The current study aims to investigate the effect of combined effects of organic fertilizers and mineral nitrogen fertilizers on soil microbial activity, fruit yield, and quality of tomato (Solanum lycopersicum L.) under semi-arid conditions over two successive summer seasons. A total of nine treatments were arranged as combinations of three levels of chicken manure (0, 12, and 24 t/ha) and three nitrogen application rates (0, 50, and 100% of the recommended dose (RDN), equivalent to 0, 143, and 286 kg N/ha). The treatment combining 24 t/ha chicken manure with 50% of the recommended nitrogen dose (T8) achieved the highest performance, with total yields of 35.15 and 35.62 ton/ha in the first and second seasons, respectively. This treatment showed the highest values of yield/plant, fruit number per plant, and average fruit weight. The treatments; T9, T8, T6, T7, T5, recorded the highest values of number of bacteria (CFU/g of soil) 105, number of fungi CFU/g of soil x 105 and dehydrogenase enzyme activity (µg TPF g− a 24 h− 2 25 °C) at 90 days after transplanting of tomato plants. Improvements in fruit nutritional value, including nitrogen content %, phosphorus content %, potassium content % and total protein content were associated with better nutrient availability and balanced fertilization. Moreover, partial substitution of mineral nitrogen with chicken manure likely reduced environmental risks by lowering chemical nitrogen inputs and enhancing soil microbial activity and nutrient cycling. These findings highlight the effectiveness of integrated nutrient management in improving tomato productivity, fruit nutritional value, and soil health under semi-arid conditions.
Alharbi et al. (Mon,) studied this question.