Effects of integrated management of water and fertilizer on the physiological characteristics and water- fertilizer use efficiency of grapes in greenhouse

This study aims to explore the effects of water-fertilizer treatments on grapevine growth, physiology, yield, and water-fertilizer use efficiency under an integrated drip irrigation in a solar greenhouse in Northeast China. Taking 3a grapevine (Vitis vinifera L. cv. Muscat Hamburg) as the test material, the integrated management of water and fertilizer was carried out in the solar energy greenhouse from 2017 to 2019. Three irrigation levels were set in the test (W1-W3): The upper and lower limits of irrigation control for W1-W3 were 50%-90%, 60%-90% and 70%-90%θf (θf is field capacity), respectively, and three fertilization levels (F1-F3): low fertilizer F1 (60%CK), medium fertilizer F2 (75%CK), high fertilizer F3 (90%CK) and a control treatment CK, the lower limit of irrigation control of CK was 80% field capacity, and the upper limit was 90% field capacity, where the application amount of various fertilizers: N-P2O5-K2O=260-119-485 kg/hm2, a total of 10 treatments. The results were as follows. 1) The fruit expansion stage was the most important period for the grapevine length of a lateral branch under the water and fertilizer integration. In the growth index of grapevine (length of lateral branch and leaf area index), the W3F1, W2F1, W2F2, and W2F3 treatments were all positive to the CK (positive treatment means superior to or no significant difference from the treatment (P>0.05)). The flowering to fruit set stage and fruit expansion stage was the most critical period to regulate the size of leaf area index (LAI) and the growth rate of LAI of grapevine using water and fertilizer. 2) In the net Photosynthetic rate (Pn) and Transpiration rate (Tr) of grapevine leaves, the W3F2, W3F1, W2F3, and W3F3 treatments were all positive treatments, compared with the CK. Instantaneous Water Use Efficiency (WUEi) was ranged from 1.60 to 3.74 μmol/(mmol), and the W2F2, W3F1, and W3F3 treatments were all positive treatments, compared with CK. 3) The effects of irrigation amount and integrated water-fertilizer on the grapevine yield reached a significant level (P<0.01). The W3F2, W3F1, W3F3, W2F3, and other treatments were positive treatments, compared with the CK. The yield reached the maximum under the W3F2 treatment. Nevertheless, excessive irrigation and fertilization can lead to a significant decrease in the WUE and fertilizer partial productivity of grapevine. The WUE reached the maximum value under the W1F2 treatment, and the Fertilizer Partial Productivity (PFP) reached the maximum value under the W3F1 treatment. Consequently, the W2F3 treatment can remain the PFP stable, where there was no significant difference between growth index, yield, WUE, and optimal level. The W2F3 treatment was evaluated as the optimal treatment, where the upper and lower limits of irrigation water control were 60%-90% field capacity, and 90%CK (N-P2O5-K2O = 240-110-449kg/hm2) of fertilizer application can save 21.19%-23.27% water and 7.52% fertilizer. Anyway, the W2F3 treatment can be expected to realize the water-fertilizer saving, stable and efficient production of grapevine in the cold areas of Northeast China.