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排序方式: 共有94条查询结果,搜索用时 31 毫秒
1.
Summary The objective of this study was to evaluate the distribution of cotton (Gossypium hirsutum cv GSA 71) root system under four depths of trickle irrigation emitter. Cotton was grown on an Amarillo fine sandy loam (fine loamy, mixed thermic Aridic Paleustalf) at Lubbock, Texas. Trickle irrigation was applied at the surface (0), 0.15, 0.3, or 0.45 m depths in amounts calculated using daily pan evaporation, crop coefficient, and crop development stage. Effects of depth of trickle irrigation were evaluated by measuring the cotton root-length density in 0.15 m increments to the 0.90 m depth at distances of 0, 0.25, and 0.5 m perpendicular to the cotton rows. The root-length distributions were not significantly (0.05%) different in the top 0.15 m when the surface irrigated treatment was compared with the 0.45 m irrigation depth treatment. Root-length densities for the 0.15 and 0.3 m treatments were not significantly different from one another nor were they different from treatments within the evaluated zones (0 to 0.3 m or 0.15 to 0.45 m). Root-length density within the 0.3 to 0.6 m zone, was not significantly different for the 0.45 m treatment compared with the surface irrigation treatment. Root-length density in the 0.6 to 0.9 m zone was not significantly different for any treatment. Emitter depth of trickle irrigation did not significantly influence the depth or distribution of cotton-root development. 相似文献
2.
D. M. Phiri B. Coulman H. A. Steppler C. S. Kamara F. Kwesiga 《Agroforestry Systems》1993,24(3):271-276
The effect of feeding maize (Zea mays L.) husk and leucaena (Leucaena leucocephala) as a mixture or separately on the voluntary intake of maize husk was studied over a 40-day period. Ten male goats with an average weight of 15 kg were used. The maize husk intake and total dry matter intake for the two feeding methods was about the same. Thus, total dry matter intake was not affected (P<0.05) by the feeding method. There was also no significant difference (P<0.05) between the two feeding methods in the digestibility values. The data were considered to indicate that there were no significant differences in the intake of maize husk when fed in a mixture with leucaena or when offered separately but at the same time. 相似文献
3.
以野生酸枣种子的种仁为试验材料,研究不同播种时期对酸枣出苗及生长的影响。结果表明,5月16日和5月6日播种出苗率最高,分别为89.61%和87.19%,显著高于4月26日的处理,极显著高于其他3个处理。5月6日播种的种苗长势最强,各生长指标最高,地径可达7.59 mm;其次是4月26日的处理。5月16日播种的种苗长势最弱,地径仅为5.80 mm,极显著低于其他5个处理。综合酸枣出苗及生长指标,酸枣育苗最佳播期为5月6日,其次为4月26日,建议当地酸枣育苗在4月下旬至5月上旬播种。 相似文献
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Kamara BI Brandt EV Ferreira D Joubert E 《Journal of agricultural and food chemistry》2003,51(13):3874-3879
The fermented leaves and stems of Cyclopia intermedia are used to brew Honeybush tea, a herbal tea indigenous to South Africa. The plant is also used to manufacture a sweet herbal infusion used for restorative properties such as soothing coughs and alleviating bronchial complaints including tuberculosis, pneumonia, and catarrh. It is claimed to have a low tannin content and no caffeine and contains various antioxidants. Continued investigations into the phenolic content of the leaves and stems of C. intermedia yielded tyrosol and a methoxy analogue, 2-[4-[O-alpha-apiofuranosyl-(1' '-->6')-beta-d-glucopyranosyloxy]phenyl]ethanol, 4-[O-alpha-apiofuranosyl-(1' '-->2')-beta-d-glucopyranosyloxy]benzaldehyde, five glycosylated flavonols, two isoflavones, four flavanones, two isoflavones, and two flavones. Structure elucidation was done by NMR, CD, and MS methods. Because flavonoids are presumed to contribute significantly toward the scavenging effects of active oxygen species, our results indicate that the tentative claimed health-promoting properties may be attributed to the presence of these and other phenolics in C. intermedia. 相似文献
6.
Seroprevalence of leptospiral antibodies among dairy cattle kept in communal corrals in periurban areas of Bamako, Mali, West Africa 总被引:1,自引:0,他引:1
Mamadou Niang Loren A. Will Mamadou Kane Alpha A. Diallo Manzoor Hussain 《Preventive veterinary medicine》1994,18(4):259-265
Sera obtained from dairy cattle in communal corral herds located near the city of Bamako in Mali, West Africa were sceeened using the microscopic agglutination test against 26 serovars representing 15 serogroups of Leptospira interrogans. Forty five percent (44.8%; 288/642) were positive to one or more serovars. This seroprevalence rate likely reflects infection since vaccination against leptospiral infection has not been practiced i Mali. The rate was higher among females. The most common titers were against antigens of serovars cynopteri (14.7%), hardjo (13.3%), pomona (9.2%), nona (8.1%), kambale (6.5%), grippotypyosa (6.4%), hebdomadis (6.2%), and pyrogenes (5.2%). 相似文献
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8.
引起植被覆盖变化的气候因子占据主导地位。研究探讨了贵州省近15年来植被指数长时间序列的变化特征、基于标准化降水蒸散指数(SPEI)的干旱时空变化特征及两者之间的相关关系,可为区域植被覆盖保护与恢复提供一定的理论依据。选择2001—2015年MODIS NDVI(1 km)及19个气象站点气温、降水数据,采用一元线性回归的方法探究贵州省近15年来植被覆盖NDVI在年、月尺度下时空演变特征,及其与气温、降水和标准化降水蒸散指数(SPEI)的相关关系。结果表明:贵州西北至东南地区多年平均NDVI呈低中高分布格局,p<0.01上的生长速率为0.051/(10 a),呈显著增加的趋势;多年平均气温、降水量的空间分布从西北到南方向呈现出低-中-高的特征,其易发生干旱的地区主要集中在贵州的西北地区,干旱在区域内的空间差异较大,黔西北、黔西南地区为易旱集中区;年均NDVI与年均SPEI、年均气温和年均降雨量的相关系数均为正值,表示NDVI与其响应因子具有一定的相关性,但与SPEI的相关性不显著,与气温和降水的相关性在p<0.01上呈显著性的正相关,且相关系数均大于0.5以上,相关程度较高;1—6月大致(p<0.01显著)呈现不显著的负相关,7—9月和11月表现为除9月(p<0.01显著)外均呈现不显著的正相关。 相似文献
9.
Godfree Chigeza Steve Boahen Melaku Gedil Eric Agoyi Hapson Mushoriwa Nicholas Denwar Therese Gondwe Abush Tesfaye Alpha Kamara Oladeji Emmanuel Alamu David Chikoye 《Plant Breeding》2019,138(4):455-464
Formal public sector soybean breeding in Africa spans over four decades, and it was initiated by the International Institute of Tropical Agricultural (IITA). As the demand of soybean continues to outstrip production, strategic projects such the Tropical Legume (TL) were initiated, in which the main goal was to enhance the productivity of soybean in the farmers’ fields in Sub‐Saharan Africa. One of the strategies to enhance the productivity of soybean in the farmers’ fields is through developing and deploying improved soybean varieties in the target countries. Through the TL I and TL II projects, a number of varieties were released in the target countries, Kenya, Nigeria, Malawi and Mozambique by employing participatory variety selection (PVS). This review provides highlights of the achievements made by IITA breeding programme and insights of what needs to be done to enhance yield improvement for soybean in Africa using demand‐driven breeding approaches. 相似文献
10.