Plant Growth And Response To Water And Nitrogen Of Potato Grown Under Plastic Cover With Drip Irrigation

The development potential of potato industry in Inner Mongolia is tremendous, but the problems are low yield level and improve resource use efficiency. The specific performance are below. First, there are shortage of water resource and low WUE in advantages growing areas. Second, fertilizer input is unbalance in different area, Excessive nitrogen input bring down yield increase benefit and efficiency of nitrogen. Mulched drip irrigation is proved Saving water festival fertilizer technology in cotton in northwest area. This technology is began to Application on potato production. But there are no applicable nutrient and moisture management measures for this technology. This research took37500kg/hm2as the target yield,through two years of nitrogen level test and water and nitrogen interactions test system, studied on potato growth, yield formation, nitrogen and water absorption by law. Builded the fast nutrient diagnosis system by fall four leaf of potato and structured N recommendation models at the different potato growth stages. The main result was expouned below.1、Plant growth of potato under plastic cover with drip irrigationThere were the two stages of biomass changes of potato in whole growth, one was Biomass rapid growth stage (seeding～Tuber bulging).another was Biomass stable stage (starch accumulating～Mature). Under suitable moisture, when the nitrogen rate was180kg/hm2, rate of accumulation of plant fresh weight emerging were25.81和32.29g/plant·d-1in tuber building stage and tuber bulging stage, respectively.2、Rule of potato yield under plastic cover with drip irrigationPotato tuber yield present increased at first and then decreased trend with N rate increasing. Under suitable moisture, the N rate mainly affected the the number of small tuber and weight of big tuber. The difference of tuber yield was effected by weight of big tuber.We found that fitting degree of quadratic model was the best. According to the quadratic model y=-2.3757x2+66.558x+2463.4(R2=0.8617), we can obtain the best N rate and yield were210kg/hm2and43931kg/hm2in Inner Mongolia Yin-shan hilly area.3、Water use characteristics of potato under plastic cover with drip irrigationThere were "massive consumption stage of water state"(seedling stage～tuber bulging stage) and"Slow consumption stage of water state"(tuber bulging stage～mature stage).Water consumption intensity showed tuber bulging stage> tuber building stage> seeding stage> starch accumulating stage> mature stage. Water consumption intensity in tuber bulging stage and tuber building stage were6.05～6.83mm·d-1and4.90～5.29mm·d-1. SWUE and WUE of treatment in1350m3/hm2water significant exceed the treatment in900m3/hm2. Under suitable moisture, both SWUE and WUE of treatment present N300> N180> NO.4、Nitrogen use characteristics of potato under plastic cover with drip irrigationN uptake rate of potato presents the single-peak curve changing trend with the "slow～quick～slow" variation, the most N uptake rate of potato was on51.14～70.39mg/plant·d-1in stage of tuber bulging and tuber building. The major factor of effection on NHI, NRE, NPEP, NAE, NPE of potato was N rate. The maximum NRE、NAE and NPE of potato were67.97%、68.06kg/kg and154.92kg/kg under90kg/hm2N rate.5、Institution of N recommendation models of potato under plastic cover with drip irrigationThe N recommendation models of Shepody in seeding stage, earlier tuber building stage, later tuber building stage, earlier tuber bulging stage, later tuber bulging stage were: Nd(afer seding15d)=(41.7-SPAD)×7.74; Nd(afer seeding25d)=(45.8-SPAD)×19.01; Nd(afer seeding35d)=(44.8-SPAD)×34.97: Nd(afer seeding45d)=(41.5-SPAD)×40.49; Nd(afer seeding55d)=(38.7-SPAD)×52.36.