盐胁迫对不同品种夏谷光合性能及水分利用率的影响

为探讨盐胁迫对不同品种夏谷幼苗生长的影响,以14个夏谷品种为试材,采用盆栽土培和对比试验的方法,研究它们在盐胁迫下的光合性能及水分利用率变化。试验结果表明：所有夏谷均表现为净光合速率下降、蒸腾速率降低、气孔导度降低和胞间CO2浓度上升;抗盐能力最强的是200131、200152和郑06—3,抗盐能力最弱的是济0515、06766—7和长生08。     

海河流域冬小麦水分生产率特征分析

以海河流域为研究对象,以农田总供水水分生产率(WUEa)和灌溉水分生产率(WUEi)为评价指标,运用对流域内典型灌区的调查资料,计算了海河流域主要作物冬小麦的用水效率并进行特征分析,得到了其水分生产率的分布和变化规律。结果表明,WUEa在田间尺度上均值为1.50 kg/m3、灌区尺度上均值为0.97kg/m3,WUE在...     

温室番茄结果期产量和品质对水分亏缺的响应

试验以甘肃武威市凉州区传统灌水量为对照(CK),设计3个灌水量水平CK、2/3CK、1/2CK,在番茄结果期研究亏缺灌溉对日光温室番茄累计产量及平均单果质量、品质、干物质分配及水分利用效率的影响。结果表明,随着灌水量的减少,水分利用率显著提高,番茄果实中的可溶性固形物、可溶性蛋白、有机酸和Vc含量均增加,果实的累计采收...     

高温厌氧环境中一株嗜热产甲烷古菌的分离鉴定

本研究采用Hungate厌氧操作技术、液体培养基和固体培养基交替传代的培养方法,从油层采出液中分离到一株产甲烷古菌DH-5.实验结果表明菌株DH-5为严格厌氧菌,菌体大小为(0.06～0.07)μm×(3.8～8.7)μm,可利用H2/CO2,但不利用其它供试底物;最适生长温度63℃;最适盐浓度0.80 g· L-1;最适pH为7.2;酵母粉为其生长必须因子;最适生长条件下其倍增时间为2.77 h.菌株DH-5与标准株Methanothermobaaer thermautotrophicus DSM 1053T (AY 196660)的16S rRNA基因序列相似性为99.8％.     

温室无线智能水表物联网应用系统

针对目前农村温室用水管理中存在的问题,设计了一种温室无线智能水表物联网应用系统。该系统主要用于温室用水的无线抄表管理,无线充值以及阀门的远程控制。利用互联网或GPRS网络将各个村镇的温室水表用水数据发送到用水管理中心,实现了远程用水查询和统计分析的功能。介绍了该系统的总体架构,并对各个组成部分的功能、原理及实现方法进行了详细论述。目前该系统已在北京部分区县进行了示范,效果良好。     

基于DRNN网络的风力辅助提水机自整定PID控制

基于风力机和离心水泵的特点,提出了一种风力辅助提水机结构及该机的控制系统。该机是一个耦合的两输入两输出时变系统,系统存在的响应较慢,负荷的随机变化及参数快时变的特性。固定参数PID控制难以适应此系统控制要求,因此,提出一种基于回归神经网络（DRNN）的两输入两输出PID控制器结构,给出了DRNN神经网络参数学习算法和PID控制器参数自整定算法。使该系统能在自然界的风速随机变化的情况下使风力机最大可能利用风能,同时与离心水泵输出功率匹配.计算机仿真结果验证了该控制策略可行性,这为以后进一步研究奠定了基础。     

Landscape irrigation scheduling efficiency and adequacy by various control technologies

Automated residential irrigation systems tend to result in higher water use than non-automated systems. Increasing the scheduling efficiency of an automated irrigation system provides the opportunity to conserve water resources while maintaining good landscape quality. Control technologies available for reducing over-irrigation include evapotranspiration (ET) based controllers, soil moisture sensor (SMS) controllers, and rain sensors (RS). The purpose of this research was to evaluate the capability of these control technologies to schedule irrigation compared to a soil water balance model based on the Irrigation Association (IA) Smart Water Application Technologies (SWAT) testing protocol. Irrigation adequacy and scheduling efficiency were calculated in 30-day running totals to determine the amount of over- or under-irrigation for each control technology based on the IA SWAT testing protocol. A time-based treatment with irrigation 2 days/week and no rain sensor (NRS) was established as a comparison. In general, the irrigation adequacy ratings (measure of under-irrigation) for the treatments were higher during the fall months of testing than the spring months due to lower ET resulting in lower irrigation demand. Scheduling efficiency values (measure of over-irrigation) decreased for all treatments when rainfall increased. During the rainy period of this testing, total rainfall was almost double reference evapotranspiration (ET_o) while in the remaining three testing periods the opposite was true. The 30-day irrigation adequacy values, considering all treatments, varied during the testing periods by 0-68 percentile points. Looking at only one 30-day testing period, as is done in the IA SWAT testing protocol, will not fully capture the performance of an irrigation controller. Scheduling efficiency alone was not a good indicator of controller performance. The amount of water applied and the timing of application were both important to maintaining acceptable turfgrass quality and receiving good irrigation adequacy and scheduling efficiency scores.     

Supplemental saline drip irrigation applied at different growth stages of two bell pepper cultivars grown with or without mulch in non-saline soil

The effect of supplemental saline (2.5 dS m⁻¹) drip irrigation and black polyethylene mulch on two cultivars of bell peppers (Capsicum annuum L.) was investigated under field conditions using a randomized complete block design with split-split plot restriction. The research included six irrigation treatments (main plots): (i) non-saline irrigation control applied throughout growth (None), (ii) saline irrigation from transplanting until formation of the first fruit set (S1S2), (iii) saline irrigation from transplanting until appearance of the first flower and from first harvest to final harvest (S1S4), (iv) saline irrigation from appearance of the first flower to first harvest (S2S3), (v) saline irrigation from fruit set to final harvest (S3S4), and (vi) saline irrigation throughout growth (All); two mulch treatments (subplots): (i) black mulch and (ii) bare soil; and two bell pepper cultivars (sub-subplots): (i) Early Sunsation and (ii) Red Knight. Production of fully ripened fruits was higher in mulched plants regardless of saline irrigation treatments. In humid areas with non-saline soil, supplemental saline drip irrigation could be used with black polyethylene mulch to save water while maintaining fruit production.     

Effect of tile effluent on nutrient concentration and retention efficiency in agricultural drainage ditches

Tile drainage is a common water management practice in many agricultural landscapes in the Midwestern United States. Drainage ditches regularly receive water from agricultural fields through these tile drains. This field-scale study was conducted to determine the impact of tile discharge on ambient nutrient concentration, nutrient retention and transport in drainage ditches. Grab water samples were collected during three flow regimes for the determination of soluble phosphorus (SP), ammonium nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃-N) concentrations and their retention in three drainage ditches. Measured nutrient concentration indicated lower SP and NH₄⁺-N, and greater NO₃-N concentrations in tile effluents compared to the ditch water. Net uptake lengths were relatively long, especially for NO₃-N, indicating that nutrients were generally not assimilated efficiently in these drainage systems. Results also indicated that the study reaches were very dynamic showing alternating increases or decreases in nutrient concentration across the flow regimes. The drainage ditches appeared to be nutrient-rich streams that could potentially influence the quality of downstream waters.     

Does silicon and irrigation have impact on drought tolerance mechanism of sorghum?

Silicon absorption by crops in the form of silicic acid confers efficient utilization of available irrigation water by minimizing transpiration losses. In present study, silicon and irrigation effects on sorghum growth dynamics and drought tolerance mechanism were evaluated during 2007-2008. Two sorghum cultivars: PARCSS2 and Johar1 were treated with two levels of silicon (Si₀ = control and Si₂₀₀ = 200 ml l⁻¹ of potassium silicate per kg of soil) and irrigation (W₀ = control, crop lower limit and W₄₀ = 40 mm of water, crop upper limit). The results depicted that silicon absorption led to increased leaf water potential, growth, transpiration, net photosynthetic rate and decreased shoot to root ratio in sorghum cultivars compared to control treatment. It can be concluded that synergistic effect of silicon fertilization with ample irrigation may improve the crop stand under drought and biotic stresses.