A linear programming assessment of the profit from strategies to reduce the prevalence of Staphylococcus aureus mastitis

We used a linear programming model to estimate the financial returns to a Staphylococcus aureus testing and control program over a 1-year period for a 100-cow herd, with a 8636-kg rolling-herd average. Six tests, which vary in sensitivity from 0.80 to 0.98 and specificity of 0.99, were examined in simulated herds with 10, 20 and 30% prevalence of S. aureus infection. Sensitivity of these results to a range of assumptions regarding rolling-herd average, milk price, somatic cell-count premium, and cost and cure rate of dry treatment were examined to determine the profits from the program. The profits of a control program are most dependent upon prevalence, cell-count premium, and cost of dry treatment. In our simulation for a 100-cow herd, a testing and control program appears to cost less than US$10 per cow per year, and pays for itself within 1 yr, except under the lowest prevalence and most-adverse conditions (low yield, high cost of dry treatment, or low SCC premium).     

Yields nutrient intake and soil fertilizing in 40 years fertilizer trials

The set of twenty long‐term field nutrition trials starting from 1957 at five sites. The sites differed by their altitude (from 180 m to 620 m) with average daily temperatures (from 6,8°C m to 9°C m) and soil type (from chernozem to brown podsolic soil) Provided mainly the following results:

? The geonomic division to the fertile sugarbeet region and less fertile potato region did not strictly differentiate the influence of fertilizer and climatic effects to the crop yields.

? The effect of fertilizing was dependent on the nutrient content and on the conditions of releasing and binding of the nutrients in soil.

? The precipitation regime has a strong influence on the effect of the nitrogen escalated doses.

? The facts concerning the nutrient intake are very precious knowledge. These facts have not been examined yet during the long‐term trials.

? The site effect, particularly its climatic conditions, on the nutrient intake is often more obvious compared to the fertilizing effect.

? Very interesting impulses for further research monitoring during the long‐term trials was contributed by “mapping”; of soil capacity to provide nutrients to plants at various sites and under different climate.     

南京牛首农副产品合作社专题调研的思考

农民专业合作经济组织是由从事同类农产品生产经营的农民自愿组织起来．在农业生产经营的产前、产中、产后等环节实行资金、技术、信息、生产、供销等互助合作与服务的经济组织，是市场经济条件下，农民进行自我服务、自我发展、自我保护的一种行之有效的组织形式。在对南京牛首农副产品合作社进行专题调研的基础上，拟从南京牛首农副产品合作社的实践分析入手，提出进一步发展壮大江宁区农民专业合作经济组织对策和建议。     

城市污泥应用于毛白杨林地施肥试验

为了妥善处置和利用城市污泥,使之变废为宝,采用城市污泥对毛白杨进行了不同立地施肥量、施肥时期试验.结果表明,污泥施肥改善了林地土壤的理化性状,对土壤具有修复作用.在不同施肥时期,不同立地条件下,施入一定量的城市污泥对毛白杨株高、胸径的生长均有促进作用,平原林地毛白杨净生长量优于丘陵地,污泥施入量以75 kg/株效果最佳.     

蒙自县森林资源特点及发展对策

蒙自县珠江流域的重点生态工程区，森林覆盖率为30．98％。其特点是：森林资源分布不均匀，树种结构单一，龄组结构不合理，针对上述特点提出了对森林资源的保护、利用和发展的对策。     

兰花矿质营养研究进展

矿质营养是提高兰花花朵品质的关键,对目前国内外兰花的氮、磷、钾等矿质营养的研究进展进行了综述,对施肥量及其对兰株的影响地总结,为确定兰花的营养诊断标准与高效施肥方案提供理论依据,对兰花的生产栽培具有指导意义。     

油松容器苗施肥的研究

本文根据研究结果论述了油松容器苗营养土中掺合尿素的最适量,一定出圃规格油松容器苗的施肥量以及施肥量的计算方法。同时还论述了1年生油松容器苗有关的化学营养诊断指标。     

贵州省桉树引种栽培现状、问题与对策

介绍了贵州省桉树的引种现状、存在问题和发展对策。贵州省引种桉树栽培成功的限制因子是寒害，主要表现为持续时间较长的低温和凝冻气候；在贵州成功引种保存的桉树种质资源基础上开展耐寒选育，是桉树能否在贵州省扩大种植的关键技术措施；贵州省桉树发展存在的主要问题是受地势和气候的影响，适宜规模化经营造林的面积较少，确定适宜种植区和种植规模应采取稳步推进的策略。     

Artificially regenerating longleaf pine in canopy gaps: initial survival and growth during a year of drought

Nitrogen fertilization in the nursery, along with altering the configuration of forest gaps, may improve the reforestation success of longleaf pine seedlings. During the very droughty 1998 growing season in Florida and Georgia, survival was higher under the forest canopy than in small (0.10 ha, 36 m diameter) and large (1.6 ha, 144 m diameter) canopy gaps. In the large gaps, survival of containerized seedlings was higher along the edges, particularly the SW edge. Shade from adult trees and the nurse effect of shrubs increased survival, while grass competition reduced survival. During dry years part of the “exclusionary zone” along the edge of canopy gaps (SW sector) may serve as a “survival zone”, at least in the short term. A model using oval-shaped gaps oriented from NW to SE, with an area of 0.25 ha is proposed to maximize the survival and growth of artificially regenerated longleaf pine seedlings.     

Management Effects on Biomass and Foliar Nutritive Value of <Emphasis Type="Italic">Robinia pseudoacacia</Emphasis> and <Emphasis Type="Italic">Gleditsia triacanthos</Emphasis> f. <Emphasis Type="Italic">inermis</Emphasis> in Arkansas,USA

The browse potential of black locust (Robinia pseudoacacia L.) and thornless honey locust [Gleditsia triacanthos f. inermis (L.) Zabel] has not been adequately tested. Our objective was to determine effects of fertilization and pollarding on biomass and foliar nutritive value in separate studies of black locust and thornless honey locust in Arkansas, USA. Shoots were sampled monthly for two consecutive growing seasons in 2002 and 2003 to determine foliar, shoot, and total aboveground biomass, shoot basal diameter, and foliar nutritive value (crude protein and in vitro digestibility). Black locust yielded more foliar biomass when pollarded at 50 or 100 cm and fertilized with 600 kg P ha⁻¹, than at 5 cm with or without P, averaging 3.5 Mg dry matter ha⁻¹. Black locust foliar crude protein and in vitro dry matter digestibility ( ≤ 170 and 534 g kg⁻¹, respectively) decreased as leaves aged, but still met maintenance needs for beef cattle (Bos taurus L.). Thornless honey locust had little agronomic potential because of slow establishment, low foliar yield (330 kg ha⁻¹), and a 2% reversion to undesirable thorny phenotype. Black locust should be considered for livestock browse when drought induces semi-dormancy of herbaceous forages.