首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到19条相似文献,搜索用时 109 毫秒
1.
研究了添加有机、无机营养物质对外加除草剂莠去津土壤(每1g土中含莠去津10mg/)中微生物生物量碳、氮和磷的动态变化过程。研究结果表明,在整个培养过程中,仅加莠去津的土壤中微生物生物量碳、氮、磷的含量均显著降低,与对照相比,分别平均降低了13.5%,10.1%,20.0%。但是,施用有机、无机营养物质的处理,土壤微生物生物量碳、氮、磷的含量均显著增加。不同处理对微生物生物量碳、氮的含量影响程度依次为:腐熟猪粪>紫云英>水稻秸秆腐熟猪粪>N、P肥配施>单施N肥>单施P肥。而对微生物生物量磷含量的影响则为:腐熟猪粪>N、P肥配施>紫云英>单施N肥>单施P肥>水稻秸秆。  相似文献   

2.
不同施肥模式对设施菜田土壤微生物量碳、氮的影响   总被引:9,自引:4,他引:5  
【目的】 本文利用天津日光温室蔬菜不同施肥模式定位试验,研究了不同施肥模式对设施菜田土壤微生物量碳、氮含量的影响,为设施蔬菜高效施肥和菜田土壤可持续利用提供依据。 【方法】 调查在第 9 茬蔬菜 (秋冬茬芹菜) 和第 10 茬蔬菜 (春茬番茄) 进行。定位试验设 8 个处理,分别为:1) 不施氮;2) 全部施用化肥氮 (4/4CN);3) 3/4 化肥氮 + 1/4 猪粪氮 (3/4CN + 1/4PN);4) 2/4 化肥氮 + 2/4 猪粪氮 (2/4CN + 2/4PN);5) 1/4 化肥氮 + 3/4 猪粪氮( 1/4CN + 3/4PN);6) 2/4 化肥氮 + 1/4 猪粪氮 + 1/4 秸秆氮 (2/4CN + 1/4PN + 1/4SN);7) 2/4 化肥氮 + 2/4 秸秆氮 (2/4CN + 2/4SN);8) 农民习惯施肥 (CF),除不施氮肥和农民习惯施肥外,其余处理为等氮磷钾处理。在不同生育时期,采 0—20 cm 土壤样品,测定土壤微生物量碳、氮含量,并分析其与蔬菜产量之间的关系。 【结果】 两茬蔬菜不同施肥模式土壤微生物量碳、氮含量总体上均随生育期的推进呈先增后降的趋势。芹菜季较高土壤微生物量碳含量出现在定植后 90 d,土壤微生物量氮较高含量出现在定植后 60 d;番茄季分别出现在定植后 20~80 d 和 60 d。芹菜季 5 个有机无机肥料配施模式土壤微生物量碳、氮含量分别在 185.0~514.6 和 34.3~79.1 mg/kg 之间,较化肥(4/4CN)模式平均分别增加 15.1%~81.7% 和 24.5%~100.0%,其中以配施秸秆模式土壤微生物量碳、氮含量相对较高,平均分别增加 62.0%~81.7% 和 81.1%~100.0%;番茄季 5 个有机无机肥料配施模式土壤微生物量碳、氮含量分别在 120.7~338.0 和 25.5~68.8 mg/kg 之间,较 4/4CN 模式平均分别增加 16.9%~86.9% 和 12.2%~109.3%,又以配施秸秆模式土壤微生物量碳、氮含量最高,平均分别增加 61.4%~86.9% 和 78.2%~109.3%。两季蔬菜不同生育期土壤微生物量碳、氮含量与当季蔬菜产量和定位试验开始以来蔬菜总产量之间均呈极显著正相关关系。 【结论】 同等养分投入量下,有机无机肥料配合施用提高土壤微生物量碳、氮的效果显著好于单施化肥,又以化肥配施秸秆效果更佳;土壤微生物量碳、氮含量与设施蔬菜产量之间呈极显著正相关关系。证明有机无机肥配施,特别是配施一定量的秸秆可有效提高土壤微生物量碳、氮含量,维持较高的菜田土壤肥力,有利于设施蔬菜的可持续和高效生产。   相似文献   

3.
稻麦轮作条件下长期不同土壤管理对供氮能力的影响   总被引:3,自引:0,他引:3  
通过种植了 25季的长期定位试验研究了稻麦轮作条件下不同土壤耕作方式和培肥制度对土壤供氮能力的影响。结果表明 ,不论免耕还是耕翻 ,0~5cm土壤的氮素释放均较持久 ,5~15cm土壤的氮素释放耕翻较免耕持久。休闲的 0~5cm土壤在免耕条件下其氮素矿化势和短期矿化氮量均远远高于耕翻 ,5~15cm和 15~30cm土壤在免耕和耕翻间则相差不大。施肥的3个处理 0~ 5cm土壤氮素矿化势和短期矿化氮量有免耕高于耕翻的趋势 ,而 5~ 15cm土层免耕明显低于耕翻 ,15~ 30cm土壤免耕与耕翻没有差异。有机肥与化肥配施的免耕与耕翻土壤中 25季作物吸氮量几乎无差异 ,不施肥和单施化肥处理的免耕土壤中作物吸氮量低于耕翻土壤。免耕条件下 ,有机肥配施化肥土壤的供氮能力仅低于休闲土壤 ,不施肥土壤最低 ;耕翻条件下 ,有机肥配施化肥土壤的供氮能力最高。各培肥处理间的差异主要表现在 0~ 5cm土层。  相似文献   

4.
2005~2008年,在内蒙古清水河县研究了免耕留低茬(NL)、免耕留高茬(NH)、免耕留低茬覆盖(NLS)、免耕留高茬覆盖(NHS)和常规耕作(T)5种耕作方式对旱坡地燕麦田耕层土壤微生物生物量碳、氮、磷的影响。结果表明:各处理土壤微生物生物量碳、氮、磷含量在不同年际间的变化趋势一致。土壤微生物生物量碳、氮含量均呈双峰曲线变化,其中,NHS和NLS处理土壤微生物生物量碳的峰值出现在拔节期和灌浆期,NH、NL和T处理的土壤微生物生物量碳的峰值出现在孕穗期和灌浆期,而土壤微生物生物量氮的峰值则出现在苗期和灌浆期。土壤微生物生物量磷呈单峰曲线变化,各处理的峰值均出现在灌浆期。不同年份间、不同生育期间,土壤微生物生物量碳、氮、磷含量的大小顺序为:NHS>NLS>NH>NL>T。其中,免耕各处理的燕麦产量相对常规耕作呈先降低后增加的趋势,以2008年为例,NHS、NLS、NH、NL燕麦产量分别较T增加了22%、17%、11%、5%。综上所述,免耕有利于提高土壤微生物生物量碳、氮、磷含量,而且可有效地增加作物产量,尤其是NHS和NLS处理比较明显。  相似文献   

5.
稻麦轮作条件下长期不同土壤管理对磷、钾和pH的影响   总被引:7,自引:1,他引:6  
免耕土壤速效磷含量在整个面均低于耕翻土壤;0~5cm土壤生物量磷含量免耕高于耕翻,5~15cm免耕低于耕翻;施肥和休闲土壤均维持了较高的有效磷和生物量磷水平。种植作物的免耕土壤缓效钾含量与耕翻土壤没有显差异,0~5cm速效钾含量呈免耕高于耕翻的趋势,休闲的免耕土壤整个剖面缓效钾和速效钾含量都高于耕翻;免耕土壤缓效钾的分布无明显的层次性,速效钾则相反;施肥明显提高土壤速效钾含量,但对缓效钾的影响不大。长期免耕没有导致土壤酸化;免耕土壤pH与耕翻土壤没有差异。  相似文献   

6.
长期施用生物有机肥对土壤肥力及微生物生物量碳的影响   总被引:42,自引:1,他引:41  
为了研究施用生物有机肥(EM堆肥,即有效微生物制剂 堆肥)对土壤肥力及微生物生物量碳的影响,进行了7年的施用15t/hm2.a有机肥、施用7.5t/hm2.a有机肥(包括EM堆肥、EM鸡粪肥和传统有机肥)、施用化肥和对照处理的田间试验。结果表明:长期施用生物有机肥的土壤肥力明显提高。随着生物有机肥用量的提高,碱性土壤的pH值逐渐降低,土壤有机质、全N、碱解氮、有效磷、速效钾、微生物生物量碳含量增加,与有机肥施用量呈显著正相关。施用化肥可一定程度提高土壤有机质、全N和有效养分含量,但作用不明显。施肥对土壤肥力和微生物量碳的影响趋势是:EM堆肥>传统堆肥>化肥>对照。土壤微生物量碳与土壤有机质、全N、碱解氮、有效磷、速效钾含量呈显著正相关,可以作为施肥过程中土壤质量变化的生物学指标。  相似文献   

7.
《土壤通报》2020,(1):164-170
为探索亚热带低丘新建果园土壤肥力快速提升方法,在浙西选择一新建红壤橘园,进行了为期2年的种植绿肥与联合施用有机肥的土壤培肥试验。试验设对照、双季绿肥、有机肥及双季绿肥+有机肥等4个处理,各处理化肥用量相同。试验结果表明,从土壤有机碳、微生物生物量碳、速效氮磷钾、酶活性及土壤容重和水稳定性团聚体等肥力指标的变化来看,培肥效果:双季绿肥+有机肥>有机肥>双季绿肥。在不施用有机肥的条件下,种植绿肥后土壤有机碳、微生物生物量碳、有效磷、速效钾、水稳定性团聚体分别比对照增加13.14%、52.00%、27.08%、18.91%、20.25%,土壤容重下降2.90%,但增幅相对较小;土壤有效态微量元素含量几乎没有变化。在种植绿肥的同时施用有机肥可显著增加土壤有机碳、微生物生物量碳、有效磷、速效钾、水稳定性团聚体,分别比对照增加94.46%、276.00%、94.41%、110.81%、86.27%,土壤容重下降9.42%;同时可明显增加土壤全磷和微量元素的含量,全磷、有效态硼、钼、铜、锌水平分别比对照增加27.27%、266.67%、72.73%、155.56%、168.18%。种植绿肥同时施用有机肥的紫云英和黑麦草生物量分别为种植绿肥的1.62~1.90和1.79~1.95倍。分析认为,由于新建红壤果园肥力低下,仅靠种植绿肥等生草技术对土壤肥力的提升有限;施用有机肥和种植绿肥方式相结合是新建红壤果园的快速培肥途径。  相似文献   

8.
为探讨施用有机肥和秸秆还田对盐渍化耕地土壤的培肥效果及改土效应,以河套灌区典型盐渍化土壤为研究对象,对比分析了不施肥(CK)、化肥(CF)、化肥+有机肥(CFM)、化肥+秸秆还田(CFS)对土壤pH、有机碳、全氮含量、速效氮磷钾含量和微生物数量的影响,并通过简单相关分析和冗余分析研究等氮条件下浅层(0~20 cm)土壤化学性质与土壤微生物数量间的相关关系,揭示不同培肥措施下土壤微生物数量差异的驱动因子,明确施用有机肥和秸秆还田这2种主要培肥措施下土壤肥力的变化特征。结果表明:与CK处理相比,CFM和CFS处理的土壤pH分别降低了1.36%~1.78%和1.02%~1.44%,土壤盐渍化得到改善;CFM和CFS处理提高了土壤有机碳和全氮含量,土壤碱解氮、有效磷和速效钾含量也显著增加,且施用有机肥的提升效果优于秸秆还田;在土壤微生物方面,CFM处理可显著提高土壤细菌数量(53.44%~59.78%)和放线菌数量(10.08%~16.79%),CFS处理可显著提高土壤真菌数量(29.99%~49.06%)。综上所述,增施有机肥和秸秆还田可有效降低土壤pH,增加土壤有机碳和速效养分;同时改善了土壤微环境,显著增加了土壤微生物数量。该研究结果可为河套灌区盐渍化土壤的改土培肥提供参考。  相似文献   

9.
不同施肥模式下设施菜田土壤团聚体养分和微生物量特征   总被引:9,自引:1,他引:8  
【目的】 针对设施蔬菜生产中普遍存在的化肥施用严重超量、化肥与有机肥配施模式不合理等现象,利用日光温室蔬菜有机肥/秸秆替代化肥模式定位试验,研究了不同施肥模式对设施菜地土壤团聚体养分、微生物量碳氮含量的影响,为设施蔬菜优质高效生产和减量施用化肥提供科学依据。 【方法】 将25%或50%的无机氮肥用玉米秸秆或猪粪中氮替代,进行温室蔬菜田间定位试验。试验共设5个处理 (各处理等氮、等磷、等钾):1) 全部施用化肥氮 (4/4CN);2) 3/4化肥氮 + 1/4猪粪氮 (3/4CN + 1/4MN);3) 2/4化肥氮 + 2/4猪粪氮 (2/4CN + 2/4MN);4) 2/4化肥氮 + 1/4猪粪氮 + 1/4秸秆氮 (2/4CN + 1/4MN + 1/4SN);5) 2/4化肥氮 + 2/4秸秆氮 (2/4CN + 2/4SN)。在定位试验第6年冬春茬黄瓜季拉秧期采取耕层土壤样品,分析土壤团聚体分布规律和稳定性,并测定各粒级团聚体中土壤养分和微生物量碳、氮含量。 【结果】 设施菜地土壤团聚体以250~1000 μm团聚体和 > 2000 μm团聚体为主,其含量分别平均为32.0%和38.4%。较4/4CN模式,有机肥/秸秆替代化肥模式提高了土壤大团聚体 (> 250 μm) 比例。配施秸秆模式对土壤团聚体分布影响相对较大,并显著提高土壤团聚体机械稳定性,平均重量直径 (MWD) 和平均几何直径 (GMD) 分别提高6.1%和11.2%。在 < 250 μm团聚体、250~1000 μm团聚体、1000~2000 μm团聚体和 > 2000 μm团聚体中,不同有机肥化肥配施模式 (3/4CN + 1/4MN、2/4CN + 2/4MN、2/4CN + 1/4MN + 1/4SN、2/4CN + 2/4SN) 土壤有机碳含量较4/4CN模式分别增加36.8%~89.6%、34.9%~100.3%、29.5%~69.2%和21.7%~72.1%,分别平均增加69.8%、76.6%、56.9%和49.2%。不同施肥模式对有机碳、全氮、硝态氮、速效磷的影响规律基本一致。土壤有机碳、全氮主要分布在250~1000 μm团聚体和 > 2000 μm团聚体中,平均分别占土壤有机碳储量的34.1%、35.2%和土壤全氮储量的34.0%、36.4%。土壤硝态氮在250~1000 μm团聚体与1000~2000 μm团聚体中含量较高,土壤速效钾、微生物量碳氮含量表现为随土壤团聚体直径的增大而提高,而速效磷则随土壤团聚体直径的增大而降低。 【结论】 设施菜田土壤团聚体优势粒级为 > 2000 μm团聚体和250~1000 μm团聚体,配施秸秆模式显著提高土壤团聚体的机械稳定性。有机肥/秸秆替代化肥模式提高土壤各级团聚体有机碳、全氮、硝态氮和速效磷含量。设施菜地土壤有机碳氮主要分布在250~1000 μm团聚体和 > 2000 μm团聚体中,而微生物量碳、氮含量随土壤团聚体直径的减小而呈增加的趋势。   相似文献   

10.
长期不同施肥对茶园土壤碳氮磷构成的影响   总被引:1,自引:0,他引:1  
《土壤通报》2015,(3):578-583
从浙西茶区采集了34个茶园表层土壤,按施肥模式分为施用有机肥+化肥、单施化肥和不施肥等3组茶园,用化学分析方法研究了长期不同施肥下茶园土壤碳、氮、磷库的变化特点。结果表明,3组施肥模式之间的茶园土壤p H和有机碳含量差异不明显;单施化肥或有机肥+化肥的茶园土壤全磷、全氮和有效磷含量明显高于不施肥茶园;全磷与全碳的比例(P/C)和全氮与全碳的比例(N/C):化肥有机肥+化肥不施肥;施用有机肥+化肥土壤的有机质结合态磷比例明显高于单施化肥和不施肥土壤,单施化肥土壤的钙结合态磷的比例明显高于施有机肥+化肥和不施肥土壤,不施肥土壤的闭蓄态磷的比例高于施有机肥+化肥和单施化肥土壤;单施化肥土壤具有较高的NO3--N/NH4+-N比和无机氮含量;施用有机肥+化肥土壤有较高比例的颗粒态有机碳、活性有机碳和微生物生物量碳。基于19项分析指标应用主成分分析方法对研究的34个土壤进行聚类的结果也表明,土壤之间碳、氮、磷库组成的差异主要与施肥模式有关。施用有机肥+化肥的茶园土壤养分较为协调。  相似文献   

11.
不同耕作方式对土壤有机碳、微生物量及酶活性的影响   总被引:12,自引:2,他引:10  
【目的】依托8年长期(2005~2012)固定道定位试验,研究不同耕作方式对土壤有机碳、土壤微生物量、土壤酶活性在0—90 cm土层的分布特征,为优化中国西北干旱区的耕作方式提供理论依据。【方法】试验包括固定道垄作(PRB)、固定道平作(PFT)与传统耕作(CT)三种耕作模式下的土壤有机碳土壤总有机碳(TOC)、颗粒有机碳(POC)、土壤微生物量碳(MBC)、土壤微生物量氮(MBN)、土壤微生物量磷(MBP)、蔗糖酶、过氧化氢酶、脲酶及小麦产量进行了测定和分析。【结果】在0—90 cm土层,不同耕作方式下的TOC、POC、MBC、MBN、MBP、蔗糖酶活性、脲酶活性均随着土层的增加呈下降趋势,过氧化氢酶活性呈先下降后增大的分布特征;在0—60 cm,固定道保护性耕作能够显著增加心土层作物生长带土壤有机碳储量,有机碳储量大小为PRBPFTCT;PRB、PFT较CT可以显著增加0—10 cm作物生长带TOC、POC、MBC、MBN、MBP含量、蔗糖酶、脲酶活性,其大小为PRBPFTCT;耕作方式对过氧化氢酶活性影响不显著;TOC、POC、MBC、MBN、MBP、蔗糖酶活性、脲酶活性、过氧化氢酶活性之间均达到了显著或极显著相关。【结论】PRB较PFT、CT能够提高耕作层(0—10 cm)土壤有机碳含量、土壤微生物量、土壤酶活性, 增加作物产量, 增大0—60 cm土层有机碳储量,耕作方式(PRB、PFT及CT)对10 cm以下土层土壤环境改善作用不明显。  相似文献   

12.
Microbial biomass phosphorus (MBP) and its relationships with other biological and chemical properties were studied on loess soil with an 11-year long-term fertilization experiment. The results indicated that inorganic fertilizers (F) improved soil microbial biomass carbon (MBC), nitrogen (MBN), and MBP levels and F plus maize stalk (SNPK) improved MBC and MBN. Manuring markedly increased soil MBC, MBN, and MBP levels. Fertilization decreased the ratios of MBC/MBN, MBC/MBP, and MBN/MBP. Microbial biomass phosphorus was positively and linearly correlated with MBC, MBN, organic carbon (SOC), total phosphorus (TP), water-soluble P, and Olsen P but negatively correlated with soil pH. Microbial biomass phosphorus constituted 2% of TP on control (CK) and inorganic fertilizer treatments and 12% on manure plots. Microbial biomass phosphorus to Olsen P ratios were 50% on CK, F, and SNPK and 80% on manure treatments. Measurements of MBP in soil containing high Olsen P were subject to analytical problems of unknown reasons.  相似文献   

13.
A 12-year field experiment was conducted to investigate the effect of different tillage methods and fertil-ization systems on microbial biomass C,N and P of a gray fluvo-aguic soil in rice-based cropping system .Five fertilization treatments were designed under conventional tillae(CT) or on tillage(NT) system:no fertilizer(CK) ; chemical fertilizer only(CF) ; combining chemical fertilizer with pig manure(PM); combining chemical fertilizer with crop straw (CS) and fallow (F). The results showed that biomass C,N and P were enriched in the surface layer of no-tilled soil,whereas they distributed relatively evenly in the tilled soil,which might result from enrichment of crop resdue,organic manure and mineral fertilzer,and surficial developent of root systems under NT.Under the cultivation system NT had slightly greater biomass C,N and P at 0-5 cm depth ,significantly less biomass C,N and P at 5-15 cm depth ,less microbial biomass C,N and equivalent biomass P at 15-30 cm depth as compared to CT,indicating hat tillage was beneficial for the multiplication of organims in the plowed layer of soil.Under the fallow system,biomass C,N and P in the surface layer were significantly greater for NT than CT while their differences between the two tillage methods were neligible in the deeper layers.In the surface layer,biomass C,N and P in the soils amended with oranic manure combined with mineral fertilizers were significantly greater than those of the treatments only with mineral fertilizers and the control.Soils without fertilzer had the least biomass nutrient contents among the five fertilization treatments.Obviously,the long-term application of organic manure could maintain the higher activity of microorganisms in soils.The amounts of biomass C,N and P in the fallowed soils varied with the tillage methods;they were much greater under NT than under CT,especially in the surface layer,suggesting that the frequent plowing could decrease the content of organic matter in the surface layer of the fallowed soil.  相似文献   

14.
有机物料输入稻田提高土壤微生物碳氮及可溶性有机碳氮   总被引:33,自引:6,他引:27  
土壤微生物量碳、氮和可溶性有机碳、氮是土壤碳、氮库中最活跃的组分,是反应土壤被干扰程度的重要灵敏性指标,通过设置相同有机碳施用量下不同有机物料处理的田间试验,研究了有机物料添加下土壤微生物量碳(soil microbial biomass carbon,MBC)、氮(soil microbial biomass nitrogen,MBN)和可溶性有机碳(dissolved organic carbon,DOC)、氮(dissolved organic nitrogen,DON)的变化特征及相互关系。结果表明化肥和生物碳、玉米秸秆、鲜牛粪或松针配施下土壤微生物量碳、氮和可溶性有机碳、氮显著大于不施肥处理(no fertilization,CK)和单施化肥处理,分别比不施肥处理和单施化肥平均高23.52%和12.66%(MBC)、42.68%和24.02%(MBN)、14.70%和9.99%(DOC)、22.32%和21.79%(DON)。化肥和有机物料配施处理中,化肥+鲜牛粪处理的微生物量碳、氮和可溶性有机碳、氮最高,比CK高26.20%(MBC)、49.54%(MBN)、19.29%(DOC)和32.81%(DON),其次是化肥+生物碳或化肥+玉米秸秆处理,而化肥+松针处理最低。土壤可溶性有机碳质量分数(308.87 mg/kg)小于微生物量碳(474.71 mg/kg),而可溶性有机氮质量分数(53.07 mg/kg)要大于微生物量氮(34.79 mg/kg)。与不施肥处理相比,化肥和有机物料配施显著降低MBC/MBN和DOC/DON,降低率分别为24.57%和7.71%。MBC和DOC、MBN和DON随着土壤有机碳(soil organic carbon,SOC)、全氮(total nitrogen,TN)的增加呈显著线性增加。MBC、MBN、DOC、DON、DOC+MBC和DON+MBN之间呈极显著正相关(P<0.01)。从相关程度看,DOC+MBC和DON+MBN较MBC、DOC、MBN、DON更能反映土壤中活性有机碳和氮库的变化,成为评价土壤肥力及质量的更有效指标。结果可为提高洱海流域农田土壤肥力,增强土壤固氮效果,减少土壤中氮素流失,保护洱海水质安全提供科学依据。  相似文献   

15.
Seasonal changes in the levels of soil microbial biomass C (MBC) and N (MBN), N-mineralization rate and available-N concentration were studied in rice–barley supporting tropical dryland (rainfed) agroecosystem under six combinations of tillage (conventional, minimum and zero tillage) and crop residue manipulation (retained or removed) conditions. Highest levels of soil MBC and MBN (368–503 and 38.2–59.7 μg g−1, respectively) were obtained in minimum tillage residue retained (MT+R) treatment and lowest levels (214–264 and 20.3–27.1 μg g−1, respectively) in conventional tillage residue removed (CT−R, control) treatment. Along with residue retention tillage reduction from conventional to zero increased the levels of MBC and MBN (36–82 and 29–104% over control, respectively). The proportion of MBC and MBN in soil organic C and total N contents increased significantly in all treatments compared to control. This increase (28% in case of C and 33% N) was maximum in MT+R and minimum (10% for C and N both) in minimum tillage residue removed (MT−R) treatment. In all treatments concentrations of N in microbial biomass were greater at seedling stage, thereafter these concentrations decreased drastically (21–38%) at grain-forming stage of both crops. In residue removed treatments, N-mineralization rates were maximum during the seedling stage of crops and then decreased through the crop maturity. In residue retained treatments, however, N-mineralization rates were lower than in residue removed treatments at seedling stage of both crops. At grain-forming stage in all instances the N-mineralization rates in residue retained treatments considerably exceeded the rates in corresponding residue removed treatments. Tillage reduction and residue retention both increased the proportion of organic C and total N present in soil organic matter as microbial biomass. Microbial immobilization of available-N during the early phase of crops and its pulsed release later during the period of greater N demand of crops enhanced the degree of synchronization between crop demand and N supply. The maximum enhancement effects were recorded in the minimum tillage along with residue retained treatment. In the dryland agroecosystem studied, two management practices in combination proved more advantageous than either practice alone in maintaining soil fertility levels. For soil fertility amelioration in dryland agroecosystems with least dependence upon chemical fertilizer input, post-harvest retention of about 20 cm shoot biomass (accounting for 25–40% aboveground biomass) of previous crop and its incorporation in soil through minimum tillage in the succeeding crop is suggested, especially in the case of cereal.  相似文献   

16.
为了探讨黑河流域保护性耕作对土壤生产力的影响,设计20cm留茬(NS20),20cm留茬压倒(NPS20),40cm留茬(NS40),40cm留茬压倒(NPS40)和传统耕作(CT)5个处理,研究了黑河流域保护性耕作对农田土壤有机质、土壤微生物量C、土壤微生物量N以及作物产量和水分利用效率的影响。结果表明,保护性耕作农田0—20cm土层土壤有机质、土壤微生物量C和N的含量均高于传统耕作,且其在剖面中的变化趋势基本一致,即随土层深度增加下降;土壤微生物量N有明显的"表聚现象";相关分析表明土壤有机质和土壤微生物量C之间显著正相关(r=0.85,p0.05),与土壤微生物量N之间无明显的相关关系(r=0.47,p0.05);保护性耕作提高了春小麦的产量,NPS20和NPS40增产效果最好,较CT分别增产53.08%和46.59%,与CT之间差异达到极显著水平;保护性耕作提高了春小麦的水分利用效率(WUE),NPS20,NS40,NPS40,NS20分别较CT的WUE提高了58.02%,43.40%,47.27%,23.78%。  相似文献   

17.
《土壤圈》2016,(2)
The influences of herbicide alone and in combination with the soil amendments with contrasting resource qualities on dynamics of soil microbial biomass C(MBC),N(MBN),and P(MBP) were studied through two annual cycles in rice-wheat-summer fallow crop sequence in a tropical dryland agroecosystem.The experiment included application of herbicide(butachlor) alone or in combination with various soil amendments having equivalent amount of N in the forms of chemical fertilizer,wheat straw,Sesbania aculeata,and farm yard manure(FYM).Soil microbial biomass showed distinct temporal variations in both crop cycles,decreased from vegetative to grain-forming stage,and then increased to maximum at crop maturity stage.Soil MBC was the highest in herbicide + Sesbania aculeata treatment followed by herbicide 4- FYM,herbicide + wheat straw,herbicide + chemical fertilizer,and herbicide alone treatments in decreasing order during the rice-growing period.During wheat-growing period and summer fallow,soil MBC attained maximum for herbicide + wheat straw treatment whereas herbicide + FYM,herbicide 4- Sesbania,and herbicide 4 chemical fertilizer treatments showed similar levels.The overall trend of soil MBN was similar to those of soil MBC and MBP except that soil MBN was higher in herbicide 4 chemical fertilizer treatment over the herbicide + wheat straw treatment during rice-growing period.In spite of the addition of equivalent amount of N through exogenous soil amendments in combination with the herbicide,soil microbial biomass responded differentially to the treatments.The resource quality of the amendments had more pronounced impact on the dynamics of soil microbial biomass,which may have implications for long-term sustainability of rainfed agroecosystems in dry tropics.  相似文献   

18.
The influences of herbicide alone and in combination with the soil amendments with contrasting resource qualities on dynamics of soil microbial biomass C (MBC), N (MBN), and P (MBP) were studied through two annual cycles in rice-wheat-summer fallow crop sequence in a tropical dryland agroecosystem. The experiment included application of herbicide (butachlor) alone or in combination with various soil amendments having equivalent amount of N in the forms of chemical fertilizer, wheat straw, Sesbania aculeata, and farm yard manure (FYM). Soil microbial biomass showed distinct temporal variations in both crop cycles, decreased from vegetative to grain-forming stage, and then increased to maximum at crop maturity stage. Soil MBC was the highest in herbicide + Sesbania aculeata treatment followed by herbicide + FYM, herbicide + wheat straw, herbicide + chemical fertilizer, and herbicide alone treatments in decreasing order during the rice-growing period. During wheat-growing period and summer fallow, soil MBC attained maximum for herbicide + wheat straw treatment whereas herbicide + FYM, herbicide + Sesbania, and herbicide + chemical fertilizer treatments showed similar levels. The overall trend of soil MBN was similar to those of soil MBC and MBP except that soil MBN was higher in herbicide + chemical fertilizer treatment over the herbicide + wheat straw treatment during rice-growing period. In spite of the addition of equivalent amount of N through exogenous soil amendments in combination with the herbicide, soil microbial biomass responded differentially to the treatments. The resource quality of the amendments had more pronounced impact on the dynamics of soil microbial biomass, which may have implications for long-term sustainability of rainfed agroecosystems in dry tropics.  相似文献   

19.
The objective of this study was to evaluate the effect of Conilon coffee (Coffea canephora) cultivated under conventional and organic management systems on the chemical and microbiological characteristics of the soil, as compared to an Atlantic forest. Chemical soil properties, microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), microbial activity (MA), and metabolic quotient (qCO2) were determined at depths of 0–10 cm and 10–20 cm in two seasons (summer and winter). Although microbiological attributes varied according to the season and soil depth, MBC provided 54.15% of relative contribution to distinguish the treatments, followed by MBN and MA. Results indicate that the cultivation of coffee under organic management is more sustainable than under conventional system. Carbon from microbial biomass was the most important soil microbiological attribute in the clustering of the different management methods. Atlantic forest soil followed by organic coffee cultivation soil showed the best soil-quality indices.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号