Studies On Nitrogen Release And Use Efficiency Of Controlled Release Nitrogen Fertilizer In Wheat Field In Chao Soil Region

By methods of simulated trial, barrel trial and field trial, this paper studied the dynamic release of nitrogen in the soil and the effects on wheat growth of two kinds of controlled release nitrogen fertilizer (CRNF) under different irrigations in Chao soil derived from alluvial deposit of Yellow River. The results were as follows:1.The N fertilizer releasing periods of CRNF-1 and CRNF-2 were longer than that of urea significantly, and the release trend of N fertilizer was something similar to the nutrition requirement of the winter wheat at different growing stages.2.The urea dissolved quickly when npplicd in soil; while CRNF-1 and CRNF-?, with multiple mineral coated films, dissolved and released nitrogen slowly, and last for more than 150 days.3. CRNF-1 and CRNF-2 could significantly increase wheat yield under different litigation conditions both in the barrel or the field trial. In the barrel (rial and Held trial, the wheat yields of CRNF-2 increased by 120.5kg/mu and I07.6kg/imi more than those of urea under 2 times irrigations, also the spike number, grain number and 1000 grain weight of CRNF-2 increased by 3.5 x 104 per mu, 1.62 grain per spike, 2.73g, respectively in the barrel trial, and by 2.1 x 104 per mu, 3.6 grain per spike, 3.93g, respeclively in the field trial.4. In a field trial, the nitrogen use efficiencies (NUE) in CRNF-1 and CRNF2treatments elevated by a range from 2.9% to 7.4% more than those of urea under the different irrigation conditions; and in the barrel trial, the NUE could increase by 25.6% more than urea treatment.5. CRNF-1 and CRNF-2 could promote wheat roots growth, more deeply with higher weights under different irrigations. Although the total consumptions of soil water were close lo that of urea treatment, the water use efficiencies (WUE) of CRNF-1 and CRNF-2 treatments were higher with the order of CRNF-2 > CRNF-1 > urea.6. The N of CRNF-1 and CRNF-2 was not only absorbed by the winter wheat but also remained more than urea in cultivate layer at harvest stage by the N tested in soil before applying and after harvesting respectively. The total NO3- -N left in the 1 m soil body were in the order of CRNF-2 < CRNF-1 < urea under different irrigation conditions in the barrel at harvest stage .7. From the economic analyses, applied conveniently with less labor input, The net gain of CRNF treatment could increased by about 80 yuan per mu more than ureatreatmnet under approptiate irrigation conditon.