Impacts of humic acid urea on soil mineral N content and quality of lettuce
To investigate the impact of humic acid urea on vegetable quality,semi-heading lettuce was chosen as the indi-cator crop,and four treatments were implemented:CK(no nitrogen fertilizer),T1(conventional urea),T2(humic acid urea),and T3(commercial organic manure).We measured the ammonium and nitrate nitrogen content and changes in both rhizosphere and non-rhizosphere soils,as well as various indicators of lettuce quality,including nitrate,oxalic acid,nitrite,soluble total sugar,and vitamin C.Using the membership function method,we analyzed the comprehensive effect of humic acid urea on lettuce quality.The results showed that the average mineral nitrogen content(ammonium nitrogen+nitrate nitrogen)in the rhizosphere soils under humic acid urea treatment was 137.77 mg·kg1,consistent with the results in non-rhizosphere soils.The nitrate nitrogen was the main soil mineral nitrogen type under humic acid urea treatment.The enrichment rates of soil ammonium nitrogen and nitrate nitrogen change from positive to negative followed the in-crease of cultivation.The fresh mass of the edible portion and the average quality membership function values under hu-mic acid urea treatment was higher compared with common urea treatment.The correlation analysis showed that the soil ammonium nitrogen was significantly positive correlated with fresh weight of edible part,and the vegetable nitrate was significantly positive correlated with soil nitrate nitrogen.To sum up,humic acid urea is beneficial to high quality vegeta-ble production,but its regulation mechanism of ammonium nitrogen and nitrate nitrogen in soil needs further studied.
NETL
NSTL
万方数据
维普
