地膜覆盖对辣椒地土壤氮素的影响

地膜覆盖在西南地区农业生产中有着广泛的应用，但关于地膜覆盖对土壤养分的研究还比较匮乏，为了揭示地膜覆盖对土壤氮素的影响，于2014 年5—9 月在重庆市北碚区进行了辣椒种植的田间试验，对地膜覆盖条件下辣椒地的土壤水热条件、氮素以及辣椒产量进行观测。相比于对照，试验期间覆膜种植土壤10、20、30 cm平均温度分别提高了2.3、2.8、2.0℃，增温效果显著，而对土壤重量含水量的影响不明显；覆膜种植条件下，土壤耕层全氮、碱解氮、铵态氮和硝态氮含量分别为1.30 g/kg、150.83 mg/kg、112.25 mg/kg、105.80 mg/kg，分别比对照处理增加了7.44%、32.84%、88.72%和73.90%；另外，地膜覆盖能够促进植株发育并提高辣椒产量，使其开花坐果期提前4 天，结果时间提前5 天，辣椒产量提高14.11%。实验结果表明，地膜覆盖在改善土壤水热条件、增加土壤氮素含量以及提高作物产量方面具有积极作用。

Effect of Plastic Film Mulch on Soil Nitrogen in the Pepper Field

Plastic film mulch has been widely used in agricultural production in southwest China, while there are only few studies about its effect on soil nutrients. In order to reveal the effect of plastic film mulching on soil nitrogen, a field experiment for exploring soil temperature and moisture, nitrogen and pepper yield under plastic film mulching was conducted in Beibei, Chongqing during May to September in 2014. The warming effect of plastic film mulching was obvious and increased with the depth of the soil layer, the average temperature of 10, 20 to 30 cm soil increased by 2.3, 2.8 and 2.0℃. But the impact on soil moisture was not obvious. In film mulching growing condition, the total nitrogen, available nitrogen, ammonium nitrogen and nitrate nitrogen in soil reached 1.30 g/kg, 150.83 mg/kg, 112.25 mg/kg, 105.80 mg/kg, and increased by 7.44%, 32.84%, 88.72% and 73.90%, respectively. In addition, plastic film mulching could promote plant development and increase the yield of pepper, made the flowering and fruit bearing period 4 d in advance, and the fructescence 5d ahead of schedule, and increased the yield by 14.11%. Therefore, plastic film mulching has a positive role in improving soil temperature and moisture condition, enhancing soil nitrogen content and increasing crop yield.