Effects of Water and Nitrogen Applications on Yield Components and Nutritional Composition of Greenhouse Tomatoes in Different Trusses

Abstract

【Objective】 Water and nitrogen are two factors influencing crop growth and yield the most. The purpose of this paper is to experimentally study their combined effect on fruit water content, nutrient translocation and accumulation, and yield components of fruits in different trusses of greenhouse tomato. 【Method】 The experiment was conducted in a solar greenhouse. It consisted of four pure nitrogen application amounts: 0 (N0), 150 (N1), 300 kg/hm2 (N2) and 450 kg/hm2 (N3), and three irrigation treatments by irrigating 50% (I1), 70% (I2) or 90% (I3) of the evaporation measured from a standard 20 cm pan (Epan) installed in the greenhouse. In each treatment, we measured fruit water (FW) content, fruit total nitrogen (FTN) content, fruit total potassium (FTK) content, and the yield components of the fruits in every truss. 【Result】 There were significant differences in fruit nutrients and yield components between the trusses. The incongruous N/K ratio in the first truss did not support the improvement of yield components. The synergistic effect of N and K in the 2nd truss resulted in the largest fruit-setting numbers and average fruit weight. Increasing irrigation amount had no significant effect on FTN and FTK contents in every truss, but significantly increased FW content, fruit-setting numbers, average fruit weight and fruit yield of every truss. However, the increase in fruit-setting numbers in every truss became small when the irrigation amount exceeded 70% of Epan. Increasing nitrogen fertilization significantly reduced FW content in every truss, promoted translocation of N and K to the fruits, and increased the fruit-setting numbers and fruit yield. However, the increase in fruit-setting numbers and yield was small or even negative when nitrogen fertilization exceeded 150 kg/hm2. Compared with N0, N1, N2 and N3 increased the average fruit-setting numbers of every truss by 13.94%, 10.38% and 10.68% respectively, and the fruit yield by 13.63%, 10.66% and 8.42%, respectively. The significant difference in fruit-setting numbers and average fruit weight in each truss between the treatments was due to the variation in translocation of nutrient and water to the fruits in different trusses. 【Conclusion】 The optimal irrigation and nitrogen fertilization for greenhouse tomato studied in this paper is to irrigate 70% of Epan and fertilize 150 kg/hm2 of nitrogen.

Keywords

• water and nitrogen
• greenhouse tomato
• fruit nutrients
• yield components