Effect of Long-Term Organic Amendment Application on the Vertical Distribution of Nutrients in a Vertisol

Soil nutrients in deep soils are important for nutrient cycling and plant growth. Organic amendments have been widely used enhancing soil health crop yield. However, little is known about the effects of organic on vertical distributions nutrients. Based a 32-year long-term amendment experiment, objective this study was to evaluate changes distribution soybean–wheat system Vertisol. The results showed that NPK with manure or straw application significantly increased carbon (SOC), total N, P, alkali-hydrolyzable available P K above 40 cm layer. Variations micronutrients primarily occurred 20 layer, highest contents were observed NPKWS NPKPM, respectively. Nevertheless, large amounts NO3−−N accumulated 120–200 depth but not application, indicating high potential risk nitrate leaching treatments. These findings suggested (manure straw) could be recommendable improving along profile. Straw incorporation as an alternative option sustainable agriculture regions inadequate resources severe leaching.