棉秆还田和有机无机复混型肥料对蕾期棉花生长及氮肥利用率的影响

为了探索不同施肥方式对黄河三角洲滨海盐碱地棉花生长的影响，在该区域内通过田间小区试验研究了3种施肥方式（常规施肥、常规施肥+棉秆还田、有机无机复混型肥+棉秆还田）和3种棉秆还田量（10 t/hm2、15 t/hm2、20 t/hm2）对蕾期棉花农学性状、干物质积累、叶片SPAD值和氮肥利用率等的影响。结果表明：与常规施肥处理相比，棉秆还田和有机无机复混型肥+棉秆还田的相关处理对蕾期棉花的农学性状有改善效果，两类处理均增加了棉花株高、分枝数和茎干重，但对棉花根长的影响不明显，除了低量棉秆还田(10 t/hm2)处理外，其他处理均增加了棉花蕾数；棉秆还田和有机无机复混型肥+棉秆还田施肥类型的中、高棉秆还田量（15 t/hm2和20 t/hm2）处理促进了棉株叶片和整株的干物质累积，同时促进了氮素向棉花叶片和蕾的转移；有机无机复混型肥+棉秆还田处理提高棉株的氮肥利用率达16.77%~23.39%，与常规施肥处理差异达显著水平(P<0.05)；蕾期棉花叶片的SPAD值与叶片的含氮量、棉花的氮肥利用率均呈正相关，其相关系数分别为0.6088和0.5879。

Effects of Cotton Straw to Field and Organic-inorganic Mixed Fertilizer Application on Cotton Growth and Nitrogen Utilization Efficiency in Cotton Budding Stage

In order to explore the impact of different fertilization methods on the growth of cotton in the Yellow River Delta coastal saline area. The field experiment was conducted to study the effects of three applications of fertilizers (conventional fertilization, conventional fertilization + cotton straw to field, organic-inorganic mixed fertilizers + cotton straw to field) and three level of cotton straw applied amount (10 t/hm2, 15 t/hm2, 20 t/hm2) on agricultural characters, dry matter accumulation, leaf SPAD values and nitrogen utilization efficiency during cotton budding stage in coastal saline-alkali land of the Yellow River Delta. The results showed that the cotton height, branch number and stem dry weight (except for root length) in both treatments of cotton straw to field and organic-inorganic mixed fertilizers + cotton straw to field were increased greatly, compared with conventional fertilization. In additional, the number of cotton bud was inversed in all treatments of cotton straw to field but the 10 t/hm2 cotton straw application treatment. The middle and high cotton straw application (15 t/hm2 and 20 t/hm2) to field in treatments of cotton straw to field and organic-inorganic mixed fertilizers + cotton straw to field increased cotton dry weight and promoted the nitrogen transferring to leaves and buds. The nitrogen utilization efficiency reached to 16.77%-23.39% in treatment of organic-inorganic mixed fertilizers + cotton straw to field, which was significant different to conventional fertilization treatment (P<0.05). The positive correlations of cotton leaf SPAD values and nitrogen content in cotton leaf and nitrogen utilization efficiency were observed in cotton budding stage and the correlation coefficients were 0.6088 and 0.5879, respectively.