长期定位施肥对碱性紫色土磷素迁移与累积的影响

在25年稻麦轮作长期定位施肥试验点上，开展了碱性紫色土水旱轮作种植制不同施肥处理土壤剖面全磷、速效磷迁移和累积以及耕层土壤全磷、速效磷随时间的变化规律研究。结果表明，单施无机磷肥土壤磷可迁移至100 cm土层，Olsen-P可迁移至40 cm土层。有机无机磷肥配施不但使土壤磷可迁移至相同深度，且迁移量更大，Olsen-P可迁移至60 cm土层。耕作25年后，施磷处理土壤耕层磷素随时间的变化显著，MNPK处理耕层土壤全磷含量年增长率为0.033 g/kg，Olsen-P的年增长率为2.56 mg/kg。试验表明，连续数年施用足量磷肥后，作物施磷量可根据具体情况酌减，以节约磷肥资源和提高磷肥利用率；施用有机肥促进了磷素从耕层向底层的迁移，是造成土壤磷素迁移的一个重要因素。     

穴施条件下肥料养分在土壤中迁移规律的初步研究

根区施肥是高效施肥的关键措施,确定根区施肥的最佳位置,需要了解肥料施用后肥料养分在土壤中的迁移规律。本研究通过室内模拟试验来研究尿素、聚磷酸铵和氯化钾复合肥穴施条件下,土壤水分、培养时间对两种土壤中氮磷钾养分迁移的影响效应。结果表明：随土壤水分由30%增加到42%,氮磷钾在土壤中的迁移距离都会显著增加,培养15d的姜堰和广德两种土壤中,铵态氮、速效磷和速效钾的迁移距离分别由9-11cm、4cm和9-10cm增加到12-14cm、5-6cm和11cm。土壤含水量增加使氮磷养分的迁移距离平均增加了约三分之一。随培养时间从15天延长到30天,30%土壤含水量条件下两种土壤中速效磷迁移距离无显著变化,而速效钾的迁移距离显著增加,铵态氮迁移距离在硝化作用弱些的广德水稻土中增加显著,而在硝化作用较强的姜堰水稻土中增加幅度较小。肥料穴施条件下铵态氮的硝化作用除受土壤水分、pH和时间因素影响外,还受肥际高浓度养分的强烈抑制作用,这种抑制作用延缓了铵态氮向硝态氮的转化,是根区一次施肥技术中氮肥持续高效供应的重要原因。总体而言,氮磷钾养分迁移距离表现为：硝态氮>铵态氮>钾>磷,肥料氮的迁移受硝化作用影响大,肥料磷的迁移受土壤水分影响较大,而肥料钾与铵态氮的迁移规律较为类似,都因土壤水分增加和时间的延长而逐渐增加。     

贵州土壤养分含量的变化与施肥管理

为了解近年来化肥施用量倍增后 ,贵州农田土壤养分含量的变化 ,在 1985年土壤调查的基础上 ,1998年再次进行了土壤和肥料调查。调查结果表明 ,在目前有机肥与化肥相结合 ,养分供应以化肥为主的施肥结构下 ,水田土壤有机质和氮、磷含量有所增加 ,旱地土壤有机质和全氮含量下降 ,土壤磷素有积累。由于钾肥施用不足 ,水田、旱地土壤钾素含量都明显降低。土壤微量元素中 ,有效态硼、锌、钼普遍增加。今后需增加钾肥的施用 ,并重视施用有机肥、秸杆还田和防治水土流失 ,以培肥土壤 ,实现农业的持续发展     

长期施用氮磷钾化肥和有机肥对土壤氮磷钾养分的影响

扼要地概述了国内外近年来关于长期施肥条件下土壤氮，磷，钾养分动态与平衡方面的研究成果，内容包括土壤氮，磷，钾养分含量及有效量的动态变化，氮，磷，钾的生态形态及转化，氮，磷，钾在土壤剖面中的迁移等。     

长期施肥对河西绿洲灌漠土作物产量及土壤养分自然供给能力的影响

为提高甘肃河西绿洲粮食高产、稳产、高效生产能力及土壤养分资源管理水平,通过设置于甘肃河西绿洲长达25年(19822~006年)的长期肥料定位试验,研究长期施肥对作物产量及土壤养分供给能力的影响。结果表明:连续25年不施用任何肥料或单施氮肥,会导致农田土壤生产能力严重衰退;氮、磷或氮、磷、钾肥配合施用能使作物持续高产、稳产;随试验年限的延续,磷肥、有机肥增产效应逐渐积累,并表现出良好的渐进性和持续性;钾肥在试验开始后最初6年(19821~987年)无显著增产效应,中期具有一定的增产作用(19881~992年),后期14年(19932~006年)显著增产。土壤磷素自然供给能力随试验年限的延续逐渐减小,而钾素的自然供给能力相对稳定。     

长期施肥稻田土壤基础地力和养分利用效率变化特征

【目的】 研究长期不同施肥措施对土壤基础地力和氮磷钾养分吸收利用效率的影响，探明土壤基础地力和氮、磷、钾养分吸收利用效率的相互关系。 【方法】 采集双季水稻种植制度下 33 年长期定位施肥试验的不施肥 (CK)、施氮磷钾肥 (NPK) 和氮磷钾肥配施稻草 (NPKS) 3 个处理的土壤，设置施肥与不施肥盆栽试验，监测水稻产量、土壤基础地力产量和基础地力贡献率、水稻氮磷钾养分吸收量、氮磷钾养分利用效率，分析氮、磷、钾利用效率对土壤基础地力贡献率的响应。 【结果】 早晚稻土壤基础地力产量和基础地力贡献率三个处理土壤大小顺序均为 NPKS > NPK > CK，NPKS 处理土壤早晚稻两季平均基础地力产量和基础地力贡献率较 CK 处理土壤分别增加 113.8% 和 93.7%，NPK 处理分别增加 100.7% 和 81.9%。在同一施肥水平条件下，早、晚稻均以土壤基础地力较高的 NPKS 处理氮、磷、钾肥偏生产力，土壤养分依存率，氮、磷、钾素收获指数较高，氮、磷、钾肥回收利用率，肥料农学效率，肥料对产量的贡献率则较低。回归分析表明，氮、磷肥回收利用率，氮、磷、钾肥农学效率，氮、钾素生理利用率均随土壤基础地力贡献率的提高呈显著或极显著降低；氮、磷、钾肥偏生产力，氮、磷、钾素土壤依存率随土壤基础地力贡献率的提高呈显著或极显著提高。 【结论】 长期施氮磷钾肥或长期氮磷钾肥配施稻草均能提高土壤基础地力，以长期氮磷钾肥配施稻草的效果更显著。在较高基础地力土壤上生产，可以在保证作物高产稳产的情况下实现减量化施肥，实现农业生产的可持续性。      

连续施肥对塿土肥力及产量的影响

对25年连续不同施肥小区土壤的养分状况和作物产量进行分析研究,结果表明:多年连续施肥,可以明显提高塿土中有机质、全氮、全磷、碱解氮、速效磷的含量,增加作物产量,即单施化肥或有机一无机肥料配合施用,都可以增强土壤养分容量及其供应强度,有利于培肥土壤,提高土壤肥力,从而提高作物产量,其中又以有机一无机肥料配合施用的效果更好。     

不同施肥条件下夏季辣椒的生长发育与养分吸收规律研究

通过田间小区试验,研究了辣椒的养分吸收规律和土壤速效养分的动态变化规律,旨在为洞庭湖区实施精确施肥、优化施肥结构以及蔬菜基地养分的系统调控提供科学依据。结果表明:有机无机肥配合施用处理较当地习惯施肥处理和纯化肥处理对氮、磷、钾养分的吸收量和利用率高。蔬菜生育期间,土壤有效氮、磷、钾含量均处于动态变化之中,总的来看,蔬菜专用肥处理土壤有效氮、磷、钾含量较高。根据辣椒对肥料养分的利用率和土壤养分状况及有效性,初步提出了增施有机肥、钾肥的优化施肥结构模式,以保证辣椒的丰产优质。     

不同施肥模式对作物-土壤系统养分收支的影响

以1 组20 年长期定位试验为基础, 针对不同施肥模式下作物-土壤系统养分收支状况进行研究。本试验共8 个处理, 分别由化肥氮(N)、磷(P)、钾(K)和循环有机肥(M)组合而成。结果表明, 养分循环再利用有利于作物产量的提高, 对大豆和玉米籽实平均增产率分别为22.9%和16.4%; 但随化肥的均衡施用, 有机肥增产作用明显降低。仅施用循环有机肥可缓解土壤养分收支赤字, 但无法实现作物高产和土壤养分收支平衡; 施用氮肥加剧土壤磷收支赤字, 同时施用氮、磷肥加剧土壤钾赤字。本研究中同时施用氮、磷、钾肥和循环肥模式可满足作物高产的养分需求, 同时能够平衡土壤养分收支, 是较为理想的施肥模式。     

长期不同施肥处理红壤旱地剖面养分分布差异

【目的】 研究长期不同施肥措施下红壤旱地的培肥效果、养分迁移特征以及环境风险，对制定红壤旱地合理的养分管理和培肥技术，促进畜禽粪便的循环利用具有重要意义。 【方法】 依托始于1986年的红壤旱地肥料定位试验，选取不施肥 (CK)、氮磷钾肥配施 (NPK)、2倍氮磷钾肥配施 (2NPK)、有机肥 (OM) 和有机肥和氮磷钾肥配施 (NPKM) 5个处理，采集0—10 cm、10—20 cm、20—40 cm、40—60 cm、60—80 cm、80—100 cm土壤样品，分析了pH值、有机质及氮磷钾养分含量。 【结果】 连续施肥28年后，红壤旱地土壤有机质、全氮、碱解氮、全磷、有效磷、速效钾等含量均随着土壤深度增加逐步降低。与对照相比，施用有机肥显著提高了0—40 cm土壤的pH值，其余处理pH有所下降。长期施用化肥后，红壤旱地土壤有效磷、全磷、碱解氮和全氮在0—20 cm耕层累积，土壤速效钾的累积则达到40 cm深；与化肥处理相比，有机肥和有机无机肥配施处理0—40 cm土壤的全氮、碱解氮、速效钾、有效磷和全磷的含量显著增加，土壤全氮和碱解氮的下移累积达到40 cm，而土壤全磷和有效磷的下移累积则达到了60 cm。红壤旱地长期施用猪粪等有机肥主要增加了0—40 cm耕层土壤的磷素累积，而在剖面80 cm以下未表现出明显累积现象。 【结论】 长期施用化肥 (28年)处理养分主要在0—20 cm红壤旱地耕层土壤累积，而长期施用有机肥或有机无机肥配施还可以明显提高20—40 cm土壤养分含量，养分下移累积作用明显。此外，红壤旱地长期施用有机肥可以缓解耕层土壤的酸化、提高耕层土壤肥力水平，是增加培肥深度的有效措施，但是长期施用猪粪导致的氮磷下渗深度增加可能引起的环境风险也应引起重视。      

蔬菜地土壤磷饱和度及其对磷释放和水质的影响

为了解蔬菜地土壤磷素的积累对水环境的影响,我们在浙江省选择了33个代表性蔬菜地,采集和分析了土壤、地表水和地下水样的磷素状况,从土壤磷饱和度的角度,研究了浙江省主要蔬菜土壤磷积累状况及其对地表和地下水水质和土壤磷释放潜力的影响。结果表明,半透膜渗析法测得的磷释放量与土壤磷积累呈正相关,磷释放量随土壤磷饱和度的提高而增加。蔬菜地土壤磷饱和度的增加可显著提高地表水体和地下水中磷的浓度,当土壤磷饱和度小于25%左右时,水体中磷浓度随土壤磷饱和度增加较为缓慢;但当磷饱和度大于25%时,水体中磷浓度随土壤磷饱和度提高迅速上升。地表水中磷浓度主要与表层土壤磷饱和度有关;地下水中磷浓度主要受深层土壤磷饱和度的影响,与表层土壤磷饱和度的相关性较小。土壤磷饱和度可很好地表征土壤磷释放和对环境的潜在影响。     

河岸水稻缓冲带宽度对排水中氮磷流失的影响

研究表明，在正常条件下，可溶态P、NH4-N和NO3-N在稻田水平方向的扩散距离较短，一般小于10m；扩散距离：可溶态P〈NH4-N〈NO3-N。缓冲带宽度（0～90m）对排水中可溶态P、NH4-N和NO3-N的浓度有很大的影响，但这种影响随施肥后时间的延长而减小。宽度大于15m的水稻缓冲带可显著地降低排水中氮磷的流失，因此在沿河用不施肥的水稻带也可有效地控制氮、磷的流失，替代一般的缓冲带，其机理与湿地相似。     

浙北平原不同种植年限蔬菜地土壤氮磷的积累及环境风险评价

长期过量施肥可导致蔬菜地土壤养分大量累积、养分利用效率下降和环境污染风险增加。以浙北平原不同种植年限蔬菜地土壤为研究对象,采用化学测试方法研究了菜地土壤氮和磷的积累及其淋失潜力的变化。结果表明,随着种植年限的增加,蔬菜地土壤全磷、有效磷（Olsen P）和NO3-N呈明显的积累;蔬菜种植年限为〈2、2～5、6～10、11～20、20～30和＆gt;30a的表土全P平均分别为0.66、0.75、1.07、1.49、2.40和2.12g·kg-1,有效P平均分别为13.2、37.8、42.2、70.2、137.9和101.7mg·kg-1,NO3-N平均分别为9.15、13.58、50.18、46.48、73.28和74.20mg·kg-1,同时土壤N和P垂直下移渐趋明显。土壤水溶性磷含量随土壤有效磷（OlsenP）积累的变化存在一个明显的突变点,相对应的土壤OlsenP临界值约为60mg·kg-1。随着种植年限增长,蔬菜地地表径流中氮和磷浓度呈明显增加,利用年限为20～30a的蔬菜地径流中可溶性P和NO3-N浓度分别约为利用年限〈2a蔬菜地的13.12和9.48倍。研究认为,长期超量施肥已导致这一地区蔬菜地土壤养分的过度积累,在蔬菜生产中应重视和提倡平衡施肥,控制土壤氮磷的积累。     

砂质土壤磷素的组成特点与释放规律研究

砂质土壤磷素主要以可提取态形式积累,有很高的释放潜力。该类土壤磷素的释放受土壤pH、土水作用时间和土壤溶液化学组成等的影响。土壤酸化、土壤溶液中Na+浓度的提高及土壤与水的作用时间增加可促进土壤磷素的释放。用淋洗方法和平衡提取等2种方法对土壤磷素的释放评价表明,淋洗方法测得的P量较小,可代表土壤短期内P释放强度;而平衡提取法提取的P数量较大,可代表土壤P长期释放的容量。     

施肥深度和用量对华南果园土壤氮磷流失的影响

Fertilizers are heavily applied in orchards of the hilly and mountainous topography of South China and may increase nutrient loadings to receiving waters. A simple runoff collecting system was used to measure the effects of different fertilization treatments on total N and P concentrations of surface runoff in a Chinese chestnut （Castanea mollissima Blume） orchard in Dongyuan County, Guangdong Province, China. In such orchards, fertilizer was typically applied in two short furrows or pits on either side of each tree. Treatments included three application depths （surface, 10 cm and 20 cm）, and three application rates （low, median and high）. Results showed that 90.5% of the runoff water samples had a total N concentration higher than 0.35 mg·L^-1 and 54.2% had a total P concentration higher than 0.1 mg·L^-1. Fertilizer application at all depths and at all but the lowest rate significantly increased total N and P concentrations in runoff water. Fertilization with chemical compound fertilizer at a soil depth of 20 cm produced significantly lower （P 〈 0.05） total N concentration in runoff than both surface and 10-cm depth fertilization, and significantly lower （P 〈 0.05） total P concentration in runoff than surface fertilization. Total N and P concentrations in runoff significantly increased with the application rate of organic fertilizers. With the exception of total P concentrations, which were not significantly different between the control and fertilization at a rate of 119 kg P ha-1 in organic form, all the other fertilization treatments produced significantly higher total N and total P concentrations in runoff than the control. A fertilization depth ≥ 20 cm and an application rate ≤ 72 kg N ha-1 or 119 kg P ha^-1 for compound organic fertilizer was suggested to substantially reduce N and P runoff losses from hillslope orchards and to protect receiving waters in South China.     

Adsorption controls mobilization of colloids and leaching of dissolved phosphorus

Loss of phosphorus (P) from agriculture contributes to the eutrophication of surface waters. We have assessed the magnitude and controls of P leaching and the risk of colloid‐facilitated transport of P from sandy soils in Münster. Concentrations of soluble reactive P in drainage water and groundwater were monitored from 0.9 to 35 m depth. Total P concentrations, P saturation, and P sorption isotherms of soil samples were determined. Concentrations of dispersible soil P and colloidal P in drainage water and groundwater were investigated. The concentrations of soluble reactive P in drainage water and groundwater were close to background concentrations (< 20 µg P l^?1). Median concentrations in excess of 100 µg P l^?1 were found down to 5.6 m depth at one of four research sites and in the lower part of the aquifer. Experimentally determined equilibrium concentrations and the degree of P saturation were good predictors of P concentrations of drainage water. Large concentrations of dispersible P were released from soil with large concentrations of oxalate‐extractable P and addition of P induced further dispersion. Colloidal P was transported in a P‐rich subsoil when there was a large flow of water and after nitrate had been flushed from the soil profile and total solute concentrations were small. We conclude that the concentration of soluble reactive P in drainage water is controlled by rapid adsorption in the sandy soils. Subsurface transport of dissolved P contributes substantially to the loss of P from the soils we investigated. Accumulation of P in soils increases the risk of colloid‐facilitated leaching of P.     

中国洞庭湖区稻田土壤氮素淋溶损失的系统研究

A two-year lysimeter study was conducted to study the effects of different fertilizers and soils on nitrogen leaching loss in a double rice cropping system by considering three major types of paddy soils from the Dongting Lake area. The results showed that N concentration in the leachate did not differ significantly among the treatments of urea, controlled release N fertilizer and pig manure and that all these fertilizers produced higher total nitrogen (TN) concentrations in the leachate compared to the case where no fertilizer was applied. The TN leaching loss following urea treatment accounted for 2.28%, 0.66%, and 1.50% of the amount of N applied in the alluvial sandy loamy paddy soil (ASL), purple calcareous clayey paddy soil (PCC), and reddish-yellow loamy paddy soil (RYL), respectively. Higher TN loss was found to be correlated with the increased leachate volume in ASL compared with RYL, and the lowest TN loss was observed in the PCC, in which the lowest leachate volume and TN concentration were observed. Organic N and NH4+ -N were the major forms of N depleted through leachate, accounting for 56.8% and 39.7% of TN losses, respectively. Accordingly, soil-specific fertilization regimens are recommended; in particular, the maximum amount of fertilizer should be optimized for sandy soils with a high infiltration rate. To avoid a high N leaching loss from rice fields, organic N fertilizers such as urea or coated urea should primarily be used for surface topdressing or shallow-layer application and not for deep-layer application.     

共施磷酸二氢钙和硫酸铵对土壤中钾形态转化的影响

Soil potassium (K) deficiency has been increasing over recent decades as a result of higher inputs of N and P fertilizers concomitant with lower inputs of K fertilizers in China; however, the effects of interactions between N, P, and K of fertilizers on K status in soils have not been thoroughly investigated for optimizing N, P, and K fertilizer use effciency. The influence of ammonium sulfate (AS), monocalcium phosphate (MCP), and potassium chloride application on K fractions in three typical soils of China was evaluated during 90-d laboratory soil incubation. The presence of AS significantly altered the distribution of native and added K in soils, while addition of MCP did not significantly affected K equilibrium in most cases. Addition of AS significantly increased water-soluble K (WSK), decreased exchangeable K (EK) in almost all the soils except the paddy soil that contained considerable amounts of 2:1 type clay minerals with K added, retarded the formation of fixed K in the soils with K added, and suppressed the release of fixed K in the three soils without K added. These interactions might be expected to influence the K availability to plants when the soil was fertilized with AS. To improve K fertilizer use effciency, whether combined application of AS and K was to be recommended or avoided should depend on K status of the soil, soil properties, and cropping systems.     

Nitrogen Fertilizer Replacement Value of Concentrated Liquid Fraction of Separated Pig Slurry Applied to Grassland

Seven grassland experiments on sandy and clay soils were performed during a period of 4 years to estimate the nitrogen (N) fertilizer replacement value (NFRV) of concentrated liquid fractions of separated pig slurry (mineral concentrate: MC). The risk of nitrate leaching when applying MC was compared to when applying mineral fertilizers. Grassland yields in 2009–2012 fertilized with MC were compared with grassland fertilized with two mineral fertilizers: granulated calcium ammonium nitrate and liquid ammonium nitrate (LAN). The mineral fertilizers comprised 50% nitrate-N and 50% ammonium-N, and MC comprised 95–100% ammonium-N. Treatment application rates included zero N and three incremental rates of N fertilization. The liquid fertilizers were shallow injected (0–5 cm). The NFRV of MCs was 75% on sandy and 58% on clay soil with granulated ammonium nitrate as reference, and 89% on sandy and 92% on clay soil with LAN as reference. Risk of nitrate leaching after application of MC, measured in residual soil mineral N post-growing season and N in the upper groundwater in the following spring, was equal to that for mineral fertilizers.     

Evaluation of Dolomite Phosphate Rock–N‐Viro Soil Mixtures for Growth of a Horticultural Crop in an Acidic Sandy Soil

Abstract

Most agricultural soils in the Indian River area, South Florida, are sandy with minimal holding capacity for moisture and nutrients. Phosphorus (P) leaching from these soils has been suspected of contributing to the eutrophication of surface waters in this region. Dolomite phosphate rock (DPR) and N‐viro soil are promising amendments to increase crop production and reduce P loss from sandy soils. Soil incubation and greenhouse pot experiments were conducted to examine the effects of Florida DPR–N‐viro soil mixtures on the growth of a horticultural crop in an acidic sandy soil and to generate information for developing a desired formula of soil amendments. Dolomite phosphate rock and N–viro soil application increased soil pH, electrical conductivity (EC), extractable P, calcium (Ca), and magnesium (Mg). N–viro soil had greater effect on soil pH, organic matter content, and microbial biomass than the DPR. Comparatively higher nitrification rates were found in the N–viro soil treatment than the DPR treatment. A systematic decrease in soil‐extractable P was found with increasing proportions of N‐viro soil from the combined amendments. Greenhouse study demonstrated that the application of DPR and N‐viro soil significantly improved dry‐matter yield and increased plant P, Ca, and Mg concentrations of radish (Raphanus sativus L.). Based on dry‐matter yield and plant N uptake, the combined amendments that contained 30% or 20% of DPR materials appear to be optimal but remain to be confirmed by field trials.