Evaluation of water and nitrogen regulation effects of wolfberry quality based on fuzzy Borda combination model
To determine optimal water and nitrogen supply thresholds for wolfberry(Lycium barbarum L.),a fuzzy Borda combination model was used to evaluate the effects of different water and nitrogen combinations on its quality.Taking the three-year-old'Ningqi No.5'wolfberry as the object,four water control levels(the upper and lower limits of soil water controlled by the percentage of soil water content to field water capacity θf)were analyzed.Full irrigation of W0(75％～85％θf),mild water deficit W1(65％～75％θf),moderate water deficit W2(55％～65％θf),severe water deficit W3(45％～55％θf)and 4 nitrogen application levels of no nitrogen application N0(0 kg·hm-2),low nitrogen application rate N1(150 kg·hm-2),medium nitrogen application rate N2(300 kg·hm-2)and high nitrogen application rate N3(450 kg·hm-2)on the appearance quality and nutritional quality of wolfberry were investigated.The results showed that:(1)Under the same water control,the fruit diame-ter of wolfberry fruit was increased by medium and low nitrogen application,while the fruit diameter of higher nitro-gen application was increased by 3.39％～5.19％.The fruit diameter of wolfberry fruit was increased first and then decreased with the increase of water deficit,in which W0,W1 and W2 were increased by 8.01％,9.44％and 6.92％compared with W3,respectively.The fruit length of wolfberry first increased and then decreased with the in-crease of nitrogen application,N2 treatment increased the most(4.39％),and decreased with the increase of water deficit,and the severe water deficit of each treatment increased by 2.50％～9.57％.Water regulation,nitrogen ap-plication level and their interaction had no significant effect on the fruit form index.The contents of total sugar,pol-ysaccharide,fat,vitamin C and flavonoid in W1N2 treatment were the highest,which were increased by 3.32％～16.93％,7.49％～54.72％,6.50％～45.89％,2.29％～47.41％and 4.14％～28.34％compared with other treat-ments,respectively.The amino acid content of W2N3 treatment was the highest,which was 11.12％～86.16％higher than that of other treatments.The protein content of W0N2 treatment was the highest,which was increased by 7.15％～71.67％compared with other treatments.The total phenol content of W2N1 treatment was the highest,which was 8.54％～65.98％higher than that of other treatments.The appearance quality and nutritional quality of wolfberry were formed when the water deficit was moderate,and the nitrogen level was low.(2)The evaluation val-ue of wolfberry quality of each treatment was significantly inconsistent due to different models.After removing the principal component analysis,the Kendall correlation coefficient of the evaluation results of the three single models of membership function analysis,grey correlation degree analysis and TOPSIS model and the evaluation results of the other two models except this single model passed the Kendall-W concordant coefficient test,which had certain compatibility and can be combined evaluation.(3)Post-test of the combined evaluation model constructed by the mean value method and the fuzzy Borda evaluation method found that the Spearman correlation coefficient between the fuzzy Borda combination evaluation model and each single model was higher than the mean value method.(4)The regression analysis of the quality evaluation value of wolfberry based on the fuzzy Borda combination evalu-ation model showed that the comprehensive quality of wolfberry was better when the water and nitrogen supply thresholds were 348.40～385.08 mm and 270.46～298.92 kg·hm-2,respectively.
wolfberrywater and nitrogen regulationappearance qualitynutritional qualityfuzzy Borda combination evaluation model
万方数据
维普
