钾肥分期施用对棉花产量及构成因素影响

为研究棉花需钾规律，找出合理的施钾方法，以‘华杂棉H318’为试验材料，大田研究了钾肥施用时期和比率对棉花产量及构成因素的影响，以及棉花在移栽期，初花期，盛花期3个时期对钾肥的需求规律。大田试验3个钾肥施用时期分别为A（基肥）、B（初花肥）、C（盛花肥）；各实验处理钾肥分两次施入，3个施钾时期组合(T)分别是AB（基肥和初花肥）、AC（基肥和盛花肥）、BC（初花肥和盛花肥）；两次钾肥施用量之比(R)有4种，分别是2:1、1:1、1:2、1:3。试验结果表明，钾肥初花期和盛花期追施（BC处理）可提高棉花子指和单株结铃数。钾肥基施时，初花期追施（AB处理）比盛花期追施（AC处理）更有利于提高单铃重、果枝数以及整体衣分。钾肥基施和盛花期追施（AC处理）产量构成因素的大小在各处理间居中，但籽棉产量却是最高。当钾肥施入比率为1:2时，可提高子指、衣分、单株结铃数、果枝数和籽棉重。所以，棉花在移栽期对钾肥需求量较少，但钾肥是移栽期必不可少的肥料，初花期和盛花期是钾肥需求量最大的时期，也是生殖生长的高峰期，对提高棉花产量具有决定作用。钾肥分两次施入，钾肥基施和盛花期追施效果较佳；适当加大盛花期钾肥施入比率（即A1C2处理），对棉花生长和发育的效果最佳，对提高产量具有重要意义。

Effects of Different Period and Assign Rate of Potassium Application on Yield and Yield Components of Cotton

To find out the appropriate potassium (K) ratio and time for maximum cotton yield, and the effect of K application on cotton yield, field experiments were conducted in 2012 on Lukou Experimental Station of Ezhou, Hubei Province. Potassium fertilizer was soil-applied in spilt on two of the three stages of cotton growth: before transplanting (A), squaring period (B), and peak bloom stages (C) of cotton, and then the treatments were: before transplanting and at squaring period (marked AB), before transplanting and at peak bloom stages of cotton (marked AC), and at squaring period and peak bloom stages of cotton (marked BC); and four application ratio rate by two times were 2:1, 1:1, 1:2 and 1:3, respectively. Fertilizer K application amount was uniform throughout all treatments. The results showed that, the highest seed index and bolls per plant were obtained at BC regime. Higher boll weight, lint percentage and fruits branch per plant were got for AB than that of AC treatment. For AC regime, the yield components of cotton was not the best, but the highest seed cotton yield was obtained. The highest yield components of cotton were got when the ratio of K application was 1:2. So, cotton demand for potassium in transplanting period (A) was less, but essential. Squaring period (B) and peak bloom stages (C) of cotton were the biggest potash demand period, and also the peak period of reproductive growth. It was significant effect on cotton yield to applied fertilizer K before transplanting and at peak bloom stages of cotton as treatment AC, and appropriately increasing the K application rate at peak bloom stages of cotton as a ratio as 1:2.