添加玉米秸秆对绿花菜尾菜堆肥植物毒性的影响

Effects of large-scale windrow composting of different ratios of corn straw to residue of green cauliflower on phytotoxicities of Chinese cabbage seeds

为揭示不同比例作物秸秆和蔬菜尾菜堆肥过程中种子毒性变化及其影响机理,开展了为期55 d的以玉米(Zea mays L.)秸秆为辅料,绿花菜(Brassica oleracea L.var.botrytis L.)尾菜为主料的工厂化条垛堆肥,分别设置加入高(湿重比4∶12)和低(湿重比1∶12)比例秸秆与尾菜的堆肥处理.测定了不同时期堆肥pH、电导率(EC)、可溶性有机碳(DOC)、硝氮(NO;-N)、氨氮(NH_(4)^(+)-N)、碳氮比(C/N)、大白菜种子(Brassica rapa L.)的发芽指数(Germination Index,GI)、相对生长指数(Relative Growth Index,RGI)和α-淀粉酶、蛋白酶、脂肪酶的变化.结果表明,高比例秸秆堆肥处理的高温(>55℃)持续期显著高于低比例处理.堆肥结束时两个处理的堆肥均呈碱性,且EC、DOC、NH_(4)^(+)-N和NO_(3)^(-)-N含量均降低,C/N呈先升后降的趋势.高比例秸秆堆肥处理种子α-淀粉酶和脂肪酶活性均高于低比例处理,但其蛋白酶活性则相反.低比例处理堆肥的GI和RGI显著高于高比例处理.堆肥的EC、DOC、NH_(4)^(+)-N含量与种子α-淀粉酶活呈显著正相关,且与GI和RGI呈负相关.高比例秸秆尾菜堆肥可提高种子脂肪酶活.本研究可为作物秸秆与尾菜工厂化条垛堆肥工艺参数优化及土地利用提供重要理论依据和决策支持.

Phytotoxicities of composts made from corn straw(Zea mays L.)and green cauliflower(Brassica oleracea L.var.botrytis L.)residue to Chinese cabbage(Brassica rapa L.)seeds were studied during large-scale,windrow composting.Factors,such as ratios of corn straw to green cauliflower residue were evaluated during 55 days of composting.During one experiment,effects of a high ratio of corn straw to green cauliflower residue(4∶12 wet mass)was compared with another at a ratio of 1∶12 wet mass.Representative compost samples were collected after various durations of composting and pH,electrical conductivity(EC),soluble organic carbon(DOC),nitrate nitrogen(NO_(3)^(-)-N),ammonia nitrogen(NH_(4)^(+)-N),carbon to nitrogen ratio(C/N)in these samples,germination index(GI),relative growth index(RGI)andα-amylase,protease and lipase of Chinese cabbage seeds determined.The high temperature(>55℃)time for the experiment using the greater ratio of corn straw to green cauliflower residue was significantly longer than that for the experiment using a lesser ratio.Composts derived from the greater and lesser ratio trials were all alkaline and contents of EC,DOC,NH_(4)^(+)-N and NO_(3)^(-)-N decreased during composting,while ratios of C/N increased then decreased.Activities ofα-amylase and lipase in Chinese cabbage seeds exposed to the composts derived from the greater ratio of corn straw to green cauliflower residue were greater than those exposed to compost derived from the lesser ratio of corn straw to green cauliflower residue;while the opposite was observed for protease activities.Values of GI and RGI were significantly greater when exposed to the lesser ratio of corn straw to green cauliflower residue than those exposed to the greater ratio of corn straw to green cauliflower residue.α-amylase activity of seeds was significantly correlated with EC,DOC and NH_(4)^(+)-N contents of composts,but negatively with GI and RGI.Lipase activities of Chinese cabbage seeds were greater when exposed to the greater ratio of corn straw to green cauliflower residue.