No-tillage and crop rotation increase crop yields and nitrogen stocks in sandy soils under agroclimatic risk
2020
Agricultural production is challenging in environments with climatic instability, high temperatures, and water deficits, particularly in sandy soils. The use of no-tillage, crop rotation, and cover crops can increase the sustainability of cropping systems under these conditions. Nitrogen (N) is important to improve carbon production and soil organic matter. The objective of this study was to evaluate the effect of summer crop rotation (sorghum or soybean), tillage system (no-tillage and conventional), and intercropping (maize and palisade grass) on crop yield (soybean and maize grain, sorghum silage and palisade grass dry matter) and soil nitrogen stocks. No-tillage system (NT) resulted in yields 6% higher for soybean, 100 % higher for sorghum and 17 % higher for maize, when compared to conventional tillage, and had no effect on palisade yield. The high palisade grass yield after soybean in 2014 decreased soil inorganic N stocks in the 0−60 cm layer, but total soil N was higher when using soybean rotation under NT and after intercropped maize in 2015. Soybean increased maize yields by 25 % (0.86 Mg ha⁻¹) and palisade yields by 46 % (1.5 Mg ha⁻¹) when compared to silage sorghum. Palisade grass decreased maize yield by 30 % with intercropping. Soybean grown under NT after maize and palisade grass intercrop improves soil N stocks and crop yields. Despite palisade grass competition decreasing maize yields in years with rainfall above the historical mean, its use is important to improve soil organic matter over time.
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