Woody peat addition increases soil organic matter but its mineralization is affected by soil clay in the four degenerated erodible soils

Abstract

Soil erosion exacerbates the reduction of soil organic matter (SOM) and destruction of soil physical structure in agricultural systems, which seriously threatens agricultural ecological environment and global sustainable agriculture development. Owing to rich SOM and nutrients of woody peat results in it’s widely applied in degraded soil for improving land productivity. But how the impacted of woody peat addition on crop growth and soil organic matter (SOM) in different textured degenerated erodible soils are not well understood. Here, along the latitudinal gradient from north to south of China, four typical regional soils collected in Northeast (black soil), Northwest (loessial soil), Central (lou soil) and South (red soil) of China, where suffered strongly soil erosion. Soil clay content was 37.0%, 16.9%, 29.6%, and 38.5% for the black, loessial, lou, and red soils, respectively. We conducted a plot incubation experiment in a fully ventilated, rainproof outdoor greenhouse for planting wheat (Triticum aestivum L.). The study is aimed to investigate the response of different texture eroded soil to crop growth and physiology, soil evaporation and soil organic matter after woody peat addition. Eight treatments have been designed for four soils with two groups. (i) the control group with no woody peat addition, B0, H0, L0 and R0; (ii) woody peat addition group, BW, HW, LW and RW. Overall, the SOM concentration altered wheat growth characteristic and grain yield in the four typical erosion degraded soils. The highest grain yield of winter wheat is 6.5 ± 1.3 g per plot in B0 and 6.5 ± 1.1 g per plot in BW, and the lowest is 0.4 ± 0.1 g per plot in R0 in red soil. But woody peat addition increased the wheat yield or yield variation, the wheat gain yield increased four times with woody peat addition (RW) than control (R0) in red soil. In addition, the results revealed that the SOM content were increased in black soil by 40.4%, in loessial soil by 40.0%, in lou soil by 101.3%, and in red soil by 94.6% when compared to the control treatments at harvest. From sowing to harvest, SOM decreased by 5.1 ± 1.8 g kg-1 (black soil), 9.9 ± 0.9 g kg-1 (loessial soil), 7.6 ± 1.8 g kg-1 (lou soil), and 6.2 ± 1.0 g kg-1 (red soil) in the soils with woody peat addition. Without woody peat addition, SOM decreased by 5.6 g kg-1 (black soil), 4.7 g kg-1 (lou soil), and 0.6 g kg-1 (red soil), but increased by 0.4 g kg-1 in loessial soil. In conclusion, woody peat addition resulted in wheat yield increasing in the degenerated soils, but it’s significant in the red soil with adequate nutrient supply and increased soil acid buffering capacity. Woody peat addition increased the SOM concentration in the four degenerated soils, but a faster decreasing rate of the ΔSOM in coarse-textured loessial soil than others medium-fine texture soils. Therefore, appropriate woody peat application and clay content is more conducive to the protection of SOM. More deeply research should have been focused on the impact of woody peat addition in coarse-textured soil on the soil environment (such as the clay type, content, and soil priming effect, etc.).