鲁南丘陵瘠薄地氮肥用量对甘薯生长和产量的影响

Effects of Nitrogen Rates on Sweet Potato Growth and Yield in Barren Hilly Regions of Southern Shandong Province

在鲁南丘陵瘠薄地区进行氮肥用量试验,分析不同氮肥施用量(0、45、90、135、180 kg/hm^2和225kg/hm^2)对甘薯生长和产量的影响,解析甘薯源、库关系,确定丘陵薄地甘薯的适宜氮肥施用量。结果表明,济薯25鲜薯和薯干产量随施氮量的增加呈先增加后下降的趋势,其中氮肥施用量为135 kg/hm^2时,鲜薯和薯干产量最高,分别为34 673.4 kg/hm^2和12 974.7 kg/hm^2;单株茎叶鲜重随氮肥施用量的增加而增加;增施氮肥会使甘薯生长平衡点(T/R=1)出现延后的趋势;氮肥施用量为135 kg/hm2时,甘薯单株薯块鲜重、干重、块根膨大速率、纯收入和投入产出比达到最大值,分别为774.5 g、289.82 g、6.22 g/d、24 619.5元/hm2和360.1%,且氮肥利用率达到最大值92%。综合分析氮肥用量对甘薯产量、经济效益和氮肥利用率的影响,鲁南丘陵瘠薄地甘薯氮肥适宜施用量为135 kg/hm2。

Using the sweet potato variety Jishu 25 as material,the experiment on nitrogen application rate was carried out in barren hilly regions of southern Shandong Province.The nitrogen application rates were set as 0,45,90,135,180 and 225 kg/hm2,and their effects on growth and yield of sweet potato were studied to analyze the relations of source and sink and to make sure the suitable nitrogen rate.The results showed that with the increase of nitrogen rates,both fresh and dry yields of root tubers increased firstly and then decreased,and they reached the highest as 34 673.4 kg/hm2 and 12 974.7 kg/hm2 respectively at 135 kg/hm2 of nitrogen rate.With the increase of nitrogen,the leaf fresh weight per plant increased,and the equilibrium point of growth had a delayed trend.When the nitrogen application rate was 135 kg/hm2,the fresh and dry weight of root tuber per plant,root tuber thickening rate,net income,input-output ratio and nitrogen use rate all reached the maximum as 774.5 g,289.82 g,6.22 g/d,24 619.5 yuan/hm2,360.1% and 92% respectively.After comprehensive analysis,the optimal nitrogen fertilizer application rate for sweet potato was135 kg/hm2 in the barren hilly regions of southern Shandong Province.