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   

河北山地森林的特点、地位和发展对策     

徐化成  陈连英  白俊格  左占生  王永宽  张重忱  郑均宝 《河北林果研究》1996,(1)

河北的山地在植被上属于落叶阔叶林地带。河北山地的森林具有立地生产力较低，人工林和天然林年龄小，多与农田、果园和牧地等交叉分布的特点。河北的山地森林在改善山区的生态环境、维持生物多样性、供应城乡居民所需的用材和烧柴及果品、为人民提供游乐活动场所等方面起着重要的作用。河北山地森林应该遵循的发展方针是：要把山区的水土保持和生态环境建设列在首位；要以林为主，协调发展农、果、林、牧的关系；在培养森林上，要采取封山育林和人工造林并重的政策；要把经济林的发展和其他林种结合起来，重视自然保护区森林公园的建设。  相似文献   

大白菜矿质营养吸收与分配规律研究   总被引：13，自引：0，他引：13  

张振贤  赵德婉 《园艺学报》1993,20(2):150-154

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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   

水稻控蘖增粒栽培技术增产原因初探     

王子立  李谋英 《杂交水稻》1995,(1):24-27

以金优桂９９、Ｗ６１５４Ｓ／特青、香Ｓ／ＧＥＲ－１等杂交组合为材料，从分蘖节位、茎杆粗细、穗粒结构等方面探讨“控蘖法”对杂交水稻的增产原因。  相似文献   

高等学校法律地位研究     

龙力李荣华  古文海 《四川畜牧兽医学院学报》2005,3(3):66-72

从考察我国高等学校法律地位的理论与现状入手,分析了高等学校在法律地位上存在的问题,探讨了高等学校的教育权,认为：当前我国高等学校的法律地位主要取决于高校自身所具有的多种社会职能,以及由多种社会职能所必然带来的法律特征.  相似文献   

篱壁式红富士苹果光照分布及结果部位对果实品质的影响   总被引：4，自引：0，他引：4  

徐胜利  陈小青  李绍华 《北方果树》2002,(1):4-6

作者对6～7年生篱壁式红富士苹果叶幕光照分布、结果部位对品质的影响进行了研究.结果表明:篱壁形叶幕光照垂直分布和水平分布的日变化相对均衡,树冠内未产生无效光区;品质垂直和水平分布与光照垂直和水平分布呈极显著正相关.中、下层中长果枝果实的果面光洁度分别为92.7%和97.2%,端正果率分别为91.6%和92.5%.  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