| In northwestern of China,the traditional potato planting adopts the bare field and ridge ditch irrigation mode,resulting the single irrigation volume is huge,which leads to the low efficiency of irrigation water utilization.The longer irrigation cycle makes the potato unable to achieve timely irrigation,which affects the potato yield and quality seriously.This experiment combining mulched drip irrigation technology with regulated deficit irrigation theory,setting mildly(55%～65%,Field Capacity,FC)and moderate(45%～55%FC)soil water deficit in potato at stage in seedling,tuber formation,tuber expansion and starch accumulation based on field experiment in Hexi Oasis area,taking full water supply during the whole growth period(65%～75%FC)as a comparision to analyze the effect of the regulated deficit drip irrigation on different growth period contained potato plant growth,water consumption characteristics,yield,quality and water use efficiency,in order to obtain a better irrigation strategy for the potato in this experiment.The main conclusions are as follows:(1)Covering the mulch film is conducive to the increase of shallow soil temperature.The highest temperature increase of 0 to 10cm in seedling stage can reach 11℃,but from the tuber formation stage,the potato stems and leaves have formed a cover layer to block the sunlight.Irradiation did not cause extreme high temperature under the film;while the increase of soil moisture was conducive to the stability of soil temperature.The variation of daily ground temperature during each growth period was less than that of water deficit treatment,and the average temperature at 15cm was1to1.5℃.(2)Due to competition among populations,the potato seedling stage and tuber formation stage were treated with water deficit,and the plant height and leaf area index were not significantly different from other treatments(P>0.05),but the stem diameter was significantly lower than other treatments14.68% to 31.64%(P<0.05),and the greater the degree of water deficit,the greater the decrease of stem diameter;the opposite of tuber enlargement period,the difference of stem diameter after water deficit treatment was not significant,but led to plant height decrease about 9.33% to 13.64%,and the leaf area index decreased by 13.2% to 19.7%,which reached a significant level.(3)The water consumption of potato plants has a great relationship with soil water content.The water consumption and water consumption intensity of CK treatment are at the highest level during each growth period.The tuber formation period and tuber expansion period are the key periods of potato water consumption.The water consumption of WD3,WD4,WD5 and WD6 treated with water deficit decreased by 30.96%,61.38%,29.80% and 61.99%,respectively,and the water consumption intensity decreased by 30.98%,61.32%,29.79% and 62.08%,respectively.The difference was significant(P<0.05),both the water consumption and the water consumption intensity of the potato showed that the water deficit was more serious,and the decrease was more significant.(4)CK treatment of commercial potato rate and potato rate were at the lowest level,tuber formation period mild(WD3) and moderate(WD4)water deficit potato commercial potato rate CK increased significantly by 14.25% and 11.01%,respectively(P<0.05),but the rate of potato was 2.78 and 3.49 times of CK treatment,which was not conducive to potato processing performance and commerciality;while the rate of water deficit in starch accumulation period(WD7)was not significantly different from that of CK(P>0.05),but the commercial potato rate was significantly increased by 12.16% compared with CK,and the potato protein and reducing sugar content increased by 18.65% and 15.62%,respectively.Therefore,it is considered that mild water deficit in the starch accumulation period is the best irrigation strategy to improve potato quality.(5)CK treatment of potato yield was the highest,reaching 35317.71kg/hm~2,but water use efficiency and irrigation water use efficiency were at a low level;tuber formation period moderate(WD4)water deficit potato water use efficiency and irrigation water use efficiency was the highest,respectively reached 7.99kg/m~3 and15.59kg/m~3,but the yield was reduced by 6.9%compared with CK.The tuber formation stage mild(WD3)water deficit potato yield was only 1.32%lower than CK,and the water use efficiency and irrigation water use efficiency were reduced by only 2.38% and 11.67%,respectively,and the commercial potato rate also reached 80.92%.Higher water use efficiency was obtained without significantly reducing potato yield,and it was considered that the mild water deficit in the tuber formation stage was regarded as the best irrigation strategy in the experiment. |
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