The Effect Of Polyolefin-coated Urea On Tomato In Greenhouse

Compared with soluble (common) urea applied 4 times, two type controlled release N fertilizers( polyolefm-coated urea), CU I (60-D N release)and CUII (100-D N release), were tested as single basal application on tomato in greenhouse in a field and pot trial. Soil NO3-N EC soil water tomato leaf chlorophyl content leaf nitrate reductase activity ^ photosynthesis rate, and plant growths yield and fruit quality were examined by stages; the safe dosage range on tomato seedling was also researched. The result belows:1. CU I CU II could provide sufficient N to tomato about 5 months from plant, and enhanced the yield by 4.99%-9.84% under the level of applied N 300 kg/hm2 ;the 1:1 mixture of CU I and CUII output more 12.50%-20.80%;the yield was not reduced decreasing applied N in CU I ;2. The polyolefin -coated urea could make the soil NO3--N EC on a higher and steady level during tomato plant developing, the CU I 50 +CUII50 was the best treatment according to the plant N need;3. Both CU I and CU II distinctly increased fruit sugar, markedly lower the NO3"-N contend and malformed-fruit rate, no change on Vc;4. The polyolefin-coated urea could evenly promote tomato growth and NPK absorb, enhance leaf nitrate reductase photosynthesis rate and water absorb ability, no marked effect on leaf chlorophyl content;5. CU I , CU II and CU I 50 +CUII50 enhanced the fertilizer utilization rate by 15.14% 17.04% and 31.50% respectively, compared to the common urea ;6. 1-2 times more N than common urea, polyolefin-coated urea did not restrain tomato seedling develop, CU I 100+CUII100 obtained the best young plant.To sum up, the 1:1 mixture of CU and CU, as single basal application on tomato in greenhouse, worth populizing in practice , leading to high quality and yield and not prone to harm seedling.