Effects of mulched drip irrigation and biochar on nitrogen accumulation, yield, water use efficiency, quality, and soil properties of peanut

Field experiments were carried out in Western Liaoning Province to investigate the effects of biochar on peanut nitrogen accumulation (NA) and soil properties in aeolian sandy soil and the relationship between NA parameters regulated by biochar and peanut quality. A split-plot design was adopted. Drip irrigation and mulched drip irrigation were used in the main plot, and three biochar application rates of B0 (0 t/ha), B1 (24 t/ha), and B2 (48t/ha) were used in the sub-plots. The results showed that different irrigation methods and biochar application significantly increased NA of peanuts, and NA of peanuts was in line with a logistic growth function (R 2 ༞0.97). In 2020 and 2021, the pod NA of MB1 compared with MB0 treatment increased by 52.28% and 32.58% at pod filling stage, respectively. B2 treatment increased soil organic matter by 109.66%, cation exchange capacity by75.94%, total N content by 5% (P༞0.05), and pH by 15.24% compared with no biochar. The correlation coefficient between soil total N and protein content was 0.73, and that between soil pH and oil was 0.83. Compared with MB2 and DB0, MB1 treatment increased yield by 62.50% and 38.30%, respectively. In conclusion, applying biochar (B1) to a peanut cultivation system in aeolian sandy soil area increased peanut NA, improved soil properties related to peanut quality, broke through environmental barriers and improved peanut quality, which is important for peanut N fixation and improving quality in the semi-arid aeolian sandy soil area of western Liaoning Province.