Effect of mulched drip irrigation on crop biomass and carbon fluxes in maize field

Abstract

The agroecosystem, a critical component of the terrestrial carbon cycle, plays an indispensable role in maintaining the balance of carbon pools and ensuring global food security. Investigating the interplay between crop yield and carbon cycle is essential for the advancement of sustainable agricultural practices. In the quest for water-efficient agricultural solutions, mulched drip irrigation emerges as a promising technique to mitigate water scarcity in agriculture. In the arid regions of northwest China, where water is a precious resource, understanding the impact of irrigation methods on the productivity and carbon dynamics of crops like spring maize is critical. Our study aimed to evaluate the influence of two irrigation methods—mulched drip irrigation (DI) and mulched border irrigation (BI)—on the biomass accumulation and carbon fluxes of spring maize by field observation and DNDC model simulation for comparative analysis. The findings based on field and flux observation data, underscore the transformative potential of shifting from BI to DI. DI was found to significantly enhance the soil's hydrothermal environment, which is crucial for fostering optimal conditions for crop growth. This improvement is instrumental in promoting the allocation of photosynthetic products to the aboveground biomass, ultimately leading to a substantial increase in grain yield. Our results indicated that the DI treatment not only bolstered the gross primary productivity (GPP) but also elevated the ecosystem respiration (RE) compared to the BI treatment. Finally, DI can increase the net ecosystem productivity (NEP) of maize fields by 6.08 %. The Denitrification-Decomposition (DNDC) model, after calibration and validation, proved to be a reliable tool for estimating ecosystem respiration under the two irrigation systems. A thorough analysis of the simulated data revealed that DI's enhancement of the soil's hydrothermal environment also led to an increase in soil heterotrophic respiration. This insight is vital as it sheds light on the complex interactions between irrigation practices and soil microbial processes, which are integral to the carbon cycle. These findings contribute to the growing body of knowledge on sustainable agricultural practices and provide a theoretical foundation for strategies aimed at achieving carbon neutrality. By adopting data-driven approaches and leveraging advanced models, we can pave the way for a more sustainable and resilient agricultural future that harmoniously balances productivity and environmental stewardship.