Tillage,lime, and poultry litter effects on plant concentrations of zinc,manganese, and copper     

L. M. Shuman  D. V. McCracken 《Journal of plant nutrition》2013,36(3):609-620

Minimum tillage cropping systems and the use of animal manures on cropland are becoming more prevalent. An experiment was initiated to determine the effects of tillage and lime/gypsum variables on uptake of zinc (Zn), manganese (Mn), and copper (Cu) by corn (Zea mays L.) and to show correlations between plant uptake of these metals and soil pH and Mehlich 1‐extractable soil metals where poultry litter was used as a nitrogen (N) source. Surface soil samples were taken in the spring and fall for two years from a long‐term tillage experiment that had been in place for nine years. There were two tillage treatments [conventional (CT) and no‐tillage (NT)] and six lime/gypsum treatments (control, 8,960 kg gypsum ha^‐1 every fourth year, 4,480 kg lime ha^‐1 every fourth year, and three treatments of 8,960 kg lime ha^‐1 in a four‐year period divided by application times into 1, 2, and 4 treatments). Poultry litter was applied each year of the two‐year experiment at a rate of 8.96 Mg ha^‐1 on a dry weight basis. Soil samples were analyzed for pH and Mehlich 1‐extractable Zn, Mn, and Cu, and plant tissue (small plant, ear leaf, stalk, and grain) was analyzed for Zn, Mn, and Cu concentrations. Lime treatments resulted in lower Zn in the small plant and ear leaf for CT, but not for NT. Plant Mn was decreased by lime and gypsum rates for small plant, ear leaf, stalk and grain for both years for CT and NT. Correlations for plant Zn versus soil pH were generally non‐significant, except for one year for ear leaf Zn (R=‐0.413**). Correlations for soil pH and plant tissue Cu were all nonsignificant. Correlations for plant Mn and soil pH were strong with R values over 0.80. Plant Mn response to treatments was found at a pH range of 4.2 to 5.8 for ear leaf and pH 5.2 to 6.2 for stalks. Plant Mn and Zn versus Mehlich 1‐extractable soil Mn and Zn, respectively, were negative. This response was possibly due to oxidation‐reduction and non‐incorporation of the lime for Mn and non‐incorporation of the lime for Zn. Also, the poultry litter was high in Zn (447 mg kg^‐1), which could have masked pH effects. It was concluded that soil sampling for plant micronutrients for NT, especially where a waste material high in micronutrients is applied, can give erratic and even erroneous results. However, lime and tillage treatments had a predictable effect on micronutrient uptake as related to soil pH.  相似文献   

基于人地关系的黄淮海平原土地整治策略   总被引：3，自引：2，他引：1  

洪舒蔓  郝晋珉  艾东  杨立  周宁  孟鹏 《农业工程学报》2013,29(24):251-259

为了整体优化土地利用,解决当前土地供需矛盾,该文基于人类活动和土地利用环境两个子系统,从人口分布、人口迁移、生产环境、生计环境、生活环境、生态环境6个方面构建人地关系综合评价指标体系,利用熵值法确定权重并计算出各县域综合评价分值,采用人地协调发展度模型测算各县市区人类活动与土地利用环境的协调发展度,根据测算结果将黄淮海平原划分为4种整治类型。研究表明,将人地协调发展度＞0.60～0.80的县市区划分为良好协调发展类,即优化整治型;人地协调发展度＞0.40～0.60的县市区划为勉强协调发展类,即优先整治型;人地协调发展度＞0.20～0.40的县市区划为轻度失调衰退类,即重点整治型;人地协调发展度0～0.20的县市区划为重度失调衰退类,即适度整治型。同时结合区域人地系统协调发展现状和土地综合整治内涵提出与各类型对应的整治策略。研究结果符合实际,为黄淮海平原制定土地整治规划提供科学决策依据。  相似文献   

潍坊市农用地集约利用评价     

洪舒蔓  郝晋珉  杨立  双文元  周宁  贾智海 《农业工程》2011,1(4):57-61

农用地集约利用是缓解当前土地供需矛盾、保障新时期社会经济持续稳定发展的必然选择。该文以山东省潍坊市12个市区县为评价单元,从土地投入水平、土地利用程度和土地利用效率3个层面构建农用地集约利用评价指标体系,采用层次分析法确定各指标权重,综合指数法计算2009年潍坊市各市区县农用地集约度,分析农用地集约利用情况,以期为潍坊市农用地集约利用和持续发展提供政策依据。结果表明:土地投入水平对农用地集约利用水平的影响最大,各市区县农用地集约利用水平表现出明显的区域性差异。   相似文献   

Emigration of hatchery‐reared Pallid Sturgeon,Scaphirhynchus albus (Forbes and Richardson), through a Missouri River dam     

Landon L. Pierce  Dane A. Shuman  Daniel A. James  Kirk D. Steffensen  Ryan Wilson  Kyle Winders  Adam McDaniel 《Fisheries Management and Ecology》2019,26(3):295-305

The middle Missouri River (MMR; Fort Randall Dam, SD to Gavins Point Dam, NE‐SD) is stocked with hatchery‐reared pallid sturgeon, Scaphirhynchus albus (Forbes and Richardson), from upper Missouri River broodstock to aid recovery of this federally endangered species. Emigration of these fish through Gavins Point Dam restores genetic connectivity that likely existed pre‐impoundment but could lead to outbreeding depression in the future. Recapture data of hatchery‐reared pallid sturgeon stocked in the MMR were evaluated to improve understanding of pallid sturgeon emigration. From 2004 to 2015, 219 emigrants were caught: 4 stocked at age ≥2 years and 215 stocked at age ≤1 year. Emigration of the 2001‐2007 year classes stocked at age 1 was a consistent phenomenon and appeared higher than emigration of year classes stocked at ages 2–3. Little evidence suggested emigration was associated with an unusually high‐water event in 2011. The annual emigration probability of individuals stocked at age 1 estimated from multi‐state mark–recapture models was 0.05 [95% confidence interval = 0.04–0.06] for fish ages ≥1 year. This study suggests that alterations to stocking practices (e.g. stocking age) may affect emigration rates and, therefore, connectivity among pallid sturgeon populations.  相似文献   

Swine abscesses caused by Lancefield's group E streptococci. VII. Specificity of the precipitin test for their detection with relation to streptococcal antigens of groups C and L     

R D Shuman  R L Wood 《The Cornell veterinarian》1970,60(4):570-581

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Resistance of chickens to Rous sarcoma virus challenge following immunization with a recombinant avian leukosis virus     

R M Shuman  M A McBride 《Avian diseases》1988,32(3):410-415

An attenuated recombinant avian leukosis virus (ALV) produced by recombinant DNA techniques was examined for its ability to provide resistance to Rous sarcoma virus (RSV) challenge. Specific-pathogen-free chicken embryos (18-day incubation) and hatched chicks inoculated with recombinant ALV produced significantly smaller tumors than sham-inoculated controls upon challenge with RSV 2 weeks postinoculation; inoculation with RAV-1 produced similar results. Specific-pathogen-free hens inoculated with recombinant ALV produced viral-protein-specific antibody that was transmitted to 100% of the progeny, as detected by enzyme-linked immunosorbent assay. Progeny of the inoculated hens produced significantly fewer tumors than sham-inoculated controls upon challenge with RSV at hatch, indicating that maternal antibody may be a factor in resistance to tumor development.  相似文献   

乳源低聚糖及其代谢的研究进展     

高舒曼  潘雨琦  张力中  董奕岑  刘小鸣  赵建新  张灏  陈卫 《乳业科学与技术》2022,45(1):48-54

乳源低聚糖因其独特的益生作用,受到人们的广泛关注.从组成上分析,不同哺乳动物来源的低聚糖成分和结构有差异.从代谢途径上分析,以双歧杆菌为代表的一些益生菌进化出了较为完整的乳源低聚糖代谢模式.从益生作用上分析,相较于其他来源的益生元,乳源低聚糖表现出更好的益生作用,如更好地增加肠道菌群的多样性、促进双歧杆菌的增殖等.  相似文献   

Normal and Flush Irrigation Effects On Phosphorus Leaching from Simulated Golf Greens in the Greenhouse     

Larry M. Shuman 《Water, air, and soil pollution》2005,160(1-4):133-144

Fertilizer nutrients have the potential to leach from porous golf greens, especially when “flushing” is practiced where 8 or 10 cm of irrigation is applied. A greenhouse experiment was carried out with 52 cm columns (15 cm diameter) made to United States Golf Association green specifications and sodded to ‘Tifdwarf’ bermudagrass to determine the amounts of phosphorus leached for two fertilizer sources (20–20–20 and superphosphate) at three rates (0, 5, and 11 kg ha^?1 added every other week for a total of 6 weeks) and two irrigation schemes (normal irrigation at 6.3 mm day^?1 and the same irrigation with an additional four flushes of 8 cm each). Weekly leachate collections for 29 weeks were analyzed for soluble P. Flushes resulted in higher P concentrations in the leachate where as much as 40% of the added P was recovered in the leachate. In contrast, normal irrigations resulted in less than 10% of the P applied moving through the columns. The two fertilizer sources gave essentially similar results. The higher P rate caused higher concentrations of P in the leachate, but P concentrations for the low rate for normal irrigation were not different than the control. For flushes, the extractable P in the top 15 cm of the rooting media was lower than for normal irrigation and the extractable P in the columns was higher. Results indicate that low rates of P should be applied to golf greens and, if flushing is practiced, it should be done when little P is in the rooting media.  相似文献   

Myosin I can act as a molecular force sensor   总被引：3，自引：0，他引：3  

Laakso JM  Lewis JH  Shuman H  Ostap EM 《Science (New York, N.Y.)》2008,321(5885):133-136

The ability to sense molecular tension is crucial for a wide array of cellular processes, including the detection of auditory stimuli, control of cell shape, and internalization and transport of membranes. We show that myosin I, a motor protein that has been implicated in powering key steps in these processes, dramatically alters its motile properties in response to tension. We measured the displacement generated by single myosin I molecules, and we determined the actin-attachment kinetics with varying tensions using an optical trap. The rate of myosin I detachment from actin decreases >75-fold under tension of 2 piconewtons or less, resulting in myosin I transitioning from a low (<0.2) to a high (>0.9) duty-ratio motor. This impressive tension sensitivity supports a role for myosin I as a molecular force sensor.  相似文献   

Factors that influence the decision to pursue an internship: the importance of mentoring     

Barbur L  Shuman C  Sanderson MW  Grauer GF 《Journal of veterinary medical education》2011,38(3):278-287

The purpose of the present study was (1) to determine if students from one veterinary school who participated in a mentoring/employment program with clinical faculty were more likely to pursue internship training than their peers and (2) to determine factors via survey that were influential to veterinary interns in making their decision to pursue post-graduate clinical training. Our hypothesis was that a mentoring relationship with clinical faculty was an important influence on the decision to participate in an internship. From 2006 to 2010, graduating students who participated in a mentoring/employment program with a clinical faculty member were 6.3 times more likely than non-participating students to pursue an internship. The majority of the participating students (90%) were initially hired/mentored as first- or second-year veterinary students. In the survey, interns ranked clinical faculty as having a greater influence than basic science faculty, private practice veterinarians, or house officers on their decision to pursue an internship; 82.8% reported that clinical faculty were most responsible for encouraging them to apply for an internship. Employment by their veterinary teaching hospital (41.5%) or directly by clinical faculty (26.2%) was commonly reported. Most interns (37%) decided to pursue an internship during their fourth year of veterinary school, 29.2% decided during their first year, and 15.3% decided in their second year. These results suggest that clinical faculty play a key role in a student's decision to pursue an internship and that it might be valuable to inform students about internships early in the veterinary curriculum.  相似文献