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1.
Information on the most influential factors determining gas flux from soils is needed in predictive models for greenhouse gases emissions.We conducted an intensive soil and air sampling along a 2 000 m transect extending from a forest,pasture,grassland and corn field in Shizunai,Hokkaido (Japan),measured CO 2 ,CH 4 ,N 2 O and NO fluxes and calculated soil bulk density (ρ b ),air-filled porosity (f a ) and total porosity (Φ).Using diffusivity models based on either f a alone or on a combination of f a and Φ,we predicted two pore space indices: the relative gas diffusion coefficient (D s /D o ) and the pore tortuosity factor (τ).The relationships between pore space indices (D s /D o and τ) and CO 2 ,CH 4 ,N 2 O and NO fluxes were also studied.Results showed that the grassland had the highest ρ b while f a and Φ were the highest in the forest.CO 2 ,CH 4 ,N 2 O and NO fluxes were the highest in the grassland while N 2 O dominated in the corn field.Few correlations existed between f a ,Φ,ρ b and gases fluxes while all models predicted that D s /D o and τ significantly correlated with CO 2 and CH 4 with correlation coefficient (r) ranging from 0.20 to 0.80.Overall,diffusivity models based on f a alone gave higher D s /D o ,lower τ,and higher R 2 and better explained the relationship between pore space indices (D s /D o and τ) and gases fluxes.Inclusion of D s /D o and τ in predictive models will improve our understanding of the dynamics of greenhouse gas fluxes from soils.D s /D o and τ can be easily obtained by measurements of soil air and water and existing diffusivity models.  相似文献   

2.
In order to utilize landfill stabilized waste (LSW) as growing substrate for plants during restoration projects, LSW were sampled from five landfills; the properties of unconsolidated samples and those after 3 years of settlement were determined in comparison with farm soil. Results showed that (i) unconsolidated LSW was a soil‐like material with high porosity and infiltration rate, which also had low bulk density and shear strength. After 3 years of settlement, its physical properties were similar to those of farm soil. (ii) The contents of available K, available N, available P, and organic matter of LSW were 5·0–21·6 times higher than the values of surrounding farm soil. (iii) The waste samples from 3/5 landfills were suitable for cultivation based on their heavy metal contents, but two samples contained over‐limit Hg and/or Zn. (iv) LSW had higher water content, and generally, less surface runoff was generated on LSW slope under natural precipitation compared with the farm soil slope. (v) Water extract of LSW had no significant effect on seed germination, and the effect of LSW on seedling growth depended on plant species. On the basis of the results, LSW can be used in ecological restoration as plant‐growing substrate, but measures should be taken to prevent heavy metal contamination and soil erosion. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

3.
土地利用方式与坡位土壤活性铝形态特征分析   总被引:7,自引:0,他引:7  
以红壤坡地为材料,研究了地带性恢复林地、农作区、人工林地茶园和桔园等4种土地利用方式下土壤pH、有机质和铝形态的分异特征。结果表明,土壤pH、有机质和3种活性铝形态含量差异显著。和恢复区相比,农作区由于大量秸秆和根茬还土,土壤交换性铝的含量显著降低,而土壤吸附态羟基铝和有机络合态铝的含量则不同程度地提高;人工林地茶园和桔园则呈现出土壤交换性铝提高的特征,吸附态羟基铝和有机络合态铝含量下降。下坡位土壤表现为堆积,土壤pH值和有机质含量增加,土壤交换性铝含量比上坡位减少,吸附态羟基铝和有机络合态铝含量增加,降低了铝的毒性。相关分析表明,土壤pH值与土壤交换性铝呈显著负相关,y=-97.6x+6009.2(R^2=0.7315),与土壤吸附态羟基铝呈显著正相关,y=2810.8x-9293(R^2=0.9003);而土壤有机质含量与土壤交换性铝呈显著负相关,y=-2963x+17616(R^2=0.8977),与土壤有机络合态铝呈显著正相关,y=553.4x-4779.1(R^2=0.4364)。说明土壤铝形态在坡面上的分异特征是坡面利用类型与地形部位共同作用的结果。  相似文献   

4.
Landscape variability associated with topographic features affects the spatial pattern of soil water and N redistribution, and thus N uptake and crop yield. A landscape-scale study was conducted in a center pivot irrigated field on the southern High Plains of Texas in 1999 to assess soil water, soil NO3-N, cotton (Gossypium hirsutum L.) lint yield, and N uptake variability in the landscape, and to determine the spatial correlation between these landscape variables using a state-space approach. The treatments were irrigation at 50 and 75% cotton potential evapotranspiration (ET). Neutron access tubes were placed at a 15-m interval along a 710 m (50% ET) and 820 m (75% ET) transect across the field. Soil NO3-N in early spring was autocorrelated at a distance varying between 60 and 80 m. Measured soil volumetric water content (WC), total N uptake, and lint yield were generally higher on lower landscape positions. Cotton lint yield was significantly correlated to soil WC (r=0.76), soil NO3-N (r=0.35), and site elevation (r=−0.54). Differences of site elevation between local neighboring points explained the soil water, NO3-N and lint yield variability at the micro-scale level in the landscape. Soil WC, cotton lint yield, N uptake, and clay content were crosscorrelated with site elevation across a lag distance of ±30–40 m. The state-space analysis showed that cotton lint yield was positively weighted on soil WC availability and negatively weighted on site elevation. Cotton lint yield state-space models give insights on the association of soil physical and chemical properties, lint yield, and landscape processes, and have the potential to improve water and N management at the landscape-scale.  相似文献   

5.
徐聪  吴迪  王磊  李传哲  杨苏  孙丽  汪吉东  张永春  艾玉春 《土壤》2021,53(3):491-498
通过对两个小麦生长季进行田间监测,探究了施用菌渣对黄河故道区低产田土壤理化性质、小麦根系生长和产量的影响.试验共设7个处理,分别为不施用菌渣(CK),施用低量(6t/hm2;S1)、中量(12t/hm2;S2)和高量秸秆质菌渣(18t/hm2;S3),施用低量(6t/hm2;B1)、中量(12t/hm2;B2)和高量木...  相似文献   

6.
Some studies on the relationship between soil erosion and subsequent redeposition of eroded soils in the same field and soil quality have been conducted in croplands, yet few studies have revealed this relationship in rangelands. We selected a toposequence with a slope of 30% and a horizontal length of 342 m from the rangeland in the northern Tibet Autonomous Region, China (31°16′N, 92°09′E) to determine the relationship between soil erosion, soil organic carbon (SOC) content and available P patterns within a hillslope landscape. Soil samples for the determination of 137Cs as well as SOC, available P and particle‐size fractions were collected at 20 m intervals along a transect of this hillslope. Soil redistribution was caused primarily by wind erosion at toe‐slope positions, but primarily by water erosion at the hillslope positions above the toe‐slope. In upper‐ and mid‐slope portions (0 m to 244 m horizontal length), SOC content is closely correlated to 137Cs concentration (r = 0.74, P < 0.01, n= 15), suggesting that SOC distribution along the slope was similar to 137Cs distribution, which itself was dependent on topographic changes. However, SOC contents in toe‐slope portions are less than those above the toe‐slope (i.e. upper‐ and mid‐slope portions), and the correlation between 137Cs and SOC in the toe‐slope portion is weaker than that above the toe‐slope. A highly significant correlation (r = 0.72, P < 0.001, n= 20) between 137Cs concentration and available P was found within the whole hillslope landscape, implying the distribution pattern of available P was somewhat different from that of SOC. We suggest that the distribution of SOC within the hillslope landscape is also affected by factors such as assimilation rates due to difference in grassland productivity at different points and different biological oxidation rates of carbon related to patterns of moisture distribution.  相似文献   

7.
不同耕作深度对红壤坡耕地耕层土壤特性的影响   总被引:2,自引:0,他引:2  
红壤坡耕地不同耕作深度对耕层质量和作物产量具有重要影响。以江西红壤坡耕地示范区耕层为研究对象,从土壤属性角度,对红壤坡耕地不同耕作深度处理下垂直深度土壤水分、容重、孔隙度、土壤紧实度、土壤抗剪强度、土壤有机质、有效磷和速效钾等进行分析。结果表明:(1)不同耕作深度对土壤孔隙度、饱和含水量和田间持水量的影响为免耕翻耕20 cm翻耕10 cm常规耕作翻耕30 cm,对容重的影响为翻耕30 cm常规耕作翻耕10 cm免耕翻耕20 cm;与常规耕作比较,翻耕30 cm使土壤饱和含水量、田间持水量和土壤孔隙度分别提高了18.17%,12.67%,5.94%,土壤容重降低6.90%。(2)不同耕作深度下土壤紧实度表现为翻耕30 cm翻耕10 cm翻耕20 cm免耕常规耕作,土壤抗剪强度表现为翻耕30 cm常规耕作翻耕10 cm免耕翻耕20 cm;与常规耕作对照,翻耕30 cm使土壤紧实度和抗剪强度分别降低27.07%和24.82%。(3)土壤有机质含量以翻耕20 cm处理下最高(13.48 g/kg),免耕处理含量最低(9.39 g/kg),土壤速效养分主要集中分布在0-20 cm土层,但20-40 cm土层中翻耕处理较免耕处理有不同程度的增加,以翻耕20 cm和常规耕作表现显著。(4)主成分分析结果表明,翻耕30 cm处理对红壤坡耕地土壤的综合改善效果最好。研究结果可为红壤坡耕地耕层土壤改善和合理耕层构建提供技术参考。  相似文献   

8.
黄土丘陵区侵蚀环境不同坡面及坡位土壤理化特征研究   总被引:1,自引:0,他引:1  
研究了黄土丘陵区纸坊沟流域阴阳坡面及不同坡位土壤水分、物理和养分特征,结果表明,与坡顶距离越远,表层土壤含水量由小变大。阴坡蒸发量小,土壤含水量较大。容重阴坡〈阳坡,距坡顶越远,土壤容重、非活性孔度越小,孔隙比、活性孔度越大,同一坡向阳坡随土层加深土壤容重增大,阴坡表层土壤容重增加幅度较下层小,容重在剖面趋于均化。阴坡对土壤的改善优于阳坡,有利于植被生长。表层土壤全氮含量阴坡〉阳坡,且随土层加深而减少。全氮和有机质在坡中下部累积。全磷在不同坡向和坡位变化不明显。速效钾在各坡位变化幅度较小且阴坡〉阳坡。阴阳坡土壤各养分有向表层富集的趋势。坡面土壤容重与土壤孔隙比、活性孔度、毛管含水量和有机质呈极显著负相关,与土壤非活性孔度和表层土壤含水量呈显著正相关,土壤有机质和土壤全氮、速效钾呈极显著正相关。在对坡面进行植被恢复时,需结合坡面土壤变化规律,因地制宜,合理利用和开发土地资源,促进植被恢复演替。  相似文献   

9.
Within-field variability in wheat grain yield and its quality always exists in production fields and depends, among other factors, mainly on various soil properties related to nutrients and water availability. The aim of the research was to examine the relationships between selected soil properties such as texture; pH; content of the available phosphorus (P), potassium (K), magnesium (Mg), and organic carbon; and winter wheat grain yield and quality under rainfed conditions. Six crop fields with winter wheat (Triticum aestivum, L.) in three sites located in different regions of Poland were examined during two seasons. The grain yield was mainly determined by the soil texture, and the majority of the chemical soil properties did not have a significant effect on grain yield. The grain quality traits were determined by the examined soil properties to a smaller degree than grain yield. The relationships were not consistent across sites and years.  相似文献   

10.
黄土丘陵区侵蚀环境不同坡面及坡位土壤理化特征研究   总被引:8,自引:2,他引:6  
研究了黄土丘陵区纸坊沟流域阴阳坡面及不同坡位土壤水分、物理和养分特征,结果表明,与坡顶距离越远,表层土壤含水量由小变大。阴坡蒸发量小,土壤含水量较大。容重阴坡<阳坡,距坡顶越远,土壤容重、非活性孔度越小,孔隙比、活性孔度越大,同一坡向阳坡随土层加深土壤容重增大,阴坡表层土壤容重增加幅度较下层小,容重在剖面趋于均化。阴坡对土壤的改善优于阳坡,有利于植被生长。表层土壤全氮含量阴坡>阳坡,且随土层加深而减少。全氮和有机质在坡中下部累积。全磷在不同坡向和坡位变化不明显。速效钾在各坡位变化幅度较小且阴坡>阳坡。阴阳坡土壤各养分有向表层富集的趋势。坡面土壤容重与土壤孔隙比、活性孔度、毛管含水量和有机质呈极显著负相关,与土壤非活性孔度和表层土壤含水量呈显著正相关,土壤有机质和土壤全氮、速效钾呈极显著正相关。在对坡面进行植被恢复时,需结合坡面土壤变化规律,因地制宜,合理利用和开发土地资源,促进植被恢复演替。  相似文献   

11.
在宁南山区黄土丘陵区开展了退耕还林还草工程效益监测研究,测定了不同坡位退耕还林还草地的土壤养分。对土壤养分单因子分析结果表明:在同一坡面上,随着坡位的降低,退耕还林还草地0—100 cm土层土壤有机质、全氮、全磷、速效氮、速效磷平均含量增加;从不同坡位退耕还林还草地各层土壤养分含量来看,随着土层深度的增加,土壤有机质、全氮、全磷、速效氮、速效磷、速效钾含量在降低。说明半干旱黄土丘陵区林带间种植的苜蓿经营粗放,加剧了土壤养分的失调。  相似文献   

12.
以江西省玉山县红壤丘陵区不同林龄(1a和15a)人工油茶林地土壤为研究对象,按不同坡位(上、中、下)、土层(0—10,10—20cm)采集土壤样品,分析其理化性质。结果表明:(1)随着油茶林龄增加,土壤容重呈减小趋势,而土壤含水量、田间持水量均呈增大趋势;土壤pH、有机质含量除上坡位外均呈显著增大趋势(P0.05);全氮、全磷、全钾均呈减小趋势;红壤坡地水平阶整地种植油茶后,土壤理化性质有所改善,土壤含水量、田间持水量和土壤有机质含量均有不同程度的增加,而土壤容重和养分(N、P、K)含量有所降低,为满足生产需要,在油茶林抚育过程中,应注意合理施肥,尤其是磷肥的施用。(2)不同坡位间土壤理化性质表现出一定的规律性。土壤容重表现为上坡位中坡位下坡位;土壤含水量在上坡位最大,而田间持水量在下坡位最小;有机质含量、全钾均为上坡位中坡位下坡位,有机质含量在各坡位间差异显著,而全氮、全磷没有显著差异;(3)与1a油茶林地相比,15a林龄的油茶林地土壤理化性质空间差异趋于均匀化。研究结果旨在揭示水平阶整地种植人工油茶复合措施的水土保持效应,为南方红壤坡地水土流失综合治理及人工油茶林地可持续经营提供理论依据。  相似文献   

13.
Abstract

An irrigated farmer's field at Hafizabad village in Dera Ismail Khan District of Northwest Frontier Province of Pakistan was sampled at a regular grid spacing of 50x15 m from surface (15 cm) to study the spatial variability of soil properties and wheat yield. The farm measured 250x75 m. Soil samples collected were analyzed for soil pH, lime content, organic matter, mineral nitrogen (N), ammonium bicarbonate (AB)‐DTPA‐extractable phosphorus (P) and potassium (K), and soil texture. A uniformly trial on wheat with a uniform rate of 120 kg N ha‐1, 90 kg P2O5 ha‐1, and 60 kg K2O ha‐1 was laid out. The results showed that the soil P had the highest coefficient of variation (CV 46%) followed by organic matter (36.20%) and clay content (33.81%). Grain yield had also a considerable variation in the field (CV=31.84%). Geostatistical technique of semivariogram analysis showed that mineral N, AB‐DTPA‐extractable K, sand, silt, and clay content had the strong spatial structure. Maps of soil fertility and crop productivity of the farm was prepared using modern geostatistical technique of kriging. The farm was divided into different management zones based on these maps for fertility management.  相似文献   

14.
Soil physical, chemical, and biological properties in a rice field located at the Surin Rice Research Center, Thailand, were evaluated as indicators for predicting organic rice (Kao Dok Mali 105 variety) production and yield. Four treatments under different management practices were studied. They included (1) conventional farming (CF) receiving chemical fertilizer application; (2) organic plot receiving green manure (GM) addition; (3) organic plot receiving rice straw (RS) addition; and (4) control plot (CT) without any external plant nutrient source. Soil quality in the four treatments was assessed based upon selected physical, chemical, and biological parameters. Key findings are as follows: cation exchange capacity (CEC), electrical conductivity (EC), pH, soil organic matter (SOM), and essential macronutrients [nitrogen (N), phosphorus (P), and potassium (K)] were low in all plots. Soil biological properties including potential N mineralization (PMN), soil basal respiration (BR), microbial biomass carbon (MBC) and microbial biomass N (MBN) in all treatments were also low. Principal component analysis (PCA), using 15 soil properties, showed significant differences among farm management practices. Soil chemical and biological properties best related to soil quality included P, N, and SOM (for chemical properties) and MBC, MBN, and BR (for biological properties). Based on significant relationships between yield (r > 0.75) and the soil properties (r > 0.55), selected soil biological (MBC, MBN, and BR) and chemical (TOP [total organic phosphorus], TK [total potassium], TN [total nitrogen], SOC [soil organic carbon], and SOM) properties were determined to be suitable soil-quality indicators, respectively. A soil-quality indicator for predicting rice yield was computed using multiple regression analyses. The regression model (Y = ?1.685 + 0.333 (MBN) + 0.640 (TK) ? 0.282 (SOC), r2 adjusted = 0.962) was used for predicting yield. Grain yield of rice (RMSE = 0.046 t ha?1, D index = 0.45) was obtained using this regression model.  相似文献   

15.
为了研究煤矿井下充填开采是否能有效保护地表耕地土壤环境,保持土壤肥力,本文以皖北矿业集团公司五沟煤矿充填开采工作面与非充填开采工作面为试验区,在2个工作面对应上方地表分别划分试验区域和对照区域,进行采样、相关土壤指标检测及结果分析。试验区域(充填开采)包括:地表沉陷区坡脚B1处(点1?~点3?)、沉陷区坡面B2处(点4?~点6?)、沉陷区坡顶B3处(点7?~点9?);对照区域(非充填开采)包括:地表沉陷区坡脚A1处(点1~点3)、沉陷区坡面A2处(点4~点6)、沉陷区坡顶A3处(点7~点9)。每个区域分别在9个采样点内按照0~20 cm、20~40 cm和40~60 cm 3个土壤深度分层采集土样,对土壤理化性质以及该区域小麦株高和经济产量进行了测定和分析。试验结果显示,充填开采区域土壤碱解氮、有效磷、速效钾和有机质在3个土层的平均含量均高于非充填开采区域。试验观测期间,3月份B1处小麦株高小于A1处,5—6月B2和B3处小麦长势均优于A2和A3处,直至收割;小麦成熟时,充填开采区域经济产量高于非充填开采区。充填开采区域地块土壤含水量高于非充填开采区域。因此,本文认为充填开采比非充填开采更能保持开采区域上覆土壤的养分和水分。但与正常土壤背景值相比,充填开采区域上覆土壤仍存在某些营养元素(如有机质及磷元素)含量不足的问题,其作为农耕地需要加强人工活动的影响,如增施肥料、加强田间管理等。  相似文献   

16.
17.
为探明不同轮作模式对宁夏南部山区旱地农田土壤肥力和谷子产量的影响,基于连续8年定位试验,研究了谷子连作(R0)、谷子–小麦–糜子轮作(R1)、谷子–胡麻–豌豆轮作(R2)和谷子–豌豆–马铃薯轮作(R3)处理对谷子产量及土壤物理和化学性质的影响。结果表明:经过两个轮作周期后,与R0处理相比,R2处理谷子产量增加13.10%,R1处理产量略有降低,R3处理产量显著降低(P<0.05)。各轮作模式均有利于降低土壤容重,提高土壤田间持水量,并且R1和R2处理土壤容重显著低于R0处理;除R3处理外,R1和R2处理有利于增加土壤孔隙度,与R0处理相比增幅分别为15.09%和21.18%。各轮作模式均有利于增加土壤>0.25 mm大团聚体总量,其中R1和R2处理可以显著降低土壤中<0.25 mm和2~0.25 mm团聚体数量(P<0.05),并显著增加>2 mm团聚体比例。各轮作模式土壤有机质含量均高于R0处理,土壤全量养分含量差异不明显;各轮作模式均有利于增加土壤微生物生物量碳、氮和有效磷含量,同时R2处理还有利于增加土壤碱解氮、速效钾和微生物生物量磷含量。综上,轮作有利于旱地土壤有机质积累,降低土壤容重,增加大团聚体数量,提高土壤微生物生物量,但不同轮作模式间存在差异,其中,R2处理更有利于增加谷子产量、改善土壤结构、培肥土壤,可以作为宁夏南部山区雨养农业旱作区的优选作物轮作模式进行推广。  相似文献   

18.
Recently the effect of plant hedgerows on controlling soil and water loss has been well recognized, and this technology has been widely applied in the world. However, there are few studies on hedgerows’ effect on soil fertility of sloping lands. With an 8-year fixed field experiment, we investigated the effect of two different hedgerows on soil fertility through comparing with the control. Our results showed that along contour lines across the field, clay particles tended to accumulate above plant hedgerows but to be eroded downward below hedgerows. Except for potassium (K), all plant nutrients and soil organic matter showed the same distribution pattern as clay particles. K, however, was evenly distributed in the field without any noticeable influence from hedgerows. Since the beginning of our field experiment, soil phosphorus (P) kept accumulating, while soil organic matter and K were in depletion. Taken together, our results suggest that better nutrient management for the sloping lands should reduce P but increase farm manure and K. As far as the whole sloping field is concerned, special attention in nutrient management should be paid to the soil stripes below hedgerows, the portions suffering from more serious soil erosion.  相似文献   

19.
不同利用方式与坡位土壤物理性质及养分特征分析   总被引:61,自引:8,他引:61  
以四川盆地西缘山地的典型坡面为材料,研究了不同土地利用方式和地形部位条件下土壤物理性质和养分的分异特征,结果表明,3个坡面地形部位(上坡位,中坡位,下坡位),下坡位土壤物理结构性能较好,而人工林与坡耕地、荒草地相比较,人工林更能增强土壤的结构性。土壤养分分异特征表明,在不同利用类型条件下。土壤有机质、氮素和阳离子交换量CEC在人工林中含量最高,且与其他两种利用类型中的含量差异显著,有机质、碱解氮和CEC三者含量差异达到极显著水平。相关分析表明,土壤表层有机质、全氮、碱解氮呈极显著正相关。而坡面位置中,与上坡位,中坡位相比,下坡位土壤养分含量普遍要高,其中CEC含量差异达到极显著水平,相关分析表明,CEC与土壤粘粒呈极显著正相关。结果说明土壤物理性质与养分特征在坡面上的分异特征是山地坡面利用类型与地形部位共同作用的结果。  相似文献   

20.
Wind erosion and accumulated sand are recognized as the primary forms of cropland desertification in the arid and semiarid region, Inner Mongolia. However, there is a lack of knowledge on the effects of wind erosion and accumulated sand on soil properties and crop growth properties in this region. A field experiment was conducted from 2001 to 2002 on desertified cropland with gradients of wind erosion and accumulated sand to investigate changes in soil and crop growth properties resulting from desertification in the Horqin sandy land. Results indicated that the soil environment degraded significantly and crop growth and biomass were seriously restrained by wind erosion. In the severely eroded cropland, soil clay, organic matter, total N and P, available N and P, average soil moisture decreased by 59.6%, 71.2%, 67.4%, 31.4%, 64.5%, 38.8% and 51.8%, respectively. Erosion increased soil pH from 8.66 to 8.92; delayed plant life cycle by 6 days, decreased plant height and diameter by 15.5% and 29.1%, and decreased above and below ground biomass and seed yield by 87.3%, 47.9% and 96.5%, respectively. Effects of a little accumulated sand were fewer on soil properties and crop growth and seed yield compared to wind erosion, severe accumulated sand effects on the cropland remain to be studied further. The results of correlation analysis showed that crop biomass and seed production were significantly correlated to organic matter, total N, pH and soil moisture under circumstance of worsened soil environment. In the windy and sandy region in Inner Mongolia, some measures to control cropland erosion should be introduced including construction of windbreak, stubble cultivation, increased organic fertilizer and spring irrigation.  相似文献   

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