The mixed application of organic amendments with dinsinct properties to optimize soil nitrate management and increase greenhouse tomato yield

Abstract Background and aims Organic amendments are widely used in agricultural production. However, applying individual amendment has certainly negative effects. The mixed application of two distinct amendments was tested to resolve the dilemma. Methods We cultivated tomato (Solanum lycopersicum) in a greenhouse for three consecutive seasons with four treatments, namely, sole application of chicken manure (CM), sole application of rice husk (RH), mixed application of chicken manure and rice husk with mass ratio of 1:4 (Mix1) and 1:2 (Mix2), respectively. Organic amendments were applied in the first two seasons to investigate the content of soli NO3--N, certain soil physical properties, and tomato growth and yield. In-situ N mineralization of four organic amendments also was determined in the last two seasons. Results In the short term, topsoil NO3--N content was in the order of CM > Mix2 > Mix1 > RH, however, in the long time, topsoil NO3--N content of CM treatment was the lowest. Compared the sole application of chicken manure, the mixed application of chicken manure and rice husk significantly decreased NO3--N content in the deep soil and significantly improved soil physical properties, such as soil water retention. Overuse of rice husk would trigger strong N immobilization. Mix2 treatment had the highest tomato yield in all the three seasons. Conclusion Our study demonstrated that the mixed application of chicken manure and rice husk could optimize soil NO3--N management, improve soil physical properties, so as to promote tomato growth, increase yield and benefit environment.