钾肥对不同收获时期青贮玉米碳水化合物积累的影响

为探讨不同施钾量对不同收获时期青贮玉米(Zea mays L.)中碳水化合物积累的影响,以青贮玉米东青1号(Z.mays L.cv.Dongqing No.1)为材料,设4个施钾用量,其中K₂O施用量分别为0,56,112和168kg·hm^-2,分别于乳熟初期(8月21日)、乳熟中期(8月28日)、乳熟末期(9月4日)、蜡熟初期(9月10日)、蜡熟中期(9月15日)和蜡熟末期(9月20日)收割取样,测定其碳水化合物含量和鲜草产量。结果表明:青贮玉米中果糖含量在乳熟初期收获最高(P<0.05),蔗糖含量在乳熟末期收获最高(P<0.05),可溶性总糖含量和鲜草产量在蜡熟初期收获最高(P<0.05),淀粉含量在蜡熟末期收获最高(P<0.05);施用钾肥可显著提高青贮玉米中果糖、蔗糖、可溶性总糖和淀粉含量和鲜草产量(P<0.05),其中施钾(K₂O)112kg·hm^-2效果最佳。综合施钾肥对不同收获时期青贮玉米鲜草产量和碳水化合物积累的影响,施钾(K₂O)112 kg·hm^-2并于蜡熟初期收获是青贮玉米东青1号栽培利用的适宜组合。

Effect of Potassium on Carbohydrate Accumulation in Silage Corn at Different Harvest Dates

In order to define the effect of potassium application amount on carbohydrate accumulation in silage corn(Zea mays L.) at different harvest dates,trials were carried out using Dongqing No.1(Z.mays L.cv.Dongqing No.1) as experimental material and the carbohydrate content and fresh yield of silage corn were measured at initial milk stage(21^th August),metaphase milk stage(28^th August),telophase milk stage(4^th September),initial dough stage(10^th September),metaphase dough stage(15^th September),and metaphase dough stage(20^th September) under treatments of four potassium fertilizer application level(0,56,112,168 kgK₂O·hm^-2),respectively.The results show that the fructose content in silage corn was highest at initial milk stage(P<0.05);the sucrose content was highest at telophase milk stage(P<0.05);the soluble total sugar content and the fresh grass yield were highest at initial dough stage(P<0.05);the starch content was highest at telophase dough stage(P<0.05).Potassium significantly affected the contents of fructose,sucrose,total soluble sugar,and starch in silage corn and the fresh yield at different harvest dates(P<0.05).Potassium applied at 112 kgK₂O·hm^-2 had the best effect on the carbohydrate content of silage corn.In summary,considering the fresh yield and carbohydrate accumulation in silage corn at different harvest dates,the optimal potassium application amount and the optimal harvest time could be 112 kgK₂O·hm^-2 and initial dough stage,respectively.