Effects of nitrogen-dense interaction on photosynthetic characteristics,dry matter accumulation and yield of dryland potatoes
In order to select suitable nitrogen application rates and planting densities for the green and sustain-able production of dryland potatoes in dryland farming area of central Gansu.In this study,'Longshu 16'was se-lected as the test potato variety.Two nitrogen application rates 200 kg·hm-2(N1)and 300 kg·hm-2(N2)and three planting densities 37 500 plants·hm-2(D1),52 500 plants·hm-2(D2),and 67 500 plants·hm-2(D3)were used,resulting in a total of six treatments.The effects of these treatments on the photosynthetic characteristics,dry matter accumulation,and yield of'Longshu 16'were examined.The results showed that the leaf area index of N1D2 treatment was 11.91%higher than that of N1D1 treatment during starch accumulation stage.At the tuber swelling stage,the activity of Rubisco enzyme in N1D2 treatment was increased by 9.05%com-pared with N1D3 treatment.From tuber swelling stage to starch accumulation stage,the photosynthetic rate,transpi-ration rate and stomatal conductance of leaves in N1D2 treatment were the largest,and the dry matter accumulation was increased by 5.29%~31.12%and 8.82%~27.49%,respectively,compared with other treatments.The yield and economic benefits were the highest under N1D2 treatment.In 2022,it increased by 6.14%~36.21%and 5.13%~169.16%compared with other treatments,and in 2023,it increased by 4.11%~29.46%and 21.56%~76.55%.The recommended nitrogen application rate for'Longshu 16'production in the Longzhong arid agricultural region is 200 kg·hm-2,with a planting density of 52 500 plants·hm-2.This combination can enhance economic benefits while maintaining yield.