Effects of drip irrigation frequency on the yield and nutrient utilization efficiency of tomato under long-season cultivation in solar greenhouse.

Abstract

To improve the utilization efficiency of nutrients and water and determine the best drip irrigation frequency for long-season tomato cultivation in solar greenhouses, we cultivated tomato grafted seedlings in soil using an integrated water and fertilizer technology: drip irrigation under mulch. Seedlings drip-irrigated with balanced fertilizer (containing 20% N, 20% P2O5, and 20% K2O) and high-K fertilizer (containing 17% N, 8% P2O5, and 30% K2O) once every 12 days were set as control (CK) and that with water once every 12 days as CK1, while other seedling groups, drip-irrigated with a nutrient solution of Yamazaki (1978) formula for tomato, were set as treatments (T1-T4). There were four drip-irrigation frequencies, i.e., once every 2 days (T1), 4 days (T2), 6 days (T3), or 12 days (T4), who received the same total amounts of fertilizer and water over the 12 experimental days. The results showed that, with the decreases of drip irrigation frequency, tomato yield, the accumulation of N, P and K in plant dry matter, the fertilizer partial productivity, and the nutrient utilization rate first increased and then decreased, peaking at the T2 treatment. Compared with CK, under the T2 treatment, plant dry matter accumulation and the accumulation of N, P and K increased by 4.9%, 8.0%, 8.0%, 16.8%, the partial productivity of fertilizer and the utilization efficiency of water increased by 142.8% and 12.2%, the use efficiency of N, P and K was better than CK by 241.4%, 466.6% and 235.9%, respectively, and the tomato yield increased by 12.2%. Under the experimental conditions, drip irrigation with the Yamazaki nutrient solution at a frequency of 4 days could increase the tomato yield, as well as the use efficiency of nutrients and water. Under long-season cultivation, these trends would result in considerable saving of water and fertilizer. Overall, our findings provided a basis for improving the scientific management of water and fertilizers under long-season tomato cultivation in protected facilities.