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矿化作用和硝化作用是土壤氮素转化的主要途径,通过室内培养试验,对设施和露天栽培方式下有机菜地土壤氮素的矿化与硝化作用进行了比较研究。结果表明,除培养第1d外,设施有机菜地土壤氮素矿化量、矿化率在整个培养期间都显著高于露天有机菜地土壤;设施有机菜地土壤硝化量、硝化率在培养前两周内高于露天有机菜地土壤;设施有机菜地土壤矿化与硝化作用总体比露天有机菜地土壤强烈。矿化作用可能与全氮、C/N、微生物活性关系密切,而硝化作用强弱可能与微生物活性有关。无论施肥与否,设施有机菜地土壤N2O排放速率在培养期间总体高于露天有机菜地土壤,前者N2O累积排放量显著高于后者,这可能与土壤C/N有关。 相似文献
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红壤氮素的矿化硝化作用特征 总被引：12，自引：4，他引：8
采用培养试验研究了侵蚀红壤,培肥后的红壤以及不同利用方式红壤氮素的矿化和硝化作用特征。结果表明,侵蚀红壤的矿化作用和硝化作用都很微弱,采用适宜的施肥措施培肥后氮素的矿化和硝化速率都有很大提高;红壤氮素的矿化和硝化速率与土壤pH、速效磷含量和有机质含量呈显著正相关。 相似文献
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用培养试验研究了添加碳源、磷和石灰石粉对第四纪红色粘土及红砂岩母质上发育的不同侵蚀程度的红壤以及经培肥后红壤的矿化和硝化作用的影响。结果表明 :上述 3个因子对矿化作用的影响较大 ,添加碳源表现出土壤矿质氮的净生物固持 ;在低磷红壤上增施磷能有效地促进红壤氮素的矿化 ;添加石灰石粉也能有效地促进 pH较低的红壤氮素的矿化。培肥后的红壤矿化和硝化作用明显增强 ,添加磷和石灰石粉进一步促进了培肥红壤矿化率和硝化率的提高。但施用石灰石粉和磷并未提高未经培肥的侵蚀红壤的硝化作用 相似文献
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闽南农业流域土壤氮矿化作用初步研究 总被引：1，自引：0，他引：1
用原位培养法对五川流域内的香蕉地、菜地、香蕉地与菜地间作地、林地、甘蔗地土壤的氮矿化作用进行了研究,结果发现不同土地利用方式下土壤氮矿化速率平均为N0.11mgkg-1d-1,其中香蕉地土壤氮矿化最高可达N1.47mgkg-1d-1;土壤硝化速率平均为N0.27mgkg-1d-1,其中菜地下土壤硝化作用强度最高可达N0.69mgkg-1d-1。土壤矿化作用同土壤湿度、温度、C/N、土壤肥力存在明显的相关关系。不同土地利用方式下温度是土壤氮矿化最主要的影响因子。闽南流域土壤年矿化量平均为N240kghm-2,部分样地最高可达N850kghm-2,而年施肥量平均N650kghm-2。相比较而言,说明了土壤矿化是我国南方流域农业土壤氮素的重要来源。 相似文献
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长期不同化肥氮用量对设施菜地土壤氮素矿化和硝化作用的影响 总被引：3，自引：2，他引：3
为揭示长期施用不同化肥氮对设施菜地土壤供氮能力的影响，选取连续种植15年不同化肥氮用量下的设施菜地土壤，采用好气密闭培养法研究长期不同化肥氮用量对设施菜地土壤氮素矿化和硝化作用的影响。供试土壤为5个氮施用水平，分别为：不施化肥氮（CK），常规化肥氮（100% N），常规化肥氮上减氮20%（80% N）、40%（60% N）、60%（40% N）。结果表明：与初始矿质氮量相比，培养结束后CK、40% N、60% N、80% N和100% N处理土壤矿质氮变化量分别为38.9、44.7、20.6、-32.7、-87.6 mg/kg；CK、40% N和60% N处理土壤矿质氮变化量分别占各自土壤全氮量的2.7%、2.5%和1.0%，80% N和100% N处理土壤矿质氮量与初始矿质氮量相比下降1.3%和3.1%；CK、40%、60% N、80% N和100% N处理土壤硝化速率分别为19.3、11.2、4.9、5.2、1.2 mg/（kg·d）。长期高量化肥氮（80% N和100% N）投入下，设施菜地土壤氮素矿化和硝化速率显著降低，土壤供氮能力下降，土壤pH降低可能是导致土壤矿化和硝化作用受到抑制的原因之一。鉴于此，设施蔬菜种植体系在现有施氮水平上应减少化肥氮投入，科学优化施肥，维持土壤的供氮能力，确保设施土壤的可持续利用。 相似文献
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利用原状土柱研究华中地区菜地土壤氮素的矿化规律 总被引：2，自引：1，他引：1
本文以华中地区两种典型的菜地土壤-黄棕壤和潮土为研究对象,采用原状土柱系统,综合考虑了大气干湿沉降、灌溉、作物携出及淋失等氮素的影响因素,通过菜地轮作(2年8季蔬菜),研究了两种土壤氮素的矿化特性。结果表明,黄棕壤氮素的矿化总量和矿化速率分别为134.52 mg和0.04 mg kg-1 d-1;潮土的矿化总量和矿化速率分别为185.93 mg和0.06mg kg-1 d-1。研究还发现,土壤氮素的矿化受季节影响较大,春夏季土壤氮素的矿化量和矿化率明显高于秋冬季,同时耕作能明显增加菜地土壤氮素的矿化量与矿化速率。试验期间通过大气沉降输入的氮素总量为118.89 mg,是氮素输入的主要方式,而湿沉降约为氮素沉降总量的81.05%。黄棕壤和潮土氮素蔬菜作物氮素的携出量分别为178.96和230.37 mg;氮素淋失量分别为103.32和113.27 mg。 相似文献
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苏打盐碱化稻田土壤氮素矿化和硝化特征及其影响因子 总被引：1，自引：0，他引：1
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土地利用方式对湿润亚热带土壤硝化作用的影响 总被引：27，自引：0，他引：27
在土壤最大持水量60%和30℃条件下对采自江西的自然土壤(森林和灌丛)和农业利用土壤(稻田、旱地和茶园)进行了实验室培养,研究土地利用对硝化作用的影响。结果表明,由于土壤呈酸性(pH4.2～6.3,平均为4.9),供试土壤的硝化作用很弱甚至缺失。当无外加铵态氮时,土壤的硝化速率与有机氮矿化速率呈显著的线性关系(p<0.01),而与土壤pH无关;当外加铵态氮使基质饱和时,硝化速率与土壤pH显著相关(p<0.01)。农业利用显著提高土壤的硝化作用能力,绝大部分自然土壤(78%)的净硝化速率小于净矿化速率,无机氮以铵态氮为主,而绝大部分农业利用土壤(74%)的净硝化速率大于净矿化速率。农业利用通过提高土壤pH、氮肥施用刺激硝化作用及改善土壤磷素供应状况等途径促进土壤的硝化作用。农业利用土壤硝化作用能力的提高增加了氮肥以硝态氮形态淋失的风险。 相似文献
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Shinya Funakawa Sota Tanaka Hitoshi Shinjyo Thammanoon Kaewkhongkha Tomoo Hattori Koyo Yonebayashi 《Soil Science and Plant Nutrition》2013,59(3):681-693
Abstract There is a large number of hill people in northern Thailand, who practices shifting cultivation. In order to analyze the soil ecological problems involved in the transition from traditional shifting cultivation to more intensive upland farming, the authors carried out comparative studies on the dynamics of organic matter and its related properties in soils both in the traditional shifting cultivation systems adopted by Karen people and more intensive upland farming practiced by Thai and Hmong people in the area. The contents of organic matter and available N in the surface 10 cm layers of soil from the fields continuously cultivated were lower than those in soils under prolonged fallow (more than 10 y) or natural forest. Based on the rate of soil respiration, the amount of organic matter decomposed within 1 y was estimated to reach nearly 10% of that stored in the upper 50 cm layers of the soil profile in the upland crop fields. These results indicate that the organic matter-related resources markedly decreased under continuous cropping. The contents of C, N, and P in the microbial biomass of the surface 10 cm layers of soil ranged from 0.37 to 2.09 mg C g?l soil, from 22.7 to 188 µg N g?l soil, and from 6.1 to 65.7 µg P g?l soil, respectively. Since the contents of microbial C, N, and P in the surface soils were generally higher under prolonged fallow and natural forests than in the fields continuously cultivated, the microbial activity and/or the amounts of C, N, and P available for biological activity seemed to have declined under continuous upland farming. The incubation experiment to assess the N mineralization pattern showed two remarkable characteristics: 1) there was an initial time lag until active mineralization of N occurred in the soils from young fallow forest and 2) the soil burning effect was observed after burning in the fields under prolonged fallow. The active process of nitrification after N mineralization was always associated with a sharp fall in soil pH, suggesting that soil acidification was promoted and basic cations were lost from the soils. In conclusion, rapid deterioration of the soil organic matter-related properties in cropping fields can be considered to be one of the ecological reasons why upland fields must be returned to fallow again a few years after forest reclamation in traditional shifting cultivation systems. Therefore, in alternative farming systems with more intensive land use, it is essential to apply organic materials into soils to decrease the rate of soil degradation, or to improve the soil fertility, in avoiding soil acidification along with nitrification. 相似文献
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Wen-Yan Han Jian-Ming Xu Kang Wei Ruan-Zhi Shi Li-Feng Ma 《Soil Science and Plant Nutrition》2013,59(5):727-739
There is growing interest in investigations into soil carbon (C) sequestration, plant nutrients and biological activities in organic farming since it is regarded as a farming system that could contribute to climate mitigation and sustainable agriculture. However, most comparative studies have focused on annual crops or farming systems with crop rotations, and only a few on perennial crops without rotations, e.g. tea (Camellia sinensis (L.) O. Kuntze). In this study, we selected five pairs of tea fields under organic and conventional farming systems in eastern China to study the effect of organic farming on soil C sequestration, plant nutrients and biological activities in tea fields. Soil organic C, total nitrogen (N), phosphorus (P), potassium (K) and magnesium (Mg), available nutrients, microbial biomass, N mineralization and nitrification were compared. Soil pH, organic C and total N contents were higher in organic tea fields. Soil microbial biomass C, N and P, and their ratios in organic C, total N and P, respectively, net N mineralization and nitrification rates were significantly higher in organic fields in most of the comparative pairs of fields. Concentrations of soil organic C and microbial biomass C were higher in the soils with longer periods under organic management. However, inorganic N, available P and K concentrations were generally lower in the organic fields. No significant differences were found in available calcium (Ca), Mg, sodium (Na), iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn) concentrations between the two farming systems. These findings suggest that organic farming could promote soil C sequestration and microbial biomass size and activities in tea fields, but more N-rich organic fertilizers, and natural P and K fertilizers, will be required for sustainable organic tea production in the long term. 相似文献
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温度对不同年限日光温室土壤氮素矿化特性的影响 总被引：3，自引：0，他引：3
【目的】日光温室作为具有我国特色的一种高强度的栽培方式,过量施肥问题突出。随着温室栽培在我国北方地区规模的不断扩大,由此带来的土壤退化和地下水污染问题值得关注。不少研究表明,随着日光温室栽培年限的增加,土壤有机质含量不断增加;且温室栽培中的土壤温度与露地存在很大差异,其土壤氮素矿化特性如何,尚缺乏研究。【方法】本研究以位于黄土高原南部陕西省杨凌示范区不同栽培年限的日光温室土壤为研究对象,采用室内好气培养法(84 d)测定不同培养温度(20℃和30℃)对不同年限温室(0 3年)土壤0—20 cm及20—40cm土层氮素矿化量,采用一级动力学方程拟合土壤氮素矿化曲线,根据土壤氮矿化势(N0)评价不同栽培年限温室土壤氮素矿化特性。【结果】1)随着日光温室栽培年限的增加,土壤有机质、全氮含量和氮素累积矿化量随之显著增加。2)30℃的土壤氮素累积矿化量高于20℃的矿化累积量;栽培年限长的日光温室矿化作用对温度的敏感程度高于年限短的温室。3)若温度和栽培年限同时增加,土壤氮素累积矿化量随之增加,说明温度和栽培年限对土壤氮素净矿化量有一定的交互作用,但差异不显著(P0.05)。4)日光温室栽培年限越长,土壤氮矿化势(N0)越大;与种植前相比,第2a、3a温室土壤氮矿化势增加了5.59和11.48倍。5)回归分析表明,0—20 cm土层土壤有机质含量每增加1 g/kg,20℃和30℃条件下土壤氮矿化势(No)分别增加2.70及3.18 mg/kg;土壤全氮含量每增加1g/kg,No分别增加37.28及43.12 mg/kg。【结论】日光温室土壤氮素矿化量随其栽培年限的增加显著增加;培养温度由20℃增加到30℃,土壤氮素矿化量也明显增加,日光温室栽培年限和温度对土壤氮矿化有一定的正交互效应。因此,在日光温室氮素管理中应考虑栽培年限和温度对土壤氮素矿化的影响,以采取针对性的氮素管理措施。 相似文献
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Jashandeep Kaur Larry J. Cihacek Amitava Chatterjee 《Communications in Soil Science and Plant Analysis》2018,49(18):2256-2266
Predicting nitrogen (N) and sulfur (S) mineralization of crop residues from the preceding crop might be a useful tool for forecasting soil N and S availability. Two soils from eastern North Dakota and three crop residues – corn, spring wheat, and soybean were used in an 8-week incubation study to estimate N and S mineralization from crop residues. The cumulative N and S mineralized were fit to a first-order kinetic model. Cumulative N mineralized ranged between 0.34 and 2.15 mg kg?1 and 0.45 to 3.41 mg kg?1 for the Glyndon and Fargo soils, respectively. Un-amended soils showed higher N mineralization than residue treated soils. For S, the highest mineralization occurred in un-amended Glyndon soil and in spring wheat-amended Fargo soil. This study indicates that crop residue additions can have a negative impact on plant available nutrients due to immobilization of N and S during the time when crops need the nutrients most. 相似文献
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温度和水分对华中地区菜地土壤氮素矿化的影响 总被引：8，自引：1，他引：7
为研究华中地区菜地土壤的矿化特征和矿化规律,拟定菜地土壤合理的氮肥施用量,本文以华中地区两种典型菜地土壤——黄棕壤和潮土为研究对象,利用室内连续培养试验研究了温度、水分对菜地土壤矿化的影响。结果表明,黄棕壤的矿化速率和氨化速率均随着温度的升高而升高;硝化速率在15%和25%含水量下随温度的升高而升高,而在35%含水量下随温度的升高而降低。潮土矿化速率在15%含水量时随温度的升高而升高,而在25%和35%含水量下随温度的升高先增加后减小;硝化速率在15%和35%含水量时随温度的升高而增加,25%含水量时随温度的升高先增加后降低;氨化作用随温度的升高而降低。黄棕壤的矿化量在含水量为25%、温度35℃时高达34.9 mg.kg 1;潮土的矿化量在含水量为25%、温度为25℃时最高,为63.9mg.kg 1。不同温度下潮土矿化量均大于黄棕壤。黄棕壤的氨化速率随含水量的增加而增加,硝化速率随含水量的增加而降低,矿化速率则在含水量25%时最大。潮土的氨化、硝化和矿化作用随水分变化不明显。本研究还发现,25%的含水量是黄棕壤微生物活性的水分临界点,潮土的水分临界点不明显。通过对土壤氮素的矿化速率与水分含量和温度之间的函数关系模拟发现,黄棕壤模拟效果好于潮土。 相似文献
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The tight coupling between nitrogen (N) and phosphorus (P) suggests that P availability may affect soil microbial N dynamics in terrestrial ecosystems. However, how P addition affects the internal N transformations in P-deficient agricultural soil remains poorly understood. We hypothesized that an increase in gross microbial N rates in P-deficient soil should occur after long-term P inputs in agricultural soils. We thus conducted a 15N pool dilution experiment to quantify the gross microbial N transformation rates after long-term mineral fertilizer applications in an upland fluvo-aquic soil (from Fengqiu with pH 8.55) and upland red soil (from Qiyang with pH 5.49) in China. We found that P addition significantly enhanced the gross N mineralization and immobilization rates when N and K were also applied, probably due to the increased soil total C and N concentrations at both soils. Also, gross nitrification rate was stimulated by P addition, perhaps because of enhanced gross N mineralization rates and associated NH4+ substrate availability. Our results showed that long-term P addition may stimulate soil gross N dynamics and hence increase overall N availability for crops in P-deficient agricultural soils. 相似文献