氮肥施用量对棉花产量及土壤脲酶活性的影响

Effects of Nitrogen Application Rate on the Cotton Yield and Soil Urease Activity

为探讨黄河流域棉区棉花产量和棉田土壤脲酶活性对尿素施用量的响应,2017年在安阳大田试验以中早熟品种冀228为试验材料,设置纯氮0、60、120、180、240、300、360kg/hm^2共7个处理(分别用N0、N60、N120、N180、N240、N300、N360表示),结果表明:施氮显著提高棉花干物质积累量,N300处理棉花单株干物质积累量最大,干物质分配到生殖器官的比例较高;N360处理棉花单株干物质较N300处理下降,而且生殖器官干物质积累量比例下降。各施氮处理较N0单株成铃数增加1.1～1.3个,单铃重增加0.2～0.4g,籽棉产量显著高于N0处理。N300处理籽棉产量最高,较N0处理增产9.6%,与N0、N60处理产量差异显著(P <0.05),与N120、N180、N240和N360处理产量差异不显著(P>0.05)。施氮显著提高收获期0～60cm土壤脲酶活性,N240处理在0～20cm、20～40cm与40～60cm土壤脲酶活性分别比N0处理增加93.2%、100.1%和51.8%。土壤脲酶活性随施氮量的增加而增强,当施氮量超过240kg/hm^2,土壤脲酶活性降低。随土层深度增加,脲酶活性呈下降趋势。在本试验条件下,施氮量为300kg/hm^2的棉花干物质积累量最大,干物质分配合理,能获得较高籽棉产量,并维持土壤耕作层较高的土壤脲酶活性,可作为本地区适宜施氮量。

To study the response of cotton yield and soil urease activity to urea application in cotton fields in the Yellow River Basin,the medium and early maturing cotton variety Ji228was used as the experimental material in Anyang field experiments in2017.In the experiment process,seven pure nitrogen treatments were set up,which were0,60,120,180,240,300and360kg/hm^2(denoted by N0,N60,N120,N180,N240,N300and N360,respectively).The results showed that nitrogen application significantly increased the dry matter accumulation of cotton.N300treatment had the largest dry matter accumulation per plant and a higher proportion of dry matter allocated to reproductive organs.The dry matter per plant of N360treatment was lower than that of N300treatment,and the ratio of dry matter accumulation of reproductive organs was decreased and the percentage of dry matter accumulation in reproductive organs was decreased.The boll number per plant increased by1.1-1.3and the boll weight per plant increased0.2-0.4g respectively,and the yield of seed cotton was significantly higher than that of N0treatment.The yield of seed cotton treated with N300was the highest,which increased by9.6%,compared with that treated with N0and N60,but had no significant difference with that treated with N120,N180,N240and N360.Nitrogen application significantly increased soil urease activity in0-60cm during the harvest period.The urease activity in0-20cm,20-40cm and40-60cm of N240treatment increased by93.2%,100.1%and51.8%,respectively,compared with that in N0treatment.Soil urease activity increased with the increase of nitrogen application.When the nitrogen application exceeded240kg/hm^2,soil urease activity decreased.With the increase of soil depth,urease activity showed a downward trend.Under the experimental conditions,the maximum dry matter accumulation of cotton was obtained when the nitrogen application rate was300kg/hm^2.If the dry matter distribution is reasonable,higher yield of seed cotton can be obtained,and higher soil urease activity can be maintained in the tillage layer of soil,which can be used as the appropriate nitrogen application rate in this area.