基于ARM的过滤器控制器的研究

在简介自动清洗过滤器工作原理、控制发展设计需求的基础上,比较分析了国内外成熟应用自动反冲洗控制系统,并找出目前控制系统存在问题,针对存在的问题提出基于ARM7的自动反冲洗控制系统,利用模块化结构、触摸式人机界面和丰富通讯接口,满足不同灌溉规模水处理需求。其相关技术产品研发与应用,能够摆脱过国外滤器厂商对控制器的垄断,将进一步促进我国自动反冲洗过滤器控制和产业化水平。     

基于CAN总线的智能化节水灌溉系统的研究

随着我国农业的迅速发展,农业的用水量日益增多。在灌溉系统中合理地利用自动化控制,大力发展节水技术,可以提高水资源利用率。针对我国农业生产中灌溉所存在的问题,设计出基于CAN总线智能化节水灌溉系统。该控制系统是通过PC客户端、传感器节点、下位机、阀门控制节点等几个部分,实现多点远距离参数检测、数据通讯和驱动执行机构,是一种经济性好、体积小、工作稳定性强、易于推广的智能节水灌溉控制系统。     

Intensification of New Zealand beef farming systems

This study used whole-farm management, nutrient budgeting/greenhouse gas (GHG) emissions and feed formulation computer tools to determine the production, environmental and financial implications of intensifying the beef production of typical New Zealand (NZ) sheep and beef farming systems. Two methods of intensification, feeding maize silage (MS) or applying nitrogen (N) fertiliser, were implemented on two farm types differing in the proportions of cultivatable land to hill land (25% vs. 75% hill). In addition, the consequences of intensification by incorporating a beef feedlot (FL) into each of the farm types were also examined.Feeding MS or applying N fertiliser substantially increased the amount of beef produced per ha. Intensifying production was also associated with increased total N leaching and GHG emissions although there were differences between the methods of intensification. Feeding MS resulted in lower environmental impacts than applying N even after taking into account the land to grow the maize for silage. Based on 2007/08 prices, typical NZ sheep and beef farms were making a financial loss and neither method of intensification increased profitability with the exception of small annual applications of N, especially to the 75% hill farm. These small annual additions of N fertiliser (<50 kg N/ha/yr applied in autumn and late winter) resulted in only small increases in annual N leaching (from 11 to 14 kg N/ha) and GHG emissions (from 3280 to 4000 kg CO₂ equivalents/ha). Limited N applications were particularly beneficial to 75% hill farms because small increases in winter carrying capacity resulted in relatively large increases in the utilisation of pasture growth during spring and summer than the 25% hill farms. Intensification by incorporating a beef feedlot reduced environmental emissions per kg of beef produced but considerably decreased profitability due to higher capital, depreciation and labour costs. The lower land-use capability farm type (75% hill) was able to intensify beef production to a proportionally greater extent than the higher land-use capability farm (25% hill) because of greater potential to increase pasture utilisation associated with a lower initial farming intensity and inherent constraints in the pattern of pasture supply.     

Deficit irrigation based on drought tolerance and root signalling in potatoes and tomatoes

Agriculture is a big consumer of fresh water in competition with other sectors of the society. Within the EU-project SAFIR new water-saving irrigation strategies were developed based on pot, semi-field and field experiments with potatoes (Solanum tuberosum L.), fresh tomatoes (Lycopersicon esculentum Mill.) and processing tomatoes as model plants. From the pot and semi-field experiments an ABA production model was developed for potatoes to optimize the ABA signalling; this was obtained by modelling the optimal level of soil drying for ABA production before re-irrigation in a crop growth model. The field irrigation guidelines were developed under temperate (Denmark), Mediterranean (Greece, Italy) and continental (Serbia, China) climatic conditions during summer. The field investigations on processing tomatoes were undertaken only in the Po valley (North Italy) on fine, textured soil. The investigations from several studies showed that gradual soil drying imposed by deficit irrigation (DI) or partial root zone drying irrigation (PRD) induced hydraulic and chemical signals from the root system resulting in partial stomatal closure, an increase in photosynthetic water use efficiency, and a slight reduction in top vegetative growth. Further PRD increased N-mineralization significantly beyond that from DI, causing a stay-green effect late in the growing season. In field potato and tomato experiments the water-saving irrigation strategies DI and PRD were able to save about 20-30% of the water used in fully irrigated plants. PRD increased marketable yield in potatoes significantly by 15% due to improved tuber size distribution. PRD increased antioxidant content significantly by approximately 10% in both potatoes and fresh tomatoes. Under a high temperature regime, full irrigation (FI) should be undertaken, as was clear from field observations in tomatoes. For tomatoes full irrigation should be undertaken for cooling effects when the night/day average temperature >26.5 °C or when air temperature >40 °C to avoid flower-dropping. The temperature threshold for potatoes is not clear. From three-year field drip irrigation experiments we found that under the establishment phase, both potatoes and tomatoes should be fully irrigated; however, during the later phases deficit irrigation might be applied as outlined below without causing significant yield reduction:

•

Potatoes

°

After the end of tuber initiation, DI or PRD is applied at 70% of FI. During the last 14 days of the growth period, DI or PRD is applied at 50% of FI.

•

Fresh tomatoes

°

From the moment the 1st truce is developed, DI is applied at 85-80% of FI for two weeks. In the middle period, DI or PRD is applied at 70% of FI. During the last 14 days of the growth period, DI or PRD is applied at 50% of FI.

•

Processing tomatoes

°

From transplanting to fruit setting at 4th-5th cluster, the PRD and DI threshold for re-irrigation is when the plant-available soil water content (ASWC) equals 0.7 (soil water potential, Ψ_soil = −90 kPa). During the late fruit development/ripening stage, 10% of red fruits, the threshold for re-irrigation for DI is when ASWC = 0.5 (Ψ_soil = −185 kPa) and for PRD when ASWC (dry side) = 0.4 (Ψ_{soil, dry side} = −270 kPa).

The findings during the SAFIR project might be used as a framework for implementing water-saving deficit irrigation under different local soil and climatic conditions.     

基于6LoWPAN无线传感器网络的农业环境实时监控系统

针对现有农业环境监控系统的不足,提出了一种基于6LoWPAN无线传感器网络的农业环境实时监控系统,该系统采用6LoWPAN构架实现互联网与无线传感器网络之间的点到点通信,无需特定的网关进行协议转换或者协议承载,从而实现了对农业环境的实时监测和控制,降低了能耗,缩短了延迟时间。该文从硬件结构、软件结构及节能等方面对此系统进行了详细阐述和分析,试验结果表明该系统的实用性和高效性,可应用于温室、农田、苗圃等区域。     

基于模糊神经系统与GIS的区域土壤侵蚀快速评价

土壤侵蚀调查与评价是水土保持工作的重要组成部分。该文对区域土壤侵蚀评价进行了尝试性研究,提出一种基于模糊神经系统和GIS技术的快速评价方法。研究中利用模糊神经系统技术从地面监测调查数据中提取土壤侵蚀强度的评价规则,建立能够全面、客观地反映特定区域范围内土壤侵蚀自然特征及规律的评价标准,在此基础之上结合GIS技术以实现对整个地区的快速评价。采用该方法进行湖北省土壤侵蚀普查,结果表明全省侵蚀面积约占国土总面积的30.1%。其中,鄂西南、鄂西北高山区土壤侵蚀情况最严重,鄂东南、鄂东北低山丘陵区次之,鄂北岗地中度侵蚀面积较大,而江汉平原基本无明显侵蚀。经验证评价结果与实际情况具有较好的一致性。     

不同地面结构育肥猪舍的恶臭排放影响因素分析

研究了冷、暖季节下生物发酵床、水泥实心、全缝隙3种不同地面结构的机械通风育肥猪舍的恶臭浓度、排放系数及地面结构、舍内温湿度、猪体重对恶臭浓度的影响.研究表明:猪舍的恶臭浓度与舍内温度、猪体重呈显著正相关(p＜0.05),恶臭浓度与相对湿度无显著相关性(p＞0.1);地面结构不同,恶臭浓度存在显著差异(p＜0.05);生物发酵床猪舍有助于恶臭减排,恶臭浓度最低,水泥实心地面猪舍的恶臭浓度最高,全缝隙地面猪舍的恶臭浓度居中;生物发酵床、全缝隙、水泥实心地面育肥猪舍的恶臭排放系数分别为(3.39±3.33)、(3.70±1.31)、(4.33±2.39) OU/(m2·s).     

基于SD模型的长沙市水资源承载力研究

基于长沙市水资源现状,为平衡居民生活用水、经济生产用水和环境生态用水之间的关系,运用系统动力学方法,建立长沙市水资源-人口-经济-生态环境的耦合系统,模型模拟了现状延续型、经济发展型、节水治污型和综合协调型四种发展模式,选取GDP、人口数量、居民生活需水量、经济需水总量、供需压力作为主要评价指标。结果表明:第一、二、三产业分别保持10%、12%、12%年增长率且节流治污情况与现状延续型保持一致的方案,供需压力将达到节流治污方案的两倍多;经济生产用水对水资源供需压力的影响远大于居民生活用水和环境生态用水;通过适当降低人均用水量来平衡因人口数量增长而增加的居民生活用水是可行的。     

松软地面机器系统研究进展

松软地面机器系统的理论研究,对农业、林业、矿业和军事等领域作业机械的发展具有重要的科学意义和工程应用价值。本文总结了松软地面机器系统基础理论,以及松软干沙地面轮壤关系最新研究进展;从土壤动物形态、结构和柔性方面阐述仿生脱附减阻机理,综述了地面机械触土部件的仿生理论基础;概括了用于地面力学特性测试的技术方法和地面机器系统研究的土槽测试系统;分析归纳了数值模拟方法在地面机器系统研究中的进展;进而对松软地面机器系统理论方法在触土部件和车辆行走机构中的应用研究进行了展望。     

冬小麦精准追肥机专家决策系统

为了实现小麦生长过程中的实时变量追肥,研究了光谱数据处理策略及目标追肥量的计算模型,开发了基于近地光谱探测技术的实时变量追肥专家决策系统,结合小麦冠层归一化植被指数(NDVI)、追肥机实际行进速度和肥料反馈量,双通道独立控制施肥机构的转速和开度,从而实时调整追肥量,实现精准变量追肥。试验结果表明,专家决策系统的控制精度达到90%以上,可以满足精准追肥的要求;拔节期,变量追肥比定量均匀施肥增施氮肥28 kg/hm2左右;变量施肥有利于改善小麦群体结构,降低产量差异性。