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稻田的非共生固氮作用是水稻田氮素循环的一个环节,它在稻田土壤氮素肥力保持中的积极作用已为许多试验所证实。 相似文献
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以能值理论方法为手段，从资源的投入和输出结构角度，对广东省惠州市惠阳区典型水稻种植户的耕牛和小型拖拉机这两种典型的农业驱动力产出系统的转化与生产效率，环境负载和可持续性进行比较分析与评价。研究表明：耕牛系统在单位面积水稻田上消耗的不可更新资源量是拖拉机系统的4.57倍；人力能值消耗是拖拉机系统的6.14倍。相对于拖拉机动力，耕牛产出动力处于较低的能量等级，其环境负载率(ELR)仅是拖拉机系统的24%，可持续能值指标(ESI)是拖拉机系统的4.25倍，但有巨大的优化空间和可能。而广东小型拖拉机系统产出驱动力的使用效率则稍高于典型65 kW拖拉机系统。从提高能值效率角度分析，减少耕牛系统生产过程中过多的人力投入，着力提高耕牛系统产出驱动力的利用效率比发展小型拖拉机系统更有潜力。生产过程中的人力投入和使用过程中的维护投入是农机驱动力产出系统不可忽视的能值投入项。 相似文献
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安徽省南陵县地区栽培红花草已有几百年的历史,农民积累有一套丰富的栽培经验,特别是近年来在党委提出"广种绿肥是开辟肥源、改良土壤、保证农业增产的重要途径之一"广种绿肥是开辟肥源、该县今年红花草栽培面积以扩大到27,492亩,占水田总面积42.62%。 相似文献
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养分从牛粪到农田的循环利用是养牛场可持续发展、资源利用和环境保护的重点研究内容。利用奶牛场废水种植水生植物被认为是一种有效的废水处理及养分循环的方法。本文研究了3种浮萍[少根紫萍0128（Landoltia punctata 0128）、膨胀浮萍7589（Lemna gibba 7589）和小浮萍9517（Lemna minuta 9517）]在厌氧发酵过的奶牛场废水中种植时的养分吸收和生物质变化。在28 d的测试期间,种植在稀释比例为1：18的厌氧发酵过的牛奶场废水中的少根紫萍01283获得最高的总氮吸收率（11.6%±1.6%）,种植在稀释比例为1：27厌氧发酵过的牛奶场废水中的少根紫萍0128获得最高的总磷吸收率（15.4%±4.4%）;相应地少根紫萍鲜重的增长率分别为0.11 g·d-1和0.17 g·d-1。3种浮萍中,少根紫萍最具有吸收牛奶场废水氮、磷并获得较高生物质的潜力。 相似文献
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Mycorrhiza helper bacteria (MHB) can promote the formation and functioning of arbuscular mycorrhizal (AM) symbiosis, but their role and application potential in coping with soil-borne diseases are still unclear. A 14-week greenhouse pot experiment was conducted to obtain several actinomycete strains helping AM symbiosis in suppressing the Phytophthora blight of pepper (Capsicum annuum L.), using a soil inoculated with Phytophthora capsici after sterilization. Five Streptomyces strains, including S. pseudogriseolus, S. albogriseolus, S. griseoaurantiacus, S. tricolor, and S. tendae, as well as the AM fungus (Funneliformis caledonium) were tested. The Phytophthora blight severity reached 66% at full productive stage in the uninoculated control, and inoculation of F. caledonium, S. griseoaurantiacus, and S. tricolor alone significantly decreased (P ＜ 0.05) it to 47%, 40%, and 35%, respectively. Compared to F. caledonium alone, additional inoculation of S. tricolor or S. tendae, which were isolated from the rhizosphere of a healthy individual in an infected field, significantly elevated (P ＜ 0.05) root mycorrhizal colonization, root biomass, fruit yield, and total K acquisitions of pepper and further significantly decreased (P ＜ 0.05) blight severity. According to the feature of enhancing disease-suppression by AM symbiosis, both S. tricolor and S. tendae were confirmed as MHB strains here. Specifically, S. tendae had a stronger performance in directly accelerating mycorrhization, while S. tricolor antagonist to the pathogenic P. capsici. Furthermore, S. griseoaurantiacus with the independent disease-suppression function was not an MHB strain here. The redundancy analyses demonstrated that when AM fungus was present, root mycorrhizal colonization replaced soil pH becoming the main factor affecting pepper Phytophthora blight. Thus, S. tricolor and S. tendae seemed to have the value of preparation and application in the future to help AM symbiosis against pepper Phytophthora blight. 相似文献
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为探明紫外辐射对昆虫病原线虫（entomopathogenic nematodes,EPN）的作用,以甘肃省分离得到的昆虫病原线虫为研究材料,用室内模拟生测法,测定了经20 W、40 W紫外线辐射后,斯氏属（Steinernema feltiae,S.kraussei）和异小杆属（Heterorhabditis brevicaudis,H.megidis）4种昆虫病原线虫9个品系的存活率,并以大蜡螟（Galleria mellonella）为供试昆虫,采用改良的ONE ON ONE法,测定了其对大蜡螟的致病力。结果表明：经UV-B辐射后供试的9个昆虫病原线虫品系存活率未发生显著变化（P>0.05）。20 W紫外辐射30 min后,S.feltiae 0639C和0663TD 2品系对大蜡螟的致病力提高,其中S.felitiae 0639C致病力显著升高（P<0.05）,侵染32 h后,寄主昆虫死亡率由13.3%升高到73.3%;S.felitiae 0661YM品系的致病力显著降低（P<0.05）,侵染32 h后,寄主昆虫死亡率率由66.7%降低到0;其余各品系致病力均无显著变化。不同辐射时长和辐射强度对S.felitiae 0639C和0663TD引起寄主昆虫死亡的时间有影响,较对照组而言,经辐射预处理后,2品系线虫引起寄主昆虫死亡的时间均提前,其中S.felitiae 0639C随着辐射强度的增大引起寄主昆虫开始死亡时间提前,而S.felitiae 0663TD随着辐射强度增加引起寄主昆虫开始死亡时间延后。不同紫外辐射时长对S.felitiae 0663TD和S.felitiae 0639C致病力无显著影响,30 min、60 min、90 min、120 min辐射处理之间差异不显著（P>0.05）。研究表明,9个供试昆虫病原线虫品系均对UV-B辐射具有一定的耐受能力;20 W UV-B辐射30 min,能刺激S.felitiae 0663TD和S.felitiae 0639C侵染和致死寄主昆虫;一定的辐射时长内（120 min）,辐射时长对S.felitiae 0663TD和S.felitiae 0639C的致病力无影响。 相似文献
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Symbiotic fungi are involved in plant flooding tolerance, while the underlying mechanism is not yet known. Since polyamines (PAs) and proline are also associated with stress tolerance, it is hypothesized that the enhancement of stress resistance by symbiotic fungi is associated with changes in PAs and/or proline. The aim of this study was to analyze the effect of inoculation with Funneliformis mosseae and Serendipita indica on plant growth, PAs, and proline and the metabolisms in peach (Prunus persica) under flooding. Two-week flooding did not affect root colonization frequence of F. mosseae, while it promoted root colonization frequence of S. indica. Under flooding, plants inoculated with F. mosseae and S. indica maintained relatively higher growth rates than uninoculated plants. Funneliformis mosseae promoted root ornithine (Orn) contentration and arginine (Arg) and Orn decarboxylase activities under flooding, which promoted putrescine (Put), cadaverine (Cad), and spermidine (Spd) contentrations. Conversely, S. indica decreased contentrations of Arg, Orn, and agmatine and Arg decarboxylase activities, thus decreasing PA contentrations under flooding. Polyamines were negatively correlated with the expression of PA uptake transporter genes, PpPUT1 and PpPUT2, in peach. Polyamine transporter genes of F. mosseae (FmTPO) and S. indica (SiTPO) were regulated by flooding, of which FmTPO1 was positively correlated with Put, Cad, and Spd, along with positive correlations of Spd with SiTPO1, SiTPO2, and SiTPO4. Under flooding, F. mosseae decreased proline concentration, while S. indica increased proline concentration and correlated with expression of a △1-pyrroline-5-carboxylate synthetase gene, PpP5CS2. It was thus concluded that F. mosseae modulated polyamine accumulation, while S. indica induced proline accumulation to tolerate flooding. 相似文献
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以红富士和冰糖心2种苹果为试材,研究0、200、300、400和500MPa超高压处理对鲜切苹果片的色变动态特性。结果表明,超高压处理能显著抑制鲜切苹果片在空气中的色变速率。采用4种三色值组合(ΔL*a*/b* 、ΔL*a*b*、Δ(ΔE)和ΔW.I.)作为色变指标研究鲜切苹果片的色变动态特性,结果表明,超高压处理和未处理的鲜切苹果片的各色变指标均随时间呈线性变化,鲜切苹果片的色变符合零级动力学反应。通过对三色值组合的优选,色变指标ΔL*a*/b*被选作反应压力对色变影响的最佳指标,并在此基础上建立了色变指标(ΔL*a*/b*)与压力(P)的关系模型。模型表明,400MPa为超高压加工鲜切水果片的较优压力。 相似文献
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1.水稻土中各类微生物数量比例和区系组成与旱地或荒地土壤有较明显时区别.芽孢杆菌中以Bac.idosus及Bac.megatherium为主,而Bac.subtilis-mesentericus等较少,此与水稻土的有机质状态似有一定关系.真菌中除一般土壤中均有的青霉、麯霉等菌外,常见的有Tuberculina、Emericellopsis及Sporormia(?)等特殊种类,它们对低氧环境似有较大的适应性.2.肥沃水稻土中除微生物数量和生化强度较高外,微生物区系与土壤肥力水平似有一定的相关性.肥力高的土壤中不对称组青霉菌合量较高,该组青霉菌的氨化作用及分解纤维素的能力均较强;同时,在肥力高的土壤中具有氢化能力的细菌数量也较肥力低者为多.3.初步结果指出,提高土壤肥力的人为措施具有改变微生物区系的可能性,然而生态地理因素对耕作土壤微生物区系仍有一定的限制作用. 相似文献
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海南省两种人工林林下物种多样性与土壤水分物理性质的关系 总被引：3，自引：0，他引：3
通过测定和比较分析海南桉树人工林和橡胶人工林的林下植物多样性、土壤水分物理特性以及林下物种多样性与土壤水分物理性质的关系,结果表明:（1）桉树林下植物种类共有22种,分属14科20属,橡胶林下植物种类共有25种,分属15科22属。（2）两种森林的土壤容重总体表现为表层小于底层,表土层中桉树林的土壤容重均大于橡胶林,而中下层的土壤容重是前者小于后者;土壤总孔隙度均随深度增加呈减小趋势,在表土层中,橡胶林土壤总孔隙度大于桉树人工林,而在底土层中两种林型接近;橡胶林的毛管孔隙度随土层增加呈递减趋势,桉树林是先减小后增加;在表土层,两种林型的土壤非毛管孔隙度表现为橡胶林大于桉树林,在底土层两种林型基本一致。两种森林的土壤毛管持水量、最大持水量、土壤田间持水量、土壤排水能力均为:橡胶林大于桉树林。（3）与橡胶林相比,桉树林植物多样性与土壤物理特性相关性较小,而负相关程度较高;土壤毛管孔隙度、排水能力对桉树林下物种多样性起促进作用,而非毛管孔隙度、田间持水量起抑制作用;橡胶林物种多样性与毛管孔隙度及非毛管孔隙度呈正相关,与最大持水量、田间持水量及排水能力呈负相关。因此,橡胶林下物种多样性、土壤水分物理特性均优于桉树林,控制两种人工林林下物种多样性大小的土壤水分因子是不同的。 相似文献
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不同耕作方式下水分管理对水稻氮素吸收利用的影响? 总被引：6，自引：2，他引：4
2008年早季和晚季,以桂旱1号和金优253为试验材料,盆栽条件下利用15N示踪技术研究了湿润灌溉、交替灌溉、水层灌溉3种水分管理模式下和免耕、常耕2种土壤耕作方式下水稻氮素与吸收利用的差异。结果表明：（1）湿润灌溉栽培降低了2种耕作方式水稻的氮肥吸收量,其中对基肥和分蘖肥吸收量的降低达显著水平;（2）湿润灌溉栽培时施入稻田中的氮肥被当季水稻吸收利用的比率下降,在土壤中的残留比率增加;（3）常耕条件下,湿润灌溉水稻氮素吸收总量明显低于水层灌溉和交替灌溉水稻,但免耕条件下湿润灌溉对水稻氮素吸收总量的影响比较小;（4）湿润灌溉时水稻产量和氮素的生产效率下降。 相似文献
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稻秸覆盖对有机茶园土壤生态环境影响的研究 总被引：12，自引：1，他引：12
对多年稻秸覆盖下有机茶园土壤生态环境的研究表明,稻秸覆盖能改善土壤养分状况,稻秸覆盖处理0～40cm土层中,有机质、全N、全P和速效性N、P、K的平均含量均比对照相应土层高,分别是对照处理的2.00倍、1.87倍、1.66倍、1.91倍、1.91倍、2.56倍;稻秸覆盖能增加土壤微生物主要类群数量,0～40cm土层中,覆盖处理的真菌和细菌分别是对照的3.54倍和4.46倍;稻秸覆盖能增加干季土壤含水量,稻秸覆盖处理的0～10cm、10～20cm和0～30cm各土层的土壤含水量分别比对照相应土层提高了26.24%、13.92%和12.38%;稻秸覆盖能改善土壤动物总数状况,稻秸覆盖处理的0～40cm土层中,土壤动物个体总数是对照处理的1.87倍。因此,稻秸覆盖值得在有机茶园中大力推广。 相似文献
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长期水耕植稻对水稻土耕层质地的影响 总被引：1，自引：0，他引：1
为了解长期水耕植稻对南方地区水田表土层颗粒组成的影响,以浙江省为研究区,采用历史资料分析、典型样区调查及定点观察相结合的方法,研究水稻土耕作层(包括犁底层)与心土层间黏粒含量的差异,分析植稻时间对水稻土不同土层颗粒组成的影响,比较植稻期间稻田排水中泥砂物质的颗粒组成与对应土壤间的差异,探讨了长期植稻对水稻土剖面质地分异的影响。对浙江省456个代表性剖面统计,与水稻土心土层比较,耕作层和犁底层黏粒含量平均下降了14%和10%。对植稻不同时间的浅海沉积物(从10～20年至80年)、第四纪红土(从5～20年至70年)和玄武岩风化物(从5～20年至35～70年)发育的水稻土比较发现,随植稻时间的增加,耕作层和犁底层土壤砂粒含量呈现增加趋势,黏粒含量明显下降,耕作层、犁底层与心土层黏粒含量的比值逐渐下降。农田排水中泥砂物质的黏粒和粉砂含量高于对应农田土壤,而砂粒含量则低于相应的土壤。分析认为,长期水耕植稻可导致耕作层土壤砂化(即砂粒含量增加,黏粒含量下降),其原因除与水耕过程中黏粒淋淀外,排水中黏粒和粉砂细颗粒的选择性流失对耕作层砂化也有较大的贡献。 相似文献
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滴灌密植枣林细根及土壤水分分布特征 总被引：6，自引：4，他引：2
为明确黄土丘陵区滴灌密植枣林（Ziziphus jujube Mill.)细根（直径＜2 mm）及土壤水分的空间分布特征,以无滴灌稀植枣林为对照,利用根钻法（洛阳铲）分别获得12 a生密植枣林地0～5.4 m和12 a生稀植枣林地0～10.4 m土层的细根干重密度,及0～10.4 m的土壤水分。结果表明：枣林细根干重密度随土层深度的增加而减少,50%以上的细根集中分布在0～0.8 m的土层中,该土层为根系密集层。密植枣林的细根干重密度较稀植枣林高,而细根最大分布深度却相反,密植枣林细根最大分布深度为5 m,稀植枣林为10 m。密植枣林土壤水分低值区的土层达3.0 m,稀植枣林延伸到4.6 m。该研究表明滴灌密植对枣林根系分布及土壤水分有显著影响,滴灌可减短枣林细根最大分布深度,滴灌条件下密植枣林整体根系较浅,有利于减轻深层土壤水分消耗。 相似文献
16.
晋北丘陵风沙区不同植被恢复模式的水土保持效应 总被引：1，自引：1，他引：0
通过对山西右玉贾家窑阳坡退耕还林约20年后的4种植被恢复模式(自然恢复草地、油松林、柠条灌丛和油松—柠条林)土壤水分、理化性质、径流量和侵蚀量的测定,探讨了不同植被恢复模式的水土保持效应。结果表明:(1)4种植被恢复模式0—100cm土层土壤平均含水量无显著差异,油松林和自然恢复草地的土壤容重高于油松—柠条林和柠条灌丛,土壤总孔隙度的变化趋势与容重相反;(2)4种植被恢复模式0—20cm土层土壤粒度组成、pH、有机质、铵态氮和速效磷无显著差异,硝态氮和速效钾差异明显(P0.05);(3)4种植被恢复模式径流量没有明显差异,但土壤侵蚀量自然恢复草地和油松林显著高于柠条灌丛和油松—柠条林(P0.05);(4)覆盖度相似条件下,根系密度、近地表植被盖度和枯枝落叶层厚度是影响林草植被水土保持效应的主要因素。 相似文献
17.
Ichiro Yamane 《Soil Science and Plant Nutrition》2013,59(1):100-103
It has been well known that the utilization rate of ammonium sulfate fertilizer by lowland rice was as low as 40 percent of the applied ammonium. This low utilization rate was due to nitrogen loss from the paddy field. There are problems as to whether the loss of nitrogen from the flooded soil was caused by the nitrification of ammonium nitrogen and its subsequent denitrification, by the evaporation of ammonium, or by the leaching of ammonium-nitrogen with percolated water. Shioiri and his associatesll clarified that this loss of nitrogen resulted largely from denitrification through nitrate reduction in 1942. After the paddy soil is flooded with water, the oxygen in furrow slice is consumed by aerobic microorganisms, and then the soil becomes reductive. Conversely the oxigen is supplied to the soil through the water from the air, and from various kinds of algae and duckweeds, which produce oxygen through photosynthesis. At the early stage the reduction by oxygen consumption is superior to the oxidation by oxygen supply, the furrow slice is reductive, and is bluish gray in color due to the presence of certain ferrous compounds. After months flooding, the oxygen supply becomes superior to oxygen consumption and the uppermost layer of furrow slice becomes brown in color due to the presence of ferric compounds. This layer corresponds to an “oxidised layer” where microorganisms live aerobically. In this oxidized layer the nitrifying bacteria converts ammonium nitrogen into nitrate nitrogen which is percolated into the reduced layer, and lost through denitrification. A large amount of ammonium sulfate fertilizer is then dressed at the uppermost layer, after flooding, the loss of nitrogen through denitrification is serious. 相似文献
18.
不同氮素用量对高肥力稻田水稻-土壤-水体氮素变化及环境影响分析 总被引：20，自引：1，他引：20
研究了分次施氮条件下不同氮紊用量对高肥力稻田水稻-土壤-水体含氮量的变化，结果表明：不同施氮水平与植物吸氮置、土壤含氮量以及田面水、渗漏水全氮含量之间具有很强的相关性。但总的来说，氮素利用率不高，有70％～80％左右的化肥氮排入到环境中，对土壤．水体和大气造成污染。在移栽期时，氮紊损失严重。土壤古氮量在水稻生长的前3个时期变化不大，但最终土壤氮素效应明显，低于150kg／hm^2的施氮量不利于土壤肥力的保持。同时用差值法估算出化肥氮对土壤氮的贡献量占化肥氮排入环境量的比例为30％～40％。田面水全氮浓度在每次施肥后第一天达到高峰．一周后全氮浓度显著下降，从环境角度，施肥后一周内是防止田面水氮素流失的主要时期。通过差值法估算的渗漏水中氮含量占化肥氮排入环境氮的比例很小，说明化肥氮当季渗漏淋失的较小。但从总量上却不可忽视，特别是施氮量大于225kg／hm^2时，会对环境造成很大的污染。 相似文献
19.
水生植物堆肥替代部分氮肥提高水稻产量与稻田土壤肥力 总被引：2，自引：0，他引：2
为评价太湖流域水生植物堆肥对水稻产量及稻田土壤肥力效应,在太湖流域典型稻田连续进行4a的田间定位试验,比较在等氮条件下不同比例的水生植物有机堆肥替代处理(有机氮替代率分别为0、20％、40％、60％、80％和100％)引起的水稻籽粒产量、产量构成因子、氮磷钾吸收量以及土壤碳氮含量和pH值变化.结果表明:与单施尿素相比,水生植物有机堆肥与尿素配施利于水稻产量的提高,并随着有机肥替代率增加,水稻产量呈先增后降;当有机肥替代率达40％和60％时产量最高.单施有机肥和单施尿素处理水稻籽粒产量相当.单施有机肥显著降低了有效穗数,有机肥和尿素配合施用则可减轻甚至消除这一效应;有机肥替代率在40％和60％时,有效穗数、穗粒数和结实率均较高.随着有机肥施用量增加,水稻秸秆氮浓度降低,籽粒氮浓度无影响;水稻磷浓度和吸收量均无显著差异;有机肥与尿素配施均显著提高了秸秆钾吸收量,有机肥替代率在80％时可显著提高籽粒钾吸收量.表层土壤全氮和有机碳含量及土壤pH值均与有机肥替代率呈显著正相关关系.有机肥-尿素配施处理下土壤全氮和有机碳均较4a前显著提高.有机肥替代率为80％和100％,土壤pH值较试验前土壤分别显著升高.由此可见,水生植物有机肥与尿素配施可以提高太湖稻作区水稻产量,增加土壤有机质含量和减缓土壤酸化程度,可作为太湖稻作区一项环保型施肥技术. 相似文献
20.
《Soil Science and Plant Nutrition》2012,58(5):451-459
ABSTRACTExcessive input of nitrogen fertilizer causes nitrogen pollution in aquatic environments. Utilizing microbial inoculants seems to be effective in decreasing the extent of nitrogen fertilizer application. Genome sequencing analysis of Azoarcus sp. strain KH32C, which was isolated from a paddy-upland rotation paddy field in Japan, showed that the strain may interact with plants. In this study, we examined the effect of inoculation of rice seeds with strain KH32C as a bacterial inoculant in paddy fields without nitrogen fertilization. Rice of three cultivars inoculated with strain KH32C were cultivated in paddy fields with different soil carbon and nitrogen levels. We investigated the growth rate of rice plants and the elemental composition of brown rice. In addition, the bacterial community structures in the rice root-associated soil were examined using molecular genetic analysis. KH32C inoculation resulted in an increase in the rice plant growth rate in the early growth phase with cultivar Nipponbare. Elemental composition analysis showed that the zinc concentration in brown rice of Nipponbare was increased by KH32C inoculation. KH32C inoculation affected the bacterial community in Nipponbare root-associated soil. The community of potential plant growth-promoting bacteria, the majority of which were in the class Alphaproteobacteria, had relatively high abundance in the early growth stage after KH32C inoculation. Our results indicated that strain KH32C can be utilized as a bacterial inoculant with the effect of promoting rice growth and enhancing the zinc content of rice grains in low nitrogen input paddy fields. 相似文献