淹水厌氧培养对水稻土中酶活性的影响

An incubation experiment with soil water content treatments of 0.15 （W1）, 0.20 （W2）, and 0.40 （W3） g g^-1 soil was carried out for two months to investigate the activities of important enzymes involved in C, N, P, and S cycling in a paddy soil from the Taihu Lake region, China, under waterlogged and aerobic conditions. Compared with air-dried soil, waterlogging resulted in a significant decrease （P ≤ 0.05） of fluorescein diacetate （FDA） and /3-D-glucosidase activities, and this effect was enhanced with increasing waterlogging time. Waterlogging also significantly inhibited （P ≤ 0.05） arylsulfatase as well as alkaline and acid phosphatase activities, but did not decrease the activities with the increase in waterlogging time. Short-term waterlogging did not affect urease activity, but prolonged waterlogging decreased it markedly. In contrast, the aerobic incubation （W1 and W2 treatments） significantly increased （P ≤ 0.05） FDA, alkaline phosphatase, and /3-D-glucosidase activities. With aerobic treatments the activities of FDA and alkaline phosphatase increased with incubation time, whereas /3-D-glucosidase activity decreased. A significant difference （P ≤ 0.05） was usually observed between the W1 and W2 treatments for the activities of FDA as well as alkaline and acid phosphatase; however,/3-D-glucosidase and urease were usually not significant （P ≤ 0.05）. No activity differences were observed between waterlogging and aerobic incubation for arylsulfatase and urease.     

水稻强化栽培对稻田土壤生物学特性的影响

采用田间试验,对强化栽培(SRI)和常规水作(TF)条件下稻田土壤微生物数量、微生物量、土壤酶活性及相关养分含量进行了研究。结果表明:与常规水作相比,强化栽培增加了土壤细菌、放线菌、真菌数量,分别提高了53.1%～173.8%、61.7%～229.4%、10.0%～55.9%,统计差异显著(p<0.05)。强化栽培土壤微生物量碳、微生物量氮比常规水作提高了12.2%～43.6%,22.7%～175.4%,统计差异显著(p<0.05)。与常规水作比较,强化栽培提高了分蘖期土壤脲酶、碱性磷酸酶、转化酶、过氧化氢酶活性,分别为12.6%、30.0%、15.1%、13.8%;强化栽培也显著增加了土壤碱解氮含量,但有效磷含量差异不显著。     

冬季作物对水稻生育期土壤微生物量碳、氮的影响

选取我国南方4种冬季作物黑麦草、紫云英、油菜、马铃薯,以冬闲田作对照,对水稻生育期土壤微生物量碳（SMBC）和土壤微生物量氮（SMBN）的短期内动态变化进行了研究。结果表明,早稻田翻耕前,冬季作物处理土壤SMBC和SMBN与冬闲田存在显著差异(P0.05),黑麦草处理SMBC为398.5 mg/kg,显著高于其他作物;紫云英处理SMBN最高,为97.8 mg/kg。在早稻整个生育期,黑麦草处理SMBC显著高于其他处理,晚稻生长过程中各处理无显著差异。冬季作物对稻田土壤微生物商(MQ)的影响,随着水稻生长发育进程有不同程度的变化,黑麦草处理在早稻整个生育期高于冬闲田。     

种植利用紫云英对稻田土壤微生物及酶活性的影响

为研究种植利用紫云英对稻田土壤的培肥作用,设不种紫云英不施化肥(对照)、种植紫云英不施化肥(紫云英)、不种紫云英施化肥(单施化肥)、种植紫云英同时施化肥(紫云英+化肥)4个处理,分析了各处理在紫云英苗期、紫云英盛花期、早稻收获期、晚稻收获期的土壤养分、酶活性、微生物数量。结果表明,与对照相比,施化肥及种植翻压紫云英均能改善土壤养分状况,紫云英与化肥配施效果最好,能够明显提高土壤速效磷、速效钾、全氮含量。施用化肥或种植翻压紫云英均能促进微生物生长,4个处理中以紫云英+化肥处理对土壤微生物生长有较好的促进作用,其次为单施化肥处理。     

坡位、土层深度和管理措施对土壤质量的影响

土地生产力对人口增长和人民生活水平提高至关重要,土壤质量评估的概念侧重于特定的土壤特性和维持一系列生态功能的能力。本项目主要研究不同管理措施下的覆盖作物、土层深度和不同坡位对土壤质量的影响。研究区位于美国密苏里的沙里顿县农场的4个小流域,其中2个试验小流域,种植了覆盖作物,采取了轮作和免耕,2012年秋种植覆盖作物,另外2个对照小流域没有覆盖作物。2012和2013年生长季持续干旱,2012-2014年,在4个流域不同坡位,不同深度(0~10cm、10~20cm和20~30cm)土层取样,分析了土壤酶活性、土壤微生物多样性和土壤养分。随着土层深度的增加,土壤酶活性和养分水平显著降低。不同坡位的养分含量、酶活性和水稳性团聚体(WSA)、碳(C)差异显著(p<0.01和p<0.05)。     

赤泥施用量对Cd污染稻田水稻产量和土壤生物性状的影响

采用盆栽试验方法,以不施赤泥为对照,分析不同赤泥施用量对Cd污染稻田水稻产量和土壤生物性状的影响.结果表明,施适宜用量赤泥能提高水稻有效穗和促进水稻生长,实现水稻增产,与不施赤泥处理相比,RM-2处理(0.5%赤泥)的水稻株高、有效穗、结实率和水稻产量分别提高了3.40%,4.20%,3.87%和6.86%.从分蘖期到成熟期,施用赤泥处理各生育期的水稻土微生物量碳、氮明显高于对照RM-0处理的.其中,RM-2处理(0.5%赤泥)各时期水稻土微生物量C(SMBC)、微生物量N(SMBN)都明显高于RM-0处理的(P<0.01).施用赤泥处理的稻田土壤细菌、真菌和放线菌数量多数情况下高于对照RM-0处理的.RM-2处理土壤细菌、真菌和放线菌菌群数量多数情况下高于其他处理的.RM-2处理土壤脲酶活性、酸性磷酸酶活性和过氧化氯酶活性均为最高,分别比RM-0处理的提高了10.5%,32.4%和15.9%,且两处理间差异均达到显著水平(P<0.05).与RM-0处理相比,施用赤泥各处理pH和阳离子交换量均有不同程度增加,但有机质的变化不明显.0.5%(W/W)的赤泥施用量较其他施用量有利于改善Cd污染水稻土生物性状,提高土壤肥力,增加水稻产量.     

冬种绿肥对水稻土硝化作用的影响

冬闲田种植绿肥是传统的水稻土培肥增产措施,但绿肥-水稻种植系统中,不同绿肥种类对硝化作用的影响规律及调控机制尚不明确.采用盆栽试验,研究了冬种紫云英、油菜、黑麦草对土壤性状及硝化作用的影响,并通过特异性细菌抑制剂(卡那霉素和大观霉素)研究了氨氧化细菌(AOB)和氨氧化古菌(AOA)对硝化作用的相对贡献.结果表明,冬种三...     

长期施肥对红壤性水稻土微生物生物量与活性的影响

土壤微生物及其活性是指示土壤增肥过程和土壤环境变化的灵敏指标.本文研究了红壤荒地开垦为水田后不同施肥制度定位施肥 16 年后水稻土的微生物生物量与活性特征,结果表明:经 16 年水稻耕植,不同施肥措施下土壤的微生物生物量和活性还处于较低水平.施肥制度显著影响了水稻土的微生物生物量 C 和基质诱导呼吸,但对基础呼吸的影响还不明显.只施用 N、K 肥对提高土壤微生物生物量和活性没有显著效果,在不施肥或施用化肥的基础上配合有机循环可以显著提高土壤微生物的生物量、代谢活性和微生物呼吸的温度敏感性,N、P、K 肥配合有机循环的施肥制度对提高土壤微生物生物量和代谢活性的作用最好.     

Fe2+对水稻生长及土壤微生物活性的影响

通过盆栽试验,模拟冷浸田土壤亚铁毒害,研究了土壤-水稻-亚铁-微生物相互作用的体系中,外加Fe2+ 不同处理水平 (0、 100、 200、 400、 800和1600 mg/kg) 对水稻苗期和分蘖期相关生理指标、 土壤微生物活性及其生态特征的影响。结果表明, 在含一定亚铁本底（207.77 mg/kg）的正常稻田土壤中,外源性Fe2+的加入将逐步抑制水稻生长、 降低土壤微生物活性。外源Fe2+浓度达100 mg/kg后,水稻的株高、 干物质积累量显著降低; 水稻叶片生理指标叶绿素含量（SPAD值）、 脯氨酸含量、 抗氧化酶系统活性则显著增加,表明外源Fe2+浓度100 mg/kg 是本研究条件下外源Fe2+ 对水稻生长产生显著毒害影响的临界点; 同时随外源Fe2+浓度的增加, 土壤微生物活性指标土壤微生物量碳、 微生物三大基础菌系总量（细菌、 真菌、 放线菌）、 功能菌系总量（氨化细菌、 固氮菌、 纤维分解菌）、 铁还原菌总量总体是先快速下降,后逐渐平稳降低。 半效应浓度EC50分析表明,外源Fe2+浓度100 mg/kg 为多数土壤微生物活性指标（微生物基础菌系总量、 功能菌系总量、 铁还原菌）EC50变化的临界值; 体系中土壤微生物活性指标和水稻生长指标的变化存在显著的相关性, 表明供试土壤亚铁对水稻生长的影响是亚铁对土壤-植物-土壤微生物系统同步影响的结果。综上结果可知,外源Fe2+浓度100 mg/kg为导致供试土壤中水稻生长及土壤微生物活性受到显著负效应的临界值,进而推知,本研究所用土壤对水稻生长和微生物活性的亚铁毒胁迫临界浓度约为300 mg/kg（含本底）, Fe2+含量超出该浓度时,需采取合理的农艺措施控制其负效应。     

农艺措施对不同生态环境稻田土壤状况的影响: Ⅰ. 土壤湿度的影响

The effects of individual and combined additions of urea (100 μg N g^-1 soil) and insecticide (triazophos at field rate, FR) under different moisture levels of air-dried soil (AD), 50% of water-holding capacity (WHC), 100% WHC and flooded soil (FS) on some selected soil properties in a paddy field soil were examined in a laboratory incubation study. The results indicated that after 21-day incubation at 25 ℃, the different moisture levels led to significant changes in the parameters studied. Flooding of soil with distilled water significantly increased the electron transport system (ETS)/dehydrogenase activity and phenol contents of the soil compared to the other moisture levels, while protein and phospholipids behaved differently at varied moisture levels with or without the addition of urea and/or triazophos. Increased ETS activity was observed with N addition at higher moisture levels while insecticide incorporation decreased it at all moisture levels as compared to the control (moisture only). The phenol contents slightly decreased and increased with N and insecticide applications, respectively. The soil protein contents were found to be unaffected among all the soil treatments at all moisture levels. However, among different moisture levels, reduced quantities of proteins were estimated at 50% WHC, suggesting more N-mineralization. Lower quantities of soil biomass phospholipids, among all treatments, were recorded at higher moisture levels (100% WHC and FS) than at the lower levels. An overall slight enhancement in phospholipid contents with N and small reduction with insecticide addition, respectively, was noticed against the untreated soil. The toxicity of fertilizer and insecticide decreased as the soil moisture contents increased, suggesting rapid degradation of agrochemicals.     

营养和病虫害管理对双季杂交水稻种植系统的土壤生态质量的共同影响

The mineral fertilizers(NPK) and pesticide,including herbicides,insecticides and fungicides,were applied alone or in combination and the soil sampling was done at different growth stages during the crop cycle to study the changes in soil organic matter,microbial biomass and their activity parameters in a paddy soil with different nutrient and pest management practices in a hybrid rice double-cropping system.A consistent increase in the electron transport system(ETS) activity was measured during the different crop growth stages of rice.The use of fertilizers(NPK) alone or with pesticides increased ETS activity,while a decline of ETS activity was noticed with pesticides alone as compared with the control.Nearly an increasing trend in soil phenol content was observed with the progression of crop growthstages,while the usage of pesticides alone caused maximum increments in the soil phenol content.The soil protein content was found nearly stable with fertilizers and/or pesticides application at various growth stages in both crops taken.But notable changes were noticed at different growth stages probable because of fluctuations in moisture and temperature at particular stages,which might have their effects on N mineralization.Marked depletions in the phospholipid content were found with the advancement of crop growth stages,while the incorporation of fertilizers and/or pesticides also produced slight changes,in which a higher decline was noticed with pesticide application alone compared with the control.     

农艺措施对不同生态环境稻田土壤状况的影响: Ⅱ. 土壤温度的影响

A 21－d incubation experiment was conducted under controlled laboratory conditions to study the effects of elevated temperatures(10,25,and 40℃)on some microbiological and biochemical properties in flooded paddy soil amended or unamended with urea at 100μg N g^-1 soil and /or insecticide(triazophos) at field rate(FR).Enhancements in temperature led to increase the electron transport system(ETS)/dehydrogenase activity and phospholipid contents of the soil,while soil organic matter phenol and protein contents decreased with increasing tenperature with or wihtout the addition of inputs.An incerease of temperature from 10℃ to 25 or 40℃ enhanced the ETS activity 2 folds (on avergae for all soils),while the inclusion of N and insecticide increased and decreased it ,respectively,compared to the control.The soil phenol and protein contents were highly correlated with temperatures(for all soils,r=-0.936 and -0.971,respectively)and the additions of N and insecticide produced slight reductions and enhancemetns in them,respectively,At a particular tempeature,the soil protein contents remained unaffected among all the soil treatments.An overall slight increase in phospholipid contents with N and a small decline with insecticide addition were noticed against the untreated soil.the toxcity of fertilizer and insecticide decrased as the incubation temperature increased suggesting faster degradation of agrochemicals with raising temperature.     

氮肥、土壤湿度和温度对稻田土壤甲烷氧化的影响

Effects of nitrogen fertilizer,soil mosture and temperature and temperature on methane oxidation in paddy soil were investigated under laboratory conditions.Addition of 0.05 g N kg^-1 soil as NH4Cl strongly inhibited methane oxidation and addition of the same rate of KCl also inhibited the oxidation but with more slight effect,suggesting that the inhibitory effect was partly caused by increase in osmotic potential in microorganism cell,Not only NH4^ but also NO3^- greatly affected methane oxidation.Urea did not affect methane oxidation in paddy soil in the first two days of incubation,but strong inhibitory effect was observed afterwards.Methane was oxidized in the treated soil with an optimum moisture of 280 g kg^-1 ,and air-drying inhibited methane oxidation entirely.The optimum temperature of methane oxidation was about 30℃ in paddy soil.while no methane oxidation was observed at 5℃or 50℃。     

Effect of mercuric chloride on electron transport system (ETS) activity in sediment

The effect of mercuric chloride (HgCl₂) on electron transport system (ETS) activity in sediment was studied using the reduction of 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride (INT) to water insoluble iodonitrotetrazolium formazan (INT-formazan) by respiring microorganisms and sediment enzymes. The effect of HgCl₂ on ETS activity was more pronounced in aerobically incubated sediment than in anaerobically incubated sediment. The EC₅₀ value for the inhibition of ETS activity in aerobically incubated sediment at 10 and 20 °C was 40.9 ± 16.2 and 48.8 ± 4.1 μg g^?1 HgCl₂, respectively. The EC₅₀ value for anaerobically incubated sediment in the presence of HgCl, at 4, 10, and 20 °C was 153.0 ± 8.1, 173.1 ± 8.2, and 199.1 ± 15.2 μg g^?1 HgCl₂, respectively.     

碳含量对再生水灌溉土壤氮素迁移转化规律的影响

为深入了解碳含量对再生水灌溉系统中氮素迁移转化的影响,该研究进行了碳含量影响下的再生水灌溉系统氮素迁移转化规律试验。利用不同碳含量的再生水灌溉种植在土柱中的黑麦草,测定各试验周期内灌溉水、土壤溶液和排水中不同形态氮的含量,分析不同生育期作物干物质产量和氮含量。结果表明,随灌溉水进入系统的氮素约有34%可被作物吸收利用,62%可通过反硝化作用去除或调节土壤氮库中的氮量,随水分下渗到根系层以下并随排水排出系统的氮量仅占灌溉水中氮量的3%～4%。从作物长势、干物质量和氮的利用量看,高碳处理优于低碳处理。试验条件下,再生水中碳含量较高时有利于氮素的转化、作物吸收利用以及氮的反硝化作用。研究结果对于以灌溉利用为目的的污水处理,具有一定的指导意义。     

长期不同施肥对黄泥田土壤酶活性和微生物的影响

以农业部耕地保育福建观测实验站的长期肥料试验为平台,研究了长期不同施肥对黄泥田土壤酶活性和微生物的影响。结果表明:与不施肥(CK)相比,单施NPK(NPK)、NPK配施牛粪(NPKM)及NPK配施秸秆(NPKS)的土壤酶活性均有不同程度的提高,其中NPKM可显著提高转化酶活性,NPKS可显著提高脲酶活性。施肥均不同程度地提高了土壤细菌、真菌及放线菌的数量,尤其是放线菌数量,提高幅度均达到显著性水平;NPKS可显著提高土壤细菌数量,NPKM可显著提高土壤真菌数量。施肥均会对真菌群落产生重要影响;单施化肥对土壤细菌群落的影响不大,增施有机物料会对细菌群落产生明显影响;施用牛粪会对放线菌优势群落产生影响。以上结果表明,有机无机配施更有利于提高土壤酶活性和土壤微生物数量,提升土壤生物肥力。     

控制性分根区灌溉对玉米根区水氮迁移和利用的影响

为探索灌水方式对根区水氮迁移和利用的影响,对盆栽玉米采用3种灌水方式（常规、交替、固定）和4个氮素水平,研究了不同根区湿润方式对玉米根区水氮迁移动态和利用的影响。结果表明：施氮后盆内土壤硝态氮含量和施氮量呈正相关,交替灌溉根区两侧土壤硝态氮分布均匀,固定灌溉根区干燥侧土壤硝态氮累积量明显大于湿润侧。交替灌溉上层土壤硝态氮残留量和常规灌溉同一层次上的残留量相当,下层的残留量比常规灌溉的大。交替灌溉的根冠比最大,固定灌溉的次之,常规灌溉的最小。交替灌溉的水分利用效率是常规灌溉的0.99～1.11倍,而灌水量是常规灌溉的0.75倍,节水效果明显。同一氮肥水平下,交替灌溉的单位干物质全氮吸收量最大,固定灌溉的次之,常规灌溉的最小。     

不同氮肥管理模式对太湖流域稻田土壤氮素渗漏的影响

针对太湖流域稻田土壤氮素流失引起的面源污染问题,以农户常规施肥处理、化肥减量施肥处理、缓控释肥处理、有机无机肥配施处理以及按需施肥处理5种稻田氮肥管理模式,探讨了不同施氮水平与肥料类型的处理对20～40 cm、40～60 cm、60～80 cm以及100～120 cm四个深度土壤氮素渗漏的影响。结果表明,20～40 cm渗漏液中总氮(TN)浓度与施肥量成正比;农户常规施肥处理会出现40～60 cm TN浓度高于20～40 cm的现象;缓控释肥处理具有较高的20～40 cm TN淋失量;溶解性有机氮(DON)是稻田氮素进入地下水的主要形态,占TN的60%～70%;减少33%的氮素施用量,可降低进入地下水体36.9%～49.0%的TN浓度。按需施肥处理能在保证产量的情况下降低施氮水平,减少氮素渗漏损失,是适宜该地区的环境友好型氮肥管理模式。     

Effects of biochar and fertilizer management on sunflower (Helianthus annuus L.) feedstock and soil properties

The need for bioenergy is increasing with increase in global energy demand, and sustainable soil and fertilizer management practices for bioenergy feedstock production are gaining importance. In this greenhouse study, we evaluated the effects of biochar and fertilizer nitrogen on soil and energy crop sunflower (Helianthus annuus L. var. Giganteus). Sunflower plants were treated with three rates of biochar, control (0 Mg ha^?1), low (25 Mg ha^?1) and high (50 Mg ha^?1), and three rates of fertilizers, 0% (control), 50% (low) and 100% (high) of the recommended nitrogen dose. Plant height, quality (chlorophyll content), biomass yield, feedstock energy, ash content and tissue nutrients were measured along with soil moisture and pH. Results showed an 11% increase in mean plant height under low biochar compared to control biochar-treated plants. High nitrogen treatment produced 26% and 18% more stalk and total above-ground plant (whole plant) biomass, respectively, compared to the control nitrogen treatment. High biochar treatment resulted in higher soil moisture holding, but lower soil pH than the control biochar treatment. Plant quality, energy and ash contents were not affected by either biochar or nitrogen. The plant tissue analysis provides a complete tissue macro- and micronutrient information on sunflower cultivar Giganteus, which was not done previously.