Preponderant effect of biochar application in peanut dry matter accumulation and fertilizer nutrient use efficiency

Objectives There have been some queries on the necessaries of production and application of biochar. We compared the effects of biochar with other organic materials to testify biochar’s advantages.

Methods Local field experiment of micro plots (2 m²) was conducted for eight years using peanut as tested materials. In the base of the same N, P and K input and without thinking about carbon input, four treatments were set up as biochar (BIO), biochar-based formula fertilizer (BF), piggery manure compost (PMC) and corn straw-returning (CS). Samples were collected in stages of seedling, flowering needle, podding, maturation of peanut in 2016. The dry matter and N, P, K contents in roots, stems and leaves were measured, and the yields of peanut were investigated at mature stage.

Results The peanut yield of BIO (7231.7 kg/hm²) was significantly higher than those of BF and PMC (accounting for 82.4% and 83.8% of BIO respectively) and the lowest treatment was CS (5623.9 kg/hm²). The peanut shelling percentage of PMC was significantly higher than those of other treatments. It was different that the characteristics of dry matter accumulation and nutrient distribution of four growth periods among different treatments. The dry matter and NPK mainly accumulated in stem-leaf in the earlier stages, and turned to pod after the podding stage. BF had a higher content of dry matter and NPK, especially had a higher nutrient partition coefficient before the stage of podding compared with the control treatments. BIO had obvious superiority in dry matter accumulation at the maturation stage (6295.0 kg/hm²), which was significantly higher than those of BF, CS and PMC (exceeded 43.1%, 36.1% and 50.8%, respectively). N, P, K accumulation of BIO continued to increase to 236.4 kg/hm², 21.7 kg/hm² and 77.8 kg/hm², respectively, meanwhile the ratio of dry matter in stem and leaf reached to 34.5%, which was significantly higher than that of the control. However, the N and K distribution coefficients in pod of BIO at the maturation stage were only 0.83 and 0.52 respectively, and were lower by 0.02–0.03 and 0.15–0.21 than those of the controls (CS and PMC), respectively.

Conclusions Under the experimental conditions, all the biochar, biochar-based formula fertilizer and piggery manure compost are more effective than straw returning in peanut yield. The application of biochar shows significant higher effect than biochar-based formula fertilizers and piggery manure compost in promoting the dry matter and NPK accumulation, especially in the dry matter and nutrient distribution in late growth period, which is conducive to higher yield and nutrient use efficiency of peanut. Biochar-based formula fertilizer and piggery manure compost show similar effect in yield and nutrient accumulation and distribution. Therefore, biochar application is recommended for fully playing its role in maintaining stable nutrient supply during the whole peanut growing season and achieving both high yield and high fertilizer nutrient efficiency.