膜下滴灌棉花氮素推荐施肥模型的研究

研究应用叶绿素仪（SPAD-502）在膜下滴灌条件下的棉花氮肥推荐。试验于2006年在石河子乌兰乌苏农业气象实验站进行，以新陆早24为材料。结果表明，不同叶位的叶片含氮量、SPAD值及叶片不同部位的SPAD值存在明显差异，SPAD值与叶绿素含量、叶片含氮量、单株吸氮量等均有较好的相关性；倒四叶的叶尖部位适合作为测试部位。盛蕾期、花期、盛花期和铃期倒四叶SPAD值与施氮量之间呈极显著线性相关；各生育期SPAD值与产量也具极显著相关。滴灌条件下最高籽棉产量为4686.5 kg/hm2，对应的施肥量为293.1 kg/hm2；最大利润（经济最佳）施肥量为207.33 kg/hm2，对应的最佳产量为4565.9 kg/hm2。各生育期SPAD的临界值分别为60.5、60.0、60.8和59.1。盛蕾期、花期、盛花期和铃期SPAD值每变动一格推荐施肥量分别为10.81、8.46、13.42和6.29 kg/hm2。

Nitrogenous fertilizer recommendation model for cotton under mulch-drip irrigation

Nitrogen recommendation for cotton under the mulch-drip irrigation condition was explored based on the measurements using chlorophyll meter (SPAD-502). Field experiment was conducted at Wulanwusu Agricultural Meteorological Experiment Station, Shihezi, Xinjiang, China, during the 2006 cotton growing seasons. The adopted cotton variation was Xinluzao24. The results showed that leaf nitrogen contents and SPAD value varied markedly in different leaf position. Significant correlation was found between SPAD and leaf chlorophyll concentration, N concentration in leaf or N absorbed content. The leaf tip position of the reverse 4th leaf from the apex of the main stem is the best measuring position because of the small deviation of measurement value. There were significant linear correlation between SPAD value and the rate of applied nitrogenous fertilizer at budding peak stage, flowering stage, flowering peak stage and bolling stage. A significant correlation between SPAD value and the cotton yield was detected as well. The highest link yield was 4686.5 kg/ha, correspondingly, the optimal nitrogenous fertilizer rate was 293.1 kg/ha under the experimental management scenario. The most profitable N rate was 207.33 kg/ha and the economic yield was 4565.9 kg/ha. The critical SPAD value at the budding peak stage, flowering stage, flowering peak stage and bolling stage were 60.5, 60.0, 60.8 and 59.1 respectively. A statistic model was evaluated for N fertilizer recommendation in cotton cultivation under drip irrigation with film mulch, the recommended N fertilizer rate is 10.81, 8.46, 13.42, and 6.29 kg/ha at budding peak stage, flowering stage, flowering peak stage and bolling stage for unit change of SPAD value.