5年间作和施氮对甜玉米和大豆产量、农艺性状的影响

Effect of Intercropping and Nitrogen Rate on Sweet Corn and Soybean Yield and Agronomic Characteristics During 5-Year Field Experiments

为探讨种植模式和施氮水平对甜玉米(Zea mays L.var.Rugosa Bonaf.)和大豆[Glycine max(L.)Merr.]产量和农艺性状的影响,于2017—2021年连续5年在江西农业大学农业科技园开展大田定位试验,设置3个施氮量(N0,0 kg·hm^(-2);N1,150 kg·hm^(-2);N2,300 kg·hm^(-2))和3种种植模式(MC,甜玉米单作;MS,大豆单作;CS,甜玉米间作大豆),分别在甜玉米和大豆的成熟期测定产量和农艺性状。结果表明,5年施氮(N1和N2)都显著增加了甜玉米鲜穗产量,但N1和N2处理间5年都无显著差异。相同施氮下间作较单作模式下的甜玉米鲜穗产量5年都无显著差异。随着种植年份的增加,不施氮的间作模式下甜玉米鲜穗产量在2020和2021年较2017年显著降低。甜玉米间作大豆模式中,甜玉米施氮(N1和N2)对大豆鲜荚产量5年都无显著影响。施氮显著增加了甜玉米株高、茎粗和穗位高。相对N2,N1仅在2017和2020年分别显著降低了单作甜玉米的茎粗和间作甜玉米的穗位高。5年数据相关性分析表明,间作模式下的甜玉米鲜穗产量与株高相关性更强,单作模式下的甜玉米鲜穗产量与茎粗相关性更强。大豆鲜荚产量主要与单株总荚数、多荚数和单荚数呈显著正相关。综合来看,施氮能显著改善甜玉米间作大豆种植模式中的甜玉米鲜穗产量和农艺性状。过量施氮(300 kg·hm^(-2))未显著增加甜玉米鲜穗和大豆鲜荚产量。从节约成本和保护农田环境考虑,施氮量为150 kg·hm^(-2)的甜玉米间作大豆种植模式有利于甜玉米和大豆的可持续发展。本研究结果为进一步优化甜玉米间作大豆种植模式提供了理论依据。

This study was aimed to investigate effects of cropping systems and nitrogen rates on the yield and agronomic characteristics of sweet corn(Zea mays L.var.Rugosa Bonaf.)and soybean[Glycine max(L.)Merr.].The five-year(2017—2021)field experiments were conducted in the Agricultural Science and Technology Park of Jiangxi Agricultural University,which was set up for three nitrogen rates(N0,0 kg·hm^(-2);N1,150kg·hm^(-2);N2,300 kg·hm^(-2),respectively)and three cropping systems(MC,mono crop of sweet corn;MS,mono crop of soybean;CS,sweet corn intercropped soybean)to measure crop yield and agronomic traits of sweet corn and soybean at their harvest stage.The results showed that compared with N0,nitrogen application(N1 and N2)significantly increased sweet corn yield,but there was no significant difference between N1 and N2.With the same nitrogen rate,compared with MC,the sweet corn fresh ear yield under CS had no significant difference in 5 years.In the intercropped system,the sweet corn fresh ear yield under N0 in 2020and 2021 was significantly lower than that in 2017.Nitrogen application didn’t significantly affect soybean fresh pod yield in the intercropped system in 5 years.Nitrogen application significantly improved height,stem diameter and ear height of sweet corn.Compared with N2,N1 application significantly reduced the stem diameters of monocropped sweet corn and the ear height of intercropped sweet corn in 2017 and 2020,respectively.The correlation analysis of 5-year showed that the fresh ear yield of sweet corn under the intercropped had a higher correlation with plant height,and the fresh ear yield under the monocropped had a higher correlation with stem diameter.Soybean fresh pod yield was mainly positively correlated with the total number of pods,the number of multiple pods and the number of single pods per plant.In a conclusion,nitrogen application could significantly improve the fresh ear yield and agronomic characteristics of sweet corn in the intercropped system.Excessive application of nitrogen(300 kg·hm^(-2))did not significantly increase the fresh ear yield of sweet corn and fresh pods yield of soybean.From the perspective of cost saving and protection of farmland environment,the sweet corn-soybean intercropping system with 150 kg·hm^(-2)nitrogen is conducive to the sustainable development of planting sweet corn and soybean.The results from this research provide a theoretical reference for the further optimizing sweet corn-soybean intercropping systems.