排序方式： 共有31条查询结果，搜索用时 31 毫秒
11.
12.
Abigail L. Scherer-Hoock BS Elizabeth A. Greene PhD Michael Lennox BS Clarissa Brown-Douglas PhD 《Journal of Equine Veterinary Science》2011,31(4):180-184
Despite being largely studied as models of equine nutrition, few published data exist on actual nutritional requirements of Miniature horses. Small equines are particularly prone to obesity, insulin resistance, and the metabolic disorders for which these are risk factors. Improper feed rationing, overfeeding in particular, puts horses at risk for these metabolic problems. Feed manufacturers, however, generally supply feeding recommendations for horses weighing ≥360 kg, whereas the average Miniature horse weighs around 100 kg. Lack of nutritional guidelines for small equines makes it difficult for owners to properly estimate the amount of hay and grain to feed their Miniature horse. The purpose of this study was to determine whether feeding recommendations provided by feed manufacturers for average-sized horses could be linearly extrapolated to Miniature horses. This study surveyed nutritional management of 12 mature Miniature horses that represented the ideal body condition of the breed. Each horse’s hay, grain, and pasture intake was recorded and the average daily digestible energy (DE) intake was calculated from those data. The daily DE intake of the surveyed horses was compared with the extrapolated recommendations published by several different sources. When linearly extrapolated to fit the body weight of a Miniature horse, recommendations significantly (P < .002) misestimated the amount of daily DE that the surveyed horses were consuming. The majority of recommendations overestimated the DE consumed by the Miniature horses per day. However, one source that was designed specifically for Miniature horses, severely (P < .001) underestimated their required DE. 相似文献
13.
[目的]掌握江川县生态环境状况、分析存在的问题,为政府制订合理的区域规划和经济发展战略提供科学依据。[方法]根据环境保护部颁布实施的《生态环境状况评价技术规范》(HJ 192—2015),运用遥感影像数据和环境状况公报数据以及统计年鉴数据,结合RS与GIS相关理论与技术,选用生物丰度指数、植被覆盖指数、水网密度指数、土地胁迫指数、污染负荷指数5个因子,对2015年江川县各乡镇生态环境状况进行评价与分析。[结果]2015年江川县7个乡镇的生态环境指数为57.954 7~66.912 1,其中以路居镇最高,大街镇最低,二者差值为8.957 4。[结论]江川县总体生态环境状况良好。 相似文献
14.
为进一步科学合理进行万州玫瑰香橙（‘塔罗科血橙新系’,C.sinensis‘Tarocco’）施肥,连续5年开展了玫瑰香橙果园土壤和叶片营养分析。结果表明,土壤中,pH和有机质低于适宜值,但都有上升趋势。N、K、Ca、Mg呈降低趋势,但均处于适宜值范围内。Cu、Mn、B表现相同趋势,但均大大高于适宜值上限。P、Zn处于低限水平,Te一直表现极度缺乏。叶片中,N、P、Ca、Mn、Fe整体表现上升趋势,且基本在适宜值范围内。Mg含量比较稳定且适宜。K、S、Cu、Zn、B始终表现缺乏,但K逐年在提高,Cu、Zn、B整体表现下降趋势。综上,结合玫瑰香橙品种特点,创新提出针对不同树龄,增施有机肥、增施一次冬肥、叶面补充中微量元素的施肥建议,广泛应用于生产。 相似文献
15.
R. B. Beverly 《Journal of plant nutrition》2013,36(8):901-920
The Diagnosis and Recommendation Integrated System (DRIS) provides advantages over the Sufficiency Range (SR) approach to diagnosing the nutrient status of soybean (Glycine max L.). However, a number of modifications to DRIS have been proposed, including the use of only one method for calculating nutrient indices, and incorporating nutrient concentrations. In previous research, the author found that derivation and interpretation of DRIS diagnoses could be simplified by: 1) using a logarithmic transformation of nutrient ratio data; 2) using population parameters rather than high‐yield subpopulation values; 3) using a single index calculation method; and, 4) incorporating a measure of the probability of yield response to a treatment. Diagnoses by the SR approach, DRIS, three revisions of DRIS, and two new concentration‐based diagnostic methods were compared using diagnostic norms derived from a data base of over 4000 soybean tissue analyses and yield observations. Virtually all diagnoses of the most limiting nutrient were the same, except that the SR method did not make diagnoses on 5 week‐old samples. Traditional DRIS diagnoses were the least conservative, indicating only the order in which N, P and K would likely limit yield. Revised methods, particularly the concentration‐based methods, indicated fewer limiting nutrients, and agreed well with the SR method. Yields in the test data set increased with nearly every nutrient application, so the least conservative DRIS showed the greatest yield advantage. No diagnostic method consistently identified the nutrient causing the greatest yield response as most limiting. 相似文献
16.
谭立 《四川畜牧兽医学院学报》2008,(4):99-102
科举制度自隋、唐确立和完善。它顺应时代潮流，是统治阶级与社会各阶层人士上下呼应、协力而为的结果。科举制度不重门第谱牒，依靠严格的考试制度拔擢人才，使得以“举荐制”为主的官僚选拔制度下产生的“魏晋风度”丧失生存土壤。 相似文献
17.
《Communications in Soil Science and Plant Analysis》2012,43(3):237-256
Abstract The Diagnosis and Recommendation Integrated System (DRIS) has proven useful in the interpretation of tissue elemental analyses for many crops, and research was undertaken to apply the same method for foliar diagnosis of soybean (Glycine max [L.] Merr.). Using a data bank in excess of 3500 tissue samples, reference values for evaluating the status of soybean with respect to N, P, K, Ca, Mg, Mn, Fe, Cu, Zn, Mo, B and Al were derived. DRIS diagnoses generally agreed with those obtained by the sufficiency range method. In addition, DRIS assessed the nutrient balance in plant tissue, and identified not only the most‐limiting element, but the order in which other elements would likely become limiting. Further, DRIS was able to diagnose plant nutrient needs earlier in the life of the crop than the sufficiency range method (5 weeks compared to 10 weeks), which would allow remedial steps to be taken earlier. Treatments indicated by DRIS to be needed gave greater yield increases than those indicated by the sufficiency range approach. Geographic differences in DRIS norms were identified, and indicate that regional derivation of diagnostic values may be necessary. 相似文献
18.
河南省平原地区森林经营研究探讨 总被引：2，自引：0，他引：2
根据河南森林经营的发展历程，探索平原地区森林经营的方式，通过对采取的措施和存在问题的分析．提出解决平原地区开展森林经营的途径和建议。 相似文献
19.
Technological interventions to address the problem of poor productivity of smallholder agricultural systems must be designed to target socially diverse and spatially heterogeneous farms and farming systems. This paper proposes a categorisation of household diversity based on a functional typology of livelihood strategies, and analyses the influence of such diversity on current soil fertility status and spatial variability on a sample of 250 randomly selected farms from six districts of Kenya and Uganda. In spite of the agro-ecological and socio-economic diversity observed across the region (e.g. 4 months year−1 of food self-sufficiency in Vihiga, Kenya vs. 10 in Tororo, Uganda) consistent patterns of variability were also observed. For example, all the households with less than 3 months year−1 of food self-sufficiency had a land:labour ratio (LLR) < 1, and all those with LLR > 1 produced enough food to cover their diet for at least 5 months. Households with LLR < 1 were also those who generated more than 50% of their total income outside the farm. Dependence on off/non-farm income was one of the main factors associated with household diversity. Based on indicators of resource endowment and income strategies and using principal component analysis, farmers’ rankings and cluster analysis the 250 households surveyed were grouped into five farm types: (1) Farms that rely mainly on permanent off-farm employment (from 10 to 28% of the farmers interviewed, according to site); (2) larger, wealthier farms growing cash crops (8-20%); (3) medium resource endowment, food self-sufficient farms (20-38%); (4) medium to low resource endowment relying partly on non-farm activities (18-30%); and (5) poor households with family members employed locally as agricultural labourers by wealthier farmers (13-25%). Due to differential soil management over long periods of time, and to ample diversity in resource endowments (land, livestock, labour) and access to cash, the five farm types exhibited different soil carbon and nutrient stocks (e.g. Type 2 farms had average C, N, P and K stocks that were 2-3 times larger than for Types 4 or 5). In general, soil spatial variability was larger in farms (and sites) with poorer soils and smaller in farms owning livestock. The five farm types identified may be seen as domains to target technological innovations and/or development efforts. 相似文献
20.
《Communications in Soil Science and Plant Analysis》2012,43(15):1731-1745
Abstract Growth and chemical composition of crop plants may be subject to alteration by systemic compounds employed for pest control. A field study was implemented to examine the effects of aldicarb on growth, chemical composition, and nutrient diagnosis of a potato crop at various growth stages. Aldicarb use resulted in increased dry matter production of leaves, stems, and tubers, and final fresh tuber weight during the second year of the study. Higher tuber yields were likely due to greater photosynthetic capacity because the increase in leaf dry matter production with time was greater in the aldicarb treatment than in control. Leaf nutrition was not influenced by aldicarb; however, leaf nutrient content varied greatly with growth stage. Similar nutrient status evaluations were generated by DRIS, regardless of pesticide treatment or growth stage. DRIS was able to diagnose nutrient limitations as early as tuber initiation 相似文献