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公顷产量12.75t～15.67t春玉米铁、锰、铜、锌吸收动态模型及分布运转规律的研究 总被引：2，自引：0，他引：2
本文阐明了掖单13春玉米公顷产量12.75t～15.67t条件下,Fe、Mn、Cu、Zn在体内浓度、分布,运转的动态变化规律;查明了其不同生育时期的吸收量、速率、比例以及最快吸收速率和出现时间;建立了Fe、Mn、Cu、Zn吸收动态模型;查明了Fe、Mn、Cu、Zn消耗系数,生产效率,百公斤籽粒吸收量;明确了不同高产春玉米Fe、Mn、Cu、Zn吸收量,吸收速率等方面的差异. 相似文献
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This paper reviews the effects that windstorm-induced drastic changes (micro-climate, soil, vegetation, and ground structural heterogeneity) have on forest insect communities. In the current context of shady and CWD-deprived managed forests, windthrow gaps act as regional biodiversity hotspots by maintaining habitat continuity in a mosaic landscape, and by facilitating the breeding and population growth of clearing specialists and saproxylic species. Windthrow gaps are dead-wood islands where forest protection and habitat conservation goals may stand against each other. Besides the quantitative effect of dead wood on bark beetle outbreaks and saproxylic diversity, the latter is favoured by key dead-wood micro-habitats such as large logs, snags and sun-exposed coarse woody debris. The role of natural enemies and sanitation operations in regulating pest outbreaks is discussed. Heterogeneous openings provide many micro-habitats favouring flower-visiting insects, phytophages on saplings, on fallen tree crowns, and on diverse understory flora, as well as ground insects on specific micro-sites. 相似文献
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R.P. Lana 《Livestock Production Science》2005,98(3):219-224
This study evaluates the effect of dry-season concentrate supplementation on growing cattle performance grazing tropical pasture and the impact of nitrogen fertilization on the growth rate of tropical pasture (tons of dry herbage mass/ha/110 days) and on the subsequent stocking rate and cattle performance during the rainy season (kg body weight gain/ha/110 days). The animal and plant responses were curvilinear to the increasing amount of nutrient supply and followed the typical saturation kinetics of enzyme systems, a Michaelis-Menten relationship. The Lineweaver-Burk data transformation explained efficiently the animal and plant responses to the nutrient supply. This methodology consists in evaluating the linear regressions of the reciprocal of animal and plant responses as a function of the reciprocal of nutrient supply. The half maximum growth rates for plant and animal to nutrient supply were verified with the proportions from .048 to .056 of the amount needed to cause .95 of theoretical maximum responses. From the curvilinear response, it can be verified that the marginal increase in animal and plant growth rate reduces as the amount of nutrient supply increases. 相似文献
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GeneraldistributionoriginaIty,wolf(CanislUPus)distributedinmostareas2o"N(Mech1974)exceptfortropicaIrainfor-estanddesert.lnatimewolfdistributedintheEurope-AsiacontinentofthenorthernsphereandtheNoFthAmericancontinentexceptforfewisIands(in-cIudingSaudiArabiaPeninsuIaandJap'n).lnNorthAmerica,thedistributionareaofwolvese\erspreadstotheSouthofMexicoadjointotheTropicofcancer(Goldman1997).ThedistributionareasofwoIveshavedecreasedgreatIysofar,especiaIlyinWestEuropeandNorthAmerica.lntheNorth… 相似文献
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小麦玉米亩产吨粮群体光合性能与配套技术的研究 总被引：3，自引：0，他引：3
小麦、玉米一年两熟是我国北方实现亩产吨粮的主要种植模式，近几年来已有较大面积的吨粮田出现，但对其栽培理论的研究仍缺乏系统性，配套栽培技术尚不完善，以高投入获得吨粮较为普遍。作者在小麦玉米亩产吨粮群体光合能力、光能利用率、最佳群体结构和配套技术等方面进行了比较深入和系统的研究，取得了一些研究成果，提出了小麦、玉米亩产吨粮的冠层光合速率和光能利用率指标，并进一步完善了配套栽培技术。 相似文献
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油菜蚤跳甲的为害分级及习性 总被引：4，自引：0，他引：4
在甘肃临夏县调查发现，春季油菜蚤跳甲的越冬成虫可潜藏在杨树的老翘皮下、地边土缝及田间表土中蛰伏。田间为害春油菜幼苗的成虫量随当时的气温而变化。田间成虫数量的调查结果往往不能代表实际的危害状况。通过对被害苗的详细调查归类，本文提出了油菜蚤跳甲为害的分级标准，建议以被害指数来表示该虫的危害程度，以便在综合防治中能准确的表示虫情。 相似文献
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1990～1991年在金坛县尧塘镇下庄村对单季晚粳武育粳2号超高产栽培技术进行了研究。两年实收单产分别为10 237.5kg·ha~(-1)和10 707.0kg·ha~(-1),较大面积单产分别高34.88％和34.19％。该示范方在主要技术环节上实现了4个转变:(1)栽培策略由穗粒并重转变为稳定适宜穗数主攻大穗,使其总颖花量达44 999.55万朵·ha~(-1);(2)由小株方形密植、主茎成穗为主,转变为宽行条栽稀植,以分蘖成穗为主,使成穗率达89.95％;(3)前、中、后期的氮肥施用比例由7.5:1.5:1.0转变为6:1:3,并增施磷、钾肥,N:P_2O_5:K_2O比例为1:0.39:0.46;(4)中期搁田由总茎蘖数超过预期穗数10％左右时一次重搁转变为达预期穗数苗时进行多次轻搁。 相似文献
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M Aufhammer H. J. Pieper J. Kásser V. Scháfhr T. Senn E. Kübler 《Journal of Agronomy and Crop Science》1996,177(3):185-196
The Suitability of Grains from Cereal Crops with Different N Supply for Bioethanol Production
The properties of grains of different small grain cereals, produced under increasing N-supply levels, for conversion into bioerhanol were investigated. Grain material of winterwheat, -rye and -triticale, two cultivars each, was used At two locations, field experiments comprising several N-fertilization levels between 0 and 180 kg N/ha were conducted. The main parameters analysed were the bioethanol output (1 bioethanol/dt grain dry matter) and the bioethanol yield (1 bioethanol/ha), both under addition and without addition of technical enzymes. Furthermore, the falling numbers, the protein content and die autoamylolytic quotient (AAQ) were determined. AAQ means the autoamylolytic bioethanol output related to die output under addition of technical enzymes. With a rising N-supply, yields/ha and die protein contents of grain increased differently. Combined with increasing protein contents, decreasing bioethanol outputs were measured, particularly with wheat, to a smaller extent with triticale, and to an even lesser extent with rye. Only with wheat were die AAQ-values significantly reduced as a consequence of rising N-supply levels. In interaction with growing conditions, cultivars and N-levels, the bioethanol yields/ha of rye and triticale equalled or even surpassed the yields of wheat, particularly under autoamylolytic-conversion processing conditions. 相似文献
The properties of grains of different small grain cereals, produced under increasing N-supply levels, for conversion into bioerhanol were investigated. Grain material of winterwheat, -rye and -triticale, two cultivars each, was used At two locations, field experiments comprising several N-fertilization levels between 0 and 180 kg N/ha were conducted. The main parameters analysed were the bioethanol output (1 bioethanol/dt grain dry matter) and the bioethanol yield (1 bioethanol/ha), both under addition and without addition of technical enzymes. Furthermore, the falling numbers, the protein content and die autoamylolytic quotient (AAQ) were determined. AAQ means the autoamylolytic bioethanol output related to die output under addition of technical enzymes. With a rising N-supply, yields/ha and die protein contents of grain increased differently. Combined with increasing protein contents, decreasing bioethanol outputs were measured, particularly with wheat, to a smaller extent with triticale, and to an even lesser extent with rye. Only with wheat were die AAQ-values significantly reduced as a consequence of rising N-supply levels. In interaction with growing conditions, cultivars and N-levels, the bioethanol yields/ha of rye and triticale equalled or even surpassed the yields of wheat, particularly under autoamylolytic-conversion processing conditions. 相似文献