Effects of nitrogen fertilizer reduction under organic and inorganic fertilizers combination on yield and quality of peanut in red soil farmland

In order to determine the effects of nitrogen fertilizer reduction under the combination of organic and inorganic fertilizers on the yield and quality of peanut in red soil farmland, we conducted a field complete randomized block experiment with seven treatments: single chemical fertilizer control (CK0, N 135 kg · hm^-2, base application 70%, topdressing 30% at anthesis), combined application of organic and inorganic fertilizers (CK1, N 135 kg · hm^-2, in which organic fertilizer replaces inorganic nitrogen by 25%, base application of inorganic nitrogen by 45%, topdressing inorganic nitrogen by 30%), nitrogen reduction by 15% under combined application of organic and inorganic fertilizer (B15), nitrogen reduction by 30% under combined application of organic and inorganic fertilizer (B30), nitrogen reduction by 45% under combined application of organic and inorganic fertilizer (B45), 15% nitrogen reduction of base fertilizer+15% nitrogen reduction of topdressing fertilizer under the combination of organic and inorganic fertilizers (B15T15), and 30% nitrogen reduction of topdressing fertilizer under the combination of organic and inorganic fertilizers (T30).We analyzed the effects of these treatments on peanut yield, agronomic characteristics, nutrient uptake and quality.The results showed that the yield of CK1 was 3 895 kg·hm^-2, 22.4% higher than that of CK0, and the yield of organic and inorganic fertilizers was 15.7%~28.0% higher than that of CK0.Under the condition of organic and inorganic combined application, the peanut yield of B15 was the highest, reaching 4 073 kg·hm^-2, which was 4.7% higher than that of CK1.However, the yield of other nitrogen reduction treatments were decreased.B15 treatment not only increased the number of peanut branches, the number of full fruits per plant, the productivity per plant, the harvest index, and the percentage of kernels, but also increased the nitrogen, phosphorus, and potassium nutrient contents in peanut stems, leaves, and kernels.The protein, oleic acid, linoleic acid contents, and other quality indicators of peanut kernels were also improved.The yield, agronomic characters and quality of peanut with B30 were better than those of T30.To sum up, B15 can improve the yield, agronomic characteristics, nutrient absorption and quality of peanuts, while reducing the base fertilizer is preferred.