黄土低山丘陵及坨甸草原区风蚀规律的研究     

张启昌  徐程阳  魏献民  宋广智  赵宝华 《吉林林学院学报》1992,(2)

本文通过对黄土低山丘陵及坨甸草原区248个风蚀图斑资料的分析,运用线性模型理论,对此地区的风蚀规律进行了研究。获得了下垫面各因素与风蚀量关系的数学模型。找出了影响风蚀的主导因素,并系统阐述了植被覆盖度和土地利用类型对风蚀量大小的影响,且与水蚀规律进行了比较分析。  相似文献   

三峡库区柑桔林水土保持效益分析   总被引：1，自引：0，他引：1  

郑巍伟  张春林 《亚热带水土保持》2006,18(1):15-18

对三峡库区2种不同建园方式的柑桔林,从建园开始连续9年定位观测柑桔林水土流失情况,结果表明,梯田柑桔林径流系数在0.047~0.153之间,径流含沙量在425~2170g/m3之间,侵蚀模数在9.37~116.67g/m2之间。25°坡地柑桔林径流系数在0.079~0.378之间,径流含沙量在500~5 050 g/m3之间,侵蚀模数在48.29~1 962.04g/m2之间。在建园初期4年内,25°坡地柑桔林径流系数、径流含沙量和侵蚀模数急剧下降,径流系数由0.378下降到0.103,径流含沙量由5050 g/m3下降到350g/m3,侵蚀模数由1 962.04g/m2下降到131.42 g/m2。4年后,覆盖度的增加有效的抵消了坡度对水土流失的影响,柑桔林覆盖度达到0.82,径流系数,径流含沙量和侵蚀模数分别为0.103~0.253,350~3404 g/m3、14.71~148.4g/m2,表现出较好的水土保持效益。  相似文献   

In situ radiometric mapping of soil erosion and field-moist bulk density on cultivated fields     

A.N. Tyler  D.A. Davidson  I.C. Grieve 《Soil Use and Management》2001,17(2):88-96

Abstract. Recent developments in in situγ ray spectrometry offer a new approach to measuring the activity of radionuclides such as ¹³⁷Cs and ⁴⁰K in soils, and thus estimating erosion or deposition rates and field moist bulk density (ρ_m). Such estimates would be rapid and involve minimal site disturbance, especially important where archaeological remains are present. This paper presents the results of a pilot investigation of an eroded field in Scotland in which a portable hyper pure germanium (HPGe) detector was used to measure γ ray spectra in situ. The gamma (γ) photon flux observed at the soil surface is a function of the ¹³⁷Cs inventory, its depth distribution characteristics and ρ_m. A coefficient, Q_Cs, derived from the forward scattering of ¹³⁷Cs γ ray photons within the soil profile relative to the ¹³⁷Cs full energy peak (662 keV), was used to correct the in situ calibration for changes in the ¹³⁷Cs vertical distribution in the ploughed field, a function of tillage, soil accumulation and ρ_m. Based on only 8 measurements, the agreement between in situγ ray spectrometry and soil sample measurements of ¹³⁷Cs inventories improved from a non significant r²=0.05 to a significant r²=0.62 (P<0.05). Erosion and deposition rates calculated from the corrected in situ¹³⁷Cs measurements had a similarly good agreement with those calculated from soil cores. Mean soil bulk density was also calculated using a separate coefficient, Q_K, derived from the forward scattering γ photons from ⁴⁰K within the soil relative to the ⁴⁰K full energy peak (1460 keV). Again there was good agreement with soil core measurements (r²=0.64; P<0.05). The precision of the in situ¹³⁷Cs measurement was limited by the precision with which Q_Cs can be estimated, a function of the low ¹³⁷Cs deposition levels associated with the weapons testing fallout and relatively low detector efficiency (35%). In contrast, the precision of the in situ ρ_m determination was only limited by the spatial variability associated with soil sampling.  相似文献   

WEPP模型中的CLIGEN与BPCDG应用对比研究     

缪驰远  何丙辉  陈晓燕  吴咏 《勤云标准版测试》2004,(6)

通过对遂宁组紫色土产流、产沙侵蚀的观测,运用迄今为止最为复杂的土壤侵蚀预测模型WEPP模型进行单次降雨侵蚀预测,与实测值比较,并对比通过气候生成器CLIGEN和断点生成器BPCDG的产生的气候参数对预测值的影响。通过分析比较结果,认为WEPP模型对遂宁组紫色土侵蚀过程预测合理,而且利用断点生成器BPCDG的预测结果要优于气候生成器CLIGEN的预测结果。  相似文献   

Influence of biomineralization on the physico-mechanical profile of a tropical soil affected by erosive processes     

《Soil biology & biochemistry》2014

Most of the soils of tropical countries are affected by erosion processes. As a result, much attention has been dedicated to the use of microorganisms to improve the geotechnical properties and stability of soils in the context of “bioengineering”. This work was carried out to analyze the effects of the use of a CaCO₃ precipitating nutrient on native microbiota with the aim of mitigating the erosion processes in a tropical soil profile. We observed that the use of nutrient B4 enabled native bacteria present in the soil to precipitate calcium carbonate, resulting in improvements in the physical, chemical, mineralogical and mechanical properties of the soil, which allowed the mitigation of the erosion processes that characterize the soil profile studied.  相似文献   

Evaluation and mapping of soil erosion susceptibility: an example from Kenya     

C.K.K. Gachene 《Soil Use and Management》1995,11(1):1-4

Abstract. The erosion susceptibility of the Erosion Research Farm at Kabete Campus was mapped using a qualitative parametric method. A grid soil survey of the 4 ha farm was combined with a map of slope gradients, slope segments being delineated by breaks in slope. Rainfall erosivity and soil erodibility were also measured. Areas with the greatest erosion susceptibility according to this method were those occupying convex slope positions and slopes of more than 30%. Field observations and soil loss measurements generally supported the erosion susceptibility rating map produced by this method. The soil and erosion susceptibility maps were useful for planning erosion control measures and for selecting suitable sites for runoff plot experiments.  相似文献   

Erosion rates obtained from check-dam sedimentation (SE Spain). A multi-method comparison     

A. Romero-Díaz  F. Alonso-SarriáM. Martínez-Lloris 《CATENA》2007

The main aims of this article are to calculate the erosion rates from sediments accumulated in the check dams and to compare the results with those of other methodologies.  相似文献   

Effects of potato–grain rotations on soil erosion, carbon dynamics and properties of rangeland sandy soils     

A. Al-Sheikh  J.A. Delgado  K. Barbarick  R. Sparks  M. Dillon  Y. Qian  G. Cardon 《Soil & Tillage Research》2005,81(2):227-238

The potential for wind erosion in South Central Colorado is greatest in the spring, especially after harvesting of crops such as potato (Solanum tuberosum L.) that leave small amounts of crop residue in the surface after harvest. Therefore it is important to implement best management practices that reduce potential wind erosion and that we understand how cropping systems are impacting soil erosion, carbon dynamics, and properties of rangeland sandy soils. We evaluate the effects of cropping systems on soil physical and chemical properties of rangeland sandy soils. The cropping system included a small grain–potato rotation. An uncultivated rangeland site and three fields that two decades ago were converted from rangeland into cultivated center-pivot-irrigation-sprinkler fields were also sampled. Plant and soil samples were collected in the rangeland area and the three adjacent cultivated sites. The soils at these sites were classified as a Gunbarrel loamy sand (Mixed, frigid Typic Psammaquent). We found that for the rangeland site, soil where brush species were growing exhibited C sequestration and increases in soil organic matter (SOM) while the bare soil areas of the rangeland are losing significant amounts of fine particles, nutrients and soil organic carbon (SOM-C) mainly due to wind erosion. When we compared the cultivated sites to the uncultivated rangeland, we found that the SOM-C and soil organic matter nitrogen (SOM-N) increased with increases in crop residue returned into the soils. Our results showed that even with potato crops, which are high intensity cultivated cropping systems, we can maintain the SOM-C with a rotation of two small grain crops (all residue incorporated) and one potato crop, or potentially increase the average SOM-C with a rotation of four small grain crops (all residue incorporated) and one potato crop. Erosion losses of fine silt and clay particles were reduced with the inclusion of small grains. Small grains have the potential to contribute to the conservation of SOM and/or sequester SOM-C and SOM-N for these rangeland systems that have very low C content and that are also losing C from their bare soils areas (40%). Cultivation of these rangelands using rotations with at least two small grain crops can reduce erosion and maintain SOM-C and increasing the number of small grain crops grown successfully in rotation above two will potentially contribute to C and N sequestration as SOM and to the sequestration of macro- and micro-nutrients.  相似文献   

Effects of postfire seeding and fertilizing on hillslope erosion in north-central Washington,USA     

P.R. Robichaud  T.R. Lillybridge  J.W. Wagenbrenner 《CATENA》2006

After the 1998 North 25 Fire in the Wenatchee National Forest, eight study sites were established on steep, severely burned hillslopes to examine the effectiveness of postfire seeding and fertilizing treatments in increasing cover to reduce hillslope erosion, and to measure the nutrient content of the eroded sediment. At each site, four 4 by 9 m plots were located with four randomly applied treatments: seed (winter wheat, Triticum estivum) at 34 kg ha^− 1, fertilizer (75% ammonium nitrate and 25% ammonium sulfate) at 31 kg ha^− 1, seed and fertilizer, and untreated control. Sediment fences were installed at the base of each plot to measure erosion rates and sample the eroded sediments. In addition, precipitation amounts and intensities, surface cover, canopy cover, and nutrient concentrations in the eroded sediments were measured for four years after the fire. Total precipitation was below average during the four-year study period, and most erosion occurred during short duration, moderate intensity summer rainfall events. The overall first year mean erosion rate was 16 Mg ha^− 1 yr^− 1, and this decreased significantly in the second year to 0.66 Mg ha^− 1 yr^− 1. There were no significant differences in erosion rates between treatments. In the first year, the seeded winter wheat provided 4.5% canopy cover, about a fourth of the total canopy cover, on the seeded plots; however, the total canopy cover on the seeded plots did not differ from the unseeded plots. The below average precipitation in the spring after seeding may have affected the winter wheat survival rate. In the fourth year of the study, the mean canopy cover in the fertilization treatment plots was 74%, and this was greater than the 55% mean canopy cover in the unfertilized plots (p = 0.04); however, there was no accompanying reduction in erosion rate for either the seeding or fertilization treatments. Revegetation by naturally occurring species was apparently not impacted by seeding during the four years of this study. The pH of the sediment as well as the concentrations of NO₃–N, NH₄–N, and K was not affected by seeding or fertilizing. The nutrient loads in the eroded sediment were minimal, with most of the nutrient loss occurring in the first postfire year. These results confirm that seeding success is highly dependent on rainfall intensity, amounts, and timing, and that soil nutrients lost in eroded sediments are unlikely to impair the site productivity.  相似文献   

Tillage and the environment in sub-tropical Australia—Tradeoffs and challenges     

D.M. Silburn  D.M. Freebairn  D.J. Rattray 《Soil & Tillage Research》2007,97(2):306-317

Tillage is defined here in a broad sense, including disturbance of the soil and crop residues, wheel traffic and sowing opportunities. In sub-tropical, semi-arid cropping areas in Australia, tillage systems have evolved from intensively tilled bare fallow systems, with high soil losses, to reduced and no tillage systems. In recent years, the use of controlled traffic has also increased. These conservation tillage systems are successful in reducing water erosion of soil and sediment-bound chemicals. Control of runoff of dissolved nutrients and weakly sorbed chemicals is less certain. Adoption of new practices appears to have been related to practical and economic considerations, and proved to be more profitable after a considerable period of research and development. However there are still challenges. One challenge is to ensure that systems that reduce soil erosion, which may involve greater use of chemicals, do not degrade water quality in streams. Another challenge is to ensure that systems that improve water entry do not increase drainage below the crop root zone, which would increase the risk of salinity. Better understanding of how tillage practices influence soil hydrology, runoff and erosion processes should lead to better tillage systems and enable better management of risks to water quality and soil health. Finally, the need to determine the effectiveness of in-field management practices in achieving stream water quality targets in large, multi-land use catchments will challenge our current knowledge base and the tools available.  相似文献