Maize straw effects on soil aggregation and other properties in arid land

Abstract

Soil structure has been destroyed due to long-term application of inorganic fertilizer in the Loess Plateau of China. Our objective was to determine how incorporation of three different rates of maize (Zea mays L.) straw affected soil aggregate size and stability within the top 30cm of arid soil on the Loess Plateau of China to provide basic theory of land utilization. Three rates of maize straw (4.5, 9.0, or 13.5Mgha−1, hereafter referred to as LS, MS, and HS) were incorporated with 255 and 90kg/ha of inorganic N and P fertilizer, respectively, 2 times in a 4-year field experiment. Water stability of five aggregate size classes (>5, 2–5, 1–2, 0.5–1, and 0.25–0.5mm) in the 0–10, 10–20, and 20–30cm depth increments was measured 3 times for each treatment and a check (CK) that received only the inorganic fertilizers. Incorporation of 13.5Mgha−1 of straw significantly increased water stability of three aggregate classes (>5, 1–2, 0.5–1mm) compared with CK and LS treatments within the surface 10cm and for aggregates >0.5mm in the 10–20cm depth increment. Within the 20–30cm depth increment water-stablity of aggregates in the 0.25–0.5mm class increased significantly as the rate of straw incorporation increased. Overall, aggregate stability was primarily increased through changes in microaggregate size distribution, especially for aggregate classes >5, 0.5–1, 0.25–0.5mm within the 0–10, 10–20, 20–30cm soil depth, respectively. Straw incorporation is a positive and effective agriculture measure to improve soil structure.