钾肥对向日葵增产潜力的影响     

乔春贵  朱学文  禹航  佟淑华  宫万明 《中国油料作物学报》1995,(2)

１９９０—１９９２年三年试验结果表明，尽管只施氮磷肥可获得高产，但在施氮磷肥的基础上按比例配施钾肥，可进一步提高向日葵的产量．钾肥的最佳经济施肥量为１５０公斤Ｋ２Ｏ／公顷，Ｎ、Ｐ２Ｏ６、Ｋ２Ｏ最适比例为２∶１∶２．  相似文献   

Response of organically managed grassland to available phosphorus and potassium in the soil and supplementary fertilization: field trials using grass–clover leys cut for silage     

S. Fortune  J.S. Robinson  C.A. Watson  L. Philipps  J.S. Conway  E.A. Stockdale 《Soil Use and Management》2005,21(4):370-376

Abstract. Effective use and recycling of manures together with occasional and judicious use of supplementary fertilizing materials forms the basis for management of phosphorus (P) and potassium (K) within organic farming systems. Replicated field trials were established at three sites across the UK to compare the supply of P and K to grass–clover swards cut for silage from a range of fertilizing materials, and to assess the usefulness of routine soil tests for P and K in organic farming systems. None of the fertilizing materials (farmyard manure, rock phosphate, Kali vinasse, volcanic tuff) significantly increased silage yields, nor was P offtake increased. However, farmyard manure and Kali vinasse proved effective sources of K to grass and clover in the short to medium term. Available P (measured as Olsen-P) showed no clear relationship with crop P offtake in these trials. In contrast, available K (measured by ammonium nitrate extraction) proved a useful measurement to predict K availability to crops and support K management decisions.  相似文献   

大豆花叶病毒对大豆生长的影响     

智海剑  胡蕴珠  刘天宇 《中国油料作物学报》1996,(1)

在人工接种江苏大豆花叶病毒（ＳＭＶ）ＳＡ株系条件下，研究了ＳＭＶ对１９个抗性不同的大豆品种９个主要性状的影响。结果表明，１３个感病品种在苗期接种ＳＡ后，除根瘤数外其余８个性状均与对照有极显著差异，受ＳＭＶ影响的程度从大至小依次为单株粒重、单株叶面积、根瘤重、茎叶干重、根干重、种子褐斑粒率、株高、百粒重。抗病品种９个性状均与对照无显著差异。感病品种在苗期与花期分别接种ＳＡ后，褐斑粒率、百粒重、单株粒重有极显著差异，早期感染ＳＭＶ其危害大于中后期感染．  相似文献   

Estimation of milk production losses due to sub-clinical mastitis in dairy cattle in Costa Rica   总被引：1，自引：0，他引：1  

T. de Graaf  R. H. Dwinger 《Preventive veterinary medicine》1996,26(3-4):215-222

Five dairy farms, situated on the slopes of the volcano Poás in the pre-mountain cloud forest ecological zone, Alajuela and Heredia Provinces, Costa Rica, provided data for estimation of the production losses due to sub-clinical mastitis. Within the same farm, cows with proven sub-clinical mastitis were matched with cows without signs of sub-clinical mastitis, according to breed, lactation number and days in lactation. A total of 529 cows were detected with sub-clinical mastitis, of which only 200 could be paired with control cows free of mastitis; each pair was used only once.

Crude milk production losses per cow with sub-clinical mastitis were estimated at 1.56 kg day⁻¹for daily milk yield. Milk production loss per affected quarter due to sub-clinical mastitis was estimated to be 17.6% on average. The decrease in milk production in heifers with sub-clinical mastitis did not differ significantly from the decrease in production in older cows. No significant difference in milk production loss was detected when the data were stratified on parity or the number of quarters affected.  相似文献   

实物期权价值忽视与国有资产流失--我国现行矿业权价值评估方法评述     

喻建良  戴塔根 《湖南农业大学学报(自然科学版)》2005,(6)

国内外研究表明矿业权价值除了投资开发的正常收益以外,还包括多种实物期权价值,而在分析了目前国土资源部推荐的7种矿业权价值评估方法以后,我们发现这些方法都存在忽视期权价值的现象.评估与拍卖矿业权的实例进一步表明当前评估方法所得出的价格与实际价值之间存在显著差异,很多造成国有资产流失,而且这种流失倾向不会因为矿业权拍卖制度的建立而消失,加强以实物期权为基础的矿业权评估方法研究与应用是解决这一问题的方向.  相似文献   

仙女湖水库集雨区面源污染防控体系建设初探   总被引：2，自引：0，他引：2  

熊明彪  胡恒  杨万勤 《中国水土保持》2006,(1):30-31

本研究针对仙女湖水库集雨区由水土流失造成的面源污染,提出了在水库集雨区建设由林草“过滤器”作用带系统、微型湿地生态系统、低效林改造系统、农业废弃物的“三化”处理系统、农业清洁生产标准化体系、小型水利水保工程系统、水土保持预防监督监测网络体系组成的综合防控体系,并介绍了综合防控的预期目标。  相似文献   

Applying the USLE Family of Models at the Sparacia (South Italy) Experimental Site     

《Land Degradation \u0026amp; Development》2017,28(3):994-1004

Soil erosion is a key process to understand the land degradation, and modelling of soil erosion will help to understand the process and to foresee its impacts. The applicability of the Universal Soil Loss Equation (USLE) at event scale is affected by the fact that USLE rainfall erosivity factor does not take into account runoff explicitly. USLE‐M and USLE‐MM, including the effect of runoff in the event rainfall–runoff erosivity factor, are characterized by a better capacity to predict event soil loss. The specific objectives of this paper were (i) to determine the suitable parameterization of USLE, USLE‐M and USLE‐MM by using the dataseries of Sparacia experimental site and (ii) to evaluate their performances at both event and annual scale. The measurements allowed to establish the relationships for calculating the factors of USLE, USLE‐M and USLE‐MM usable at the Sparacia experimental area. At first, for slope‐length values greater than 33 m, the calibration of USLE model at event scale pointed out that sediment delivery processes, that is processes involving deposition of the transported eroded soil particles, occur. The analysis showed that USLE and USLE‐M tend to overestimate low event soil losses, while for USLE‐MM, this tendency is less pronounced. However, the USLE‐MM performed better than USLE and USLE‐M and was able to reproduce better than other two models the highest soil loss values that are the most interesting from a practical point of view. The results obtained at annual scale were generally consistent with those obtained at event scale. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

塔里木河流域水土流失动态变化分析          下载免费PDF全文

刘雨曈 《水生态学杂志》2022,43(3):105-112

研究塔里木河流域土地利用变化、年径流量和输沙量变化特征及其相关关系，以期促进水土资源的合理开发和利用，为塔里木河流域的生态环境治理提供科学依据。水文数据为2005-2020年流域焉耆站、同古孜洛克站、卡群站、西大桥站、阿拉尔站年径流量、年输沙量，土地利用数据为1980-2015年土地利用空间分布数据。结果表明：（1）1980-2015年，土地利用面积比例变化为-1.07%~1.16%，耕地面积增幅为1.16%，沙地面积增幅0.30%，草地面积降幅1.07%；（2）流域内各主要河流多年平均径流量为22.99×108~67.46×108 m3，多年平均输沙量63.20×104~3070.00×104t；开都河多年平均含沙量为0.24 kg/m3，其余河流平均含沙量均大于4kg/m3；塔里木河流域年径流量和年输沙量均呈现下降变化趋势，且年输沙量的变异性（40.89%~73.11%）大于年径流量（15.54%~35.37%）；（3）各主要河流的年径流量、年输沙量与耕地和城乡居民用地的占比均呈负相关关系，与林地、草地、沙地等均呈现正相关关系。建议合理进行土地开发，禁止盲目开荒种田，充分运用智能化手段开展在线动态监测，及时掌握水土流失情况，恢复和重建塔里木河流域生态。  相似文献   

Einfluß der Erosion auf die Standortproduktivität im Silomaisanbau     

J. Goeck    E. Cordsen    G. Geisler  H.-P. Blume 《Journal of Agronomy and Crop Science》1988,161(1):57-64

Influence of erosion on productivity of maize ( Zea mays L.) cultivation
Accelerated erosion was monitored in Eastern Schleswig-Holstein (F.R.G.) during the last decades. The objective of this study was to compare agricultural productivity of upper, middle and base slope segments to the respective soil parameters, reflecting results of long-term erosion.
Five soil catenas were surveyed. Each catena was divided into three segments representing an eroded area (upper segment), an area with an equilibrium between erosion, accumulation and soil development (middle segment) and an area with accumulation (base slope segment).
In 1986 soil qualities, growth characters and yield components of maize were analysed for each slope segment. At eroded slope segments vegetation cover and yield were significantly lower than at middle and base slope segments. Middle slope segments (equilibrium between erosion, accumulation and soil development) snowed balanced soil quality parameters and high maize yields with a desired combination of yield components.  相似文献   

泰安市水土流失区中低产田的治理开发     

魏玉杰  于洪太 《中国水土保持》1994,(7):28-30

泰安市水土流失区中低产田的治理开发魏玉杰，于洪太，张玉梅（泰安市水土保持科学研究所，２７１０６０）随着小流域综合治理开发，形成了具有山区特色的小流域经济系统。在此系统中，农业资源不仅得到了合理利用、培育和更新，而且实现了高效转化与增值，形成了生态与经...  相似文献