Sahrah Fischer1, Thomas Hilger2, Hans-Peter Piepho3, Irmgard Jordan4, Jeninah Karungi5, Erick Towett6, Keith Shepherd6, Georg Cadisch2. 1. Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), University of Hohenheim, Garbenstr. 13, 70599 Stuttgart, Germany. Electronic address: Sahrah.fischer@uni-hohenheim.de. 2. Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), University of Hohenheim, Garbenstr. 13, 70599 Stuttgart, Germany. 3. Institute of Crop Sciences, University of Hohenheim, Fruwirthstr. 20, 70599 Stuttgart, Germany. 4. Center for International Development and Environmental Research, Justus Liebig University Giessen, Senckenbergstraße 3, 35390 Giessen, Germany. 5. Department of Agricultural Production, Makerere University, Wandegeya, Makerere, P.O. Box 7062, Kampala, Uganda. 6. Land Health Decisions, World Agroforestry Centre, United Nations Avenue, Gigiri, PO Box 30677, Nairobi 00100, Kenya.
Abstract
Crops that grow on soils with higher fertility often have higher yields and higher tissue nutrient concentrations. Whether this is the case for all crops, and which soil and management factors, or combinations mostly affect yields and food nutrient concentrations however, is poorly understood. Here, the main aim was to evaluate effects of soil and management factors on crop yields and food nutrient concentrations in (i) grain, fruit and tuber crops, and (ii) between high and low soil fertility areas. Total elemental concentrations of Mg, P, S, K, Ca, Fe, Zn, Mn and Cu were measured using a portable X-Ray Fluorescence Spectrometer (pXRF) in maize grain (Zea mays; Teso South, Kenya: n = 31; Kapchorwa, Uganda n = 30), cassava tuber (Manihot esculenta; Teso South: n = 27), and matooke fruit (Musa acuminata; Kapchorwa, n = 54). Soil properties measured were eCEC, total N and C, pH, texture, and total elemental content. Farm management variables (fertilisation, distance to household, and crop diversity) were collected. Canonical Correspondence Analyses (CCA) with permutation rank tests identified driving factors of alterations in nutrient concentrations. Maize grain had higher correlations with soil factors (CCA > 80%), than cassava tuber (76%) or matooke fruit (39%). In contrast, corresponding correlations to management factors were much lower (8-39%). The main soil properties affecting food nutrients were organic matter and texture. Surprisingly, pH did not play an important role. A positive association of crop diversity with nutrient concentration and yield in lower fertility areas was observed. Considering, food nutrient composition, apart from yield, as response variables in agronomic trials (e.g. fertilisation or soil improvement strategies), would contribute towards discounting the notion that crops growing on fertile soils always produce healthy and high quality foods.
Crops that grow on soils with higher n class="Chemical">pan class="Chemical">fertility often have higher yields and higher tissue nutrient concentrations. Whether this is the case for all cropn>s, and which soil and management factors, or combinations mostly afpan class="Chemical">fect yields and food nutrient concentrations however, is poorly understood. Here, the main aim was to evaluate efpan class="Chemical">fects of soil and management factors on crop yields and food nutrient concentrations in (i) grain, fruit and tuber crops, and (ii) between high and low soil fertility areas. Total elemental concentrations of Mg, P, S, K, Ca, Fe, Zn, Mn and Cu were measured using a portable X-Ray Fluorescence Spectrometer (pXRF) in maize grain (Zea mays; Teso South, Kenya: n = 31; Kapchorwa, Uganda n = 30), cassava tuber (Manihot esculenta; Teso South: n = 27), and matooke fruit (Musa acuminata; Kapchorwa, n = 54). Soil properties measured were eCEC, total N and C, pH, texture, and total elemental content. Farm management variables (fertilisation, distance to household, and crop diversity) were collected. Canonical Correspondence Analyses (CCA) with permutation rank tests identified driving factors of alterations in nutrient concentrations. Maize grain had higher correlations with soil factors (CCA > 80%), than cassava tuber (76%) or matooke fruit (39%). In contrast, corresponding correlations to management factors were much lower (8-39%). The main soil properties affecting food nutrients were organic matter and texture. Surprisingly, pH did not play an important role. A positive association of crop diversity with nutrient concentration and yield in lower fertility areas was observed. Considering, food nutrient composition, apart from yield, as response variables in agronomic trials (e.g. fertilisation or soil improvement strategies), would contribute towards discounting the notion that crops growing on fertile soils always produce healthy and high quality foods.
Authors: Irmgard Jordan; Anna Röhlig; Maria Gracia Glas; Lydiah Maruti Waswa; Johnny Mugisha; Michael B Krawinkel; Ernst-August Nuppenau Journal: Foods Date: 2022-01-26