Performance of simple irrigation scheduling calendars based on average weather data for annual ryegrass

Poor irrigation management in pastures can lead to yield and quality reduction as well as loss of income through extra pumping and leaching of nitrate fertiliser. A number of irrigation scheduling techniques of varying levels of sophistication have been developed over the years to address limited irrigation water availability and maximise productivity. Despite this, the adoption of irrigation scheduling tools by farmers remains low. The objective of this study was to assess the use of simple irrigation scheduling calendars based on average weather data to improve irrigation management in ryegrass. The calibrated Soil Water Balance (SWB) model was used to generate simple irrigation calendars and assess effectiveness for different scenarios by mechanistically simulating water dynamics and pasture growth. Scheduling irrigation using the calendars gave similar irrigation applications, water losses and yields compared to a more scientific real-time scheduling (in response to soil water depletion by the crop). While site-specific irrigation scheduling calendars can easily be generated by consultants and irrigators, even simpler monthly estimates of average daily water use can also be useful. Application of calendars by farmers is encouraged to improve water and nutrient use efficiency of irrigated pastures, if real-time irrigation scheduling is not employed.     

庐山自然保护区秋色叶树种观赏特性及其园林造景应用

介绍庐山保护区秋色叶树种观赏特性,从造景的角度,探讨秋色叶树种在园林中的应用,并提出开发对策。     

树形结构对果树生产能力的影响分析

果树树形与结构是影响果树产量的重要因素,笔者结合国内外的研究状况,综述了不同树形结构对光能利用率、营养与生殖、抗逆性、产量品质、实际生产的影响,指出适宜的栽植密度、合理的树形结构是保证果园光照良好,产量和品质提高的重要措施。     

From shallow to deep waters: habitats used by larval lampreys (genus Petromyzon and Lampetra) over a western European basin

Abstract –  Habitat requirements of lamprey ammocoetes (Petromyzon marinus and Lampetra genus) were investigated, for the first time, from shallow to deep waters, at different spatial scales across the Gironde‐Dordogne continuum, thanks to a water suction dredge. Fish‐habitat relationships were assessed through two complementary statistical analyses: habitat‐use curves and habitat suitability models using the Boosted Regression Trees (BRT) technique. Analyses were performed on a small‐size data set that was characterised by the low prevalence of lamprey. The sea lamprey larvae occurred in deeper areas than their Lampetra genus counterparts. ‘Pools’ of 2 m’ depth and more were optimal habitats for the former species. Among the environmental variables retained to model lamprey occurrences, the mesohabitat (a categorical variable) was demonstrated to be highly influential, in terms of fine grain‐size substratum and vegetation cover. These preliminary results suggest that monitoring using the water suction dredge method may contribute to sea lamprey conservation.     

Needle Collection Time for Nutrient Evaluation in Christmas Tree Production

Christmas tree needle sampling to evaluate nutrient need is an established practice. Data to support the recommended fall sampling time in Oregon and Washington were not found. In addition, the recommendation for needle sampling of Fraser fir in North Carolina was made without data from winter months. The goal for this article is to affirm or modify recommended needle sampling time. Needles of Douglas fir, Turkish fir, Nordmann fir, Noble fir, Grand fir, and Fraser fir Christmas trees were collected monthly for a year, dried, and analyzed for nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and boron (B). No single period was found for any species when needle nutrient concentration was stable for all elements determined. Needle collection time was chosen by integrating cultural practices, likelihood of nutrient deficiency, and needle nutrient concentration changes for species grown in an area. Needle collection is recommended during February in western Oregon and Washington. The current sampling time, fall, is logical for Fraser fir Christmas tree production in North Carolina.     

绥宁县林下经济现状与对策

对绥宁县林下经济的现状进行了阐述，分析了存在的问题，并提出了相应的对策。     

大豆秸秆菌糠喂牛的效果研究

本试验用大豆秸秆菌糠替代50％,70％和100％粗饲料（干玉米秸）饲喂鲁西牛。结果表明,大豆秸秆菌糠替代粗饲料的比例以50％为宜,日增重比 对照组高131g,提高29．91％,差异极显著（P＜0．05）。     

Testing variability in pathogenicity ofPhytophthora cactorum, P. citrophthora andP. syringae to apple, pear, peach, cherry and plum rootstocks

The relative virulence ofPhytophthora cactorum andP. syringae originating from almond trees, and ofP. citrophthora originating from citrus, to apple, pear, peach, cherry and plum rootstocks, was studiedin vivo andin vitro. Results of the different experiments were in good agreement. All testedPhytophthora isolates showed little virulence to pear rootstocks-causing only minor crown rot symptoms - and no virulence at all to apple rootstocks. In contrast, they were highly virulent to stone fruit rootstocks, causing crown rot disease. The non-pathogenicity of these isolates to pome rootstocks could be interpreted as strict host specificity.     

山东苹果主要病虫害化学防治技术

山东省苹果园害虫优势种群是蚜虫、桃小食心虫、苹小卷、金纹细蛾、害螨等 ;病害主要是斑点落叶病、轮纹病。根据不同病虫害的发生发展规律和烟台农科院多年来的化学防治试验研究 ,明确了不同苹果品种上适用的有效药剂和不同药剂的杀虫 (菌 )谱、用药适期、施药方法 ,制定了相应的防治策略 ,提出了合理用药、交替施药和安全喷药等诸多注意事项     

福建果树根部的芒果半轮线虫记述

 芒果半轮线虫(Hemicriconemoides mangiferae Siddiqi,1961)在福建省一些果园发生。寄主有龙眼(Euphoria longana)、荔枝(Litchi chinensis)、芒果(Mangifera indica)、橄榄(Canarium album)、枇杷(Eriobotrya japonica)和葡萄(Vitis vinifera)等果树。雌虫唇部正面、环纹和阴门,雄虫侧带以及幼虫角质膜刺突等细微结构用扫描电子显微镜观察。