钾肥分期施用对苏丹草生长和产量的影响

Effect of KCl application by stages on growth and yield of sorghum sudanese

在大田条件下研究了KCl分期施用对苏丹草产量及生长性状的影响。结果表明,基肥施用一定量KCl对基本苗数量影响不大,过量施用KCl则对苏丹草基本苗产生抑制作用。施钾没有导致苏丹草叶片质量比例下降。施用KCl明显提高苏丹草对蚜虫的抵抗能力,5个施钾处理所寄生的蚜虫数量平均为不施钾的27.2%。施用KCl显著增加苏丹草鲜草产量和经济效益,在钾肥用量相同时,不同施钾时期及钾肥用量分配对产量产生显著影响。在5个施钾处理中,以50%作基肥、在第2、3和4次收获后平均施用余下50%钾肥的增产效果最好,比对照增产16615kg/hm2,增产幅度达26.1%,每千克K2O增收苏丹草46.2kg;而KCl一次性作基肥施用增产效果较差。

A field trial was carried out to study the influence of KCl application by stages on yield and growth of sorghum sudanense. The result showed that a certain amount of KCl did not have negative effect on sorghum sudanense seedling number, but high rate KCl at basal dressing caused the inhibition of base seedling number. The quality of leaf to sorghum sudanense did not decrease with potash application. It was showed KCl improved the grass resistance to aphid, which the average aphis number on sorghum sudanense of all K applied treatments was as low as 27.2% of that of no K treatment. The result demonstrated that KCl fertilization significantly improved both grass yield and benefit, and at the same K rate, quite difference among treatments with K application different time and different rates at each time. The total yield with treatment of half K as basal dressing and half K as topdressing after the second, third and fourth harvest was the highest which increased grass yield by 26.1% （increased yield 16615 kg/hm^2） based on no K treatment.