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A. J. LOW 《European Journal of Soil Science》1973,24(2):249-259
Relatively little has been published in Great Britain relating yields with quantitative assessments of the structure of soils. This paper gives examples of the kind of correlations found, a selection from many years' observations. Where the quantity of soil nutrients or disease was not a limiting factor, the yields of cereals, peas, and red beet were related to the stability of the structure which in turn depended on the number of years the soil had been out of grass. On a soil of weak structure it was found that stabilizing, with a conditioner, the structure developed by cultivation at a moisture content below field capacity resulted in a marked increase in both yield and size grade of cauliflowers. 相似文献
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土壤研究成果引用标本的搜集整理研究 总被引:1,自引:1,他引:1
本文首次提出了土壤研究成果引用标本的名称(简称成果标本)与含义,同时阐明其搜集整理的目的、意义、原则和步骤。从而使土壤研究成果从论文为主的独秀之花,迸发成为土文并茂的丰硕之果。丰富土壤科学研究内容。 相似文献
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焚烧秸杆对土壤有机质和微生物的影响研究 总被引:55,自引:3,他引:55
采用直接灼烧法和稀释平板法研究了焚烧秸杆对土壤有机质和微生物的影响。结果表明:焚烧秸杆使土壤有机质减少16.56%;土壤微生物中的细菌、放线菌和真菌分别减少了85.95%、78.58%和87.28%。 相似文献
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14C-PP333在土壤及作物中的残留 总被引:1,自引:0,他引:1
研究了^14C-PP333在小麦、水稻、芹菜中的残留。结果表明,^14C-PP333在作物中的残留水平随土壤中滞留水平的提高而提高。小麦籽粒残留水平为1.31 ̄0.75ppm,水稻籽粒为0.22ppm,芹菜为0.013 ̄0.032ppm。^14C-PP333在水稻植株中残留水平由高到低为穗梗〉叶〉茎〉谷壳〉根〉米;小麦为叶〉籽粒〉穗其余部分〉根〉茎;芹菜为叶〉根〉茎。施入^14C-PP33313个 相似文献
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以棕壤为例研究了15对不同肥力水平的典型棕壤、棕壤型水稻土的特征微团聚体(<10m和>10m)的组成比例,结果表明该比例即微团聚体(<10m)/微团聚体(>10m)可成为土壤肥力水平的一个综合指标。以该指标为标准的典型棕壤和棕壤型水稻土肥、瘦地区分界数分别为0.25和0.35,小于此二值分别为各自肥地,反之亦反。土壤培肥措施可使肥、瘦地特征微团聚体的比例降低并提高土壤肥力水平或根本改变瘦地肥力实质。 相似文献
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Crop canopy sensors can provide valuable information about in-field nitrogen (N) variability in maize (Zea mays L.) and can serve as the basis for in-season N recommendations. However, few studies have been conducted to determine how the sensors compare. Therefore, a study was conducted using the two most prominent crop canopy sensors (NTech's GreenSeeker? red and Holland Scientific's Crop Circle? amber) to determine if the different sensors recommended different amounts of N at the V12 maize growth stage. Results show that each sensor recommended the same amount of N at the V12 growth stage (N recommendations by sensor were not significantly different). The N algorithms developed for each sensor also calculated unbiased N recommendations suggesting that the methodology of algorithm development was valid as was the estimate of required N at maize growth stage V12. Therefore, both crop canopy sensors performed equally in terms of N recommendations in this study. 相似文献
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植物性脲酶抑制剂对作物营养和土壤特性的影响 总被引:6,自引:1,他引:6
采用15N 尿素进行盆栽试验 ,研究了 4种植物材料 (P1、P2 、P3、P4 )作脲酶抑制剂对高粱和水稻营养效应及土壤特性的影响。结果表明 ,4种植物性脲酶抑制剂对水稻和P1对高粱生长、地上部干重有明显的提高作用 ,且植株叶绿素a b值变幅小。植物性脲酶抑制剂 (除P3外 )提高水稻叶片氨基酸含量 1 2 9%~ 2 5 1 %和植株氮素利用率 5 2 %~ 7 7% ,亦促进高粱植株对氮素的利用。 4种植物性脲酶抑制剂提高两种作物氮素表观利用率 4 3 %~ 1 9 2 %和水稻磷、钾吸收量 ,而对高粱磷、钾吸收有降低作用。植物性脲酶抑制剂能提高两种作物的土壤碱解氮含量。淹水条件下植物性脲酶抑制剂持续作用时间相对较短 ,水稻生长 3 6d ,土壤脲酶活性变化不大 ;高粱生长 48d ,土壤脲酶活性降低 1 0 5%~ 1 8 3 %。 相似文献
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A study of 13 sample plots (0.01 ha) in 6 forests showed that the average number of topsoil samples required per plot to secure 95 per cent confidence limits for a range about the mean of 10 per cent was 6 for total nitrogen, 9 for total phosphorus and 29 for 0.5 M acetic acid extractable nutrients (calcium, magnesium, phosphorus and potassium). In some plots 95 per cent confidence intervals, based on 5 composite samples, for extractable nutrients were as large as the range of mean values for different plots within a forest. High variability within plots causes large variation in correlation coefficients between tree growth and soil properties so that the intensity of sampling should be of the order indicated above to identify factors affecting growth. For predicting timber yield the accuracy of regression equations containing predictors of high within-plot variability is too low to be of practical value. The sampling effort required to achieve a given level of precision does not increase greatly when plot size is increased from 0.01 to 0.1 ha. Since Yield Class, the most useful measure of growth, is not designed for areas less than 0.5 ha, the use of the larger plot size is recommended. 相似文献
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Dualex and SPAD are devices developed for the purpose of testing crop nitrogen (N) status. These instruments were used in a wheat experiment in order to compare their respective performance in assessing leaf nitrogen (N) concentration, response to N topdressing application, soil nitrate (NO3)-N levels and in predicting grain yield. The experiment included different N rates in 2005 and 2006 in the Montérégie region of Quebec, Canada. Dualex readings correlated negatively with SPAD readings, leaf N concentration, soil NO3-N content and wheat grain yield. SPAD alone and the ratio of SPAD to Dualex measurements (Chl/Phen) were linearly related to N application rate but no effect of N application rate was found for individual Dualex parameters. However, both SPAD and Dualex readings were affected by year effects. The Dualex was also capable of indirect evaluation of in-season soil NO3-N accumulation and the prediction of wheat yield, but more so as Chl/Phen. 相似文献
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长期施肥的作物产量和土壤肥力变化 总被引:76,自引:8,他引:76
本文是全国化肥试验网1981年以来进行的70个长期肥料试验的总结。主要研究在不同种植制中长期施用化肥或有机肥或两者配合施用条件下作物的产量、肥料效应和土壤肥力变化。结果表明,化肥只有氮磷钾配合时,才能获得高产,稳产;化肥与有机肥配合可进一步提高产量。氮肥肥效普遍较高,磷钾肥肥效因地区和作物有较大差异和变化;有机肥有叠加效应,肥效逐年上升。从土壤理、化和生物性状测定结果看出,有机肥能明显提高土壤肥力,氮磷钾化肥配合也能提高土壤肥力。根据养分平衡及产量、肥力的变化,提出了合理的肥料结构。 相似文献
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贵州多山,地形多变,气候区域性特征明显,加之岩性斑杂,以致促成土壤类型分化强烈,特性各异。因而,在长期生产实践中,人们选择了多种利用方式,以适应土壤和其它环境条件的特点;并在利用过程中以各种措施持续地改造着某些不利于生产的自然属性,使生产水平得以不断提高。 相似文献
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R. F. HAMMOND 《European Journal of Soil Science》1974,25(1):63-66
Techniques for preparation and preservation of peat soil monoliths for display purposes are described. Impregnation with a low molecular weight polyethylene glycol polymer has been found to be extremely effective in stabilising the natural structural features of peats. 相似文献
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通过盆栽试验 ,研究了不同管理调控措施包括施肥、灌溉、应用化学改良剂对盐渍土壤盐分分布和作物体内盐分离子吸收和分布的作用机制。结果表明 ,施用化学肥料可增大土壤电导率 ;灌水量增加可降低土壤电导率 ;施用改良剂CaSO4早期可引起土壤表层电导率升高 ,但到作物生长中、后期已与不施改良剂的相近。施肥、灌溉改善了作物生长条件 ,提高了作物的抗盐害能力。灌溉总量 375mm、三天一次的灌溉方式在降低土体盐分浓度、抑制土壤碱化方面优于两天一次的灌溉方式。大麦具有将Na 截留在茎中 ,从而减少Na 对叶片伤害的功能。大麦茎和叶中的Cl-含量都高于K 和Na 含量 ,显示较多的Cl-通过根部向地上部运输。在增加植株中K 含量、降低Na 含量 ,减轻植株盐分离子胁迫方面改良剂表现出良好的调控效果 相似文献
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Z. Adimassu K. Mekonnen C. Yirga A. Kessler 《Land Degradation \u0026amp; Development》2014,25(6):554-564
The effects of soil bunds on runoff, losses of soil and nutrients, and crop yield are rarely documented in the Central Highlands of Ethiopia. A field experiment was set up consisting of three treatments: (i) barley‐cultivated land protected with graded soil bunds (Sb); (ii) fallow land (F); and (iii) barley‐cultivated land without soil bund (Bc). For 3 years (2007–2009), the effect of soil bunds on runoff, losses of soil and nutrients, and crop productivity was studied. Daily runoff and soil and nutrient losses were measured for each treatment using standard procedures while barley yield was recorded from the cultivated plots. The results showed that Sb brought about significant reduction in runoff and soil losses. Plots with Sb reduced the average annual runoff by 28 per cent and the average annual soil loss by 47 per cent. Consequently, Sb reduced losses of soil nutrients and organic carbon. However, the absolute losses were still high. This implies the need for supplementing Sb with biological and agronomic land management measures to further control soil erosion. Despite these positive impacts on soil quality, Sb do not increase crop yield. Calculated on a per‐hectare basis, Sb even reduce crop yield by about 7 per cent as compared with control plots, which is entirely explained by the reduction of the cultivable area by 8·6 per cent due to the soil bunds. Suitable measures are needed to compensate the yield losses caused by the construction of soil bunds, which would convince farmers to construct these land management measures that have long‐term beneficial effects on erosion control. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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