应用积分GM(1,1)模型进行杉木炭疽病预测预报的研究   总被引：1，自引：0，他引：1  

朱建华  叶剑雄  张再福  陈红梅  傅瑞树 《福建林业科技》2002,29(1):23-25

以积分生成代替传统的累加生成方法 ,并用双向差分建立积分GM (1,1)灰色预测模型进行杉木炭疽病预测预报的研究 ,结果表明积分GM (1,1)模型能较好地预测杉木炭疽病在三明市的发生  相似文献   

羊草＋杂类草群落生物量动态模式的研究   总被引：4，自引：0，他引：4  

多立安  田德昌  李敬兰  赵彬  佟振宇 《黑龙江畜牧兽医》1994,(8):4-6

对黑龙江肇州县羊草＋杂类草群落地上生物量的季节动态、地下生物量的分布以及地上生物量与降雨量、温度之间的关系进行了分析．结果表明，在生长季内，群落地上生物量动态模式呈单峰型，符合四次多项式模型增长，最大地上生物量出现在８月５日，其值为１９７．３ｍ２而后下降；群落地下生物量分布由上至下呈负幂函数变化，其模型为：Ｂｕ＝Ｙ·（Ｄ＋１０）－ｘ．其中在０－３０ｃｍ土层中，群落地下生物量占总地下生物量的７７％～８２％．  相似文献   

WEPP模型中的CLIGEN与BPCDG应用对比研究     

缪驰远  何丙辉  陈晓燕  吴咏 《勤云标准版测试》2004,(6)

通过对遂宁组紫色土产流、产沙侵蚀的观测,运用迄今为止最为复杂的土壤侵蚀预测模型WEPP模型进行单次降雨侵蚀预测,与实测值比较,并对比通过气候生成器CLIGEN和断点生成器BPCDG的产生的气候参数对预测值的影响。通过分析比较结果,认为WEPP模型对遂宁组紫色土侵蚀过程预测合理,而且利用断点生成器BPCDG的预测结果要优于气候生成器CLIGEN的预测结果。  相似文献   

Re-defining tillage erosion: quantifying intensity–direction relationships for complex terrain     

T.A. Quine  Y. Zhang 《Soil Use and Management》2004,20(2):124-132

Abstract. Current tillage erosion models account for the influence of tillage direction in the magnitude of the soil (tillage) transport coefficient. It is argued here that this is counter-intuitive and causes significant problems in modelling tillage erosion in areas of complex terrain. This article examines whether a re-modelling of tillage erosion is possible that separates tillage direction (an interaction with the landform) from the soil transport coefficient (a measure of tillage intensity representing the combination of implement erosivity and soil erodibility). Experimental data for mouldboard ploughing upslope, downslope and cross-slope at Coombe Barton Farm, Devon are examined. Integration of data for all directions into a single relationship, which relates translocation in the direction of tillage to slope in the direction of tillage and translocation perpendicular to tillage to slope perpendicular to tillage, is not possible using previously published methods of analysis. However, when total translocation distance is regressed against the tangent of the slope at 45° to the tillage direction (bisecting the tillage direction and the direction of overturning) it is found that a single relationship can be used to describe tillage in all three directions. Therefore, this relationship is used to determine a single value of the soil transport coefficient ( k _fTa) for constant soil and implement conditions but different tillage directions. This redefinition of tillage is important both for true estimation of tillage erosion severity, the adirectional coefficient being 40% larger than the directional coefficient, and for modelling of tillage erosion in complex terrain. These improvements are vital when tillage erosion simulation is used to direct soil conservation strategies.  相似文献   

多花黑麦草播期试验(1987～1988年)     

易克贤  詹爱民  刘斌  王贵兰  周省善  陈哲忠  肖小文  傅新如 《江西农业大学学报》1991,(6)

本试验研究了7个不同播期对多花黑麦草出苗、生产性能的影响.结果表明:在江西清江种草养畜试验站从8月中旬至11月中旬均可播种多花黑麦草,尤以9月中旬至10月中旬更为适宜.  相似文献   

Effect of Nitrogen Rate and Stubble Height on Dry Matter Yield,Crude Protein Content and Crude Protein Yield of a Sorghum–Sudangrass Hybrid[Sorghum bicolor (L.) Moench × Sorghum sudanense (Piper) Stapf.] in the Three‐Cutting System     

S. Iptas  A. R. Brohi 《Journal of Agronomy and Crop Science》2003,189(4):227-232

In this study, the effects of nitrogen (N) rate (60, 120, 180 and 240 kg N ha^?1 applied in three equal dressings at seeding and after the first and second cuttings) and stubble height (7, 14 and 21 cm) on the dry matter (DM) yield, crude protein (CP) content, and CP yield of a sorghum–sudangrass hybrid [Sorghum bicolor (L.) Moench × Sorghum sudanense (Piper) Stapf., cv. Pioneer 988] in the three‐cut system was investigated. The N rate had no significant effect in the first and third cuttings, but in the second cutting DM yields increased significantly with increase in N rate. The highest yield of 9.1 t ha^?1 was obtained with 80 kg N ha^?1 for the average of 2 years at the second cutting, but no significant difference was found among the 40, 60 and 80 kg N ha^?1 rates. CP content and yield were not significantly affected by N rate at the first and third cuttings, but CP content and yield were significantly affected by application of N at the second cutting. Stubble height had a significant effect on CP content at the third cutting. However, it had no significant effect on CP content at the first and second cuttings. Stubble height had a significant effect on the CP yield at the first cutting, but no significant effect on CP yield at the second and third cuttings.  相似文献   

互联网环境下的暖通CAD组件模块的开发方法研究     

张泉  张国强  陈在康 《湖南农业大学学报(自然科学版)》2003,30(5)

针对单机环境下暖通CAD软件重复开发量大、开发周期长等现状，提出了基于互联网环境的三层体系结构及其开发的通用环境，即整个暖通CAD系统被分为不同逻辑块，开发和管理的工作向服务器方转移，从而使分布处理数据成为可能，基于组件的软件开发是互联网环境中应用软件的主要开发方式，以构架为组装蓝图，以可重用组件为组装预制块，支持组装式软件重用，从而克服人力和物力的浪费，进而为了重用暖通CAD已开发出的功能模块，给出组件逆向工程的开发方法、组装流程和组件管理过程。  相似文献   

氮素用量和密度对玉米营养体产量的影响   总被引：22，自引：11，他引：11  

何世炜  常生华  张建全  王夏仙  杨虹民 《草业学报》2003,12(1):74-79

研究了氮素施用量和密度对玉米营养体产量的影响。结果表明，增施氮素和增加种植密度对玉米营养体产量有显著的增产效应，在密度为15万株／hm^2，施氮237kg/hm^2时，玉米营养体产量最高，为32584.7kg/hm^2，比常规种植密度9万株/hm^2增产26％。玉米营养体产量乳熟期最大，适宜收割期宜在灌浆期。营养体生产较籽实生产收获期提前了50d，利用玉米营养体收获后的生长余季（8月1日－10月20日）生产毛叶苕子营养体，二者合计生产绿色营养体3．88万kg/hm^2，粗蛋白5638．51kg/hm^2，分别是籽实生产的1．5，3．77倍。光，热，水生产效率较籽实生产提高了47．8％。  相似文献   

叶面喷施丰产素在黄瓜上的应用效果     

石岭  尉红菊  王若菁  赵清岩 《内蒙古农业大学学报(自然科学版)》1994,(3)

本试验在黄瓜上叶面喷施丰州牌丰产素，其浓度分别为２０００倍、４０００倍和６０００倍。试验结果表明，３种浓度对黄瓜的生长势都有增强的作用，并对早期产量有较大的提高。其中２０００倍液对早期产量的增产幅度最大，比对照提高４２．８１％。并且对黄瓜的营养成份有不同程度的影响，其中６０００倍液对维生素ｃ和含糖量都有较大的提高，因此，对黄瓜品质的改进有较好的效果。  相似文献   

哈达门国家森林公园游客量动态预测   总被引：3，自引：0，他引：3  

韩鹏  王胜兴 《内蒙古林学院学报》1996,18(2):28-32

根据哈达门国家森林公园的票房数据，应用灰色系统理论建立旅游量灰色动态模型。基此，对哈园游客量进行了中短期预测，其预测检验精度为９３．７２。旨在对该园建设、管理等项决策提供科学依据。  相似文献