| The experiment was conducted in the agriculture experimental station of Shandongagricultural university in2010and2011. This research contained field and15N micro-zoneexperiments, adopted the ideas which included two cultivation measures and four nitrogenapplication levels, studied the effects of subsoiling and controlled urea on the nitrogen useefficiency. Denghai3and Zhengdan958were chosen as the experimental materials.Meanwhile it had discussed the effects of subsoiling and controlled urea on corn upperaccumulation of dry matter distribution, fertilizer nitrogen accumulation and distribution,fertilizer nitrogen and soil nitrogen uptake, soil residual nitrogen, and preliminarily identifiedthe acceleration of subsoiling and controlled urea was the highest one. The main researchresults were as follows:1Effects of subsoiling and controlled urea treatments on the maize yieldNitrogen fertilizer can significantly increase maize yield, meanwhile cultivationmeasures, corn varieties and nitrogen application levels can all affect the maize yield. Underthe same maize varieties and cultivation measures conditions, controlled urea had played arole as “early control, late retainâ€, the conventional urea applied for two times treatment couldmake nitrogen fertilizer efficiency retrusion properly, while the conventional urea applied forone time treatment could cause burn seedlings and nitrogen leaching waste easily.Consequently, the performance of corn yield was the controlled urea treatment> theconventional urea applied for two times treatment> the conventional urea applied for onetime treatment> non-N application treatment. Under the same maize variety and nitrogenlevel conditions, the subsoiling after rototilling for stubble breaking treatment could improvethe soil environment, provide a more reasonable soil layer structure, make for the plantabsorbing nutrition. Therefore, the performance of corn yield was the subsoiling afterrototilling for stubble breaking treatment> the rototilling for stubble breaking treatment.Under the same cultivation measure and nitrogen level conditions, while the performance ofthe corn yield had a different result.2The effects of subsoiling and controlled urea treatments on the shoot nitrogenaccumulation of allocation and utilization in maizeAlong with the growth period retrusion, the performances of the dry matter and shootnitrogen accumulation, distribution were consistent. The nitrogen accumulation in maize is gradually increasing, but the range of increasing is gradually reducing, the nitrogenaccumulation arrives the highest amount at harvest time. At the flowering stage, the nitrogenaccumulation of the controlled and subsoiling treatment leaves was the most amounts, andhad a significant difference with other treatments, and ensured plenty of dry matteraccumulation after the flowering stage, meanwhile increased the transport amount to the grain.The tendency of the20d after flowering was the same as the anthesis stage, but the nitrogenaccumulation of grain had made up about a third, and the distribution ratio of stem and leafhad a obviously reducing. At the harvest time, the nitrogen accumulation of grain had madeup more than a half, the nitrogen accumulation of the controlled urea and subsoiling afterrototilling for stubble breaking treatment leaves had the most amount, it was thus clear thatthe controlled urea and subsoiling after rototilling for stubble breaking treatment indeed couldget the highest dry matter accumulation. Meanwhile at the harvest time, the controlled ureaand subsoiling treatment could significantly increase NRE, NAE, NPFP, NUENTA, NCP andAANAA.3Effects of subsoiling and controlled urea treatments on nitrogen fertilizer distribute inmaize shootThe nitrogen fertilizer maize leaves got was significant higher than that of stem. Exceptthe different nitrogen applied level treatment, the nitrogen fertilize amount got by leaves andstem was the highest one. The subsoiling after rototilling for stubble breaking treatment gotmore nitrogen fertilize than the rototilling for stubble breaking treatment. The performance of20d after the anthesis stage was the same as the anthesis stage, but then grain had got somenitrogen from nitrogen fertilize. The performance of the nitrogen fertilize got by maize wasthe same as that of20days after the anthesis stage, but the nitrogen fertilize got by leaves andstem had been a little reducing, while the nitrogen fertilize had been got a lot by grain, and theperformance between two kinds of maize in two years had some differences.4Effects of subsoiling and controlled urea treatments on maize nitrogen fertilizer andsoil nitrogen use efficienceThe different treatments had a certain influence on nitrogen fertilizer and soil nitrogenuse efficience. At the anthesis the effects of different treatments on nitrogen fertilizer and soilnitrogen had the same performance. Except the nitrogen applied level, the trend was0, U, T,C increasing in turn. Under the same maize variety and the nitrogen applied level, the amountof subsoiling after rototilling for stubble breaking treatment was much higher than therototilling for stubble breaking treatment. The effects of different treatments on the nitrogenfertilizer in shoot had the same tendency, but for soil nitrogen, under the same maize variety and cultivation measure, the conventional urea applied for two times treatment had the highestamount, and had a more significant difference with other treatments. The nitrogen fertilizer atharvest time had the same tendence with the20d after anthesis. By the way, the effects on thatbetween the maize varieties in two years were different.5Effects of subsoiling and controlled urea treatments on soil nitrogen residual amountMaize variety had a non-significant effect on soil nitrogen residual amount in two years,while the nitrogen application levels and cultivation measures had an obvious effects on soilnitrogen residual amount in the0-100cm soil. At the anthesis, under the same cultivationmeasures, the performance of15N percentage composition in the0-40cm soil was U<T<C,and the performance of that in the40-100cm soil was U>T>C. Under the same nitrogenapplication levels, the performance of15N percentage composition in the0-40cm soil wasS>R, and the performance of that was S<R in the40-100cm soil. At the harvest time, theperformance of15N percentage composition in the0-100cm soil had the same order, the15Npercentage composition of the subsoiling treatment in the0-40cm soil had more decline thanthe rotation, and that in the40-100cm soil had more rise. At the Denghai3anthesis of2010,in the0-100cm soil, the nitrogen fertilizer in the0-40cm soil had more amount than that inthe40-100cm soil, and had an obvious difference among the different treatments. Under thesame cultivation measures, the nitrogen fertilizer of the controlled urea treatment in thesurface layer was higher, and that was lower in the deep layer, and had an obvious differencewith other treatments. Under the same nitrogen application levels, the nitrogen fertilizer of thesubsoiling treatment in the surface layer was lower, and that was higher in the deep layer, andhad an obvious difference with other treatments. At the Denghai3harvest time, in the0-100cm soil, the nitrogen fertilizer in the0-40cm soil still had more amount than that in the40-100cm soil, and had an obvious difference among the different treatments. Meanwhile thenitrogen residual amount had a decline in the0-40cm soil and that had an increase in the40-60cm soil. Under the same cultivation measures, the nitrogen fertilizer residual amount ofthe controlled urea in the40-60cm soil had a minimum chang, and an obvious difference withother treatments. Under the same nitrogen application levels, the nitrogen residual amount ofthe subsoiling after rototilling for stubble breaking treatment in the40-60cm soil had thebiggest amount, and had an obvious difference with other treatments. The nitrogen fertilizeramount of Denghai3was higher than that of Zhengdan958in the surface layer, but thenitrogen fertilizer in the deep layer had a no obvious difference. |
