鱼排泄物与分泌物对水稻土壤酶活性及土壤养分的影响

Effects of Fish Excrement on the Soil Environment of Paddy Fields

为探究稻鱼共生系统中鱼类排泄物及分泌物对土壤酶活性的影响,以中早35为试验材料,采用盆栽培养方式,进行施加排泄物+鱼池水灌溉(MP)、施加排泄物+自来水灌溉(MW)、常规自来水灌溉栽培(CK)的比较实验。通过模拟稻-鱼共生系统,测定土壤全量养分、土壤酶活性和灌浆期水稻叶绿素含量的变化,探究其对土壤环境的影响。结果表明,鱼排泄物及分泌物对土壤全量养分、土壤酶活性和叶绿素含量均有不同程度的影响。土壤全量养分的检测结果显示,10月21日(水稻收割后)MP处理的土壤全氮、全磷、全钾含量均高于CK处理。10月21日,各处理的土壤过氧化氢酶活性具有显著性差异(MP>MW>CK),MP与MW处理的脲酶活性分别是CK的2.25倍和1.75倍;影响指数表明,相较CK,MP和MW对脲酶活性的促进率分别达到10%~125%和70%~75%,对蔗糖酶活性的促进率分别达2.9%~28.4%和14.1%~44.3%,对过氧化氢酶活性的促进率为10%~125%和106%~254%。综上分析表明,鱼类排泄物和分泌物的加入在水稻生长后期提高了土壤脲酶、土壤过氧化氢酶和土壤蔗糖酶活性,增加了土壤全氮、全钾含量,鱼类溶于水的分泌物增加了土壤全磷含量,起到不间断施肥的作用。稻鱼共生模式在减少化肥施用量的同时保证水稻生长的营养需求,有利于稻田的可持续发展。

In order to clarify the impacts of the excrement and secretion from fish on soil enzyme in rice-fish symbiotic system,a pot experiment was carried out by stimulating rice-fish symbiotic system and monitoring the soil environment.There were three treatments in this study,including excrement and fish pond water irrigation(MP),excrement and waste water irrigation(MW),and conventional monoculture irrigation as the control(CK).The soil enzyme activity,total content of nutrients and the change of chlorophyll content during filling stage were measured.Our results show that fish excrement and secretion had different influences on the soil enzyme activity,soil nutrient and chlorophyll content.On October 21,catalase activities of the three treatments displayed significant differences,as MP>MW>CK.The urease activity of MP and MW was 2.25 times and 1.75 times of that of CK,respectively.The influence index showed that,compared with CK,the promotion rate of MP and MW on the urease activity reached 10%—125%and 70%—75%,respectively.The promotion rate of the sucrase activity reached 2.9%—28.4%and 14.1%—44.3%,respectively,for MP and MW,whereas their promotion rate of catalase activity was 10%—125%and 106%—254%,respectively.Our results indicate that the content of total nitrogen,total phosphorus and total potassium in the soil after rice harvest treated with MP was higher than that treated with CK.In summary,our present research suggests that the addition of fish excrement and secretion should improve the soil enzyme activity and the total soil nutrients,playing the role of continuous fertilization.The rice-fish symbiotic system can ensure the nutrition demand of rice growth while reducing the application of fertilizer,which is beneficial to the sustainable development of rice field.