Effects of different controlled release periods of nitrogen on photosynthetic characteristics and dry matter accumulation and distribution of sweet potato
Four nitrogen fertilizer treatments with different controlled release periods of 30 d(T30),50 d(T50),70 d(T70)and 90 d(T90)were set up in the field to investigate the effect of the controlled release periods of nitrogen on photosynthetic characteristics,dry matter accumulation and distribution of sweet potato[Ipomoea batatas(L.)Lam.],with the cultivar JiShu25 as the test material and using common compound fertilizer with equal nutrient content as control(CK).The results showed that the appropriate controlled release periods(30～70 d)of nitrogen improved the photosynthetic performance of sweet potato leaves in the middle and late stage(80～160 d),and promoted the rapid accumulation and transfer of underground dry matter of sweet potato.The photosynthetic terms,dry matter accumulation(accumulation amount,accumulation rate)and distribution(distribution ratio,root-shoot ratio)index of sweet potato leaves in the middle and late stage were significantly higher than CK.Among them,the treatment with controlled release periods of nitrogen of 50 d and 70 d were better.The photosynthetic rate,chlorophyll SPAD,underground dry matter accumulation amount,root-shoot ratio of T50 and T70 increased by 14.01%,11.32%,21.75%,18.48%and 15.62%,11.84%,20.65%,18.84%in the har-vest time(160 d).Underground dry matter accumulation and distribution index in the late stage(120～160 d)were lower than CK when the controlled release periods of nitrogen achieved 90 d.This indicated that long controlled release periods of nitrogen had an in-hibiting effect on the rapid accumulation and transfer of underground dry matter of sweet potato.
sweet potato[Ipomoea batatas(L.)Lam.]nitrogencontrolled release periodphotosynthetic characteristicsdry mat-ter accumulation and distribution
万方数据
维普
