Research On Variation Of Carbon、Nitrogen Forms Of Different Fermentation Beds In Bio-bed Pig Raising

With the rapid development of society, the contradiction between the traditional medicinal powder raise pattern and cultivated land resources has become increasingly prominent, and the environmental pollution is becoming more and more serious. All life activities of livestock and poultry are in the litters in bio-bed raising mode, and the key of the emerging mode is management and maintenance of litters. Therefore, to explore the degradation of organic matters in litters and influence factors, and the transformation rules of different nutrient forms and the effect to the lower soil layer under the litters becomes very interesting meaningful. Moreover, it’ll also be accepted to help us select appropriate litter ratio in practical breeding process, and make accurate evaluation about the use time of pig farms according to the environmental effects. To evaluate the effects of different compositions of fermentation beds on litter carbon and nitrogen cycle in pig pens, three different fermentation beds, which included sawdust(S), sawdust + rice husk(SR) and sawdust+rice husk+straw (SRS) were carried out in Liuhe Pig Bio-bed farms, Nanjing. The physical and chemical properties of fermentation beds (pH, moisture dynamic change, TN,NH4+-N,NO3--N,TOC and DOC) and four greenhouse gases (CO2, N2O, NH3 and CH4) were recorded and analyzed during the experimental period. According to the experimental data, the main conclusions are as follows:(1) TOC has a downward trend in all the three types of fermentation beds. Especially, the value of TOC has a significant reduction by using SRS, which declined by 26.3%, in contract to the original value. There is a significant difference of the value of DOC in three different fermentation beds, especially in 40-60cm. The value of DOC in SRS has the largest content of TOC, which reach to 31.4%, while the SR and S only occupy 16.3% and 5.8%, respectively.(2) The carbon in bio-bed litters is mainly loosed by the situation of CO2-C. The loss of CO2-C in S is largest, which occupy 87.5% of all the loss weight, while the loss weight of the other two kinds of fermentation beds arrive to 40%. Straw contribute to the rapid degradation of TOC, which also have a significant effect on DOC. At some extent, straw increase the loss of gassy carbon and total carbon.(3) There was a significant difference of the value of TN, NH4+-N、NO3--N in three different fermentation beds.TN had a upward trend in all the three types of fermentation beds.The value of TN in SRS had the largest change. The change of SR and S were similar. Especially in 40-60cm, the value of TN had a significant increase by using SRS, which improved to 17.7g·kg-1. SRS’s NH4+-N、NO3--N was higher than S and SR during the experimental period.(4) The loss of litter nitrogen in all the three types of fermentation beds was 32.17%,39.95% and 41.05% of total nitrogen input. The loss of N2O-N in S is largest, which occupy 17.34% of all the loss weight. The total amounts of NH3-N emission in the three treatments during the feeding period occurred in the last one month. At some extent, straw increase the loss of gassy carbon and total carbon.(5) CO2 and N2O were the main patterns of the three greenhouse gases. Carbon dioxide equivalent emissions of CO2 and N2O accounted to 99.3%-99.6% in the total carbon dioxide equivalent emissions of CH4, CO2 and N2O.61%-68% of the total amounts of N2O emission in the three treatments during the feeding period occurred in the last one month.(6) Between the three treatments, the total amounts of CO2 and N2O emissions during the experimental period were not significantly different (P>0.05), while CH4 emissions were significantly different (P< 0.01). Among the three treatments, the largest amount of CH4 emission was SRS (18.60g·m-2), followed by S (8.10g·m-2) and then it was lowest in SR (7.57g·m-2). SRS’s carbon dioxide equivalent emissions was higher than S and SR, while S’s and SR’s carbon dioxide equivalent emissions were not significantly different.The carbon dioxide equivalent emissions per unit area in three beds during the experimental period were not significantly different (P>0.05).