Effect Of Combined Application N Fertilizer And Manure On Soil N Supply Capacity In Greenhouse Condition

In recent years, over-application manure and chemical fertilizer was a main problem with the faster development of greenhouse. N fertilizer and manure combined application not only have a high ability to modulate the N supply of soil souble N (soil mineral N, SMN; soil souble organic N, SSON) and soil retain N (fixed ammonium, FA; soil microbial biomass N, SMBN), and also have a great significance for safety and efficient fertilizer management under greenhouse conditions. However, there was limited knowledge about N fertilizer and manure combined application how to modulate the N supply of soil souble N and soil retain N under N fertilizer and manure application in greenhouse. The effect of different fertilizer sources (different application rates of N:NO-0 kg/hm2, N1-187.5 kg/hm2, N2-375.0 kg/hm2, N3-562.5 kg/hm2; N fertilizer combined with manure fertilizer:MNO, MN1, MN2, MN3; CK: no application of fertilizer and M:only application manure-75000 kg/hm2) on the dynamic during the tomato growth period and profile distribution in fallow period of soil FA and soil mineral N contents were studied by field plot experiment under the greenhouse cultivation. Meanwhile, we analysis the relationship between soil souble N, soil retain N and tomato yield or quality, and to evaluate the soil soluble N and soil retain N which play an important role in N supply. The main conclusions from the study were as followed:(1) The fertilizer application showed significant increasing effect on soil soluble N and soil retain N contents (P< 0.01) for 0-30 cm soil layers compared with no fertilizer treatment, and SMN, SSON and FA were highest at the first ear fruit period, while SMBN content was highest at the second ear fruit period; the fertilizer application increased the content of SSON in the 0-10 cm layer and SMN and soil retain N in the 0-50 cm layer significantly (P< 0.05) compared with no fertilizer treatment in the fallow period, the soil soluble N and soil retain N were highest in the surface layer (0-10 cm), and accumulation occurred in the 20-30 cm soil layer.(2) Application fertilizer rate had significant effect on SMN, SSON and SMBN (P< 0.01) during the growth period and fallow period, however, there was no significant effect on FA content; meanwhile, FA accounted for a large part of soil soluble N+soil retain N.(3) The combined application of N fertilizer and manure treatments significantly (P< 0.05) increased soil soluble N and soil retain N contents compared to N fertilizer treatments in the 0-30 cm soil layers, especially SMN content had more increased and more amplification occurred in the first ear fruit period; SMN, FA and SMBN contents in 0-50 cm soil layers and SSON content in 0-10 cm soil layer were significantly increased in the combined application of N fertilizer and manure treatments compared with N fertilizer treatments in the fallow period. In general, N2 (375.0 kg/hm2) and M (75000 kg/hm2) application demonstrated the highest values for soil souble N and soil retain N.(4) There were significant positive correlation (P< 0.01 or P< 0.05) among SMN, SSON, FA and SMBN in 0-30 cm soil layers, while the significant positive correlations was weaken with soil depth during the tomato growth period; there were significant significant positive correlations (P< 0.01 or P< 0.05) among SMN, SSON, FA and SMBN in the fallow period, and soil total N (TN) is the main factor which effect on SMN, FA and SMBN content.(5) The quality and the yield of tomato did not show significant differences between N fertilizer treatments and application with manure treatments (P> 0.05). In general, combined at a rate of N 375.0 kg/hm2 and M 75000 kg/hm2 application demonstrated the highest tomato yield and quality. It is worth mentioning that SMBN in the first and second ear fruit period was in favour of tomato yield, moreover, the Vc content was more higher when increased the soil souble N in the harvest period. In order to further reduce the organic acid content and increase sugar/acid ratio, to improve tomato quality which properly reduce the FA in the second ear fruit period and increase soil souble N in the first ear fruit period are required.As mentioned above, soil soluble N and soil retain N had a close relation to N immobilization and release; the N fertilizer and manure application increase contents and percentage of soil souble N and soil retain N by field plot experiment under the greenhouse cultivation. The appropriate rate of N fertilizer and manure application (M:75000 kg/hm2; N2: 375.0 kg/hm2) could modulate the soil N supply better and increases soil nutrient contents in greenhouse cultivation.