Effects of Biochar Application on Soil Hydrothermal Environment, Carbon Emissions, and Crop Yield in Wheat Fields under Ridge–Furrow Rainwater Harvesting Planting Mode

Abstract

The ridge–furrow rainwater harvesting (RFRH) planting mode is widely used in arid and semi-arid areas to solve the problems of agricultural water shortage and low productivity. However, the impact of film mulching on the stability of soil carbon pools makes this planting mode vulnerable to the risk of increased soil carbon emissions and carbon pool losses. In order to clarify the relationship between soil carbon emissions and hydrothermal factors, as well as the regulatory effect of biochar application on soil carbon sequestration and reduced emissions under this planting mode, we set up a biochar application experiment. The effects of the biochar application (at 10 Mg ha−1 biochar and 20 Mg ha−1 biochar) on the soil water dynamics, soil temperature changes, CO2-C and CH4-C flux dynamics, grain yield, carbon emission efficiency, and the net ecosystem carbon budget in wheat fields under the RFRH planting mode were investigated, with no biochar application as the control. The results showed that applying biochar increased the soil water content, soil average temperature, cumulative CH4-C uptake, wheat grain yield, and carbon emission efficiency by 3.10–12.23%, 0.98–3.53%, 59.27–106.65%, 3.51–16.42%, and 18.52–61.17%, respectively; reduced the cumulative CO2-C emissions by 7.51–31.07%; and increased the net ecosystem carbon budget by 2.91 Mg C ha−1 to 6.06 Mg C ha−1. The results obtained by equation fitting showed that in wheat fields under RFRH, the CO2-C emission fluxes had negative and positive exponential relationships with the soil water content and soil temperature, respectively, while the CH4-C uptake fluxes had no significant correlation with the soil water content and had an inverse U-shaped quadratic function relationship with soil temperature. Overall, these results suggest that the application of biochar to wheat fields under RFRH can improve grain yield, farmland carbon emission efficiency, and the net ecosystem carbon budget, and change wheat fields from a carbon source to a carbon sink. These results can provide a theoretical basis and technical support for efficient, green, and sustainable production in farmland in arid and semi-arid areas.

Productivity of Winter Wheat Cultivated by Direct Seeding: Measuring the Effect of Hydrothermal Coefficient in the Arid Zone of Central Fore-Caucasus

“…As outlined above, the academic and practical narratives on the relationship between the hydrothermal conditions of soils and the environment and the productivity of winter wheat is abundant [15,54,56,[87][88][89][90][91], but fragmented in terms of revealing the territory-specific effects [1,3,75,92]. This study's findings contribute to bridging that gap by describing the impact of climate change on ecological and genetic indicators of growth and development of winter wheat cultivated in Central Fore-Caucasus.…”

“…Numerous studies on the relationship between hydrothermal parameters of soil and the environment and the productivity of crops show that droughts depress the genetic and physiological systems of winter wheat plants (in terms of accumulation and attraction of assimilates, the rate of ontogenesis phases, etc.) [1][2][3][4][5][6]. In arid environments, where the yields are particularly vulnerable to the slightest changes in climatic conditions, low humidity associated with high temperature deteriorates the productivity of winter wheat crops radically [7][8][9][10][11].…”

“…To moderate the damaging effects of droughts on crops in arid zones, various genetic and breeding methods and agronomic techniques have been developed, including, among others, direct seeding with superficial soil surface scarification [50], broadcast winter wheat seeding methods for timely seeding and improved labor distribution [16], seed-drills to supply small grain producers in semi-arid rain-fed areas with solutions to combat nonuniform seedling emergence [51], reduction of herbicide application during a transition period from conventional tillage to conservation tillage for soil and environment safety [52], the application of biochar to wheat fields under ridge-furrow rainwater harvesting [3,53], and various improvements to seeding and soil cultivation machinery that allow better preservation of soil moisture [1,19,32,[54][55][56]. However, no specific genes for productivity, species immunity, and drought tolerance of plants have been isolated, localized, and sequenced so far.…”