Study on suitable nitrogen fertilizer dose under green manure crop-rice rotation system

A 3-year location test for green manure crop-rice rotation system was conducted to determine the effects of N fertilizer dose on soil fertility,rice yield and nitrogen use efficiency.The results showed that successively returning winter green manure crop to farmland increased soil fertility and rice yield and reduced nitrogen fertilizer demand to gain a high rice yield.Compared with winter fallow-rice rotation system,the rotation system of Astragalus sinicus(or Vicia faba)-rice increased by 10.27%(or 9.99%) in rice yield,but decreased by 30.34%(or 29.65%) in N fertilizer dose.Considering such factors as rice yield,nitrogen fertilizer use efficiency and economic benefit,the suitable nitrogen fertilizer doses for winter fallow-rice,winter Astragalus sinicus-rice and winter Vicia faba-rice rotation systems were 16 kg667 m2,12 kg667 m2 and 12 kg667 m2,respectively.