Effects Of Mulched Patterns On Dry Maize Matter Accumulations And The Nitrogen Availability

Water and fertilize are two key factors which affect the cropping production, to effectively use limited water and fertilizer resources is esurience for sustainable agricultural development. In order to utilize nitrogen fertilizer effectively and reduce the accumulation of residual NO₃^--N in soil profiles. Maize under the treatment of completely mulched alternating narrow and wide ridges with furrow planting (CMRF) in the arid area of Loess Plateau in Gansu was taken as a research object. Designed and implemented four different cultivation practices, namely flat-planting with no mulching (NM), half-mulching with flat-planting (HM), and complete-mulching with flat-planting (CM) and completely mulched alternating narrow and wide ridges with furrow planting. Being to study the effect of different mulching patterns on the rules of nitrogen dynamics in soil between different locations of farmland furrows at the different stages of corn. Dry matter accumulation and grain yield, accumulation and transformation for maize and the accumulation status of NO₃^--N, NH₄⁺-N, Total-N and efficiency of nitrogen use. We used the method of positioning experiments. The main results were showed as follow:In the whole growth period of mulching treatments NO₃^--N content of 0¹0cm soil layer was highest and were significantly higher than that of NM, indicating there existed NO₃^--N surface accumulation in mulching treatments. NO₃^--N content of all treatments under 140cm soil layer was accumulated. NO₃^--N content of soil profile in the each growth period of maize with different mulching treatment changed insignificantly; NO₃^--N content of soil in different layers also changed insignificantly. Allover the dynamic changes of NO₃^--N and NH₄⁺-N content tend to consistent: the content Volatility declined in 0⁸0cm, stable in 80¹40cm and certain rebounded in 140²00cm with the layer deeper. With soil depth increases soil mineral content of nitrogen reduce in different growth period of every treatment. But changes in different mulching patterns and growth periods were significant; the CMRF absorption of nutrients for deep processing is the best.2. Content of Total-N in each treatment increased with the soil layer deeper; generally it could be described by"S"curve. The effect of CMRF treatments on soil deep layers of Total-N influence were stronger than those other treatments. TN content changes of 170²00cm layer under NM was greatest. The total content of TN in the 200cm of different treatments was: CMRF> HM >NM> CM. The soil layers of nitrogen absorption under mulching treatments were more than NM from August, the absorption to deeper nutrients was increased under mulching treatments.3. Different mulching treatments had significant effect on grain yield, the yield under the CMRF treatment was more than 6.96% compared to CM and 49.84% to HM, NM was no yield. The entire transfer index between same organs changes insignificant. The average transfer amounts of dry matter under the CM and HM treatments were the highest, it is 1300.00kg/hm2, NM treatment was the smallest, 833.33 kg/hm2. The transfer amounts, transfer efficiency and percentage of dry matter transference in leaf, stem, and cob of maize between organs was leaf > stem > cob. The dry matters transfer efficiency in this three organs under different treatments was HM>CMRF>CM. The dry matters transfer efficiency under different treatments was HM>CMRF>CM were 52.95%, 41.36% and 40.99%. The contribution of dry matters transfer's amounts and transfer efficiency to grain yield was highest. The contribution of photosynthetic dry matters transfer amounts to grain yield was between 17.03%²6.34% in later growth stage. It shows, to larger extent, the grain yield was determined by photosynthetic productivity in later growth stage. The dry matters transfer amounts, transfer efficiency and percentage of N transference in total plants was HM> CMRF >CM.4. The CMRF significantly enhanced on plants to soil nitrogen use and the transport of nitrogen into grain. The average nitrogen accumulation in the whole growth period was: CMRF> CM > HM> NM. Compared with CM and NM, grain nitrogen accumulation of CMRF was increased by 20.48% and 87.87%, as well as transport of nitrogen to grain biomass yield of CMRF was 37.60% higher than that of HM, maize yield was increased by 49.84%. Treatments of complete mulching could significantly promote N accumulations in plant. N concentration was generally decreased with maize growing stage promoting, but the nutrients accumulation was increased. N accumulation dynamics of maize could be described by"S"curve, except that of NM treatment. N accumulation tendencies of maize were increased with its growing stage promoting, the highest N accumulations were in maturity. N maximum accumulation of maize was on August.9th. The N accumulations in kernel of CMRF were greater than other treatments.5. The CMRF conducive to improving nitrogen harvest index and nitrogen use efficiency. CMRF was nitrogen harvest index was significantly increased by 22.55% compared with HM. During different treatments nitrogen use efficiency of maize was significantly different at 0.05 levels, CMRF was significantly increased by 53.98% than NM.