Evaluating the Impact of Irrigation and Drainage Policies on Agricultural Sustainability

Farmers in the Broadview Water District in central Californiahave been improving irrigation practices in response to risingirrigation water prices and reductions in water supply since1989, when incentive policies were first implemented to reducethe volume of subsurface drain water generated in theDistrict. The average salinity of water deliveries hasincreased, over time, as the District has recycled largeamounts of drainage water to achieve regional restrictions ondrainage water discharge. We review irrigation and drainageactivities in Broadview since 1986 with an emphasis on thesustainability of crop production when drainage discharge islimited. Average cotton yields in Broadview have declined inrecent years, both nominally and in comparison with averageyields reported for the large county in which Broadview islocated. Average tomato yields in Broadview have increased inrecent years, but county-wide yields have exceeded Broadviewyields with greater frequency than in the late 1980s. Theseobservations suggest that average crop yields in Broadview maybe starting to reflect the increasing salinity of soil andwater resources, which may be due in part to persistentrestrictions on drainage water discharge.     

辽宁农村信息化发展现状及展望

农村信息化发展对于辽宁现代农业发展和新农村建设具有十分重要的意义。系统分析了近年来辽宁农村信息化发展的现状及取得的主要成效,并结合今后一个时期内辽宁农村信息化发展工作计划,提出具有一定针对性的措施与建议。     

矿区复垦土壤种植小麦的重金属安全性

为分析矿区充填复垦土壤种植农作物的生态安全性,以中国徐州市柳新矿区复垦场地为例,对照当地农田土壤,对充填场地种植小麦不同部位As、Cd、Cr、Cu、Hg、Pb、Zn 7种重金属元素含量进行检测,分析了Cd、Cr在成熟小麦不同器官中的分布、富集情况,并利用单项污染指数法和综合指数法对小麦籽粒进行了风险评价。结果表明,三场地中Cd 和Hg在未成熟苗中的含量小于成熟茎中的含量,Cr、Cu和Zn则与之相反,Pb和As的含量规律性不太明显;复垦场地小麦未成熟根的重金属含量都小于成熟根中的含量;比照地中除Cr 和Zn之外,其余元素在未成熟根中的含量均大于成熟根的含量;参照粮食污染限量标准,小麦籽粒中Cd和Cr含量均超标。风险评价显示三场地小麦籽粒中Cd、Cr单项污染指数达到轻度至重度水平,综合污染指数处于轻度污染至中度污染水平之间。该研究对矿区粮食安全的监控具有重要的实际应用价值。     

洪水灌溉土壤中速效磷淋溶积累特性的试验研究

通过在大同市御河灌区进行的洪水灌溉试验,研究了在不同的灌水定额下,洪水灌溉后土壤剖面上速效磷的淋溶积累规律。上层土壤中速效磷养分的含量与灌溉所用洪水的含沙量、泥沙中的速效磷含量、土壤中速效磷的背景值等有关;深层土壤中的速效磷含量受到淋溶作用的影响,上层淋溶的速效磷一般在下层土壤中有所积累,速效磷的淋溶与积累量与灌水定额的大小有关。研究结果给大面积引洪灌溉和引洪补源提供参考。     

缓释尿素在辽宁中部水稻上应用效果报告

2010年在辽宁省中部地区水稻上开展一次性底施缓释尿素田间试验。结果表明：在辽宁中部地区水稻上一次性施用缓释尿素比施用普通尿素,增产效果非常明显,开原和大石桥试验点增产31.1～57.0kg/667m2,增产率为5.9%～10.9%;辽中试验点增产34.7～88.9kg/667m2,增产率为10.1%～21.3%。     

辽宁花生产业发展探讨

花生是辽宁主要油料作物之一,种植区域以辽西北半干旱地区为主,但一直以来花生产量处于较低水平,种植品种比较单一,种植技术以传统栽培方式为主。对辽宁花生产业发展潜力剖析表明,全省花生产量仍有增长空间,花生品质较受市场欢迎,花生种植效益逐步提高,自主选育品种增多,加工企业逐渐发展。为了进一步促进花生产业发展,还需要加快品种改良、提高机械化作业水平、推广先进适用技术、发展深加工业等,有效延长花生产业链条。     

优化丹东地区农机化运行机制的探讨

介绍丹东地区农机化发展现状,从运行主体、运行动力、运行目标等方面,阐述我国农机化运行机制的内容,结合丹东地区实际,分析农机化发展中存在的问题,从发展大农机战略、建立合理的管理模式、增强社会化服务功能等5个方面,提出优化丹东地区农机化运行机制的具体建议。     

FlUENT在研究温室通风中的应用

国内外应用FLUENT研究温室通风的文献大多对其模拟结果进行重点讨论,而对应用过程及应用细节部分一般不做详述,所以很难从这些文献中总结FLUENT在温室通风研究中的应用经验.为此,在阅读大量国外及国内研究成果的基础上,并结合自己的实际模拟经验,对FLUENT在温室通风研究的过程及应用细节进行了全面详细的介绍.同时,具体讨论了用FLUENT对温室通风进行模拟涉及到的一系列问题.FLUENT作为模拟软件其应用是一个不断尝试的过程,丰富的模拟经验将提高模拟效率及模拟结果的准确性.     

水利工程管理中存在的问题与对策

随着我国经济的发展和人口的增长,水利事业在国民经济中的命脉和基础产业地位愈加突出,水利事业的地位决定了水利基础设施的重要性。针对我国水利工程管理现状及存在的问题,提出加强水利工程管理的方法及建议,以期为我国水利工程的发展提供参考。     

农产品价格波动对出口的影响及成因分析

运用引力模型分析价格波动对农产品出口贸易的影响,并对价格波动成因进行拓展分析。结果显示,中国农产品价格波动对农产品出口存在显著地抑制效应,农产品价格每上升1%会造成农产品出口额下降0.09%。细分产业后,抑制效应明显放大,并且价格波动的出口抑制效应在农业、渔业和林业三个细分产业中依次增强,具体而言,农产品价格每上升1%,农业出口额会下降0.32%,渔业出口额会下降0.44%,林业出口额会下降0.49%。进一步研究发现,CPI与人民币汇率变动显著增强了农产品价格波动水平,CPI每波动1%,会造成农产品价格同向波动0.77%,人民币汇率每波动1%,会造成农产品价格同向波动1.91%,人民币汇率变化对农产品价格波动的影响更大。另外,自由贸易协定在一定程度上抵消了价格波动所带来的贸易抑制效应,但效果有限。     

农业高职院校应用写作课程教学改革探讨

在农业高职院校应用写作教学中,普遍存在理论与实践脱节、所学不能致用的情况。从教学内容编排、教学计划制定、课堂教学方法、社会实践4个方面,提出农业高职院校应用写作课程教学改革的具体措施,为学校培训高素质的人才提供参考。     

丹东城郊农机化发展状况与问题分析

丹东城郊的机械化基础好、水平高,在农业生产中占有不可替代的主体地位。总结丹东城郊农业机械化的发展特点,详细分析其在发展农业机械化过程中存在的重点问题,为加快本地区农业机械化发展提供有益的参考。     

辽宁省农业标准化工作模式探析

辽宁省以县为单位进行农产品产地环境质量监测与评价,大规模开展农业标准化生产,取得了很好的成效。总结辽宁省开展农业标准化工作采取的措施和模式,分析工作中存在的主要问题,并提出相应的对策,为推动农业标准化生产提供有益参考。     

对《种子法》存在问题的探讨

《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。     

覆盖措施对红壤丘陵区花生生理状况的影响

着重探讨红壤丘陵区花生不同覆盖下生长状况的差别。研究结果表明不同覆盖对花生生理状况有较大影响。其中有覆盖的小区土壤含水率高于裸地 ,覆盖的小区日均土壤水分蒸发量小于裸地。另外覆盖条件下的小区花生产量和平均地温高于裸地     

The role of performance assessment in real time system management

This paper discusses paddy irrigation development in Malaysia in relation to real-time systems management and the role of performance assessment in such a system. The Muda Irrigation Scheme real-time management system is given as an illustration. This system has shown that, with performance assessment, managers are more prepared and able to respond quickly to issues faced in the day to day systems operations. In this system, demand-supply matching can be made faster and with improved utilisation of effective rainfall and uncontrolled flows. Opportunities for saving uncontrolled flows in the paddy fields can be identified in time. With dryseeding method, the system has been successful in sustaining production in severe water shortage situations. Into the 90s and beyond, no major infrastructure investments in irrigation systems are expected. Irrigation managers must be committed towards excellence in performance. This can be achieved through improved real-time performance assessment. Some aspects of performance assessment that could be improved are in its roles in meeting cropping intensity targets, accurate demand-supply matching, meeting water savings target and in alerting managers to potential crisis situations. Carefully designed and installed, performance assessment can also improve organisational and staff management.     

玉米免耕播种机发展现状与前景

为促进辽宁省玉米免耕播种机行业的健康有序发展,详细介绍我国免耕播种机的发展背景及玉米免耕播种机的研制现状,针对辽宁省玉米免耕播种机存在的主要问题,提出切实可行的发展建议。     

辽宁省无公害农产品、绿色食品质量安全发展措施

近年来,农产品质量安全问题得到了高度重视。简述辽宁省无公害农产品、绿色食品的发展情况,详细介绍近年来辽宁省为确保无公害农产品、绿色食品质量安全所采取的主要措施,同时指出今后无公害农产品、绿色食品质量安全工作中需注意的问题,以进一步推进农业标准化工作。     

Analysis of antibiotic residues in liquid manure and leachate of dairy farms in Northern Germany

The scientific interest in the fate of antibiotic substances in the environment has increased during the past decades. Especially in animal husbandry, the assumed quantity of antibiotics excreted has caused major concerns as the environment can be contaminated by these compounds via different paths. In this study in Northern Germany, manure and leachate samples from dairy farms were analysed in order to verify if this kind of animal husbandry can be a source of antibiotic residues found in the environment. Neither in liquid manure nor in leachate were the analysed antibiotics detected. These results clearly show the minor importance of dairy cows as sources of antibiotic residues in the aquatic environment. To explain this fact, we propose the three following reasons: (i) the amount of antibiotics administered in dairy farming is low compared to pig or poultry production; (ii) manure storage is a useful process to minimize the antibiotic residues as the substances applied to dairy cows are sensitive to degradation processes during that period; (iii) excreted directly on grasslands, the substances degrade very quickly or adsorb to soil and are therefore not present in the leachate.     

西丰县玉米田土壤肥力分析及施肥建议

为了解西丰县玉米田土壤肥力状况,通过采集土壤样品进行14个土壤养分指标的测试分析,以对本地区土壤肥力状况做出评价,并根据养分丰缺情况及土壤质地特点,提出玉米配方施肥建议：西丰县西部和东南部地区以一次性施肥为宜;中北部地区应适当增加施肥量,并以分期施肥为主。