田间条件下土壤氮素运移的模拟模型Ⅱ田间检验与应用

本文通过冬小麦春季生长阶段的田间试验检验了土壤水、热和氮素联合模拟模型，结果表明土壤含水量、土壤温度以及土壤无机氮含量的模拟计算值与实测值吻合程度较好．应用经检验的模型和有关参数，模拟计算了不同灌水条件下土壤氮素动态，结果看出：在本试验条件下，在冬小麦返青到收获期间，各灌水处理１ｍ深处总体上不存在土壤无机氮淋洗渗漏，而是不同程度的上升补给．反硝化和氮挥发是氮素损失的主要途径．     

基于无线传感器网络的智能灌溉系统研究

针对我国水资源紧缺以及农田节水灌溉的需求,根据现有的农田灌溉装备条件,应用领域作物、土壤、水源布点等情况,分析了目前实现精确农业亟待解决的关键技术问题,提出一套采用无线传感器网络技术、适合大面积农田智能灌溉控制方法。分析结果表明,该系统通过无线传感技术完成智能化灌溉,可很好地实现节水。且该系统工作稳定,具有一定的推广应用价值。     

砾石土质条件下葡萄滴灌生育期土壤含水率变化规律研究

为探究酿酒葡萄在砾石土质条件下的土壤含水率变化规律及合理灌溉制度,选取贺兰山东麓砾石土典型试验区,以五年生赤霞珠品种为研究对象,设计2 550、2 850、3 225、3 600 m3/hm24个不同定额的灌水处理,应用TDR土壤水分剖面仪和土壤水势仪,监测生育期滴灌前后不同土层含水率与水势变化,针对监测数据从灌水处理整体与单个生育期不同角度进行分析,研究酿酒葡萄在砾石土条件下不同滴灌定额土壤含水率变化规律,最终提出生育期适宜灌溉制度。研究结果表明:随着灌溉定额的增加,土壤含水率在0~40cm土层范围内变化较明显;不同深度土层土壤水势变化规律与灌溉定额的大小有关;1m深土壤水分蓄存比并不是随着灌水量的增加而增大,而是当灌水量达到某一定额时,随着灌水量的增加,土壤水分蓄存比减小,砾石土单次灌水量高于300 m3/hm2时,土壤水分蓄存比较低,易产生深层渗漏。     

无源自动水喷淋系统

文章通过对民爆行业消防系统功能现状分析,指出了某些现实存在的问题,肯定了无源自动水喷淋系统是一种能自动监测温度异常或险情发生后立即自动采取灭火动作的本质安全消防技术。     

新时期云南高原农业灌溉发展趋势研究

为了把握新时期农业灌溉发展面临国家扶贫攻坚和西部大开发、"一带一路"和长江经济带建设、气候变化导致热区扩大等机遇发展高原农业,针对最严格水资源管理"三条红线"控制、立体地形和气候差异、工农业生产与河道生态争水等问题,通过对云南省各水资源四级区套县的高原农业灌溉现状调查分析,研究了云南省农业高效节水减排与生态节水型灌区工程布局、分区农业灌溉的非常规水资源利用、灌溉定额的分区管理、农业节水管养机制建设等重点领域。上述研究成果有助于云南省四大板块高原特色农业的可持续发展。     

节水灌溉条件下作物系数和土壤水分修正系数试验研究

考虑土壤水分调控所产生的作物生长滞后效应与补偿生长效应,对节水灌溉条件下作物蒸发蒸腾量ETc的理论计算模型进行了研究。根据灌溉试验资料,确定了冬小麦、夏玉米、棉花及水稻作物的作物系数Kc,得出节水灌溉条件下主要农作物土壤水分修正系数Ks的计算公式。覆膜旱作节水灌溉模式的水稻需水量计算实例结果显示,计算值与实测值较为吻合,模型具有较高的精度。     

Heavy metal accumulation in vegetables irrigated with water from different sources

The present study was carried out to assess levels of different heavy metals like iron, manganese, copper and zinc, in vegetables irrigated with water from different sources. The results indicated a substantial build-up of heavy metals in vegetables irrigated with wastewater. The range of various metals in wastewater-irrigated plants was 116–378, 12–69, 5.2–16.8 and 22–46 mg/kg for iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn), respectively. The highest mean levels of Fe and Mn were detected in mint and spinach, whereas the levels of Cu and Zn were highest in carrot. The present study highlights that both adults and children consuming vegetables grown in wastewater-irrigated soils ingest significant amount of these metals. However, the values of these metals were below the recommended maximum tolerable levels proposed by the [Joint FAO/WHO Expert Committee on Food Additives (1999). Summary and conclusions. In 53rd Meeting, Rome, June 1–10, 1999]. However, the regular monitoring of levels of these metals from effluents and sewage, in vegetables and in other food materials is essential to prevent excessive build-up of these metals in the food chain.     

Survey of Irrigation Methods in California in 2001

Reliable information on irrigation methods is important for determining agricultural water demand trends. Therefore, a study was conducted during 2002 to collect information on irrigation methods that were used by growers to irrigate their crops in 2001. The results were compared to earlier surveys to assess trends in cropping and irrigation methods. A one-page questionnaire was developed to collect information on irrigated land by crop and irrigation methods. The questionnaire was mailed to 10,000 growers in California that were randomly selected from a list of 58,000 growers by the California Department of Food and Agriculture, excluding rice, dry-land, and livestock producers. From 1972 to 2002, the area planted has increased from 15 to 31% for orchards and from 6 to 16% for vineyards. The area planted to vegetables has remained relatively static, while that planted to field crops has declined from 67 to 42% of the irrigated area. The land irrigated by low-volume (drip and microsprinkler) irrigation has increased by about 33%, while the amount of land irrigated by surface methods has decreased by about 31%. Sprinkler usage has decreased in orchards and vineyards, but it has increased in vegetable crops.     

Field Verification of Two-Dimensional Surface Irrigation Model

A two-dimensional (2D) model of unsteady shallow-water flow in surface irrigation was developed to evaluate the influence of field-grading precision on surface irrigation performance. This paper presents field data for verification of this 2D model. No attempt was made here to evaluate irrigation performance. Verification of such models relies on independent estimates of parameters for infiltration and roughness. To accomplish this, water surface elevations were measured at 26 points within a 3 ha level basin. A double-bubbler system was used to obtain relative water depths. Field surveys were used to convert these to water surface elevations and field water depths, from which surface water volumes over time were computed. The infiltration function was determined by matching inflow minus surface volume over time with computed subsurface volume. A value of Manning n (0.05) was found for which advance and water depth hydrographs were both well predicted with the 2D model. Differences in advance for a plane versus undulating field surface were minor, except near the end of advance.     

库坝池窖联合高效利用水资源技术推广成效与经验

宁南山区降水主要集中在7—9月,而旱灾一般发生在春夏之交的3—5月,降水的时空分布与作物需水不匹配.为了解决宁南山区水资源利用率低等现状问题,利用彭阳县陈沟村已建成的蓄水池等水土保持拦蓄工程,开展水利部科技推广项目"库坝池窖联合高效利用水资源技术引进与示范",通过合理调节水资源的时空分布,制订适用的水资源管理分配制度,发展节水高效灌溉技术,实现"秋水春用、低水高用".2013年共调蓄水量6 100 m3,水分生产效率提高0.34~30.04元/m3,增加示范户农民纯收入5.0%~16.9%,带动更多群众致富.