Effects of controlling apple orchard productivity on soil moisture and photosynthetic characteristics

Abstract

Aims Our objective is to explore the effects of controlling productivity on resource use in an apple orchard in order to improve sustainability and efficiency. Methods We investigated the effects of different productivities (3.6 × 105,3.15 × 105,2.7 × 105,2.25 × 105 and 1.8 × 105 ind.hm–2) on soil moisture and photosynthetic characteristics in 'Fuji' apple trees during the fruit-bearing period using a neutron probe (503DR) and Li-6400 portable photosynthetic analysis system. Important findings Soil moisture at every soil layer increased with decreased productivity,with the maximum increment of 31.02% at the 60 cm depth. Within the 600 cm profile,water storage capacity could increase 15.41%. With decreased productivity,midday depression of photosynthesis was abated,net photosynthetic rate (Pn) increased,the highest Pn increased 25.71% compared with the control treatment (3.6 × 105 ind.hm–2),the transpiration rate (Tr) was decreased in the afternoon and the optimum water use efficiency (WUE) was improved by 34.12% compared with the control. There were significant correlations between water storage capacity (WSC) and Pn,Tr and WUE (Pearson correlation coefficients of 0.973**,–0.543* and 0.992**,respectively). The regression model of WSC (x) and WUE (y) was y = 0.002 3x – 1.480 6,R2 = 0.984 4**. Controlling productivity improved soil moisture and photosynthetic characteristics and increased WUE,improving harmonious,sustainable development of nature,the economy and society in the apple production area.