Nitrogen and Phosphorus Transformation of Soil and Growth of Maize in Black Soil Area by Different Tillage Patterns and Biochar Addition

[Objective] This study aimed to investigate the effects of different tillage patterns and biochar addition on soil nitrogen and phosphorus transformation and maize growth and development in farmland in the black soil area. [Methods] Through a field experiment, two tillage treatments (deep tillage and shallow tillage) and five biochar addition treatments (0, 3, 6, 9, and 12 t/hm2) were set up to investigate the combined effects of different tillage patterns and biochar addition on soil nitrogen and phosphorus fractions, enzyme activities, and physiological characteristics of maize. [Results] (1) Deep tillage and shallow tillage in combination with biochar addition could effectively improve soil structure, increase the geometric mean diameter of agglomerates, and reduce the percentage of damage. The deep tillage treatment was more effective than the shallow tillage treatment. (2) The addition of biochar improved soil nitrogen-phosphorus fractions, urease activity, and alkaline phosphatase activity, and the effect of applying biochar at the rate of 9 t/hm2 was the best, which was more pronounced in the deep tillage treatment. (3) The application of biochar up to 9 t/hm2 under deep tillage treatment increased the total nitrogen and phosphorus contents and glutamine synthetase activity of leaves and decreased the acid phosphatase activity. (4) The yield of corn under deep tillage condition with the addition of 9 t/hm2 of biochar was as high as 17.37 t/hm2, which was increased by 28.9% compared with that of 0 of biochar. [Conclusion] The deep-tillage treatment and addition of 9 t/hm2 biochar provided a reference for the nutrient environment and crop growth in agricultural fields in the black soil area.