Contrasting effects of corn straw biochar on soil water infiltration and retention at tilled and compacted bulk densities in the Yellow River Delta

Abstract

During field application of biochar, the bulk density of tilled soil initially decreases and then increases over time, until reaching the initial level of compacted soil. This study evaluated the optimal biochar particle size for promotion of water infiltration and retention in a saline soil with various bulk densities after application. Corn straw biochar, pyrolyzed at 450 °C for 0.5 h, was prepared in different particle sizes (S1 ≤ 0.25 mm, S2 = 0.25–1 mm, and S3 = 1–2 mm) and separately mixed into the 0–30 cm soil layer at two rates (R1 = 10 g kg−1 and R2 = 100 g kg−1), with tilled (D1 = 1.1–1.43 g cm−3) and compacted (D2 = 1.45 g cm−3) bulk densities. Five models were applied to simulate water infiltration into biochar-amended soils. Compared with the non-biochar control, the S1 treatment increased cumulative water infiltration by 41% (bulk density = 1.26 g cm−3) to 11% (bulk density = 1.45 g cm−3). However, the effect of the S3 treatment on cumulative water infiltration shifted from positive (+19.3%) to negative (–22.4%) with increasing bulk density. The S2 treatment resulted in the highest water retention at the tilled bulk density, whereas a significant increase (12.7%) in water retention was observed in the S1 treatment at the compacted bulk density. The Kostiakov–Lewis, Kostiakov, and United States Department of Agriculture – Natural Resources Conservation Service models performed better than the Philip and Horton models to describe the relationship between cumulative water infiltration and infiltration time, except for the D2R2S1 treatment. This study provides evidence for amelioration of saline soil by straw biochar in the Yellow River Delta.

Effects of poly-γ-glutamic acid and poly-γ-glutamic acid super absorbent polymer on the sandy loam soil hydro-physical properties

“…Infiltration model. The impacts of γ-PGA and γ-PGA SAP on soil water infiltration were analyzed and depicted using the Kostiakov infiltration model, as well as Philip infiltration model, respectively [33].…”

Effects of biochar nanoparticles as a soil amendment on the structure and hydraulic characteristics of a sandy loam soil

“…Biochar nanoparticles increased the contact angle of the mixed layer, which might alter infiltration rates and induce preferential water flow (Rasa et al, 2018; Yi et al, 2015). Previous studies have shown that different biochar application amounts and particle size significantly decreased water infiltration (Sun et al, 2019). However, the biochar application rate in most studies was >1.0%, and the particle size was greater than millimetre level (Pu et al, 2019; Yang et al, 2019).…”

Impacts of Biochar on Hydro-Physical Properties of Sandy Soil under Different Irrigation Regimes for Enhanced Tomato Growth

“…Chen et al [34] found that commercially available biochar nanoparticles (NBC) not only affected the volume of soil pore by blocking space between soil particles, but it also reduces cumulative infiltration by 13.75%. Sun et al [35] also found that biochar application decreased water infiltration.…”