Biochar affects soil water content but not soybean yield in a sandy southeastern U.S. soil

Abstract

Drought is the greatest abiotic cause of soybean [Glycine max (L.) Merr.] yield loss in rainfed systems in the United States. Preplant incorporation of powdery biochar to soil cultivated with soybean in these water-stressed regions presents the potential to increase volumetric soil water content (VSWC) between rainfall events and ameliorate the impact of intermittent water stress. However, VSWC and the aboveand belowground response of soybean to biochar amendment are not well understood. This 2-yr field study (2014)(2015) evaluated the effectiveness of incorporating powdery (325 μm) biochar to 0.2-m soil depth to increase soil water storage in a coarse-textured soil in the southeastern United States. Soybean yield, aboveground biomass accumulation, root morphology, and VSWC in the soil profile to 1-m depth were assessed under three biochar rates (0, 2.5, and 10 Mg ha -1 ) and two water treatments (rainfed and irrigated). In 2014, application of 10 Mg biochar ha -1 increased the cumulative soil water storage in the top 1-m soil depth. Biochar application did not affect soybean yield or root morphology. Biochar only elicited changes in fresh weight of pods during reproductive stages, which indicates biochar's limited benefit to the water status of this shoot component. Irrigation increased yield by 28% compared with the rainfed treatment. Our study provides evidence that field application of biochar to soybean may be a sustainable practice to sequester recalcitrant C in the soil when biochar is available to producers, but its benefits on protecting soybean yield from water stress might depend on other factors such as soil texture, rainfall amount, and frequency. INTRODUCTIONSoybean [Glycine max (L.) Merr.] is the world's top oilseed crop cultivated either for food and fuel purposes (Ritchie &

Effect of Biochar Application on the Improvement of Soil Properties and Buckwheat (Fagopyrum esculentum Moench) Yield on Two Contrasting Soil Types in a Semi-Arid Region of Inner Mongolia

“…They also found that the SWS was positively linked with the biochar application rate, as demonstrated in numerous studies [45,46]. Possible reasons for the increment in SWS are the reduction in soil bulk density and improvement in soil aggregate after biochar addition, which facilitates the soils in retaining more water [43].…”

“…Our findings are consistent with those of Razzaghi et al [42], whose global-scale meta-analysis on the effects of biochar incorporation on soil moisture retention indicated a notable augmentation in the water retention capacity of the treated soils that was particularly discernible in soils characterized by coarse textures. Additionally, the clay and silt contents are important factors that can interact with biochar to form a soil matrix, resulting in increased water-holding capacity [43]. Moreover, higher biochar application rates may be needed for soils characterized by high sand content to achieve an equivalent effect.…”