Impact of straw management on seasonal soil carbon dioxide emissions, soil water content, and temperature in a semi-arid region of China.

The use of crop residues as mulching materials or organic fertilizer, instead of burning, can help improve the soil organic carbon (SOC) and crop grain yield. An experiment was conducted for three consecutive seasons from 2013 to 2016, to study the effect of no straw (S0), S1/2 (700 kg/ha soybean straw, and 3000 kg/ha wheat straw), and S1 (1400 kg ha-1 soybean straw, and 6000 kg/ha wheat straw) treatments in wheat-soybean multi-crop system. The randomized complete block design was used with three repeats. Compared with the S0 regime, a significant increase of 0.5%-8.7% and 1.4%-27.7% in soil CO2 emission was observed in the S1 regime during all growth stages of summer soybean and winter wheat, respectively. Soil temperature of S1/2 and S1 was 0.1-1.1 °C and 0.3-1.4 °C higher than that of S0 during the seeding stage and greening stage for wheat, during 2013 to 2016. During wheat season, soil moisture was higher in the S1 than in the S0 treatment. Likewise, wheat, soybean crop resulted the same results. Soil CO2 emissions increase with the increasing in soil temperature, and 73.4-73.9% of the variation could be explained by seasonal variation in soil temperature in wheat season. Similarly, 69.5-74.7% of the variation in soil CO2 emissions is recorded by seasonal variation in soil temperature in summer soybean season. Meanwhile (S1) increased the SOC and grain yield of wheat and soybean when compared to S0. Straw input increasing soil CO2, grain yield and SOC content, considering the benefits of straw inputs to crops yield and SOC content, It is concluded that the addition of straw improve agriculture production. However, the types of straw inputs in order to promote the sequestration of soil organic carbon with the decrease in greenhouse gas emission is the future research direction for agriculture development in Guanzhong region of China.