蚓堆肥热干扰后对土壤质量和作物生长的影响

Effects of Thermal-Disturbed Vermicompost on Soil Quality and Crop Growth

了解热干扰对蚓堆肥肥效的影响有助于指导其规模化加工和应用,促进有机废弃物的高效循环利用。通过模拟不同热干扰梯度(30、40、50、60和70℃)研究蚓堆肥自身性质的变化,将新鲜的蚓堆肥置于烘箱中加热20 h,并于温室中采用盆栽试验探究经过热干扰后的蚓堆肥对土壤性质及番茄生长的影响。结果表明,随着热干扰温度的升高,蚓堆肥的pH、可溶性有机碳及铵态氮含量呈上升趋势且在最高温干扰处理下达到最高,但硝态氮和速效钾含量呈下降趋势;微生物生物量碳氮含量先上升后下降,而其中参与碳氮循环的酶活性逐渐降低。经不同热干扰处理后的蚓堆肥施入土壤后,相比30℃的对照,蚓堆肥经热干扰后番茄的地上部生物量提高了2倍左右,根系生物量增加了56%~115%;伴随蚓堆肥热干扰温度的增加,植物氮磷钾养分的吸收量逐渐提高,蚓堆肥对土壤氮磷钾养分的供应量(土壤速效养分与植物有效养分吸收量之和)先升高后下降并在50℃干扰处理后达到最高;土壤pH及可溶性有机碳含量逐渐升高,土壤微生物生物量碳氮含量呈先上升后下降的趋势且在70℃干扰后降至最低,而土壤中参与碳氮循环的酶活性变化趋势不一致,但与对照相比总体呈上升趋势。总之,热干扰导致蚓堆肥生物活性下降及养分有效性增加,相应地,热干扰后的蚓堆肥施入土壤后能明显促进作物氮磷钾养分的吸收,有利于蚓堆肥发挥其肥效。因此,蚓堆肥加热处理有利于其发挥短期培肥和植物促生功效,而其长期效果有待今后在更大时空尺度上的研究。

【Objective】This study is oriented to explore effects of thermal-disturbed vermicompost on soil quality and crop growth in expectation that all the findings may help guide large-scale processing and application of the manure and promote high-efficient recycling and utilization of organic waste.【Method】Fresh vermicompost was placed into an incubator for 20 hrs of incubation under a set temperature(30,40,50,60,and 70℃)separately,The incubated vermicomposts were sampled for analysis of changes in basic property,and then packed into pots separately for pot experiment in a well-lit greenhouse to explore effects of the incubated vermicompost on soil properties and tomato growth.【Result】Results show that with the temperature in incubation rising from 30℃to 70℃,pH,and the contents of dissolved organic carbon and ammonium in the vermicompost increased and reached the highest at 70℃,but the content of nitrate and available potassium declined and the activities of the enzymes involved in carbon and nitrogen recycling did,too,while microbial biomass carbon and nitrogen increased first(at 40℃)and then declined(at 70℃).Microcosm study shows that compared to CK(vermicompost incubated at room temperature(30℃),the vermicomposts incubated at higher temperatures significantly increased shoot and root biomasses of the tomato in the pot experiment by about 200%and 56%~115%,respectively.With incubation temperature rising,the plant uptake of NPK increased steadily.NKP supply(the sum of soil available nutrients and effective nutrient uptake of the plant)of the vermicompost increased first and declining with the incubation temperature rising,and was the highest in Treatment 50(where the vermicompost was incubated under 50℃).Soil pH and dissolved organic carbon in the vermicompost increased gradually with rising incubation temperature.Soil microbial biomass carbon and nitrogen increased first and then declined and was the lowest in Treatment 70.Activities of the soil enzymes involved in carbon and nitrogen recycling varied from treatment to treatment,but on the whole did exhibit a rising trend.【Conclusion】To sum up,thermal disturbance may cause vermicompost to decline in bio-activity,but increase in nutrient availability.So application of thermal disturbed vermicompost can significantly promote plant uptake of NPK.Obviously thermal disturbance may help vermicompost bring its nutrient availability into full play.It is,therefore,concluded that thermal disturbance of vermicompost is beneficial to building up of soil fertility in a short term and to plant growth as well.However,future studies should shift their focus on long-term effect of the application of thermal-disturbed vermicompost on larger spatial and temporal scales.