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硒以及硒钴配合施用对紫花苜蓿生长的调控效应 总被引:4,自引:2,他引:2
通过叶面喷洒硒肥以及硒钴配合肥研究其对不同生育期内紫花苜蓿生长的调控作用.结果表明:(1)2种微肥在苜蓿分枝期到开花期期间施用均能显著提高其茎叶比,降低鲜干比;(2)硒肥仅增加苜蓿营养生长期间的地上生物量,硒钴配合肥则显著增加苜蓿整个生长期间的地上生物量;(3)2种微肥均能够显著增加紫花苜蓿10~20cm土层中的地下生物量,有利于苜蓿对耕作层内土壤营养和水分的吸收和利用,其中叶面喷洒硒钴配合肥使10~20cm和0~50cm土层中的地下生物量比对照分别提高了18.9%和7.5%,比单施硒肥效果好;(4)硒肥以及硒钴配合肥对30~50cm土层地下生物量的生长有明显的抑制作用,影响到紫花苜蓿的抗旱能力且硒钴配合肥比硒肥的影响更大. 相似文献
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在郑州黄河滩区紫花苜蓿草地上基施4种硒钴配施肥料(低硒低钴型、低硒高钴型、高硒低钴型和高硒高钴型)的田间试验,研究微肥基施3年后对土壤肥力的影响。结果表明:基施当年(2008)0~20cm土层中Se的有效含量平均提高了16.67%(P0.01),种植苜蓿3年后(2011);通过苜蓿吸收和富集,0~20cm土层中Se含量平均下降9.76%(P0.05);基施当年高钴肥料能使0~20cm土层中Co的含量平均提高8.24%(P0.05),种植苜蓿3年后,Co的含量平均下降5.74%(P0.05),土壤中Co的含量相对平衡,低钴肥料对土壤中钴的有效含量影响不显著(P0.05)。硒钴配施肥料会显著降低土壤中Cu、Mn和Zn3种微量元素的有效含量(P0.05),对土壤中Fe的含量影响不显著(P0.05)。试验结果提示,基施硒钴配施肥料,会降低土壤中速效钾的含量,但对土壤中碱解氮、速效磷以及有机质含量没有显著影响;硒钴配施还有降低土壤的容重和提高土壤孔隙度的作用,多次施用会破坏土壤的结构;4种硒钴配施肥料基施后能够显著影响土壤中硒的有效含量。 相似文献
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硒钴配施对紫花苜蓿产草量和品质的影响 总被引:3,自引:1,他引:2
在河南省黄河滩区,研究叶面喷洒硒肥以及硒钴配施,对紫花苜蓿产草量和品质的影响。结果表明:2种微肥在分枝期到开花期能够显著地提高苜蓿茎叶比,降低鲜干比,增加干物质含量;从开花期到成熟期能显著地提高其株高;硒肥仅能提高苜蓿营养生长期的产草量,而硒钴配施则能显著提高总产草量;硒以及硒钴配施不但能显著提高青干草中的硒钴含量,而且能显著提高Fe、Mn、Cu、Zn、Mo和B等微量元素的含量,其中以Se和Mo的提高幅度最大;硒钴配施能显著提高干草粗蛋白质、粗灰分和钙的含量,显著降低含水量和粗纤维含量,改善牧草品质。 相似文献
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硒钴肥对苜蓿生长的影响 总被引:2,自引:1,他引:1
在郑州沿黄滩区,研究叶面喷洒硒和硒钴肥(Na2SeO3·5H2O和CoSO4·7H2O)对苜蓿(Medicago sativa L.)地上、地下部生长的影响。结果表明:2种肥料从苜蓿株高15 cm开始,每隔15 d喷1次,每次用量分别为57和408 g/hm2,共喷4次,能显著提高分枝期到现蕾期的净光合能力和干物质生产速率(P<0.05);单施硒肥能显著增加从分枝期到现蕾期的有效光合叶面积,降低呼吸作用;硒钴配施能促进0~20 cm耕层苜蓿根瘤菌及根系的生长,但不利于30 cm土层以下的根系生长,虽然能增强苜蓿对表土养分和水分的利用能力,但影响其抗旱力。 相似文献
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紫花苜蓿生长年限对土壤理化性状的影响 总被引:10,自引:0,他引:10
2003~2005年在内蒙古民族大学试验农场连续3年测定了紫花苜蓿试验田土壤理化性状的变化.结果表明,随生长年限的增加,紫花苜蓿地0~30cm土层的土壤容重减小了0.026g/cm3,总孔隙度增加了1%,有机质的含量增加了0.8g/kg,碱解氮的含量增加了33.69 mg/kg,速效磷的含量下降了6.94 mg/kg,速效钾的含量下降了121.04 mg/kg.有机质的增加以10~20cm土层最为明显,碱解氮的增加在0~10cm和10~20cm两个土层均较明显,速效磷的减少在0~10cm土层最大,速效钾的减少在各土层均较为明显.说明紫花苜蓿高产栽培中必须重视磷、钾肥的施用,特别是要提高追施钾肥的水平. 相似文献
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高寒牧区醉马草草丛肥岛效应的研究 总被引:1,自引:0,他引:1
对高寒牧区醉马草(Achnatherum inebrians)草丛肥岛效应进行了研究。结果表明:(1)醉马草草丛中心土壤养分明显高于空地。(2)醉马草草丛对土壤养分富集作用从土壤表层向深层递减,从中心向边缘递减。(3)从草丛中心到距草丛100cm土壤养分含量变化规律为:有机质在0~20cm土层先减小后不变,在20~30cm土层持续不变;全氮和速效钾先减小后不变;全磷和速效氮在0~10cm土层先减小后增加,在10~30cm土层先减小后不变;全钾无明显规律;pH在0~20cm土层先升高后不变,在20~30cm土层先降低、再不变、后升高;速效磷在0~20cm土层先减小后增加,在20~30cm土层先减小后不变。整体而言,醉马草草丛全氮和速效钾、全磷和速效氮变化规律一致,其他养分变化规律各异。 相似文献
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魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
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本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
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以国际标准强毒R株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离MG,并收集感染鸡所产蛋分离MG。结果表明,人工感染48小时后上、下呼吸道及肺已被全面感染,96小时气囊已被感染,120小时输卵管已能分离到MG,卵巢始终分离不到MG。人工感染鸡自144小时便能在其所产蛋中分离出MG。药物治疗能在72小时内消除感染,油乳剂苗则需24天后逐渐降低蛋内MG分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内MG,但以研制的种蛋浸泡剂药浴效果为最好。 相似文献
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REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献
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Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献