Effects of organic fertilizer application rate and intermittent drought period on yield and quality of tomato

【Objective】To explore the effects of applying different amounts of organic fertilizer and intermittent drought in different periods on the growth, yield, water and fertilizer effect and quality of tomato, and to provide a theoretical basis for scientific application of organic fertilizer to potted tomato in greenhouse under different periods of intermittent drought conditions to achieve high yield and excellent quality.【Method】Potted tomato experiment was carried out in greenhouses, and 16 treatments were designed with two factors of organic fertilizer application amount and intermittent drought in different periods. The application amount of organic fertilizer was set as no fertilizer(F0), low fertilizer(F1), medium fertilizer(F2) and high fertilizer(F3), the application rateswere 0, 600, 1200 and 1800 kg/ha;for different periods of intermittent drought, normal irrigation at the whole growth stage(A0), drought at seedling stage(A1), drought at flowering stage(A2) and drought at fruit stage(A3) were set.【Result】The application amount of organic fertilizer and intermittent drought in different periods had significant effects on the growth, yield, water and fertilizer effect and quality of tomato(P<0.05). Normal irrigation and medium and high amounts of organic fertilizer(A0F2 and A0F3) resulted in higher plant height, stem diameter, root dry weight, stem dry weight, leaf dry weight, chlorophyll content, and fresh weight of above ground and underground parts, and thus higher biological yield and economic yield were obtained. However, tomato fruit quality was poor, among which A0F2 had the highest economic yield, 67.76 t/ha;PFP decreased with the increase of fertilizer application rate, and reached the maximum in A0F1. The intermittent drought and low amount of fertilization in different periods were not conducive to plant growth and development, and the yield and water use efficiency(WUE) of tomato were low. The highest WUE of tomato was in A1F2 and A0F2, and there was no significant difference between the two(P>0.05). The quality of tomato was improved by intermittent drought and medium organic fertilizer treatment at different periods. A3F2 treatment had the best quality, and the contents of vitamin C, lycopene, soluble sugar and sugar acid ratio were high, which were 3.30 mg/kg, 6.28 mg/100 g, 22.42 mg/kg and 13.03, respectively;A1F2 obtained higher yield. The principal component analysis and comprehensive evaluation showed that A3F2 and A1F2 treatments had higher yield, better water and fertilizer effect and better quality of tomato.【Conclusion】In tomato planting, organic fertilizer content and intermittent dry period should be regulated according to the requirements. Under drought stage, applying medium fertilizer at seedling stage can avoid excessive growth and make tomato yield high. Applying medium fertilizer at fruit stage decreases tomato yield but can improve the quality, and save fertilizers and reduce environmental pollution.