Abstract:

To address the problem of poor water and fertilizer retention capacity and its low utilization efficiency of the wind-sandy soil in southern Xinjiang, five treatments were set up, namely W₁, W₂, W₃, and W₄ with different irrigation frequencies and a control treatment (CK) based on farmers’ habitual irrigation. The irrigation quotas for the entire growth period of W₁, W₂, W₃, and W₄ were consistent at 3975 m³/hm², and the irrigation quota for CK treatment was 4500 m³/hm². During before planting stage and seedling stage-initial fruit setting stage, the irrigation amounts of W₁, W₂, W₃, and W₄ treatments were the same, which were 450 and 75m³/hm² respectively. The irrigation amounts for CK treatment were 450 and 300 m³/hm² respectively during these two periods. At the beginning of fruiting stage, drip irrigation frequencies are once every two days (W₁), once every three days (W₂), once every four days (W₃), once every six days (W₄), and once every six days (CK) were adopted. In the middle of fruiting stage, drip irrigation frequencies are once every three days (W₁), once every four days (W₂), once every four days (W₃), once every six days (W₄), and once every six days (CK). At the end of fruiting stage, drip irrigation frequencies are once every five days (W₁), once every six days (W₂), once every six days (W₃), once every six days (W₄), once every six days (CK). The effects of different irrigation frequencies on tomato’s plant height, stem diameter, root characteristics, leaf photosynthetic characteristics, soil nitrate nitrogen distribution and yield quality were studied. The results of the experiments showed that: (1) the increase of irrigation frequencies had no significant effect on the plant height of tomato at the fruiting stage, but it was beneficial to the increase of its stem diameter. (2) With the increase of irrigation frequencies, Pn, total root length and root surface area of leaves were significantly increased, but there was no obvious effect on Tr, Gs, Ci and root volume. (3) The high-frequency irrigation treatments (W₁, W₂) were conducive to the accumulation of nitrate nitrogen in the 0-20 cm soil layer, and the low-frequency irrigation treatments (W₄, CK) leached the nitrate nitrogen in the soil below 40cm. (4) Increasing the frequency of irrigation significantly increased tomato yield, water use efficiency, soluble sugar and soluble solids mass.

Key words: tomato, water use efficiency, irrigation frequency, sandy soil, facility agriculture, yield, nitrate accumulation