施钾对湖南主要双季稻区钾肥效应及钾素平衡的影响

研究了不同施肥处理(在丘陵双季稻区和洞庭湖双季稻区分别施以0,112.5,150.0,187.5 kg/hm~2的K_2O)对水稻单产和钾肥效应及钾素平衡的影响.结果表明,洞庭湖双季稻区稻田中缓效钾和全钾含量均较高,土壤供钾能力强,土壤中钾基本上能够满足水稻对钾素营养的需要,能够获得较高的单产,施钾效果不显著.在2类双季稻区土壤上施用氮肥的增产效果明显大于施用钾肥的.由差值法测得,丘陵双季稻区和洞庭湖双季稻区早稻NPK_1,NPK_2,NPK_3处理的平均钾素利用率分别为28.8%,43.0%,晚稻NPK_1,NPK_2(1-1),NPK_3处理的分别为44.4%,26.5%.在每季水稻施钾量(施K_2O)为112.5,150.0,187.5 kg/hm~2的条件下,钾素平衡处于亏缺状态,但钾素的亏缺随钾肥用量的增加而降低(洞庭湖双季稻区的NPK_3处理出现了钾素盈余).

Effect of potassium application on its efficiency and balance in double rice regions in Hunan Province

The effect of potassium application on rice yield,potassium efficiency and potassium balance double rice regions was studied by applying 0,112.5,150.0,187.5 K~2O kg/hm~2 K fertilizer in field experiment.The results showed that the contents of K slowly available and total K of in Dongting lake double rice regions is obviously higher than that in hilly double rice regions.In Dongting regions,due to high soil K supply capacity from the soil itself K from the soil can meet rices K requirement basically for high grain yield;The effect Of potassium application was not remarkable while in type 2 double rice regions,the yield increase produced by N fertilizer application was much higher than that by K fertilizer application in.The balance evaluation led to the conclusion:the average value of K recovery for early rice in three treatments NPK_1,NPK_2,NPK_3 in the two kinds of double rice regions was 28.8%and43.0%,respectively ;while that for late rice in three treatments NPK_1,NPK_2(1-1),NPK_3 was 44.4% and 26.5%,respectively with potassium application of 112.5,150.0,187.5 K20 kg/hm~2,there was a deficit in potassium balance,while and the deficit amount of its decreased with K application increasing (even surplus in NPK_3 treatment in Dongting Lake double rice regions).