The Effect Of Long-Term Application With Pig Manure On Soil Aggregate And Organic Carbon Componentsin Rice-Wheat Rotation

Aiming at the safety problem of Chengdu plain consumption of livestock and poultry manure,a long-term field experiment was carried out to reduce the use of chemical fertilizers instead of pig manure.This study investigated the effect of soil aggregate stability and soil organic carbon content change on relationship between the rice wheat rotation system of pig manure application rate.In addition,it is significant to provide a scientific support for the regional aquaculture waste recycling and maintain good farmland ecosystem.Field experiment was conducted using conventional nitrogen fertilizer as the standard for pig manure application,.The total nitrogen content in pig manure instead of chemical nitrogen fertilizer.The application amount of N,P₂O₅ and K₂O were 180 kg·hm^-2,75 kg·hm^-2 and 90 kg·hm^-2,respectively.The treatments were as follows:?1?CK;?2?conventional fertilizer?NPK?;?3?50%conventional fertilizer and 50%pig manure,?NKM1?;?4?100%pig manure nitrogen,NKM2;?5?150%pig manure nitrogen,?NKM3?;?6?200%pig manure nitrogen.The distribution and stability of soil aggregates,aggregate organic carbon?TOC?,water soluble organic carbon?WSOC?,dissolved organic carbon?DOC?,readily oxidized organic carbon?ROC?,total glomalin?TG?and easy-extracted glomalin?EEG?were studied.The results shows:?1?The composition and stability of soil water stable aggregates changed significantly after applying pig manure.Water-stable aggregates that size greater than 5mm was the highest?36.5%?compared with size of 2-5mm and 1-2mm in treatment of M3.pig manure treatment The soil water stable aggregate content of 0-20cm depth soil?more than 5mm,2-5mm and 1-2mm?was significantly increased compared with CK processing.,The 2-5mm aggregate content in M3 treatment improved by 189.2%compared with CK treatment.The aggregate content in the size more than 0.25mm with the treatment of M3 was 78.2%and the aggregate was higher than the NPK treatment significantly.The average diameter of water stable aggregates?MWD?was in the order of CK<NPK<NKM1<M2<M4<M3.There was no significant difference in R_0.25 contents and MWD value between two M2 treatment and M3 treatment.The application of pig manure has a certain influence on the distribution of soil aggregate in 20-40cm soil layer.The difference of R_0.25 and MWD values between pig manure treatments was not significant.?2?The addition of pig manure significantly increased 0-20 cm soil layer soil particles agglomeration of total organic carbon?TOC?and active organic carbon?ROC,DOC,WSOC?content.In the same particle size,the TOC content and its components in each treatment in the order of M4>M3>M2>NPK>CK.while the changes of 5mm and 2-5mm aggregates the content of TOC was the most significant showed asan increase of 18.79-35.58%,17.91-37.46%respectively.The increase of ROC and DOC content in 2-5mm and 1-2mm aggregates was the highest,and the content of WSOC in 0.5-1mm granular aggregate increased the highest.The fraction of active organic carbon in macro aggregate was higher than that in micro aggregate.In the 20?40 cm soil layer,under the treatment of pig manure application,the TOC of soil grain size aggregate increased less than the corresponding content of 0-20cm.There was no significant difference in the content of active organic carbon.?3?The total glomalin?TG?and easily extractable glomalin content?EEG?were significantly increased using pig manure in the treatment of 0-20cm soil particle size aggregation.The TG and EEG content and its components in each treatment in the order of M3>M4>M2>NPK>CK.M2 treatment increased>5mm particle of EEG and was higher than that of other particle size,53.8%boost over CK processing.20?40 cm layer,There were no significant changes in TG and EEG contents of soil particle size aggregates.Production with 10279 kg/hm²?M2?pig manure should be appropriate.?4?The total glomalin?TG?and easily extractable glomalin content?EEG?were significantly increased using pig manure in the treatment of 0-20cm soil particle size aggregation.The TG and EEG content and its components in each treatment in the order of M3>M4>M2>NPK>CK.M2 treatment increased>5mm particle of EEG and was higher than that of other particle size,53.8%boost over CK processing.20?40 cm layer,There were no significant changes in TG and EEG contents of soil particle size aggregates.Production with 10279 kg/hm²?M2?pig manure should be appropriate.