东北地区种植业机械化水平的灰色关联辨识

发展农业机械化是东北老工业基地振兴的重要内容.为此,对现阶段东北地区种植业机械化装备水平、生产经济系统的投入产出状况以及环境状况进行了科学的分析,运用灰色关联分析方法对其进行系统的辨识,这对于东北农业的发展、增加农民收入、加快农村富余劳动力转移,优化农业和农村经济结构具有重要意义.     

The feasibility of using variable rate water application under a central pivot irrigation system

The purpose of this paper was to assess the feasibility and significance of applying spatially variable irrigation under a central pivot system at the Federal German Agricultural Research Center, Braunschweig, Germany. The assessment was based on soil moisture holding capacity, soil depth variation and root development. Soil texture analysis was carried out by sampling on a 60 meter grid. The German Agro-Meteorological Model was applied to simulate the water balance in the crop-soil-atmosphere system for the growing season 2003/4. The research findings are presented in terms of six scenarios: 20, 30, 40 mm water application depths per irrigation under both variable rate application and uniform application. The comparison revealed that the loss of water was higher for the uniform application scenarios than that for the variable rate application (VRA) scenarios for the applications of 20 and 30 mm. The VRA scenario of 20 mm water application was found out to be the best option for water conservation.     

属性识别模型在水利水电规划方案综合优选中的应用

针对目前水利水电规划方案综合优选方法中存在的问题，提出了基于变异系数权重的水利水电规划方案综合优选属性识别模型。该模型采用反映评价指标特征值之间差异性的参数——变异系数作为评价指标的权重，减小了权重确定的主观性，且模型求解方法简单易学。实例分析表明，这一模型和方法是合理、可行的。     

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:

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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.

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Fresh tomatoes

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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.

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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.     

污水灌溉条件下作物对土壤重金属吸收特征比较

通过采样和化学测试，对污水灌溉条件下，小麦、水稻、蚕豆和油菜果实中Cu、Zn、Pb、Cr和Cd的含量及土壤中重金属本底浓度进行测定和分析。结果表明，污水灌溉对4种作物吸收土壤重金属的能力影响不显著，而不同作物种类对这种吸收能力的影响表现出显著的差异。     

印度Leh地区沙棘籽油中脂肪酸测定

本文分析了印度Leh地区沙棘籽油中脂肪酸各成分的含量,结果显示沙棘种子含油量为17.61%,籽油富含油酸(23.012%)和亚油酸(30.162%).     

实行季节性梯度农用水价对农业节水的有效性研究

从价格调控对农业用水资源的配置作用出发，分析了目前农业节水中的水价问题，得出农用水将普遍收费的必然趋势。重点提出了季节性梯度农用水价的概念并对其含义进行了深入说明。最后通过在“冬小麦节水高产省肥简化‘四统一’栽培技术体系”中的实例研究，认为季节性梯度农用水价对农业节约用水是可行的。     

基于二分法的微灌毛管水力设计

根据微灌毛管水力学特性,采用二分法搜索原理,并与逆递推法相结合,提出微灌毛管水力解析与设计方法。利用计算机编程从毛管末端向毛管进口逆序递推,可以快速、方便地求解出毛管各个孔口的压力和流量,设计毛管运行的水力参数,校核平均流量、流量偏差率等设计控制指标。实例验证结果表明,该设计方法具有直观、简便和快捷的特点,易为非专业人员理解与应用,具有较高的求解效率和计算精度。     

PWM变量喷雾系统动态雾滴分布均匀性实验

由于PWM变量喷雾作业过程中喷头不连续作业,喷雾的均匀性特别是喷雾机运动方向上的均匀性较难控制,为此通过高速电磁阀、不锈钢压力罐、压力传感器、气泵、调速输送带等构建了一套动态PWM变量喷雾实验平台,并对该平台动态喷雾雾滴分布特性进行实验研究。采用水敏试纸作为获取动态雾滴分布状态手段,通过图像处理技术以区域内雾滴覆盖率的变异系数作为动态雾滴分布均匀性判定指标,评估了在不同PWM控制信号频率、不同PWM控制信号占空比及不同喷雾压力下的单个喷头动态雾滴分布均匀程度。经实验表明,变异系数随控制信号占空比的增大而减小,控制信号频率对动态喷雾雾滴分布均匀性有较大影响,变异系数随控制信号频率增大而减小,喷雾压力对变异系数影响较小,喷雾压力越大变异系数越大。     

联合收获机前进速度模糊控制系统多目标遗传优化

针对联合收获机前进速度模糊控制系统参数设计具有主观性,导致作业性能不理想的问题,以切纵流联合收获机样机为研究对象,构建联合收获机前进速度模糊控制系统仿真模型,并建立控制性能和收获性能的优化目标函数来衡量联合收获机的作业性能,利用多目标遗传算法对模糊控制系统的隶属函数和输送槽、割台螺旋输送器和切流滚筒对前进速度的影响因子进行优化。通过对优化前后模型仿真对比和两组田间试验数据分析,表明优化后的控制系统在受外界干扰情况下控制性能得到了较好的保持,收获性能在喂入量变化不大情况下,单位平均损失率分别由1.45%和1.26%降至1.12%和1.14%,联合收获机的总体作业性能得到改善。