Manure combined with chemical nitrogen can increase wheat yield, reduce nitrate leaching

A 6-yr (2014-2020) experiment to study the effects of manure combined with chemical fertilizers on wheat (Triticum aestivum L.) yield, soil nitrate nitrogen content and nitrate nitrogen reserves in Semi-arid region of northwest China The experiment was conducted by two factors: (1) manure, and (2) five chemical nitrogen rates of 0, 75, 150, 225, and 300 kg N ha(-1). The research show that the 6-year mean the manure group significantly increased the ear number compared with the no-manure group, significant increased wheat production except for N225 and N300 treatments; the no-manure group highest ear number and kernels per ear was N225 treatment, the highest 1000-kernel weight was N75 treatment; the manure group the highest ear number was N225 treatment, the highest kernels per ear was N300 treatment and the highest 1000-kernel weight was NO treatment. With the increase of nitrogen application rate, the yield increased first and then decreased. It can be seen from the curve that the no-manure treatment highest yield was 5766 kg ha(-1) with N-rates 242.5 kg ha(-1); the manure treatment highest yield was 6202 kg ha(-1) with N-rate 190.2 kg ha(-1); the manure treatment could reach the yield 5766 kg ha(-1) only with N-rates 97.2 kg ha(-1). The manure treatment could reduce 59.9% nitrogen to reach the highest yield 5766 kg ha(-1) compared with no-manure treatment. Manure treatment did not increase soil nitrate nitrogen and nitrate nitrogen storage with less than 150 kg N ha(-1) compared with no-manure treatment. Application of manure in Semi-arid region was recommended that 30 t ha(-1) manure combined with 75-150 kg N ha(-1).