors, is a broad analysis of weed occurrence in wheat crop. From an agricultural point of view, weed structure is of great importance. The article is properly prepared and under the journal scope. Visualizations are of good quality.

I have some comments needs to be addressed:

1) Abstract L3: Explain what you mean by "substantial" or use the correct term, perhaps "more noxious.

2) L46: use a more suitable term for composite such as yield, yield, etc.

3) L53: use 9 instead of 9.0

4) L55: Replace our with the

5) L70: use 28 instead of twenty-eight

6) L71: “Weeds are ubiquitous and…….” , delete “are ubiquitous and”, be shorter and direct. Avoid the use of unnecessary terms and expressions

7) L97-99: “The current research…………. cultivated”, move these lines to the beginning of the paragraph

8) L107: use herbicides instead of weedicides

9) L113-116: use the correct font size for all the equations

10) L121-122: these expressions are confusing; you mean 3 samples in the first and 3 in the third. Are you referring to the same samples at each site or are they different?

11) L146: Replace electrical conductivity with E.C., use the proposed abbreviations

12) L179-182: “Physio-chemical……….edaphic factors”. Interpretation for discussion. Focus on describing only results, any interpretation or conjecture about them make it in the corresponding section

13) L183-185: delete, this is Methodology

14) L205-239: abbreviate the genus that were already mentioned above: like Trifolium repens --- T. repens

15) L241-245: delete all unnecessary terms

16) L268: Correct like C. didymus (9 fields) and U. dioica (5 fields)

17) L273: replace alpha with α

18) The conclusions need to be corrected because the first paragraph repeats the research methodology and analysis of the results obtained.

19) Rewrite this conclusion in a shorter and clearer way, maybe: Furthermore, most soil factors were positively correlated with weeds, therefore, the competition and niche separation among them was negligible

Final Recommendations: Overall, I think the experiments and various analysis carried out are interesting, and in general, the manuscript is well organized, but above mentioned correction must be addressed for acceptance.

Reviewer #2: Title: Assessment of Composition and Spatial Dynamics of Weed Communities in Agroecosystem under Varying Edaphic Factors

GENERAL EVALUATION:

The manuscript titled as “Assessment of Composition and Spatial Dynamics of Weed Communities in Agroecosystem under Varying Edaphic Factors” deals with the investigation of weed distribution and its relation with some soil properties in 15 wheat fields in Pakistan. The subject of the manuscript is considered as quite suitable for the journal. Authors have great field, laboratory and computer-based job, but some aspects should be improved in this article to be fully suitable for publication.

In general, the writing style and the use of English language are satisfactory. But there are some slight shortcomings. I listed some more corrections, recommendations and questions below for the authors to improve the manuscript.

TITLE: Title is OK.

ABSTRACT:

- Second sentence must be deleted; it could be moved to Intro section.

- Number of wheat fields (15) should be included.

KEYWORDS

- Change “Soil texture” with “Soil properties”.

- Change “Weed control” with “Weeds”.

INTRODUCTION

1. Page 1, Last line: What is “ESP”? If it is a reference, number it and list it in the Reference section.

2. Page 1, Last line: Change “most consuming yield” with “mostly-consumed agricultural product”.

3. Page 2, Paragraph 1, Line 2: Use a better term instead of “our crops”.

4. Page 2, Paragraph 1, Line 3: Use a better term instead of “folks”.

5. Page 2, Paragraph 1, Line 4: Delete commas.

6. Page 2, Paragraph 2, Lines 3-6-7: Change “percent” to “%”. Check whole manuscript.

MATERIALS AND METHODS

1. Paragraph 1, Line 2: Change “ten square-shaped quadrats” to “ten square-shaped quadrats on each of the 15 wheat fields (a total of 150 quadrats)”.

2. Paragraph 1, Line 6: Use “herbicides” instead of “weedicides”.

3. Section Weed identification: Briefly explain how you identified the weeds.

4. Use smaller fonts for all three equations.

5. Section soil sampling:Change “Three soil samples” to “Three soil samples from each of the fifteen wheat field”

6. Section soil sampling- Line 3: Check the unit “gm-1 kg”.

7. Section soil sampling: Delete “Configuration”.

Page 7, Paragraph 3, Line 2: Use “total dissolved solids (TDS)” instead of “TDS”.

Page 8, Paragraph 1: Check the grammar of the sentence: “was established”, “was adopted”.

Page 8, Paragraph 1: Use small letters for the software names (EXCEL, CANOCO).

RESULTS

Page 9, Last Paragraph, Line 2: Add “Figure 4” at the end of the first sentence.

Page 9, Last Paragraph: Do not list all pairs, please summarize the top several pairs (3-5 pairs) with the highest correlation.

Page 10, Last Paragraph: Do not list all pairs, please summarize the top several pairs (3-5 pairs) with the highest correlation. Include the figure number for this finding. Also, Latin names must be given in italic format.

Figure 6 and Figure 7: Make the legend a little bit bigger. Include the full name for the acronyms (TDS, OM, EC) at the end of the caption in parenthesis.

Section “Correlation between weed ….” Line 2: “different ecological factors” or “different edaphic factors”.

Line 6: “and” should not be in italic format.

Figure 9: Put a note what the asterisk signs (*) mean at the end of the figure caption.

DISCUSSION

Page 14, Line 297: Delete the comma in “Khattak, et al. [24]”.

Page 14, Line 303: Delete the comma in “Hyvönen, et al. [31]”.

Page 14, Line 304: Delete the two commas in “Marwat, et al. [32],”.

Page 14, Line 306: Replace “along” with “along with”.

Page 14, Line 307: Delete the comma in “Gupta, et al. [33]”.

Page 15, Line 334:Delete the comma in “Zhang, et al. [38]”.

Page 16, Line 345:Delete the comma in “Zhang, et al. [40]”.

Page 16, Line 359:Delete the comma in “Stevens, et al. [42]”.

Page 17, Line 365:Replace “Medagascar” to “Madagascar”.

Table 1: Include the full names for the acronyms (TDS, EC, OM) at the bottom of the table.

CONCLUSIONS

- Number of wheat fields (15) should be included into the second sentence.

- Use clear statements for the findings. Give your recommendations.

REFERENCES

Reference no 2: Check the typing (two dots)

Reference no 24: Check the title (“Underunder”)

Reference no 34: Check the title (Latin names must be in Italic)

Reference no 40: Check the journal name

Reference no 42: Check the journal name

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

3 Mar 2022

PONE-D-22-00689

Responses to reviewers’ comments

We are really thankful to the reviewers who have taken their time to make this manuscript better. Track-change mode was adopted to make changes in the manuscript in this revision.

Reviewer 1

Sr # Reviewer’s comment Response

1 The article submitted for review: Assessment of Composition and Spatial Dynamics of Weed Communities in Agroecosystem under Varying Edaphic Factors, is a broad analysis of weed occurrence in wheat crop. From an agricultural point of view, weed structure is of great importance. The article is properly prepared and under the journal scope. Visualizations are of good quality.

I have some comments needs to be addressed: Thank you for appreciating the scope of our manuscript. We have addressed the concerns you mentioned in the best possible way.

2 1) Abstract L3: Explain what you mean by "substantial" or use the correct term, perhaps "more noxious. This line has been removed from the abstract now.

3 2) L46: use a more suitable term for composite such as yield, yield, etc. Correction has been made

4 3) L53: use 9 instead of 9.0 Corrected as suggested.

5 4) L55: Replace our with the Corrected as suggested.

6 5) L70: use 28 instead of twenty-eight Corrected as suggested.

7 6) L71: “Weeds are ubiquitous and…….” , delete “are ubiquitous and”, be shorter and direct. Avoid the use of unnecessary terms and expressions Corrected as suggested.

8 7) L97-99: “The current research…………. cultivated”, move these lines to the beginning of the paragraph. Corrected as suggested.

9 8) L107: use herbicides instead of weedicides Corrected as suggested.

10 9) L113-116: use the correct font size for all the equations Corrected as suggested.

11 10) L121-122: these expressions are confusing; you mean 3 samples in the first and 3 in the third. Are you referring to the same samples at each site or are they different? We have now explained it a little bit more to resolve the ambiguity.

11) L146: Replace electrical conductivity with E.C., use the proposed abbreviations Corrected as suggested.

12) L179-182: “Physio-chemical……….edaphic factors”. Interpretation for discussion. Focus on describing only results, any interpretation or conjecture about them make it in the corresponding section Thank you for the suggestion, we have modified the desired portion and follow the pattern.

13) L183-185: delete, this is Methodology Deleted.

14) L205-239: abbreviate the genus that were already mentioned above: like Trifolium repens --- T. repens We have now given abbreviated the genus names except their first use in the manuscript.

15) L241-245: delete all unnecessary terms Corrected as suggested.

16) L268: Correct like C. didymus (9 fields) and U. dioica (5 fields) Corrected as suggested.

17) L273: replace alpha with α Replaced.

18) The conclusions need to be corrected because the first paragraph repeats the research methodology and analysis of the results obtained. The extra detail from the conclusions is now omitted.

19) Rewrite this conclusion in a shorter and clearer way, maybe: Furthermore, most soil factors were positively correlated with weeds, therefore, the competition and niche separation among them was negligible. The conclusion is revised now.

Final Recommendations: Overall, I think the experiments and various analysis carried out are interesting, and in general, the manuscript is well organized, but above mentioned correction must be addressed for acceptance. Thank you very much.

Reviewer 2

Sr # Reviewer’s comment Response

1 GENERAL EVALUATION:

The manuscript titled as “Assessment of Composition and Spatial Dynamics of Weed Communities in Agroecosystem under Varying Edaphic Factors” deals with the investigation of weed distribution and its relation with some soil properties in 15 wheat fields in Pakistan. The subject of the manuscript is considered as quite suitable for the journal. Authors have great field, laboratory and computer-based job, but some aspects should be improved in this article to be fully suitable for publication.

In general, the writing style and the use of English language are satisfactory. But there are some slight shortcomings. I listed some more corrections, recommendations and questions below for the authors to improve the manuscript. Thank you for your appreciation. We have now revised the manuscript according to your suggestions.

2 TITLE: Title is OK.

3 ABSTRACT:

- Second sentence must be deleted; it could be moved to Intro section.

- Number of wheat fields (15) should be included. The 2nd sentence from the abstract is now deleted.

4 KEYWORDS

- Change “Soil texture” with “Soil properties”.

- Change “Weed control” with “Weeds”. Changed.

5 INTRODUCTION

1. Page 1, Last line: What is “ESP”? If it is a reference, number it and list it in the Reference section.

2. Page 1, Last line: Change “most consuming yield” with “mostly-consumed agricultural product”.

3. Page 2, Paragraph 1, Line 2: Use a better term instead of “our crops”.

4. Page 2, Paragraph 1, Line 3: Use a better term instead of “folks”.

5. Page 2, Paragraph 1, Line 4: Delete commas.

6. Page 2, Paragraph 2, Lines 3-6-7: Change “percent” to “%”. Check whole manuscript. We have Corrected as suggested all of these changes now.

6 MATERIALS AND METHODS

1. Paragraph 1, Line 2: Change “ten square-shaped quadrats” to “ten square-shaped quadrats on each of the 15 wheat fields (a total of 150 quadrats)”.

2. Paragraph 1, Line 6: Use “herbicides” instead of “weedicides”.

3. Section Weed identification: Briefly explain how you identified the weeds.

4. Use smaller fonts for all three equations.

5. Section soil sampling:Change “Three soil samples” to “Three soil samples from each of the fifteen wheat field”

6. Section soil sampling- Line 3: Check the unit “gm-1 kg”.

7. Section soil sampling: Delete “Configuration”.

Page 7, Paragraph 3, Line 2: Use “total dissolved solids (TDS)” instead of “TDS”.

Page 8, Paragraph 1: Check the grammar of the sentence: “was established”, “was adopted”.

Page 8, Paragraph 1: Use small letters for the software names (EXCEL, CANOCO). We have Corrected as suggested all of these changes now.

7 RESULTS

Page 9, Last Paragraph, Line 2: Add “Figure 4” at the end of the first sentence.

Page 9, Last Paragraph: Do not list all pairs, please summarize the top several pairs (3-5 pairs) with the highest correlation.

Page 10, Last Paragraph: Do not list all pairs, please summarize the top several pairs (3-5 pairs) with the highest correlation. Include the figure number for this finding. Also, Latin names must be given in italic format.

Figure 6 and Figure 7: Make the legend a little bit bigger. Include the full name for the acronyms (TDS, OM, EC) at the end of the caption in parenthesis.

Section “Correlation between weed ….” Line 2: “different ecological factors” or “different edaphic factors”.

Line 6: “and” should not be in italic format.

Figure 9: Put a note what the asterisk signs (*) mean at the end of the figure caption. We have Corrected as suggested all of these changes now.

8 DISCUSSION

Page 14, Line 297: Delete the comma in “Khattak, et al. [24]”.

Page 14, Line 303: Delete the comma in “Hyvönen, et al. [31]”.

Page 14, Line 304: Delete the two commas in “Marwat, et al. [32],”.

Page 14, Line 306: Replace “along” with “along with”.

Page 14, Line 307: Delete the comma in “Gupta, et al. [33]”.

Page 15, Line 334:Delete the comma in “Zhang, et al. [38]”.

Page 16, Line 345:Delete the comma in “Zhang, et al. [40]”.

Page 16, Line 359:Delete the comma in “Stevens, et al. [42]”.

Page 17, Line 365:Replace “Medagascar” to “Madagascar”.

Table 1: Include the full names for the acronyms (TDS, EC, OM) at the bottom of the table.

We have Corrected as suggested all of these changes now.

9 CONCLUSIONS

- Number of wheat fields (15) should be included into the second sentence.

- Use clear statements for the findings. Give your recommendations.

The 2nd sentence is modified now and recommendations have also been added to the end of the conclusion section.

10 REFERENCES

Reference no 2: Check the typing (two dots)

Reference no 24: Check the title (“Underunder”)

Reference no 34: Check the title (Latin names must be in Italic)

Reference no 40: Check the journal name

Reference no 42: Check the journal name

We have Corrected as suggested all of these changes now.

Submitted filename: Responses to reviewers comments.docx

Click here for additional data file.

15 Mar 2022

24 Mar 2022

PONE-D-22-00689R2

Responses to reviewers’ comments

Authors wish to thank to the worthy Editor and reviewers who have taken their time to make this manuscript better. Track-change mode was adopted to make changes in the manuscript in this revision.

Journal Requirements:

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

RESPONSE: We have carefully revised the manuscript according to the journals style of formatting. Thank you for your help.

2. Thank you for stating the following in your Competing Interests section:

(No competing interests)

Please complete your Competing Interests on the online submission form to state any Competing Interests. If you have no competing interests, please state "The authors have declared that no competing interests exist.", as detailed online in our guide for authors at http://journals.plos.org/plosone/s/submit-now. This information should be included in your cover letter; we will change the online submission form on your behalf.

RESPONSE: Thank you for highlight this point. The authors have declared that no competing interests exist.

3. We note that Figure 1 in your submission contain map images which may be copyrighted. All PLOS content is published under the Creative Commons Attribution License (CC BY 4.0), which means that the manuscript, images, and Supporting Information files will be freely available online, and any third party is permitted to access, download, copy, distribute, and use these materials in any way, even commercially, with proper attribution. For these reasons, we cannot publish previously copyrighted maps or satellite images created using proprietary data, such as Google software (Google Maps, Street View, and Earth). For more information, see our copyright guidelines: http://journals.plos.org/plosone/s/licenses-and-copyright.

We require you to either (1) present written permission from the copyright holder to publish these figures specifically under the CC BY 4.0 license, or (2) remove the figures from your submission:

a. You may seek permission from the original copyright holder of Figure 1 to publish the content specifically under the CC BY 4.0 license.

We recommend that you contact the original copyright holder with the Content Permission Form (http://journals.plos.org/plosone/s/file?id=7c09/content-permission-form.pdf) and the following text:

“I request permission for the open-access journal PLOS ONE to publish XXX under the Creative Commons Attribution License (CCAL) CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/). Please be aware that this license allows unrestricted use and distribution, even commercially, by third parties. Please reply and provide explicit written permission to publish XXX under a CC BY license and complete the attached form.”

Please upload the completed Content Permission Form or other proof of granted permissions as an "Other" file with your submission.

In the figure caption of the copyrighted figure, please include the following text: “Reprinted from [ref] under a CC BY license, with permission from [name of publisher], original copyright [original copyright year].”

b. If you are unable to obtain permission from the original copyright holder to publish these figures under the CC BY 4.0 license or if the copyright holder’s requirements are incompatible with the CC BY 4.0 license, please either i) remove the figure or ii) supply a replacement figure that complies with the CC BY 4.0 license. Please check copyright information on all replacement figures and update the figure caption with source information. If applicable, please specify in the figure caption text when a figure is similar but not identical to the original image and is therefore for illustrative purposes only.

The following resources for replacing copyrighted map figures may be helpful:

USGS National Map Viewer (public domain):

http://viewer.nationalmap.gov/viewer/

The Gateway to Astronaut Photography of Earth (public domain):

http://eol.jsc.nasa.gov/sseop/clickmap/

Maps at the CIA (public domain):

https://www.cia.gov/library/publications/the-world-factbook/index.html and

https://www.cia.gov/library/publications/cia-maps-publications/index.html

NASA Earth Observatory (public domain):

http://earthobservatory.nasa.gov/

Landsat: http://landsat.visibleearth.nasa.gov/

USGS EROS (Earth Resources Observatory and Science (EROS) Center) (public domain):

http://eros.usgs.gov/#

Natural Earth (public domain):

http://www.naturalearthdata.com/

RESPONSE: Thank you for your suggestions. The previous map was not copyrighted, it was original made by the 2nd author, but now for more clarity and to avoid any complications, we have made a new map using QGIS.

4. Please include captions for your Supporting Information files at the end of your manuscript, and update any in-text citations to match accordingly. Please see our Supporting Information guidelines for more information:

http://journals.plos.org/plosone/s/supporting-information.

RESPONSE: We have incorporated your suggestion into the revised MS. Thank you.

5. Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

RESPONSE: We have incorporated your suggestions into the revised MS. Thank you.

Additional Editor Comments:

• I have read your revised manuscript where most of the comments of reviewers have been addressed. However, the revised version has two major issues, one of them is formatting and other is language of the manuscript.

• Please incorporate tables and figures within the text and get your manuscript edited from a native speaker.

• One more issue is low number of references used in the introduction section, of which none has been used in the discussion. Please use the references used in discussion in the the introduction section and vice versa.

• Please improve your manuscript carefully and submit an improved version for further evaluation.

RESPONSE: Thank you for your comment. We have carefully revised the whole MS and addressed all these issues. Language has now been edited by native English speaker Professor Susan Anne Churchill who is working in Linguistic department of Fujian Agriculture and Forestry University China. Some of the relevant references in the introduction are now given in the discussion and vice versa. We have made a new map. We are hopeful you will like it and the manuscript in general. Thank you for your help.

Submitted filename: Responses to Reviewers.docx

Click here for additional data file.

28 Mar 2022

Assessment of composition and spatial dynamics of weed communities in agroecosystem under varying edaphic factors

PONE-D-22-00689R2

Dear Dr. Noman,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Ansar Hussain

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Thank you for addressing the queries raised by the reviewers. I am pleased to accept your manuscript for publication in Plos One.

Reviewers' comments:

13 May 2022

PONE-D-22-00689R2

Assessment of composition and spatial dynamics of weed communities in agroecosystem under varying edaphic factors

Dear Dr. Noman:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

If we can help with anything else, please email us at plosone@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr. Ansar Hussain

Academic Editor

PLOS ONE