不同浓度猪场沼液对甜高粱产量及重金属沉积的影响

Effects of Different Concentrations of Swine Biogas Slurry on the Yield and Heavy Metal Deposition of Sweet Sorghum

为研究不同猪场沼液浓度对甜高粱鲜草产量、水分、pH及重金属沉积的影响,试验分6组,分别用含沼液0(全水)、20%、40%、60%、80%、100%的溶液对甜高粱进行浇灌,每4 d浇灌1次,连续浇灌12次后,当株高3.5 m左右时进行甜高粱收割测产,并分析甜高粱全株鲜草的水分含量、pH、重金属含量。结果表明,自播种至收割生长期75 d,浇灌量为5994 t/hm^(2);甜高粱鲜草产量最高的是100%沼液组,为106.54 t/hm^(2),极显著高于其他组(P<0.01),且产量随着沼液浓度的增加而增加;各组间鲜草水分含量和pH差异均不显著(P>0.05);沼液浇灌增加了甜高粱鲜草中汞的含量,但未增加铅、铬、镉和砷的含量,5种重金属(铅、汞、铬、镉、砷)在鲜草中的沉积量均低于国家标准限量值。因此,猪场沼液可作为甜高粱牧草的液体肥料进行浇灌,试验用沼液的浇灌量应控制在6000 t/hm^(2)左右,甜高粱生长至株高3.5 m时的产量为102.0~106.5 t/hm^(2),其重金属沉积均低于国标限量值,可作为畜禽饲养的青绿饲料,为甜高粱吸纳沼液能力及鲜草用于青绿饲料的重金属安全性研究提供基础数据。

In order to study the effects of different concentrations of biogas slurry in pig farms on the yield,moisture content,pH and heavy metal deposition of sweet sorghum,6 groups were designed,sweet sorghum was irrigated with the solution containing with 0(full water),20%,40%,60%,80%,100%biogas slurry respectively.Sweet sorghum was irrigated once every 4 days.After 12 consecutive irrigation,sweet sorghum was harvested when the plant height was about 3.5 m.The yield of sweet sorghum was measured,and the moisture content,pH,and heavy metal content of the fresh grass were measured.The results showed that during the 75 days from planting to harvesting,the irrigation amount was 5994 t/hm^(2),The average yield of sweet sorghum fresh grass in 100%biogas slurry group was the highest(106.54 t/hm^(2)),which was extremely significantly higher than other groups(P<0.01),and the yield of sweet sorghum increased with the increase of biogas slurry concentration.The moisture content and pH of fresh grass in each group had no significant difference(P>0.05).The biogas slurry irrigation increased the content of mercury in the fresh grass of sweet sorghum,but it did not increase the content of lead,chromium,cadmium and arsenic,and the amount of 5 kinds of heavy metals(lead,mercury,chromium,cadmium,arsenic)deposited in the fresh grass was lower than the national standard limit values.Therefore,biogas slurry of pig farm could be used as liquid fertilizer for sweet sorghum forage.The amount of biogas slurry used in this experiment should be controlled at about 6000 t/hm^(2),and the yield of sweet sorghum was 102.0-106.5 t/hm^(2)when the plant height reached 3.5 m,the deposited amount of heavy metals were lower than the national standard limit values.Sweet sorghum could be used as green forage for livestock and poultry feeding,and the research results could provide basic data for studying the ability of sweet sorghum to absorb biogas slurry and the safety of heavy metals used by fresh grass in green feed.