减氮结合覆盖对旱地冬小麦花后生理性状及产量的影响

摘要

在渭北旱塬雨养农作条件下,结合当地氮肥施用过量的现状,于2012~2016年4个冬小麦种植季度,以无氮裸播为对照,研究了减氮结合覆盖 (农户模式,农户减氮,垄覆沟播,全膜穴播,秸秆覆盖) 对旱地冬小麦花后生理性状及产量的影响.结果表明:减氮结合覆盖较农户模式并不一定会降低小麦产量,其中全膜穴播连续3年增产分别高达175、725和1022 kg/hm2.叶绿素相对含量SPAD值随氮肥施用量的增加呈先升高后降低的趋势,而氮肥对冬小麦花期旗叶光合速率的影响虽未达到显著水平,但施氮也促进了光合速率的提升,其中覆盖处理对SPAD值及光合速率有一定的负效应.另外,过量施氮与不同覆盖处理的花期根系活力较农户减氮显著降低了30.6% ~38.5%.开花期旗叶硝酸还原酶活性不仅随着施氮量的增加而提高,也对除垄覆沟播外的其它覆盖处理有显著正效应,其中全膜穴播与秸秆覆盖处理较农户减氮分别提高了4.2%和5.8%.%Based on the local situation of excessive application of nitrogen fertilizer in Weibei rainfed semi-arid area, the effects of reduced nitrogen fertilizer combined with soil surface management on physiological characteristics of winter wheat after anthesis were determined in the winter wheat growing seasons during 2012~2016. The experiment was carried out in a random-ized complete block design with three replicates, including six treatments: (i) un-mulched with un-fertilization as control, (ii) local farmer sowing pattern (N 195 kg/hm2), (iii) reduced nitrogen fertilizer in local famer sowing pattern (N 150 kg/hm2) and three mulching treatments for nitrogen reduction (N 150 kg/hm2) were (iv) ridges mulched with plastic film and row-seeding in the furrow, (v) whole field plastic mulching with soil covering on the top of the plastic mulch and bunch-seeding, (vi) straw mulch all year round, respectively. Results showed that compared to the local farmer sowing pattern, the soil surface mulching might increase or reduce the grain yield of winter wheat, for example, the yield for treatment of whole film plastic mulching and bunch-seeding for three consecutive years were 175, 725, 1 022 kg/hm2higher than that of local farmer sowing pattern, respectively. In addition, the SPAD value increased firstly and then decreased with the increasing of nitrogen, and the effect of nitrogen fertilizer on photosynthetic rate of flag leaf in winter wheat was not significant, but it in-creased with the increase of fertilizer application rate. Mulching treatment had a negative effect on photosynthetic rate. The root activity of excessive application of nitrogen and mulching, compared with reduced nitrogen fertilizer in local famer sowing pat-tern, significantly reduced by 30.6% ~38.5%. The flag leaf nitrate reductase activity in flowering period also increased with the increase of amount of nitrogen fertilizer, it increased by 4.2% and 5.8%, respectively, for bunch-seeding with the whole film and the straw mulching than local farmer sowing pattern.