内蒙古土地市场发展与对策探讨     

张裕凤  孙兴辉 《干旱区资源与环境》2004,(Z3)

土地资源的市场配置是实现土地资源合理利用的基本途径,内蒙古土地市场的现 状是一、二级市场均有一定发展,其协调运转机制初步形成,制度建设也取得进展。针对土地 市场存在的问题,提出垄断土地一级市场的土地供应,增强其规范性、强化土地二级市场管理、 规范土地交易行为、加强对集体建设用地流转管理的对策。  相似文献   

旱地有限补充供水与覆盖保水效果研究   总被引：1，自引：0，他引：1  

高世铭  朱润身 《干旱区资源与环境》1996,10(2):10-17

本文针对旱地作物长期受水分亏缺制约的问题，为了使有限降水资源得以高效利用，研究了几种作物需水关键期有限补充供水以及覆盖保水的效应，表明旱地有限供水的高效性和对提高经济效益的显著作用。提出了实现有限降水资源富集叠加高效利用建设旱区高产高效农田的技术途径。  相似文献   

中国水果供给结构性变化的实证研究   总被引：1，自引：0，他引：1  

刘汉成 《农业现代化研究》2005,26(4):313-316

为分析中国水果供给的结构性变化，本文构造中国水果的供给模型，将1978-2001年24年划分为两个时期，利用Chow检验分别回归后发现我国水果供给的各种弹性均发生了明显的结构性变化，从而得出果农对价格的反应能力和敏感性增强、对农资投入的依赖性增强等重要结论。  相似文献   

番茄对钾的吸收和分配的研究     

罗庆熙  许瑛 《西南大学学报(自然科学版)》1994,16(5):483-485

对两个番茄品种，吸钾量的研究表明，“渝抗二号”番茄对Ｋ＾＋的吸收率较高，“早丰”番茄地上部分Ｋ＾＋的分配较多。当用ＮａＮＯ３代替营养液中的ＫＮＯ３后，Ｋ＾＋的分配比例与完全培养液中的植株相似，但分配到地上部的比例较小。加Ｎａ＾＋后，“渝抗二号”植株的叶和茎中的含Ｋ＾＋量比“早丰”更多，表明不同番茄品种在不同的Ｋ＾＋和Ｎａ＾＋环境中，有着明显不同的离子吸收和分配机制。  相似文献   

ZIKA种母兔饲粮适宜营养水平的研究   总被引：2，自引：0，他引：2  

唐良美  谢晓红  刘曼丽  兰永化 《中国养兔杂志》1994,(3)

连续三年在相同的繁殖季节，使用齐卡Ｎ系母兔１４８只，分别观察测定了四种不同营养水平组合日粮对不同繁殖状态母兔繁殖能力的影响。结果表明：在延期繁殖（母兔断奶后再配种）条件下，不同能量、蛋白水平对母兔繁殖性能的影响差异不显著（Ｐ＞０。０５），但中能高蛋白（ＤＥ１０．８８兆焦／公斤、ＣＰ１９％）的第３组日粮略胜于其它组合。由此得出，在引延期繁殖的ＺＩＫＡ能繁母兔，适宜的营养水平为：消化能（ＤＥ）１０兆焦／公斤，粗蛋白（ＣＰ）１９％，粗纤维（ＣＦ）１０％。在母兔进行半频密繁殖（母兔产后第１４天开始配种）情况下，高能高蛋白（ＣＤＥ１２．１３兆焦／公斤、ＣＰ１９％）饲粮对提高繁殖性能的效果明显优于高能低蛋（ＤＥ１２．１３兆焦／公斤，ＣＰ１５％）和低能低蛋白（ＤＥ１０．８８兆焦／公斤）和ＣＰ１５％）饲粮（Ｐ＜０．０５），尤其对提高母兔泌乳力效果明显（Ｐ＜０；０１），因此，实行频密（产后立即配种）或半频密繁殖的母兔，适宜营养水平为消化能１２兆焦繁殖的母兔，适宜营养水平为消化能１２兆焦／公斤，粗蛋白１９％，粗纤维９－１２％．  相似文献   

浙江淳安新安江开发公司封山育林效益研究   总被引：2，自引：0，他引：2  

汪祖辉  郭仁鉴  叶钟节  方炳法  童修耀 《浙江林学院学报》1989,(2)

浙江省淳安县新安江开发公司所属16个国营林场22475.53hm~3荒山迹地,封山育林30年,现有天然次生林总蓄积量135万m~3,年总生长率8.07％,活立木直接经济价值2.25亿元。到1987年止公司已获中间利用净收入2135万元。近20年累计天然次生林比无林地多涵蓄水10亿m~3,每年进入水库的泥沙量减少80％,对调节水库水源、延长发电年限、纯洁水质都起到良好作用。公司长期实施的5项管护技术,把封山育林提高到科学经营水平,在千岛湖区成功地建立了森林生态屏障。  相似文献   

Differences in Wheat Cultivar Response to N Supply. I: Differences in Grain Yield Formation     

F. Diekmann  G. Fischbeck 《Journal of Agronomy and Crop Science》2005,191(5):351-361

Two-year field trials with winter wheat cultivars Batis and Toronto were conducted in Southern Bavaria, Germany, to investigate the possible causes of cultivar differences in response to N supply varying in total amount and time of application. Cultivar-related differences in grain yields were observed in treatments with low and medium N supply. High doses of N supply resulted in grain yield adjustment or grain yield advantage for cv. Toronto. The results of this study revealed a consistent, genotypic pattern in response to N fertilization in spite of strong seasonal effects. Systematic modifications in canopy growth rates in response to N supply were of particular relevance and a main factor for differences in tillering intensity resulting in modified stand densities. In the present study, cultivar differences in spike development and interactions with N supply related more to abortion than to initiation processes for number of spikelets and number of flowers per spikelet. High grain density (grains per m²) of cv. Toronto was evident during reproduction stages even under conditions of medium N supply. However, decreased growth rates during the later part of grain filling in combination with low 1000 grain weight, which was barely modified by N fertilization, allowed only partial utilization of this potential. It is assumed that sink limitations were of particular relevance for grain yield development in cv. Toronto, while cv. Batis combined a less intense response to N supply with more stability in the development of grain yield components.  相似文献   

Epidemiology of beet necrotic yellow vein virus in sugar beet at different initial inoculum levels in the presence or absence of irrigation     

G. Tuitert  Y. Hofmeester 《European journal of plant pathology / European Foundation for Plant Pathology》1994,100(1):19-53

A field experiment was set up in 1988 to study the development of rhizomania disease of sugar beet at different inoculum levels of beet necrotic yellow vein virus (BNYVV) in soil. Five, tenfold different, inoculum levels were created by addition of the approximate amounts of 0, 0.5, 5, 50 and 500 kg infested soil per ha (the latter corresponding to 0.01% v/v calculated to the tillage layer). A drip irrigation treatment was applied to study the influence of soil moisture on disease. Susceptible sugar beet, cv. Regina, was grown for three consecutive years.In the first year, root symptoms were not observed, but BNYVV-infected plants were detected by ELISA in low numbers at all inoculum levels at harvest. After late drilling in 1989, high numbers of infected plants, up to 90–100% in plots with the highest inoculum level, were detected already in June. Root symptoms were also observed from June onwards. In both these years disease incidence increased in time and was significantly influenced by the initial inoculum level. In the third year, the whole field was heavily diseased, and only for the non-irrigated plots incidence differed for different initial inoculum levels. The expression of symptoms by BNYVV-infected plants was influenced by initial inoculum level, thus by the amount and timing of primary infection.Root weight at harvest was not affected, but sugar content decreased with increasing inoculum level already in 1988, leading to a reduction in sugar yield of 10% at the highest inoculum level. In 1989, both root weight and sugar content decreased progressively with increasing inoculum level, resulting in sugar yield reductions of 11–66% (down to approximately 3000 kg ha^–1) for low to high inoculum levels compared to the control. As the control plots became contaminated, all yields were low in 1990, still showing a decrease with increasing inoculum level in the non-irrigated plots, but an overall mean sugar yield of 3323 kg ha^–1 for the irrigated ones.Sodium and -amino nitrogen content of the root, additional quality parameters determining extractability of sucrose, showed an increase and decrease, respectively, with increasing initial inoculum level already in the first year. The relative differences in contents compared to those from the control were largest for Na content. A significant negative correlation was found between Na (mmol kg^–1 root) and sugar content (% of fresh weight); linear for 1988, exponential for 1989 and 1990.In spring 1989, the infestation of individual plots was assessed using a quantitative bioassay estimating most probable numbers (MPNs) of infective units of BNYVV per 100 g dry soil. The relationship between the MPns determined and root weight, sugar content and sugar yield at harvest could be described by Gompertz curves. The increase in disease incidence with increasing MPN in 1989 was adequately fitted with a logistic equation.  相似文献   

京郊保护地秋季番茄的氮素供应及利用   总被引：4，自引：0，他引：4  

白优爱  贺建德  陈清  李晓林 《中国蔬菜》2004,1(2):7-9

研究了氮素供应水平对保护地番茄产量、养分吸收和氮素利用的影响。结果表明,氮素供应量(N)为225kg·hm~(-2)时番茄的产量最高,但随着施氮量的增加,番茄产量反而有所下降。增施氮肥对番茄地上部N、P、K的吸收没有明显的影响。在京郊传统生产条件下,保护地番茄生产相对合适的氮素供应水平(播前根层起始土壤无机氮含量+化学氮素用量)为510 kg·hm~(-2),但如果考虑番茄生长期间土壤氮素的矿化作用,番茄生产的氮素供应水平应为584kg·hm~(-2)。  相似文献   

利用人工增雨为农田需水服务的信息系统框架   总被引：1，自引：0，他引：1  

李应林  高素华 《干旱区研究》2004,21(3):246-249

针对我国北方地区水资源严重短缺、农田水分供需矛盾日益尖锐的现状 ,提出了首选人工增雨为农田补水的思路 ,并初步设计了一个利用人工增雨为农田需水服务的农田需水信息系统框架。  相似文献