Combining biochar with cotton-sugarbeet intercropping increased water-fertilizer productivity and economic benefits under plastic mulched drip irrigation in Xinjiang, China.

Intercropping and biochar application are two main practices that can conserve land, improve water and fertilizer use efficiency and crop yields. However, the performance of the combination of different biochar application amounts and intercropping system is not clear. The objectives of this study were to determine how biochar and intercropping affected soil water, soil pH and nutrients, plant growth, yield, irrigation water - fertilizer use efficiency, and economic benefits for cotton monoculture and cotton-sugarbeet intercropping system, and find the optimal biochar application amount and application years. A three-year cotton-sugarbeet intercropping with biochar application experiment were conducted compared with cotton monoculture. The biochar was continuously applied to the field at the rates of 0, 10, 50 and 100 t ha−1 in 2018, 0, 10, 25, 50 and100 t ha−1 in 2019 and 0, 10, 25 and 30 t ha−1 in 2020. The soil water, nutrients, cotton growth, cotton and sugarbeet yields, water and fertilizer use efficiency and economic benefits were studied. The combination of biochar and cotton-sugarbeet intercropping has several positive effects compared to the cotton monoculture system. The soil water condition was improved. The comprehensive fertility of soil was increased by 3.9–28.3%. The cotton yields, water and fertilizer use efficiency and economic benefits were increased by 0.5–43.8%, 43.3–135.3% and 11.5–65.6%, respectively. The multicriteria assessment showed that the biochar application amount at 10 t ha−1 treatment performed the best with the highest scale every year. The multivariate nonlinearity equation implicated that three years of a continuous biochar application amount of 16.6 t ha−1 was an efficient mode to improve IWUE. The research provides a new insight for agricultural production in the arid and semi-arid. [Display omitted] • Biochar application and intercropping increased cotton yields. • Biochar at 10 t ha−1 increased cotton yields and economics the most. • Intercropping with 3-year continuous biochar application at 16.6 t ha−1 is recommended. [ABSTRACT FROM AUTHOR]