Guan'gai paishui xuebao (Feb 2022)
The Effects of Biogas Slurry Irrigation on Aggregation and Stability of Fluvo-aquic Soil in Huang-Huai-Hai Plain
Abstract
【Objective】 Irrigation with biogas slurry is not only a way to deal with the wastes produced by livestock industry, but can also improve soil quality and facilitate nutrient availability. Considering that soil aggregate is unit often used to quantity soil structure, we investigate how biogas slurry irrigation combined with fertilization affects aggregation of typical soils in Huang-Huai-Hai Plain in north China. 【Method】 The experiment was conducted in a field of fluvo-aquic soil; it compared three treatments: irrigation with biogas slurry (BS), chemical fertilization (CF), combining biogas slurry irrigation and chemical fertilization (BS+CF). Nitrogen (N) applications in all treatments were kept the same, and a blank treatment was taken as the control (CK). In each treatment, we measured aggregates of different sizes in the topsoil using the dry and wet sieving method. 【Result】 Irrigation with the biogas slurry altered aggregate composition. Compared to the CK, the treatments increased the mass proportions of the mechanically-stable aggregate >0.25 mm by 2.14%~3.17%, and of the water stable aggregates>0.25 mm by 56.44%~164.20%. The treatments also impacted the skewness constant and kurtosis constant of both mechanically- and water-stable aggregates, by improving aggregate stability due to the decrease in slaking, especially BS+CF. Biogas slurry irrigation significantly reduced aggregate destruction and increased aggregate stability, both at significant level. The aggregates in BS+CF treatment were most stable, have the largest weight and geometric diameters and the least fractal dimension. 【Conclusion】 Biogas slurry irrigation combined with chemical fertilization improved soil aggregation and soil quality. It can be used as an improved agronomic practice to deal with the wastes produced by livestock industry and to improve soil productivity.
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