施氮量和栽插密度对甘薯群体发育和产量形成的影响

Effect of nitrogen application rate and planting density on population development and yield production of sweetpotato

于2014—2015年连续两年进行大田试验,研究不同施氮量(不施氮、施纯N 75kg/hm^2和150kg/hm^2,分别用N1,N2,N3表示)与栽插密度(4万株/hm^2、5万株/hm^2、6万株/hm^2和7万株/hm^2,分别用M1,M2,M3,M4表示)对甘薯群体发育和产量的影响.结果表明:施氮可显著提高甘薯前期的最大蔓长、地上部鲜质量,对分枝数、结薯数影响不显著,栽插密度对最大蔓长、分枝数、单株薯块数的影响均未达显著水平,且二者的交互效应不显著.施氮量和栽插密度均显著提高不同发育时期叶面积指数,促进群体发育.不同栽插密度下收获期地下部质量综合表现为M4>M3>M2>M1,不同施氮水平下综合表现为N2>N1>N3;二者交互作用以N2M2处理产量最高,为15 585kg/hm^2,N1M1最低,为10 680kg/hm^2,施氮量、栽插密度及二者的交互作用对收获期地下部质量的影响均达显著水平.施氮量对甘薯产量构成的影响主要体现在单株薯块数和单株薯块质量,而栽插密度则对单株薯块数、单株薯块质量和平均薯块质量均有显著影响.施氮量和栽插密度对薯块商品率的影响均达极显著水平,二者的交互效应也达显著水平.施氮量与栽插密度的合理搭配可提高单株结薯数、平均薯块质量和商品率,提高收获期甘薯产量,本试验条件下,N2M2处理收获期产量最高,其对应薯块的商品率为94.71%,均为所有处理中最佳.

A two-factor(N application rate and planting density)complete experiment had been conducted for two years of 2014~2015 to study effects on population development and yield production of sweetpotato as well as the interaction effect of two factors.The results showed that N application rate can significantly increase the maximal vine length and aboveground fresh weight of sweetpotato in the early stage except the branch numbers and nodule numbers,while all the effects of planting density on the maximal vine length,branch numbers and nodule numbers cannot reach the significant level,the interaction effect of two factors on the growth and development of sweetpotato in the early stage cannot reach the significant level;but two factors can significantly improve the leaf area index of sweetpotato in different development period.The comprehensive root yield under different planting density was M4>M3>M2>M1,and under different N application rate was N2>N1>N3.The N2M2 treatment had the highest root yield of 15 585 kg/hm^2 in all of the combinations of two factors,while the N1M1 treatment had the lowest root yield of 10 680 kg/hm^2,and the effects of N application rate,planting density and their interaction on root yield of sweetpotato all can reach the significant level.The effect of N application rate on yield components mainly reflected in the per plant tuber numbers and per plant tuber quality,while the effect of planting density on yield components mainly reflected in the per plant tuber numbers,per plant tuber quality and average tuber quality.The effects of tow factors on the commodity rate of potato tubers reached a very significant level.So the suitable combination of them can increase the per plant tuber numbers,average tuber quality and commodity rate,and increase the tuber yield of sweetpotato ultimately.Under the experimental conditions,N2M2 treatment had the highest yield production,and the commodity rate(94.71%),so it was the best among all treatments in this experiment.