| This paper addresses the safety of drip irrigation of apples with domestic reclaimed water.Based on the demonstration base of Hongxingda fruit industry in Xuanhe Town,Shapotou District,Zhongwei City,a randomized group test and an orthogonal test were conducted to systematically investigate the effects of different water quality,irrigation quota,fertilizer application and root restriction factors on the growth,photosynthesis,yield and quality of apples with domestic reclaimed water drip irrigation.This study provides a theoretical basis for the promotion of efficient water-saving irrigation.The main research results are as follows.(1)A two-factor,three-level randomised group trial was conducted to reveal the effects of different combinations of domestic reclaimed water quality and irrigation quotas on apple growth,photosynthesis,yield and quality.The study showed that the Q3W3 treatment(domestic reclaimed water+high water)increased growth indicators by 12.1%to 32.67%,Pn by 17.69%and yield by 26.35%compared with the control,and all quality indicators were within reasonable limits.Under the test conditions(180.4 mm rainfall and gravelly soils),the better combination of water quality and quantity was the Q3W3 treatment,that is,apples with domestic reclaimed water and a fertility irrigation quota of 6480 m3/hm2,which had a better effect on yield and quality and efficiency.(2)A randomised zonal trial was used to reveal the pattern of effects of different combinations of domestic reclaimed water quality,irrigation quotas and side-limiting roots on apple growth,photosynthesis,yield and quality.The study showed that the use of T3 treatment(domestic reclaimed water+lateral root-limiting surface mulch+high water)increased Pn by 17.24%,yield by 40.23%,total sugar and vitamin C content by 14.40%and 19.77%respectively,and other qualities were within reasonable indexes than the control.On balance,the better combination of water quality-quantity-root restriction under the trial conditions was the T3 treatment,that is,apples with domestic reclaimed water,a fertility irrigation quota of 6480 m3/hm2 and side root restriction ground cover,which increased yield and improved quality and efficiency.(3)A three-factor,three-level orthogonal test was used to reveal the effects of different quality of reclaimed domestic water,irrigation quota and fertiliser application on apple growth,photosynthesis,yield and quality.The study showed that the effects of different quality of reclaimed water on apple new shoot length,Pn and yield were in the order of reclaimed water>mixed irrigation>Yellow River water.Apple yield increased with increasing irrigation quotas and fertiliser application,respectively.The order of influence of the three factors on apple yield was drip irrigation rate W>fertiliser application F>drip water quality Q,all reaching significant levels.The optimum combination of Q1W3F3,that is,using domestic reclaimed water,an irrigation quota of 6480 m3/hm2 and a fertiliser application rate of 31 7 kg/hm2,resulted in an apple yield of 39250 kg/hm2 with high growth and photosynthetic indicators and good quality. |
