Study On Technique Of Nitrogen Conservation In Composting With Swine Manure

Organic fertilizer has more benefits on fertilizing soils and improving the quality of crop than chemical once, and the application of organic fertilizer is stressed especially on organic agriculture and harmless agriculture. However, there are many shortages in the technique of traditional composting, such as intense volatilization of ammonia which result in reducing amounts of nutrients of organic fertilizer and polluting air around, which led to gradual descent of organic fertilizer's application degree when chemical fertilizer has been introduced in crop produce. So it is of great importance to upgrade the technology of composting and to elevate the utilization of organic waste resource.This paper, based on the investigation of swine manure in Sichuan Yaan, have studied the effect of three method on reducing the volatilization of ammonia, and on the increasing the nitrogen content in organic fertilizer product, and on the accelerating the maturity of compost. The results followed by:1. Recently more ten years, the ingredients content in swine manure from traditional feeding mode (feeding pig without chemical additives) maintain former level without obvious change. But obvious change has taken place from the feeding mode of large hoggery and farmer's feeding mode which feeding swine with chemical additives. With the aspect of abundant nutrients, the concentration of total nitrogen, total phosphor and total potassium in swine manure from large hoggery is most, and is next from farmer's feeding with chemical additives mode, the content of abundant nutrients from traditional mode is low compared to that in form two feeding mode, but is higher than that of means level, provided by national service central of agricultural techniques popularization (NSCATP), which is test results in 1990s; With the aspect of trace element such as copper and zinc, the content of copper and zinc in swine manure from large hoggery is respectively 15 and 6 times of the value provided by NSCATP. And for the mode of farmer's feeding with chemical additives, the concentration is 7 and 3 times respectively of that value provided by NSCATP. The content of copper and zinc in manure from traditional feeding mode is as much as that value provided by NSCATP.2. The volatilization of ammonia from the compost reduced, and total nitrogen content has risen when swine manure composted with organic material. After 65 days, 7.84g/kg of ammonia has volatilized from treatment of net pig manure (PM). Compared to treatment PM, 5.08g/kg, 6.48g/kg and 3.01g/kg respectively hasvolatilized from treatments composted with rice straw (PMS), rape straw (PMRS) and mushroom residue (PMMR). Compared to PM treatment which total nitrogen content has deceased 0.18g/kg, total nitrogen of PMS treatment, PMRS treatment and PMMR treatment has increased 6.03g/kg, 4.03g/kg and 4.71g/kg respectively.Moreover, the additive of organic materials has increased the decomposed amounts of organic matter in compost, and has sped up the maturity of compost. Compared to PM treatment in which the decomposed amount of organic matter is just 6.80%, obvious elevations of the decomposed rate has found out in treatments composted with organic material, because organic materials enhance the porosity of the pile and hence aeration. So 32.4% of organic matter has decomposed in PMS, 31.3% and 26.2% of organic matter has decomposed in PMRS and PMMR respectively. Fresh materials acted as bulking agents can enhance the more decomposed amount than the decayed one. And the same trend has found in the decomposition of coarse fibre with organic matter: organic material acted as bulking agent can enhance the decomposition of coarse fibre in the process of compost, the decomposition of coarse fibre in PMS, PMRS and PMMR add up to 18.24%, 16.49% and 7.19% respectively, and only 5.37% of total coarse fibre has been decomposed in control treatment. If compost has been considered as maturity when the index of germination has been up to 80%, the time of germination index for treatment PMS, PMRS and PMMR to be up to 80% is 30 days, 45 days and 37days respectively. But control treatment is far away from maturity in the end of compost.On all accounts, straw is best selection for bulking agent when swing manure has to be disposed to organic fertilizer.3. The intensity of ammonia volatilization has been alleviated when the water-soluble organic carbon, which is most easy to be eaten by microorganisms, has been elevated when starch made from red potato. The loss amount of ammonia is up to 5.08g/kg in control treatment within entire composting course, the amounts of lost nitrogen in treatment PMSHS (the ratio of starch to straw is 1:10) and PMSLS (the ratio of starch to straw is 1:20) are 5.04g/kg and 4.82g/kg respectively through the volatilization of ammonia. Furthermore, the volatilizing fastigium of ammonia has been delayed: the fastigium of control treatment appeared 0-30th day, and 10th -40th day for treatment PMSHS and PMSLS. Total nitrogen in every treatment has increased when water-soluble organic carbon has been elevated and rice straw acted as bulking agent. 37.4% and 35.4% of total organic matter has been decomposed in treatment PMSHS and PMSLS respectively, Compared to 32.4% in control treatment,the decomposed rate of organic matter rise when water-soluble organic carbon has been elevated. And after 30days,compost in every treatment has become mature.On all account, the ratio of starch to rice straw is 1:10 is more feasible.4. The volatilizing intensity of ammonia can be further alleviated, to different extend, when inorganic amendments have added to the swine manure and rice straw composting. Compared to control treatment in which 5.08g/kg has lost through volatilization of ammonia, the volatilizing amount of ammonia has decreased by: 16.6%(PMSV), 23.5%(PMSCS), 38.1%(PMSCP), 59.0%(PMSP), 60.4%(PMSCL) and 66.7%(PMSAS). And total nitrogen has increased by: 35.6%( PMSV), 35.2%( PMSCS), 36.5%( PMSCP), 43.7%( PMSP), 32.2%( PMSCL) and 34.3%( PMSAS).Compared to control treatment in which 25% organic matter has been decomposed, acid inorganic amendments such as vitriol and phosphor can further enhance the decomposition of organic matter, the decomposed percentage of PMSV and PMSP is up to 30.0% and 28.6% respectively. And calcium sulphate does not affect the decomposition of organic matter, the decomposed percentage of calcium sulphate is 25.8% as much as that of control treatment, the treatments that composted with calcium superphosphate and aluminum sulfate, especially with calcium chloride, has lower decomposed percentage of organic matter. When germination capacity of each treatments compost have tested, the order of the index of germination has been found: PMSP (98%)>PMSAS (90%)>PMSCS (90%)>PMSV (87%) >PMSCP (75%)>PMSCL (73%). the treatments adding with calcium chloride and calcium superphosphate have not matured fully.On all accounts, phosphor is best inorganic amendment.