Water consumption, soil nitrate-nitrogen residue and fruit yield of drip-irrigated greenhouse tomato under various irrigation levels and fertilization practices

Abstract

The excessive irrigation and chemical fertilizer application in the greenhouse can lead to resources waste, environmental pollution and instable or even reduced fruit yields. A four-season experiment was conducted with three irrigation levels (W1, 100%ETc; W2, 75%ETc; W3, 50%ETc, where ETc was the crop evapotranspiration) and five fertilization practices (CC, chicken manure and chemical fertilizer; SO, only soluble organic fertilizer; SC, only soluble chemical fertilizer; SOSC, soluble organic and chemical fertilizer; CK, a control with no fertilizer) to explore their integrated effects on the growth, water consumption, soil nitrate-nitrogen residue and fruit yield of drip-fertigated greenhouse tomato. The results showed that the root shoot ratio in autumn (3.21 ×10−2) was greater than that in spring (2.05 ×10−2). Fruit dry matter had the most significantly positive relationship with fruit yield in both autumn and spring seasons; however, leaf dry matter, stem dry matter and leaf SPAD had significantly positive relationship with fruit dry matter only in autumn. The average fruit yield over the four growing seasons was 70.68, 67.16 and 62.66 t ha−1 under W1, W2 and W3, respectively. The SOSC increased plant height, dry matter, leaf SPAD and fruit yield of tomato and reduced soil nitrate-nitrogen residue (0–60 cm), while both SO and SOSC obtained greater root shoot ratio. Both SC and SOSC showed greater water consumption at the seedling stage, blooming and setting stage than CC; however, the water consumption at the harvest stage under both SO and SOSC was greater than that under SC. Under W1, plant overgrowth occurred under SC, resulting in lower fruit yield. The difference in fruit yield between CC and SC reduced with the increasing water stress. Overall, the combination of soluble organic and chemical fertilizer along with 100%ETc irrigation (W1SOSC) was more conducive to promoting tomato yield (73.40 t ha−1) and reducing soil nitrate-nitrogen residue , while the combination of soluble organic and chemical fertilizers along with 75%ETc irrigation (W2SOSC) had the potential of achieving water-saving greenhouse tomato production in arid and semiarid regions.