Effects of Dripping Fertigation on Soil Nitrogen Metabolism in Apple Orchard of Weibei Plateau | 渭北苹果园滴灌施氮肥对土壤氮迁移的影响

Chinese. 采用滴灌和浇灌2种灌溉方式,结合梯度施肥和测定土壤溶液中氮含量,研究渭北旱塬矮化红富士苹果园不同氮素形态在土壤中的迁移、富集和转化特性。结果表明：滴灌施肥显著降低氮素的迁移、富集和转化作用;在不同氮素形态中,以urea-N为主,NO-3-N次之,NH＋4-N最小;当施肥量为0.32 kg・株-1时,2种灌溉方式对氮素迁移、富集和转化作用的影响差别不明显,施肥量达到1.2 kg・株-1时,浇灌施肥方式下氮素的迁移、富集和转化作用极显著高于滴灌,尤其在40～ 80 cm土层更加明显。综合比较,滴灌施肥明显降低了苹果园不同氮素形态的迁移、富集和转化作用,增加了土壤中氮素的含量,尤其是有效态氮的含量,全年施肥量在0.64～ 1.2 kg・株-1时能相对减少氮肥的损失。

English. This study focuses on the characteristics of the movement,transformation and leaching of different nitrogen forms in soil by dripping and pouring fertigation with fertilizer gradients by determining the nitrogen content of soil solution in a Red Fuji apple orchard in Weibei dry plateau. The results showed that different application methods of fertilization were the key factor to affect the movement,accumulation and transformation of different nitrogen forms in soil. The dripping fertigation decreased significantly the nitrogen movement,accumulation and transformation compared with pouring fertigation. The urea-N was main form of N leached,followed by NO-3-N,and then NH＋4-N leached. Neither dripping nor pouring had obvious effect on nitrogen loss when the fertilizer concentration was 0. 32 kg・tree- 1. However the nitrogen movement,accumulation and transformation was significantly higher with pouring fertigation than with the dripping fertigation when the fertilizer application amounts were added to 1. 2 kg・tree- 1,especially in the 40-80 cm soil layers.By comprehensive comparing and analyses,dripping fertigation significantly decreased the leaching loss of different nitrogen forms in soil,and increased nitrogen content,especially available N in soil. The nitrogen loss will be decreased when fertilizer application is 0. 64- 1. 2 kg・tree- 1in the whole year.