A proposed method to determine adequate amount of fertilizers to be applied to crops

To determine the adequate amounts of fertilizers to be applied to crops is one of the most important problems in the field of soil science.     

Proximity to a forest leads to higher honey yield: Another reason to conserve

Although tropical forest conservation is a top priority for human and environmental health, deforestation persists, mainly because of food and economic needs. No community will totally give up economic activities for the sake of ecological integrity, unless it is given alternative economic activities from which to draw its livelihood. Beekeeping in the forest buffer zone instead of traditional destructive honey-harvesting from forest trees is one such option at Arabuko Sokoke Forest (ASF) in Kenya. ASF is a dry coastal forest which is home to endangered and threatened fauna and is a hotspot considered a priority for conservation. In order to find out whether honey quantity and quality differed with distance from the forest, we studied honey yield per harvest (kg) and obtained samples from hives placed at varying distances from ASF in two successive years. Honey yield increased with proximity to the forest. Indeed the yield almost doubled in hives placed less than 1 km from the forest compared to those placed more than 3 km from the forest. All the honey samples met internationally required quality standards, although sugar levels were at the lower limit. This study demonstrates that the conservation of tropical forest ecosystems can have real local economic benefits. The documentation of the services provided by nearby natural areas should help make conservation of these areas a priority, even for the local communities.     

自动分析曲线线型并可绘图的计算机程序

本程序图文并茂,直观性强。而且,引入常数k的曲线模拟模型可提高精确度百倍以上,使其更适合理化特性或理论曲线的模拟分析。     

Adsorption of Orthophosphate to Humic-Fe-Complexes and to Amorphous Fe-Oxide

The adsorption of orthophosphate to humic surfaces was studied in a model experiment. The adsorption maximum of humic substances greatly increased with higher concentrations of organically complexed Fe (III), indicating that orthophosphate was bound to humic surfaces via metal bridges. The molar ratio P_adsorbed/Fe was nearly 1 for Fe freshly complexed to humic substances, whereas the ratio for amorphous Fe-oxide was a tenfold lower. An increase in pH from 5.2 to 6.2 lead to an increase of P-adsorption of about 30% in the case of humic-Fe-surfaces, which could be explained by an increased accessibility of adsorption sites at pH 6.2. The addition of a 0.01 M CaCl₂-matrix increased orthophosphate adsorption at pH 6.2 but not at pH 5.2. This could be explained by electrostatic interactions caused by the Ca⁺⁺ ion.     

巩固退耕还林成果水利项目的实践与成效

退耕还林工程是我国改善生态环境、促进可持续发展的重要工程,是解决水土流失、土地沙化等生态恶化现状而采取的重大战略举措。五寨县属退耕还林工程区,为了保证退耕还林成果不反弹,在退耕项目区又实施了巩固退耕还林水利项目。通过实施,改造基本农田253.33 hm2,配套排洪渠6000 m,建旱井13眼,年新增粮食产量98.5万kg,人均增产745 kg,人均增收700元。     

立足山地开发 搞好水土保持

立足山地开发搞好水土保持王培根，李复水（湖南省芷江侗族自治县水利水电局．４１９１００）芷江侗族自治县位于湖南省西部．是湖南省边远山区贫困县之一。全县总面积２０９９ｋｍ２，辖２９个乡镇，３０３个村。境内以丘陵山地为主。地表坡度大于２５°的坡地面积占总土...     

涪陵地区“长治”小流域成效显著

涪陵地区“长治”小流域成效显著曾发初（四川省涪陵地区水保办，涪陵市６４８０００）１９８９～１９９３年，国家安排我区“长治”一期六条小流域，共治理面积５６２．２７ｋｍ２，涉及涪陵、丰都、武隆三县（市）沿长江、乌江两岸的２０个乡（镇），２８７个行政村，３...     

武陵山区水土流失亟待治理

武陵山区水土流失亟待治理潘佑堂，杨胜刚（湖南省水利水电厅，长沙４１０００７）一、自然条件及社经状况武陵山区位于湖南西部、西北部，西与贵州交界，北与湖北毗邻，包括湘西土家族苗族自治州和张家界市的全部、怀化地区的新晃、芷江、麻阳、辰溪、沅陵及常德市的石门...     

安化县坡耕地的治理及效益

安化县坡耕地的治理及效益夏远主，吴海安（湖南省安化县水利水电局，４１０４００）彭成初（湖南省安化县水土保持站）安化县是一个自然条件较差的山区县，土地总面积川５０．５ｋｍ２，其中２５°以上的坡地占土地总面积的７９．５％，平地仅占２．８％。全县农业人口８...     

搞好水土保持是减轻水旱灾害的有效途径

搞好水土保持是减轻水旱灾害的有效途径魏再勋（湖南省水利水电厅，长沙市４１０００７）８０年代以来，湖南省的水土保持工作取得了长足的进展，但水土流失危害仍然是湖南人民的心腹大患。洞庭湖多次发生洪涝灾害，便是水土流失造成湖泊日益淤积萎缩的结果。１９９４年６...     

引入市场新机制 治理开发小流域

引入市场新机制治理开发小流域张明（山西省水利厅水保局，太原市０３０００２）孙斌（山西省造林局）一、我省水土保持工作的回顾山西省是全国水土流失最严重的省份之一，水土流失面积占总土地面积的６９％，经过４０年的努力，保存治理度达３０％。纵观多年来的水土保持...     

红壤山丘综合开发治理试验研究

红壤山丘综合开发治理试验研究杨端生（湖南衡山县水利水电局，４２１３００）红壤主要发育于第四纪红土、红色砂岩、花岗岩、板页岩，海拔５００ｍ以下的低山、丘陵、岗地广泛分布。红壤士的共同特性是呈酸性反应，有机质较少，磷、氮偏缺；不同之处是发育于花岗岩、红砂...     

依法防治水土流失让“三湘四水”更好地造福人民

湖南省山丘区面积占总面积的８０％，水土流失比较严重。解放后虽累计治理了１．７万ｋｍ２，但由于边治理、边破坏．８０年代末仍有水土流失面积４．７万ｋｍ２，年土壤侵蚀量１．５７亿ｔ，造成严重危害。近几年来，认真贯彻水土保持法，依法防治水土流失，大搞荒山造林、封禁治理和小流域综合治理开发，取得了显著成效。要进一步加强领导，建立健全水保监督执法体系，多渠道增加投入，加快水土流失防治步伐。     

湘中丘陵山地的水土流失及其防治

湘中丘陵山地的水土流失及其防治杨谷声（湖南省水利水电厅，长沙４１００６７）湘中丘陵山地位于湖南省中部，其范围包括衡阳市及娄底地区的全部，邵阳市的邵东、邵阳、新邵、隆回四县，益阳地区的安化、桃江二县，湘潭市的湘乡和长沙市的宁乡县，共２３个县（市、区），...     

Response to Fertilization Associated to Leaf Mineral Content in Strawberry

Leaf mineral content along the crop cycle may explain differences in response to fertilization among strawberry genotypes. A two year field experiment was conducted using responsive (‘Camarosa’, ‘Ventana’) and nonresponsive (‘Camino Real’, ‘Candonga’) to fertilization genotypes under proportional increases in nutrients supply: from a control dose “C” [120 kg nitrogen (N) ha^?1, 70 kg phosphorus pentoxide (P₂O₅) ha^?1, 220 kg potassium oxide (K₂O) ha^?1, 40 kg calcium oxide (CaO) ha^?1 and 20 kg magnesium oxide (MgO) ha^?1] to “1.33C” and “1.66C” in 2007 and to “1.5C” and “2C” in 2008. Response to fertilization was high (45–120%) at begining of harvesting and low (10-28%) at middle and end of harvesting. Correlation between leaf area and total yields was high (r ≈ 0.73) at begining of harvesting, except on ‘Camino Real’ (late and compact genotype). At begining of flowering and harvesting, responsive genotypes showed higher potassium (K) and lower calcium (Ca) leaf contents than nonresponsive genotypes, accentuated with the fertilization increase.     

Contribution to the taxonomy ofVicia species belonging to the sectionFaba

Summary Vicia faba belongs to the sectionFaba. While the other species of the sectionV. narbonensis, V. johannis andV. bithynica cross enough well each other,V. faba seems to be strongly isolated from them. In addition the chromosome morphology ofV. faba differs from the other species of the section which among themselves are enough homogenous in this respect.To contribute to a wider knowledge on the taxonomical position ofV. faba in its section, electrophoretical and karyological analysis of 500 individuals belonging to 50 populations of different origin were carried out.The analyzed species were:V. faba, V. narbonensis, V. serratifolia, V. bithynica, V. galilaea andV. johannis.

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Beitrag zur Taxonomie derVicia-Arten der SektionFaba

Zusammenfassung Vicia faba gehört zur sect.Faba. Während andere Arten der Sektion (V. narbonensis, V. johannis undV. bithynica) untereinander relativ gut kreuzbar sind, istV. faba von ihnen deutlich isoliert. Darüberhinaus unterscheidet sichV. faba in der Morphologie seiner Chromosomen von den anderen Arten der Sektion, die in dieser Hinsicht eine relativ einheitliche Merkmalsausprägung zeigen. Um zu einer besseren Kenntnis der systematischen Stellung vonV. faba innerhalb der Sektion beizutragen, wurden chromatographische und karyologische Analysen von 500 Individuen aus 50 Populationen verschiedener Herkunft durchgeführt. Analysiert wurdenV. faba, V. narbonensis, V. serratifolia, V. bithynica, V. galilaea undV. johannis.

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Vicia, Faba

Vicia faba Faba. (V. narbonensis, V. johannis, V. bithynica) ,V. faba ë . ,V. faba , . V. faba , 500 50 . :V. faba, V. narbonensis, V. serratifolia, V. bithynica, V. galilaea, V. johannis.

     

玉米苗期根系生长与耐低磷的关系

在田间筛选试验的基础上,利用两个磷高效(181和186)、两个磷低效(153和197)玉米自交系,进一步研究了这些自交系苗期耐低磷能力差异及其与根系生长的关系。结果表明,在低磷胁迫(P.5.78.mg/kg)下,所有自交系玉米地上部重量、初生根重、次生根重及磷累积量降低,但磷高效自交系181和186受影响程度显著小于153和197。在试验所处的玉米生育时期(6叶龄),磷对所用自交系的初生根及次生根数量没有影响。比较181和197的根系形态,在低磷胁迫下,磷低效自交系197的初生根侧根长、轴根长均显著下降,磷高效自交系181则下降幅度很小。而且,低磷使181初生根的侧根/轴根比值、根长度/根重比值较高。说明低磷胁迫下,181自交系可以将根中的有限的养分及干物质作更合理的分配,促进细根的生长,从而获得较长的根系。     

Golfer exposure to chlorpyrifos and carbaryl following application to turfgrass

Exposure of golfers to pesticides following their application to turfgrass is of concern to regulators, turfgrass professionals, and consumers. Multipathway exposures were evaluated for golfers on turfgrass treated with chlorpyrifos and carbaryl. Air concentrations and transferable foliar residues (TFRs) were measured to assess potential respiratory and dermal exposures, respectively. At the same time, exposure to individuals simulating the play of golf was determined by dosimetry and urinary biomonitoring. Individual golfer exposure was determined in 76 rounds of golf following eight applications of chlorpyrifos and two applications of carbaryl. Estimated exposures to golfers following full course and full rate applications of chlorpyrifos and carbaryl were 19-68 times below current U.S. EPA acute reference dose (Rfd) values, indicating safe exposures under U.S. EPA hazard quotient criteria. Dermal exposure was determined to be the dominant exposure pathway to golfers, accounting for approximately 60% of the chlorpyrifos absorbed dose and 100% of the carbaryl absorbed dose. This study also provides a set of transfer factors (TFs) that may be used to determine dermal exposure of golfers to pesticides using transferable residue data.