Effects of a plastic cover on soil moisture change in a Mediterranean climatic regime     

J. L. Díaz‐Hernández  T. Salmerón 《Soil Use and Management》2012,28(4):596-605

Water deficit is a serious problem for most agricultural crops, especially in arid–semiarid regions, and limits sustainable development. Production can be improved by reducing evapotranspiration and loss of infiltrated water by the use of a plastic cover. We monitored soil moisture fortnightly over 1 yr using a neutron probe near four trees in an olive grove (Olea europaea, var. Arbequina), two of which had a plastic cover buried in the topsoil around them. These trees were monitored using three neutron probe access tubes per tree to compare the behaviour of soil moisture over time with two other identically instrumented and nearby trees with no cover. Analysis was based on the resultant moisture profiles. The plastic cover retained moisture and increased soil water residence time. During the dry season, the amount of water retained in the plots was at most 15–20% greater in the mid‐season and at least 5–6% greater at the end of season than in the central part of the plots near the trunk. The plastic cover was effective to ca. 50 cm with maximum water content near the soil surface. During the wet season, the cover did not affect soil water. Soil moisture was greater near the tree trunk as a result of stemflow and throughfall.  相似文献   

辐射诱变育种在牧草和草坪草中的应用     

徐远东  何玮  王琳  范彦 《草业与畜牧》2010,(6):1-4

对辐射诱变育种的概念、主要类型及特点、诱变材料的选择、诱变的程序及其在牧草、草坪草方面的应用研究情况进行综合叙述.  相似文献   

涵江区农产品质量安全现状及对策初探     

曾伟 《福建农业科技》2012,(8):69-71

分析福建省莆田市涵江区农产品质量安全工作取得的成绩和存在的问题,从提升全区的农产品质量安全水平的角度,提出对策建议。  相似文献   

The Innovativeness and Heterogeneity of Foreign‐Invested High‐Tech Companies in Shanghai     

Ingo Liefner  Yehua Dennis Wei  Gang Zeng 《Growth and change》2013,44(3):522-549

China has taken a foreign direct investment‐based approach toward increasing its capital and knowledge base, and developing into an innovative economy. However, little quantitative evidence exists about the factors that drive innovations of foreign‐invested enterprises (FIEs) there. This paper uses survey data from high‐technology firms in Shanghai to discuss factors affecting their innovativeness. It takes the concepts of absorptive capacity, export orientation, and innovation‐related cooperation as a starting point. It highlights how the interplay of strategies and resources affects innovativeness and heterogeneity of FIEs. The most innovative FIEs are endowed with a strong human capital base and R&D activities, which at the same time target export markets and whose cooperative partners involve firms other than their parent company. The results underline the necessity to differentiate between the different types of FIEs when examining their innovativeness.  相似文献   

东兰县林地质量等级划分及其管理   总被引：1，自引：0，他引：1  

李伟  梁耀  任湘莉 《陕西林业科技》2013,(2):1-5

利用数量化理论Ⅰ模型和土壤类型、土层厚度、海拔高度、坡度、坡向、坡位、石砾含量等7个因子和交通区位因素,对东兰县林地质量等级进行了划分,结果显示东兰县林地质量可分为5级,各级林地面积及其占林地总面积的比例分别为Ⅰ级2 343.3m2、1.2%,Ⅱ级23 622.0hm2、12.5%,III级87101.6hm2、46.2%,IV级45 176.0hm2、24.0%,Ⅴ级30 223.6hm2、16.1%,提出了不同等级林地的相应培育方向和管理措施。  相似文献   

萝卜肉质根膨大过程中主要农艺学性状的变化   总被引：2，自引：0，他引：2  

刘贤娴  王淑芬  李莉娜  王伟  牟晋华 《山东农业科学》2010,(4):31-33

以不同皮色、肉质色萝卜为试材，采用常规方法对肉质根膨大过程中的主要农艺学性状进行了系统测定。结果表明，萝卜生长过程中，地上部与地下部的生长同步进行，地上部的生长状况，影响肉质根的膨大，进而影响产量；育种过程中，选择根重／叶重比值大的品种有利于提高产量和品质。  相似文献   

五个典型柑桔品种的落花落果规律调查     

王男麒  彭良志  冉渝  邢飞  黄翼  周薇  唐玉琴  吴玉婷  刁莉华 《中国果业信息》2013,42(6)

以成年纽荷尔脐橙、兴津温州蜜柑、沙田柚、尤力克柠檬和圆金柑为材料，探索其花果脱落规律。结果表明，最终坐果率与总花量（含花蕾）显著负相关（P < 0.01）；平均单株花果脱落总数量为兴津温州蜜柑 > 纽荷尔脐橙 > 沙田柚 > 圆金柑 > 尤力克柠檬；平均单株花果脱落总干重为兴津温州蜜柑 > 纽荷尔脐橙 > 沙田柚 > 尤力克柠檬 > 圆金柑；纽荷尔脐橙、兴津温州蜜柑和沙田柚第一次生理落果数量大于第二次生理落果，尤力克柠檬和圆金柑第二次生理落果数量大于第一次生理落果。因此，纽荷尔脐橙、兴津温州蜜柑和沙田柚应重点防止第一次生理落果，尤力克柠檬和圆金柑应重点防止第二次生理落果。  相似文献   

中稻高产施肥技术     

谢保忠  陈蔚  王万福  张绍安 《现代农业科技》2012,(5):118

综述了中稻高产施肥的关键技术,包括秧田合理施肥、大田施足基肥、科学安排大田各生育阶段施肥比例、看苗巧施穗粒肥等内容,以期指导中稻的合理施肥。  相似文献   

椰糠替代泥炭作观赏凤梨基质的研究   总被引：4，自引：0，他引：4  

李伟  郁书君  崔元 《热带作物学报》2012,33(12):2180-2184

以奥斯塔拉凤梨为试材,广东泥炭、进口泥炭、蛭石、珍珠岩、海南椰糠为栽培基质材料,按不同比例混合,选用国内外较为通行的改良配方,设定3个营养液浓度进行无土栽培试验.试验以土壤栽培为对照,通过测定基质的物理特性和植株的株高、冠幅、光合速率以及叶片元素(氮、磷、钾、镁、钙、铜、锰)含量,探讨不同基质对奥斯塔拉凤梨生长的影响.结果表明:奥斯塔拉凤梨无土栽培最佳基质配方为:进口泥炭∶蛭石∶珍珠岩=1∶1∶1,而在椰糠∶蛭石∶珍珠岩=1∶1∶1中生长的整齐度最好,可见,椰糠完全可以替代泥炭广泛应用于园艺生产栽培.  相似文献   

Genetic Diversity and Population Structure in the Heavily Exploited Korean Rockfish,Sebastes schlegeli,in Korea     

Hyesuck An  Mi‐Jung Kim  Kwangjae Park  Keechae Cho  Bongseong Bae  Jaewoo Kim  Jeong‐In Myeong 《Journal of the World Aquaculture Society》2012,43(1):73-83

The Korean rockfish, Sebastes schlegeli, is a valuable and intensively exploited species in Korea. We discuss the genetic diversity and genetic structure of four Korean rockfish populations using eight microsatellite loci. In total, 161 different alleles from 138 individuals were observed. Average allele number per locus ranged from 2.5 to 23 and allelic richness varied from 13.38 to 14.63 within a population. Despite a long history of stocking practices, we found very high levels of polymorphism (mean heterozygosity = 0.810), which is comparable to other congeneric species. No significant difference in genetic diversity and molecular genetic variance (F_ST and R_ST) was observed among four local samples (P > 0.1). Little indication of contemporary inbreeding (F_IS= 0.051) or population structure (K = 1) was detected. This absence of differentiation may reflect high levels of gene flow along the coast of Korea. Our study demonstrates that rockfish in Korea should be managed as a single unit. Currently, the species does not appear to be genetically threatened, but the potential for a rapid loss of genetic diversity remains. This information on the genetic characteristics of Korean rockfish populations has important implications for fisheries management and conservation efforts, and will aid in the sustainable exploitation of the fishing resources and the preservation of biodiversity.  相似文献