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1.
Abstract. Between 1978 and 1985 16 experiments tested crop response to subsoil loosening by either the Wye Double Digger or a winged subsoiler. Additionally, response to incorporation of 350 kg ha of P2O5and K2O into the subsoil was tested. Soil types were mainly well-drained light-and medium-textured soils in arable rotations. Subsoil loosening increased the yield of spring-sown crops on sandy soils in years of moderate to severe drought. Response was associated with deeper rooting and improved water extraction from the subsoil. No yield increases were recorded with autumn-sown crops which were largely grown on the medium and heavy textured soils. There was a trend towards yield reductions on deep silty soils in wetter years. At one site only did the response to phosphorus and potassium fertilizer incorporated into the subsoil exceed that of fertilizer applied to the topsoil.  相似文献   

2.
The availability of fertilizer P in six P-deficient tropical soils from Brazil, Kenya, Malaysia and Indonesia was assessed by grass in a pot experiment. Grass dry matter yield (D) and fertilizer P(F) were fitted to a Mitscherlich equation: D= a?b exp(?cF), and P uptake (U) and F to the linear equation: U=α+βF. Fitted parameter β equals the proportion of P recovered in one crop and it varied widely between soils, ranging from 12 to 51%. Quantitative assessments of fertilizer-P availability could also be made using dry-matter data alone if the rates of fertilizer used were well distributed along the response curve, when Mitscherlich parameter c was correlated well with β. Chemical measurements were made on uncropped soil. Phosphate sorption isotherms were measured, using 32P to assess exchangeable and non-exchangeable phosphate. The availability parameters c and β were correlated best with parameter be, the phosphate buffer capacity derived from the fitted Freundlich isotherm for exchangeable phosphate, suggesting that the mobility of exchangeable phosphate is a major influence on P availability. Al and Fe were extracted with acid oxalate, citrate-dithionite and pyrophosphate reagents, and parameters c and β correlated best with Al extracted by acid oxalate. These relationships were inverse, showing that Al in disordered mineral forms lowers the availability of fertilizer P.  相似文献   

3.
Fertilizer application, particularly nitrogen (N), is important in cool‐season grass forage production. Subsurface (knife) placement of N often has resulted in higher forage yield and N uptake of tall fescue (Festuca arundinacea Schreb.) compared to surface‐broadcast fertilization, but further studies were needed to indicate whether soil pH, phosphorus (P), or potassium (K) modifies the response. Experiment I tested responses of forage yield and N and P concentration to N, P, and K amount and placement. Two types of fertilizer placement ‐ broadcast and knife ‐ were used with 13, 112, or 168 kg N; 0 or 19 kg P; and 0 or 37 kg K/ha in a factorial arrangement. Yields increased by 53% as N fertilization went from 13 to 112 kg/ha and by 69% as N increased from 13 to 168 kg N/ha. Forage yield was increased 26% from knife compared to broadcast fertilizer placement. P application increased forage production by 13%, but K application had no effect on yield. Forage N concentrations increased by 25% as N fertilization went from 13 to 112 kg/ha and by 38% as N increased from 13 to 168 kg N/ha. Effects of added P and fertilizer placement on N concentration often resulted in interactions among factors. Forage P generally was increased by added P, with some effects of interactions among N rate, P rate, and placement. In Experiment II, fescue responses to N placement were tested where different soil characteristics had been established by previous lime and fertility treatments. Forage yield, N concentration, and N uptake were highest where 9.36 Mg/ha of lime were applied as compared to the control. Previous fertility treatments had no significant (P<0.05) effect. When N was knifed, forage yield was related positively to available soil P but not to pH or K. Yield and forage N concentration and uptake were increased by 20, 11, and 33%, respectively, as a result of knife versus broadcast N application.  相似文献   

4.
生土条件下冬小麦对氮、磷、钾的原始响应   总被引:11,自引:5,他引:11  
配方施肥是提高作物肥料利用率和产量品质的重要措施。但氮、磷、钾营养元素之间的相互关系仍然存在一些不确定性,不同土壤肥力及不同的研究方法是造成这一结果的原因。本研究采用肥力极低的生土为基质,探讨了氮、磷、钾、有机肥及不同组合、配比对冬小麦产量和品质性状的影响。结果表明,只有磷素存在才能使小麦正常生长发育,单施氮、钾以及氮钾配施都不能保证小麦生长的基础代谢,不能形成正常产量。磷对氮的效应远大于氮对磷的效应。在土壤营养极度匮乏的非耕作土壤条件下,磷素是产量与品质形成的第一限制因素,可能作为土壤肥力形成的原始起动因素。  相似文献   

5.
等养分条件下稻草还田替代双季早稻氮钾肥比例的研究   总被引:7,自引:4,他引:7  
【目的】研究等量氮磷钾养分投入条件下,长期稻草原位全量还田配施化肥对双季早稻氮 (N)、磷 (P)、钾 (K) 养分吸收累积、转运及养分利用的影响,为南方稻区稻草资源有效利用,维持并提高土壤肥力及水稻合理施肥提供理论依据。【方法】以江西温圳国家级耕地质量监测点长期定位试验为研究对象,陆两优 996 为供试材料,在不施化肥和施用化肥基础上设稻草还田、稻草烧灰还田和稻草不还田共 6 个处理,除空白对照外,所有处理养分投入量相等。于 2015 年在早稻移栽期、分蘖期、幼穗分化期、抽穗期和成熟期取地上部植株样,分析水稻植株不同部位的 N、P、K 含量和累积量以及转运比例,并计算 N、P、K 养分利用效率。【结果】稻草还田提高了水稻产量,施肥条件下稻草还田处理比稻草烧灰还田和稻草不还田处理平均增产 2.9%~ 6.4%,比不施肥区产量增幅高达 23.8%~ 26.0%,且差异达显著水平。无论是施肥区处理,还是无肥区处理,与稻草烧灰还田和稻草不还田处理相比,稻草还田植株中 K 含量及 N、P、K 积累量在整个生育期均较高,而 N、P 含量在生育后期较高,N、P、K 积累量以施肥区处理大于相应的无肥区处理;稻草还田提高水稻 N、P、K 养分农学效率、回收率和养分偏生产力,且 N、K 差异达显著水平,同时显著增加 K 的收获指数;稻草还田还提高了抽穗至成熟期茎鞘中 N、P、K 的转运量、转运率及转移养分对籽粒的贡献率,而叶片各处理间差异不显著。【结论】稻草还田配施化肥能提高水稻产量,同时还可以调节 N、P、K 养分的积累和转运,提高养分的吸收利用效率。本试验条件下,稻草还田可替代化肥氮肥 (N) 29.5%、磷肥 (P2O5) 4.0% 和钾肥 (K2O) 50.0%。综合考虑,稻草还田相比稻草烧灰还田而言是南方稻区土壤养分管理实现高效利用的有效途径之一。  相似文献   

6.
对不同土壤肥力水平下元白菜施氮、磷、钾和锌肥的效应研究表明,不同土壤肥力水平下,元白菜施氮、磷、钾和锌均能显著增加产量,分别增产12.0%~35.8%(平均24.5%)、5.3%~14.1%(平均9.7%)、11.2%~15.3%(平均12.9%)和7.5%~11.3%(平均9.1%)。在较高、中等和较低土壤肥力水平下,元白菜经济最佳施氮(N)量分别为310.5、326.1~336.6和378.9 kg/hm2,适宜磷(P2O5)用量依次为60、60~90和90~120 kg/hm2。不同土壤肥力水平地块元白菜适宜施氮时,氮肥(N)利用率在15%~20%,适宜施磷时磷肥(P2O5)利用率在9.3%~11.0%;元白菜上钾肥利用率随土壤钾素水平的降低而呈增加的趋势,不同土壤肥力地块元白菜施K2O 120 kg/hm2时钾肥(K2O)利用率平均为20.4%。  相似文献   

7.
不同土壤肥力水平下元白菜施氮、磷、钾和锌的效应   总被引:2,自引:0,他引:2  
对不同土壤肥力水平下元白菜施氮、磷、钾和锌肥的效应研究表明,不同土壤肥力水平下,元白菜施氮、磷、钾和锌均能显著增加产量,分别增产12.0%~35.8%(平均24.5%)、5.3%-14.1%(平均9.7%)、11.2%.15.3%(平均12.9%)和7.5%~11.3%(平均9.1%)。在较高、中等和较低土壤肥力水平下,元白菜经济最佳施氮(N)量分别为310.5、326.1~336.6和378.9kg/hm^2,适宜磷(P2O5)用量依次为60、60-90和90~120kg/hm^2。不同土壤肥力水平地块元白菜适宜施氮时,氮肥(N)利用率在15%~20%,适宜施磷时磷肥(P2O5)利用率在9.3%~11.0%;元白菜上钾肥利用率随土壤钾素水平的降低而呈增加的趋势,不同土壤肥力地块元白菜施K2O120kg/hm^2时钾肥(K2O)利用率平均为20.4%。  相似文献   

8.
长期施氮、磷、钾化肥对玉米产量及土壤肥力的影响   总被引:53,自引:3,他引:53  
以1990年建立的国家褐潮土土壤肥力与肥料效益长期监测基地(北京昌平站)的长期肥料定位试验为研究平台,研究了不同施肥制度对玉米产量和土壤肥力的影响。结果表明,长期均衡地施NPK肥或NPK与有机肥配施,可以显著提高玉米产量和土壤有机质、全氮、全磷、速效氮、速效磷、速效钾等肥力指标,并能提高土壤微量元素的含量;而不均衡施肥(N、NK、NP、PK)导致相应的营养元素的耗竭。相关分析表明,在褐潮土上增施磷肥和有机肥对提高玉米产量具有重要的作用。  相似文献   

9.
Abstract

In Western Australia soil samples to measure soil‐test phosphorus (P) are collected November to March when soils are usually dry. Most of the soils are hard‐setting when dry and it is difficult to penetrate and collect soil samples to 10 cm using the traditional sampler, which is a 2.5 cm diameter tube that is pushed into the soil by foot. Farmers collect too few soil samples at shallow depths to measure soil‐test P. In Part 1 of this paper, it was shown that soil‐test P can vary markedly for individual soil samples collected from uniform areas in paddocks. Consequently, an adequate number of soil samples needs to be collected and bulked from defined areas to measure soil‐test P. Phopshorus accumulates near the top of the soil of (i) pastures since P fertilisers are applied to the surface of pastures, and (ii) crops sown by minimum (conservation) tillage. Crops are increasingly being sown using conservation tillage methods. Collecting too few soil samples to a shallow depth can result in large errors when estimating the current P status of soils and determining optimum fertiliser application levels. A new rotating blade method of collecting soil samples to the standard 10 cm depth for measuring soil‐test P was compared with the traditional sampler. The new sampler successfully penetrated hard‐setting soils to the standard depth and the soil samples it collected produced similar soil‐test P as the traditional sampler. Consequently, the same soil‐test P calibrations determined using the traditional sampler can also be used for the new sampler. The new sampler is, therefore, recommended for collecting soil samples to measure soil‐test P. It should have application wherever hard‐setting soils pose a problem for soil P testing.  相似文献   

10.
This paper, complementing the first part (Shaxson et al., 2014), sketches the outlines of an ecologically-based approach to better care of soils, within the overarching context of ‘land husbandry’, contributing to more-effective conservation of soil and water. It suggests an up-dated paradigm which concentrates more on renewing and conserving the biologically-moderated spaces in the soil in the root-zone rather than on the solid soil-particles themselves. When read in sequence, the two papers offer contributions to better understanding of both the problems and the possibilities for solving the ongoing uncertainties of how best to repair damaged lands, to maintain and improve those areas already in use, and to safeguard the potentials of those as-yet-unopened areas which surely will be brought into production in the future, by the planning and executing of optimum strategies for assuring sustainability of their uses into the future. These two papers do not set out to challenge existing knowledge, but rather to suggest additions to, and alternative interpretations of, what may already be known. The conclusions suggest some important amplifications to any curriculum for the training and/or up-dating of people involved in those subject-areas which contribute to better land husbandry and more-effective conservation of soil and water, as well as to the buffering of soils’ productive capacities against the possible adverse effects of climate change.  相似文献   

11.
The residual values of fertilizer P in six tropical soils were assessed from the response of grass in a pot experiment. The comparison was made between residues of P that had been applied to a previous crop (also grass) and fresh P applied to uncropped soil. Yields of dry matter and P uptakes were fitted to Mitscherlich and linear equations respectively, and the availabilities of fresh and residual P were assessed by fitted parameters of these equations. With sufficient residual P, the maximum yields were close to those obtained with fresh P, but residual P always had a lower availability than fresh P. The residual value was assessed by the ratio of the availability parameters for residual and fresh P and these values showed that there were differences between soils in the decline of P availability. Residual value was not directly related to the initial availability of P. The P uptake responses to both fresh and residual P were correlated significantly with buffer capacity for exchangeable sorption of phosphate and Al extracted by acid oxalate. This suggested that there is an available fraction of residual P, the uptake of which is influenced by the sorption and mobility of phosphate in soil, in the same way as for fresh fertilizer P.  相似文献   

12.
豫东潮土区大蒜氮磷钾推荐施肥研究   总被引:1,自引:1,他引:0  
通过大蒜氮肥用量和丰缺指标多点田间试验研究,采用Excel进行统计分析,建立不同氮肥用量与产量的效应函数,推荐大蒜氮肥用量369.9 kg/hm2;以土壤中速效磷、速效钾养分的测定值及其相对产量拟合回归方程,再以相对产量的55%、75%、80%、90%划分土壤养分丰缺指标,同时结合大蒜的目标产量,进行磷、钾施肥量的推荐,分别为200、300 kg/hm2。  相似文献   

13.
Annual potassium (K) balances have been calculated over a 40‐year period for five field experiments located on varying parent materials (from loamy sand to clay) in south and central Sweden. Each experiment consisted of a number of K fertilizer regimes and was divided into two crop rotations, mixed arable/livestock (I) and arable only (II). Annual calculations were based on data for K inputs through manure and fertilizer, and outputs in crop removal. Plots receiving no K fertilizer showed negative K balances which ranged from 30 to 65 kg ha?1 year?1 in rotation I, compared with 10–26 kg ha?1 year?1 for rotation II. On sandy loam and clay soils, the K yield of nil K plots (rotation I) increased significantly with time during the experimental period indicating increasing release of K from soil minerals, uptake from deeper soil horizons and/or depletion of exchangeable soil K (Kex). Significant depletion of Kex in the topsoil was only found in the loamy sand indicating a K supply from internal sources in the sandy loam and clay soils. On silty clay and clay soils, a grass/clover ley K concentration of ~2% (dry weight) was maintained during the 40‐year study period on the nil K plots, but on the sandy loam, loam and loamy sand, herbage concentrations were generally less than 2% K.  相似文献   

14.
为构建山地植烟土壤良好耕层,在保山市碱性植烟土壤区域设置随机区组大田试验,以深耕(30 cm)为主处理,不同培肥模式为副处理,于耕作前和烤烟收获后测定主要土壤理化性质,采用Illumina MiSeq测序技术分析微生物多样性、种群丰度、群落结构和功能类群特征,探讨深耕培肥对碱性植烟土壤质量改善效果。多样性分析结果显示,深耕配施生物有机肥和化肥处理的微生物种群的Chao指数和Shannon指数差异性不显著,但促进了微生物尤其是真菌群落组成结构差异性增强。微生物群落组成分析结果表明,与耕作前相比,化肥处理的Proteobacteria(变形菌门)、Acidobacteria(酸杆菌门)、Mortierellomycota(被孢霉门)和Basidiomycota(担子菌门)的丰度显著增加,Actinobacteria(放线菌门)和Ascomycota(子囊菌门)种群丰度显著降低;增施生物有机肥处理的Proteobacteria和Mortierellomycota的丰度显著增加,Chloroflexi、Acidobacteria和Basidiomycota的丰度显著下降;与化肥处理相比,增施生...  相似文献   

15.
Mechanically loosened subsoil has been shown to be prone to recompaction. We addressed a sandy loam that had been mechanically loosened by a subsoiler to a depth of 35 cm in 1997 and again in 1998. Perennial grass/clover was grown with limited traffic intensity in 1999 and 2000. A recompaction experiment was conducted in 2001 and 2002 when the soil was grown with oat and winter wheat, respectively. Using the formerly loosened plots, on-land ploughing was compared with traditional mouldboard ploughing with the tractor wheels in the furrow. In addition, the loosened plots were either light-trafficked (<6 Mg axle load and <100 kPa inflation pressure) or heavy-trafficked (10–18 Mg axle load and 200 kPa inflation pressure), respectively. Finally, the soil loosened by non-inversion deep tillage was referenced with a conventional ploughing–harrowing tillage system that never received the subsoil treatment. The conventional treatment was also grown with the grass/clover in 1999 and 2000. On-land ploughing and light traffic was applied in 2001 and 2002 instead of traditional ploughing and traffic for the conventional treatment. Penetration resistance and bulk density was recorded in the field. Undisturbed soil cores were taken in 1998, 1999 and 2002 from the 7–14, 18–27 and 25–30 cm layer and used for measuring total porosity, pores >30 μm and air permeability at −100 hPa matric potential. The results showed that on-land ploughing mitigated recompaction of the upper part of the formerly loosened subsoil. In contrast, only small differences in recompaction between heavy and light traffic were observed. The mitigation of subsoil recompaction was needed for the loosened soil to provide an upper subsoil with similar—not better—pore characteristics than the non-loosened soil in the conventional treatment. The structural conditions in the plough pan improved for the conventional treatment from 1998 to 2002 as indicated by an almost doubling in air permeability. This was interpreted as being related to the growing of grass/clover ley in 1999 and 2000 combined with a shift from traditional tillage and traffic to on-land ploughing and light traffic when growing cereals in 2001 and 2002. Results on root growth and crop yield are reported in an adjoining paper.  相似文献   

16.
Potassium release from saturated spherical aggregates of three clay soils to Ca-resin was measured and compared with release in suspensions (Talibudeen et al., 1978). The diffusion coefficient for K was calculated from measurements of the tortuosity factor using 36Cl, volumetric water content and buffer power. Release of K is in the order: suspensions >2–3 mm > 6–8 mm aggregates. A computer model incorporating diffusion analysis and release of K shows that in the aggregates the rapidly diffusing exchangeable K, Kex, is best measured by the extrapolated intercept of a desorption isotherm (24 h equilibration), and is 8–55% less than that extracted by NH4OAc leaching. Release of K within the aggregates (Knex, a fraction approximating to Talibudeen's peripheral K) is delayed until after about 95% of Kex has been depleted which takes 1–2 days. The effective release rate of Knex inside the aggregates is ~ 17% less than in soil suspensions. Diffusion imposes only small limitations on the release from aggregates of Knex. This rate of release depends on the frequency of resin changes.  相似文献   

17.
采用室内扩散模拟试验研究了施用大颗粒尿素(PUR)、辣椒专用复混肥(LCCF)、辣椒专用缓释复混肥(LSRF)土壤的氨挥发特性,并采用土培试验研究了LSRF、LCCF、普通复合肥(OCCF)、市场非包膜缓释复合肥(MSRF)对‘渝椒五号’和‘改良早丰’辣椒产量、氮磷钾养分吸收利用、土壤有机质及酶活性的影响,探讨LSRF的应用效果。结果显示,室内扩散模拟试验中,前28 d氨释放速率总体表现为PURLCCFLSRF不施肥(CK),28 d以后LSRF的氨释放速率略高于PUR和LCCF处理。培养70 d时,PUR、LSRF和LCCF的氨挥发量分别为71.87 mg·kg-1、54.29 mg·kg-1和63.49 mg·kg-1,LSRF比PUR和LCCF分别降低了24.5%和11.7%。土培试验中,LSRF处理显著提高了2个辣椒品种的果实重量,‘渝椒五号’和‘改良早丰’分别较OCCF处理增产64.7%和33.8%。与OCCF处理相比较,LSRF处理增加了土壤有机质含量、土壤脲酶、蔗糖酶和过氧化氢酶活性,提高了辣椒对氮磷钾养分的吸收利用。‘渝椒五号’和‘改良早丰’LSRF处理的氮素表观利用率较OCCF处理分别增加62.5%和123.1%,‘改良早丰’和‘渝椒五号’LSRF处理的磷素表观利用率分别较OCCF处理提高了14.0倍和3.2倍,钾素表观利用率分别较OCCF处理提高了28.7%和120.9%。  相似文献   

18.
Abstract

To evaluate the impact of soil clay mineralogy on the utilization efficiency of potassium fertilizers by rice, potassium fixation studies were made on fourteen soil clays having a range of mineralogical compositions. Soil clay with monomineralic beidellite fixed the highest proportion (76%) of the added potash, followed by clays containing either dominant or major vermiculite (51–66%). Fixation was significantly less severe (<35%) in vermiculitic clays containing hydrous mica. All the clays with mineralogical suites without beidellite or vermiculite, but consisting of montmorillonite, chlorite, hydrous mica, halloysite, kaolinite, and x‐ray amorphous material did not fix appreciable amounts (<18%) of the applied potassium.  相似文献   

19.

Purpose

Arbuscular mycorrhizal (AM) fungi are crucial for ecosystem functioning and can contribute to the formation and maintenance of soil aggregates through the exudation of glomalin by extraradical hyphae. Monitoring fertilization effects on AM fungi may help us to develop sound management strategies. The objectives of this study were to investigate the impacts of long-term fertilization on AM fungal parameters and to find out the key factor that affects the diversity and function of AM fungi.

Materials and methods

A long-term fertilization experiment established in a sandy loam soil at northern China has received continuous fertilization treatments for 21 years, including control; mineral fertilizers of NK, PK, NP, and NPK; organic manure (OM); and half organic manure N plus half mineral fertilizer N (1/2 OMN). Top soil samples (0–15 cm) from three individual plots per treatment were collected for the analysis of chemical properties and fungal parameters. The population size of soil AM fungi was determined by real-time PCR, and the community composition was analyzed using PCR-denature gradient gel electrophoresis (DGGE), cloning, and sequencing techniques. The external mycelium of AM fungi was assessed using the grid-line intersect method, and the glomalin-related soil protein (GRSP) was extracted with citrate solution using bovine serum albumin as a standard.

Results and discussion

Long-term fertilization significantly increased (P?<?0.05) soil organic C content, AM fungal population, species richness (R), Shannon–Wiener index (H), and GRSP content, except for the P-deficiency (NK) fertilization treatment. OM had a significantly greater (P?<?0.05) impact on AM fungal population and GRSP content compared to mineral fertilizers but significantly decreased the length of external mycelium compared to the control (P?<?0.05). Fertilization also changed the community composition of AM fungi, and the P-deficiency treatment again had the slightest influence. In addition, most species recovered from the DGGE profiles belonged to three genera, Glomus, Diversispora, and Archaeospora. Redundancy analysis showed that the population size and species richness of AM fungi and the GRSP content all significantly correlated to soil organic C content (P?<?0.05).

Conclusions

Long-term P-containing fertilization, especially the application of OM, greatly increased the population size, species richness, and species diversity of AM fungi, as well as the contents of GRSP and soil organic C, but tended to decrease the length of external mycelium, while the P-deficiency fertilization had no such effect, suggesting that P was the key factor to maintain soil fertility as well as soil AM fungal diversity in this sandy loam soil.  相似文献   

20.
红壤交换性钙、镁和钾的分布及施肥对其影响   总被引:1,自引:0,他引:1  
A leaching experiment was Carried out with repacked soil columns in laboratory to study the leaching process of a red soil derived from sandstone as affected by various fertilization practices.The treatments were CK(as a control),CaCO3,CaSO4,MgCO3,Ca(H2PO4)2,Urea,KCl,Multiple(a mixture of the above mentioned fertilizers) and KNO3,The fertilizers were added to the bare surface of the soil columns,and then the columns were leached with 120 mL deionized water daily through perstaltic pumps over a period of 92 days,At the end of leaching process,soils were sampled from different depths of the soil profiles ,i.o.,of 92 days,At the end of leaching process,soils were sampled from different depths of the soil profiles,I.e.0-5cm,5-10cm,10-20cm,20-40cm,and 40-60cm,The results showed when applying Ca,Mg,and K to the bare surface of the soil columns,exchangeable Ca^2 ,Mg^2 ,and K^ in the upper layer of the soil profile increased correspondingly,with an extent depending mainly on the application rates of Ca,Mg,and K and showing a downward trend,CaCO3,CaSO4,MgCO3,and Ca(H2PO4)2 treatments had scarcely and effect on movement of exchangeable K^ ,while CaCO3,and CaSO4 treatments singnificantly promoted the downward movement of exchangealble Mg^2 although these two treatments had no obvious effect on leaching losses of Mg,The fact that under Urea treatment,exchangeable Ca^2 and Mg^2 ,were higher as compared to CK treatment showed urea could prevent leaching of exchangeable Ca^2 and Mg^2 ,the obvious downward movement of exchangeable Ca^2 and Mg^2 was noticed in KCl treatment ,In Multiple treatment,the downward movement of exchangeable Ca^2 and Mg^2 was evident,while that of K^ was less evident,Application of KNO3 strongly promoted the downward movement of exchangeable Ca^2 and Mg^2 in the soil profile.  相似文献   

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