施氮对不同品种玉米产量、氮效率的影响

随着人们对农田氮肥过量施用导致肥料利用率下降和农田地下水硝酸盐污染等问题认识的逐渐加深,不同品种玉米氮素营养效率的研究得到普遍重视。本文选择在我国主要应用的15个玉米品种,在0、120kg.hm 2、240 kg.hm 2氮水平下,通过田间试验研究了施氮对不同品种玉米产量和氮效率的影响。结果表明:"郑单958"、"32D22"、"滑玉14"、"豫丰335"、"新单29"、"中科11"和"漯单9号"在施氮量为120 kg.hm 2时产量最高;"先玉335"、"浚单18"、"蠡玉13"、"浚单20"、"农大108"、"NE8"、"豫禾988"和"洛玉4号"在施氮量为240 kg.hm 2时产量最高。以产量差异的显著性关系为标准进行聚类分析,可将15个玉米品种分为高产、中产、低产3个类型。在3个氮水平下,"蠡玉13"都表现为高产品种,"先玉335"都表现为中产品种,"豫丰335"和"豫禾988"都表现为低产品种。根据玉米在中氮和高氮水平下的氮效率,可以将其划分为4个类型,"郑单958"、"浚单20"、"蠡玉13"、"浚单18"和"漯单9号"为双高效型,"农大108"、"NE8"、"豫禾988"、"豫丰335"和"洛玉4号"为双低效型。根据产量和氮效率的聚类分析结果,"蠡玉13"和"浚单20"在中氮和高氮时都是高产又高氮效率的品种;"郑单958"和"漯单9"在中氮时是高产高氮效率的品种;而"豫丰335"、"豫禾988"、"NE8"和"洛玉4号"在中氮和高氮时都是低产又低氮效率的品种;"农大108"在高氮时是低产又低氮效率的品种。玉米产量与氮营养性状的相关性分析结果表明,氮吸收效率对产量的影响较小,氮素利用效率与秸秆吸氮量之间存在抑制作用,氮素利用效率与氮收获指数间有很好的协同作用。通径分析结果表明,在3个施氮水平下,玉米氮素利用效率对产量有较大的作用,而氮素吸收效率对产量的作用很小。在低氮水平下,氮素利用效率和籽粒吸氮量对产量起决定性作用;在高氮水平下,氮素利用效率起主要作用。

Effect of nitrogen fertilization on maize yield and nitrogenefficiency of different maize varieties

Efficient use of nitrogen(N) fertilizer is essential for increased economic returns of maize and minimum potential nega-tive effects of N on water and soil.Efforts at improving yield potential have focused on maize varieties with high N use efficiency(NUE).The effects of N fertilizer on yield and NUE were determined in a conducted field experiment in Xuchang County of Henan Province,China.A total of about 15 common maize varieties in China were used under 3 N doses(0 kg·hm 2,120 kg·hm 2 and 240 kg·hm 2).The results showed that "Zhengdan958","32D22","Huayu14","Yufeng335","Xindan29","Zhongke11" and "Luodan9" had the highest grain yield at 120 kg·hm 2 N dose.Also "Xianyu335","Xundan18","Liyu13","Xundan20","Nongda108","NE8","Yuhe988" and "Luoyu4" had the highest yield at 240 kg·hm 2 N treatment.Based on yield difference,15 maize varieties were classified as high-yield varieties,medium-yield varieties and low-yield varieties.At the three N doses,"Liyu13" was identified as a high-yield variety,"Xianyu335" as a medium-yield variety,and "Yufeng335" and "Yuhe988" as low-yield varieties.Based on nitrogen efficiency(NE),15 maize varieties were classified into 4 NE grades under medium and high nitrogen treatments."Zhengdan958","Xundan20","Liyu13","Xundan18" and "Luodan9" were classified as double high-efficient type;and "Nongda108","NE8","Yuhe988","Yufeng335" and "Luoyu4" as double low-efficient type.Cluster analysis on yield and N efficiency showed that "Liyu13" and "Xundan20" were high-yield and high-NE varieties under medium and high N application dose;"Zhengdan958" and "Luodan9" were high-yield and high-NE varieties under medium N application dose;"Yufeng335","Yuhe988","NE8" and "Luoyu4" were low-yield and low-NE varieties under both medium and high N application doses;"Nongda108" was low-yield and low-NE variety under high N application dose.Correlation analysis for grain yield and N content showed that N uptake efficiency little influenced yield.While NUE inhibited straw N accumulation,it synergized N harvest index.Path analysis indicated that yield was determined mainly by NUE and that for all the treatments,N uptake efficiency little influenced yield.NUE and grain N uptake significantly in-fluenced yield under low N conditions,but it was true form NUE under high N conditions.