Effect of Combined Application of Chicken Manure and Inorganic Nitrogen Fertilizer on Yield and Quality of Cherry Tomato

Unreasonable application of inorganic nitrogen (N) fertilizer on cherry tomatoes (Solanum lycopersicum var. cerasiforme) has resulted in serious environmental threats. The advantages of application of organic manure combined with inorganic N fertilizer for vegetable production systems have been reported widely, but there are still few studies on cherry tomato production. Therefore, this study aims to determine the impact of a combined application of organic manure (in form of chicken manure at different application rate of 0 and 40 t ha⁻¹) with inorganic N fertilizer (in form of urea at various N application rates of 0, 160 and 320 kg N ha⁻¹) on the fruit yield and quality of cherry tomato across two seasons. Results showed that inorganic N application exhibited positive effects on fruit yield and its associated components of cherry tomato. However, there was no significant difference in terms of fruit yield and its associated components between the two N rates of inorganic N (160 and 320 kg N ha⁻¹), indicating that fruit yield is not improved significantly when the N application rate exceeds some threshold. Under chicken manure application treatments, however, an increased N rate did not show a positive effect on fruit yield. Importantly, chicken manure application has greatly increased fruit yield and fruit quality (represented by membership function indicator) by 43% and 23%, respectively in comparison with zero manure application. In particular, the soluble protein and titratable acid were increased by 124% and 118%, respectively. Overall, these results suggested that chemical N fertilizers could be largely replaced with chicken manure. Furthermore, the combined application of organic with inorganic N fertilizers seems to be a promising management practice for reducing the reliance on use of inorganic N fertilizer, while mitigating the environmental burden for cherry tomato production.