土壤钾水平对不同熟性棉花光合作用及产量的影响

  目的  施钾是保障土壤钾素供应和棉花高产的必要手段，缩节胺化学封顶是调节棉花生物量分配的重要措施，合理协调两者的关系是棉花提质增产的前提，因此探究包膜含缩节胺氯化钾对土壤钾素形态及棉花生长特性的影响，可为维持土壤钾素平衡及实现棉花减肥高产提供依据。  方法  采用盆栽试验，共设7个处理，分别为一次基施包膜含缩节胺氯化钾（CRKMC，0.15 g kg⁻¹土）、减量30%包膜含缩节胺氯化钾（CRKMC70%）、控释氯化钾（CRK）、减量30%控释氯化钾（CRK70%）、分次施用普通氯化钾（KCl）、减量30%普通氯化钾（KCl70%）及空白对照（CK）。测定棉花生育期内土壤钾素含量、棉花株高、茎粗、光合特性和产量。  结果  CRKMC处理的籽棉产量最高，较CRK和KCl处理分别显著增加了13.80%和22.58%，且CRKMC70%处理棉花产量与CRK处理相比不减产。此外，CRKMC处理显著提高了棉花植株茎粗、净光合速率、SPAD值和钾素农学利用率，且蕾期后CRKMC处理的土壤速效钾、缓效钾和水溶性钾含量高于KCl处理。蕾期至盛花期，速效钾部分转化为缓效钾储存，使得缓效钾含量升高，且各控释处理效果优于普通钾肥。  结论  一次基施包膜含缩节胺氯化钾可有效保障土壤钾素供应，提高土壤固钾潜力并优化棉花生长特性，为实现棉花高产、优化用工提供技术支撑。

Dry matter production,nutrient uptake,and growth of cotton as affected by potassium fertilization

  Objective  Potassium (K) application is a necessary means to ensure soil K supply and high yield of cotton. Chemical capping with mepiquat chloride (MC) is an important measure to regulate the distribution of cotton biomass. Reasonable coordination of the relationship between the two is the premise of cotton quality improvement and yield increase. Therefore, the effects of MC containing K chloride in the envelope on soil K morphology and cotton growth characteristics were explored, so as to provide basis for maintaining soil K balance and achieving weight loss and high yield of cotton.   Method  A pot experiment was conducted to study the effects of coated K chloride containing MC on soil K morphology and cotton growth characteristics. There were seven treatments, including basal application of coated K chloride containing mepiquat chloride (CRKMC, 0.15 g kg⁻¹ soil fertilizer), reduced 30% K dosage of CRKMC (CRKMC70%), basal application of controlled release K chloride (CRK), reduced 30% K dosage of CRK (CRK70%), and split applications of ordinary K chloride (KCl), reduced 30% K dosage of KCl (KCl70%) and no K fertilizer used (CK). Soil K content, cotton plant height, stem diameter, photosynthetic characteristics and yield were measured during cotton growth period.   Result  The results showed that the seed cotton yield of CRKMC treatment was the highest, which was significantly increased by 13.80% and 22.58% compared with that of CRK and KCl treatment, respectively. The cotton yield of CRKMC70% treatment did not decrease compared with that of CRK treatment. In addition, CRKMC treatment significantly increased cotton plant stem diameter, net photosynthetic rate, SPAD value and agronomic utilization. The soil available K, slowly available K and water-soluble K content of CRKMC was higher than that of KCl after bud stage. From bud stage to blooming stage, the available K was partially converted to slow K storage, which increased the content of slow K, and the effect of each controlled release treatment was better than that of ordinary K fertilizer.  Conclusion  One-time application of coating K chloride containing MC could effectively ensure soil K supply, improve soil K fixation potential, optimize cotton growth characteristics, and provide technical support to achieve high yield of cotton and optimize labor.