| While with the increase of the amount of livestock and poultry,the waste emission increased,which polluted the environment around the farm.This paper studies the changes of the main nutrients nitrogen and phosphorus in different manure removal modes and manure natural stacking modes in large-scale pig farms.Based on this,the farmland carrying capacity of livestock and poultry manure in Daqing City is analyzed,which is The manure resource utilization technology provides theoretical support.First,the total waste emission of livestock manure in Daqing city,cultivated land load and its time characteristic and space distribution were analyzed and the estimated results were as follows: cultivated land load of the manure was 7.54,lower than the standard 30 t/hm~2;that of TN was 38.39,lower than the standard 170 kg/hm~2;that of TP was 8.86,also lower than the standard 35 kg/hm~2.With above it could be concluded that the waste emission was within the bearable range so it would not be harmful.Second,to study the changes of pig manure components collected from different cleaning manners,three groups were set which were dry cleaning group,water immersion group(content of TS was 3%,5% and 7%)and water flushing group(content of TS was 3%),300 g fresh and complete pig manure of each group was weighed to the experiment.There were 9 experiment and each experiment repeated twice.The results showed that,using the dry cleaning group as control,in manure of water flushing group,the average content loss rate of the total N,total P and total C was 16.18%,18.62% and 22.26%,respectively;in that of water immersion group,8.68%,4.85% and 13.67%.The loss in water flushing group was the biggest,next was the water immersion group,while in dry cleaning group was beneficial to the subsequent treatment such as aerobic composting and fermenting methane.Third,the effect of different piling height on the components in manure which was piled up for 28 d was studied.The experiment was set to two groups as height20 cm and 35 cm,each group repeated 3 times.The samples were collected when piledfor 7d,14 d,21d,28 d and the day when just piled.The results showed that,the difference of piling height was not significant(P > 0.05),so it had no use to be considered.The average content of total N,P,C,p H and water was4.62%,7.01%,35.40%,6.84 and 77.84%,respectively,when the manure was just piled.And was 3.72%?5.63%?34.53%?8.29 and 68.19%,respectively,when piled for 28 d.It could be piled temporarily due to few loss.The average C/N and water content of each group was 9.32% and 68.19% after piled for 28 d,and the optimum range of C/N was from 20 to 35,the optimum water content range was from 55% to 65%.Fourth,to analyze whether the manure composed under natural situation could reach completely rotten with no any other padding or conditioner,collecting the samples composed for 2,4,6,8,10,12 months and set six experiment groups,each group repeated 3 times to ensure the data.The results showed that,there was seldom change of average C/N which maintained from 9.20 to 11.01,lower than the rotten standard 15-20;converted C/N to T,the change of T was from 1.08 to 1.29,it would also not meet the standard T<0.6.So the manure pile could not reach completely rotten because the sufficient C source resulting in the low C/N.Last,the land bearing capacity of livestock waste in Daqing city was analyzed through estimating.The results were as follows: the land bearing capacity(N as the base)was 3.26,the corresponding max pig equivalent was 32476152.60;the land bearing capacity(P as the base)was 2.72,the corresponding max pig equivalent was27096667.20.Both were much greater than the current 4168311.70,which indicated that the cultivate area in Daqing city could absorb the manure waste of livestock and even had great capacity,so it will be more development space for livestock and poultry industry in Daqing city. |
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