Estimation of the Effects of Maize Straw Return on Soil Carbon and Nutrients Using Response Surface Methodology

Abstract

Straw incorporation is generally considered an effective agricultural management practice that improves nutrient cycling and maintains soil fertility. To study the interactive effects of straw returning factors on soil organic carbon and available nutrients, a 17-month (May 6, 2016 to October 6, 2017) experiment was conducted on straw incorporation by using response surface methodology under a three-factor (straw length, amount, and burying depth), five-level quadratic orthogonal rotation experimental design. Weight was assigned to each indicator for soil carbon and nutrients and then a comprehensive indicator was established. Then, a second-order polynomial model of the three straw returning factors was established using response surface methodology. Results indicated that 17 months after straw incorporation, straw amount and burying depth had significant effects on the comprehensive indicator of soil carbon and nutrients. Straw length and the interactions of straw amount and burying depth showed no significant effects on the comprehensive indicator of soil carbon and nutrients. It was concluded that 17 months after straw incorporation, the highest value of the comprehensive indicator of soil carbon and nutrients was achieved when the straw length, amount, and burying depth were approximately 17–20 cm, 740–840 g m−2, and 9–13 cm, respectively, which can be recommended as the most suitable parameters for use in straw returning in the study area.