| Custard apple has high nutritional value and economic benefits,and has broad planting prospects in Yunnan Province.The unique stereo climate of the dry-hot valley region of Yunnan is suitable for the growth of custard apple,but there are unregulated irrigation and unreasonable fertilization during the cultivation of custard apple in the dry-hot valley region.Since the growth of custard apple is sensitive to changes in the soil environment due to its shallow root system,which leads to the decline in yield and quality.In this paper,the effects of water-fertilizer-gas coupling irrigation on the growth,yield and quality of custard apple in the dry-hot valley region were studied by setting the three levels orthogonal experiment and the five levels orthogonal rotation combination design experiment with three factors of irrigation,fertilization and dissolved oxygen,in order to explore the irrigation mode of water-fertilizer-gas comprehensive regulation is suitable for the growth of custard apple in dry and hot valley area and realizes the increase of custard apple production and quality.The research conclusions are as follows:(1)By setting the amount of irrigation(60%ETc,80%ETc,100%ETc),fertilization(1500 kg·hm-2,1700 kg·hm-2,1900 kg·hm-2)and dissolved oxygen(6mg·L-1,8 mg·L-1,10 mg·L-1)orthogonal experiments were used to study the response of the growth,photosynthesis,yield and quality of custard apple to different water,fertilizer and oxygen combination treatments.The influence of the three factors of water,fertilizer and gas was analyzed by range analysis,and the variance analysis was performed on the significance of each factor,the results showed that there were differences in the order of the effects of irrigation amount,fertilizer amount and dissolved oxygen on the various indicators of custard apple,and the significant effects of irrigation amount,fertilizer amount and dissolved oxygen on the various indicators of custard apple were also different.Among them,the influence of the three factors on the yield per plant of custard apple is as follows: irrigation amount >fertilizer amount > dissolved oxygen,and the amount of irrigation water and fertilizer has highly significant effect on the yield of custard apple per plant,while the amount of dissolved oxygen has no significant effect.A comprehensive analysis of the responses of the growth,yield and quality indicators of custard apple to different treatments in the experiment,the W3F2O1 treatment with 100%ETc irrigation,1700kg·hm-2 fertilizer and 6 mg·L-1 dissolved oxygen was recommended,it suitable for the growth of custard apple and improve the yield and quality of custard custard,the water-fertilizer-gas coupling irrigation treatment obtained the highest yield per plant of custard apple 9.83 kg.(2)The three factors of water,fertilizer and dissolved oxygen were subdivided,and the orthogonal rotation experiment of three factors(irrigation amount,fertilizer amount and dissolved oxygen amount)and five levels(-1.682,-1,0,1,1.682)was used to study the responses of 13 sub-factors of 4 factors of custard apple growth,photosynthesis,yield and quality to different combinations of irrigation water,fertilizer and dissolved oxygen.The quadratic regression equation of each indicators of custard apple and the amount of irrigation,fertilization,dissolved oxygen and their interaction was constructed,and through the analysis of variance significance,single factor effect analysis,interaction response surface analysis and regression equation analysis,the three factors of water,fertilizer and dissolved oxygen on the 13sub-factors of the 4 factors of custard apple were determined to determine the significance,the order of influence and the law of interaction effect.Among them,the three-factor significance analysis results of water,fertilizer and dissolved oxygen yield per plant of custard apple showed that the influences were in order of irrigation water,fertilization,and dissolved oxygen,and the influence of water and fertilizer reached a very significant level,and the amount of dissolved oxygen had a significant effect.Based on the analysis of the regression equation established in this experiment,Based on the regression equation analysis of the yield per plant of custard apple in this experiment,the yield per plant was higher than 9.57 kg under 90.18%ETc ~95.02%ETc,1780.86 kg·hm-2 ~ 1836.86 kg·hm-2 and dissolved oxygen 7.72 mg·L-1 ~8.56 mg·L-1 coupling irrigation.The optimal value of the model determined that the amount of irrigation water is 100%ETc,the amount of fertilizer is 1819 kg·hm-2,and the amount of dissolved oxygen is 10 mg·L-1 custard apple yield per plant reached the maximum of 9.93 kg. |
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