Partial substitution of chemical fertilizer with microbial organic fertilizer improves soil properties, yield and quality of tomato

The partial substitution of chemical fertilizer with microbial organic fertilizer (OF) may be more beneficial and sustainable in crop production. This study aimed to examine the rate of partial substitution of chemical fertilizer (CF) with microbial OF that could improve soil chemical properties and maintain high fruit yield and quality in tomato, and to determine the extent of contribution of the agronomic traits to fruit yield in tomato. The experiments were conducted in the field from February to June in 2020 and 2021 and arranged in RCBD with four treatments: 100% chemical fertilizer (control) and 25, 50 and 75% substitution of CF with microbial OF. The agronomic parameters such as plant height, leaf number, shoot dry weight and fruit yield as well as fruit quality were measured. The results showed that partial substitution of CF with microbial OF significantly promoted plant growth and fruit yield and improved fruit quality in tomato via the improvement of soil chemical properties. The 25% substitution of CF with microbial OF could be optimal for tomato production in Hung Yen province, Vietnam which has the fluvisol and loam soil. Furthermore, the tomato fruit yield was greatly influenced by the number of fruits per plant (r2 =0.89), fruit weight (r2 =0.49) and the shoot dry weight (r2 = 0.40). The changes in these three agronomic traits collectively contributed to 95% changes in the tomato yield. The present findings suggested that farmer can substitute CF with 25% microbial OF and focus more on increasing the number of fruits per plant to optimize fruit yield in tomato.