不同灌溉方式下土玉米根际硝态氮的分布

实验着重研究分根条件下常规灌溉、交替灌溉和固定灌溉玉米苗期根际硝态氮的分布, 研究结果表明不同灌水方式下,玉米根际硝态氮的分布不同.在这3种灌水方式的湿润区,NO-3-N的累积趋势为交替灌水＞固定灌水＞常规灌水.     

膜下滴灌条件下滴水量和滴水频率对棉田土壤水分分布及水分利用效率的影响

通过两年的田间试验,研究了滴水量和滴水频率对膜下滴灌棉田土壤水分分布及棉花水分利用效率的影响.结果表明:从整个生育期来看,当滴水量(375 mm)相同时,高频滴灌(每3天1次)处理0～20 cm土层含水率较高而深层土壤湿润不够;低频滴灌(每10天1次)处理有利于水分的下渗和侧渗,深层土壤含水率较高,但水分补给不及时,表层土壤偏低;总体上中频滴灌(每7天1次)处理有利于水分在土壤剖面中的均匀分配.当滴水频率相同时,滴水量越大,土壤含水率越高,40 cm以下土层含水率也越高.不同处理的棉田耗水规律基本一致,苗期较低,平均不高于1.7 mm·d-1,蕾期开始上升至花铃期达到最高,日均耗水量可达8.7 mm·d-1,吐絮期回落到1.0 mm·d-1左右.总耗水量与降水和滴水量密切相关,而与滴水频率无关;滴水频率对棉花水分利用效率无显著影响,但水分利用效率随滴水量的增大而显著降低.少量滴灌(300 mm)虽然可以获得较高的水分利用效率,但减产严重,过量滴灌(450mm)无显著增产效应,水分浪费严重.在当地棉田自然条件下,采用中量(375 mm)+中低频(每7天或10天1次)的滴灌模式为宜.     

膜下滴灌条件下滴水量和滴水频率对棉田土壤水分分布及水分利用效率的影响

通过两年的田间试验,研究了滴水量和滴水频率对膜下滴灌棉田土壤水分分布及棉花水分利用效率的影响.结果表明： 从整个生育期来看,当滴水量(375 mm)相同时,高频滴灌(每3天1次)处理0～20 cm土层含水率较高而深层土壤湿润不够;低频滴灌(每10天1次)处理有利于水分的下渗和侧渗,深层土壤含水率较高,但水分补给不及时,表层土壤偏低;总体上中频滴灌(每7天1次)处理有利于水分在土壤剖面中的均匀分配.当滴水频率相同时,滴水量越大,土壤含水率越高,40 cm以下土层含水率也越高.不同处理的棉田耗水规律基本一致,苗期较低,平均不高于1.7 mm·d^-1,蕾期开始上升至花铃期达到最高,日均耗水量可达8.7 mm·d^-1,吐絮期回落到1.0 mm·d^-1左右.总耗水量与降水和滴水量密切相关,而与滴水频率无关;滴水频率对棉花水分利用效率无显著影响,但水分利用效率随滴水量的增大而显著降低.少量滴灌(300 mm)虽然可以获得较高的水分利用效率,但减产严重,过量滴灌(450 mm)无显著增产效应,水分浪费严重.在当地棉田自然条件下,采用中量(375 mm)+中低频(每7天或10天1次)的滴灌模式为宜.     

Film mulch with irrigation and rainfed cultivations improves maize production and water use efficiency in Ethiopia

Improving productivity of maize (Zea mays L.) and water use efficiency is of great significance for agriculture in Ethiopia. In this study, the effects of ridge‐furrow with film mulch cultivation were tested on maize yields in Melkassa, Ethiopia. Three field experiments (drip irrigation, furrow irrigation and rainfed) were conducted each with randomised complete block design with three replicates. The drip irrigation experiment was conducted in the dry season and constituted three film mulch methods (non‐mulch, transparent film mulch and black film mulch) with three irrigation levels (357, 435 and 515 mm). The furrow irrigation experiment was also conducted in the dry season and constituted two film mulches (non‐mulch and transparent film mulch) with three irrigation levels (484, 674 and 865 mm). The rainfed experiment was conducted in the rainy season and constituted three mulches (non‐mulch, transparent film mulch and black film mulch) with two farming methods (ridge‐furrow farming and flat farming). In the drip irrigation experiment, the highest maize yields (5.9 ± 0.6 t ha^?1) and irrigation water use efficiency (9.6 ± 1 kg ha^?1 mm^?1) were recorded in the treatment using black film mulch with high irrigation, with increases of 68% and 68.4% compared to using non‐mulch treatment at that irrigation level. In the furrow irrigation experiment, maize yields and irrigation water use efficiency reached 7 (± 0.8) t ha^?1 and 9.1 (± 1.9) kg ha^?1 mm^?1 in the treatment using transparent film mulch with medium irrigation (674 mm), with increases of 46% and 46.8% compared to that with non‐mulch treatment. In the rainfed experiment, the film mulch rather than farming method had positive effects on the maize yields and rainwater use efficiency. The average maize yield reached 8.5 (± 0.7) t ha^?1 in the film mulch treatments, with an increase of 39% than using the non‐mulch treatment. Compared with that of non‐mulch treatment, the net income in the film mulch treatments increased by 94% in the furrow experiment and 31% in the rainfed experiment. Our results indicate that the ridge‐furrow with film mulch system can be recommended for water‐saving irrigation with low cost in dry seasons, and film mulch with flat farming can be recommended in rainy seasons for maize production in Ethiopia. This study provides strong evidence that maize productivity can be effectively improved in Ethiopia and other similar areas of the world using this simple and cost‐effective technology.     

日光温室渗灌效果研究

对日光温室渗灌和沟灌的土壤环境,室内空气环境,作物生育及病毒状况,水分利用效率等进行了研究,结果表明,与沟灌相比,渗灌可增加土壤水稳定性团粒81．4％,降低土壤容重21．2％,增加土壤孔隙度29．0％,提高土壤温度1．1－1．7℃,降低空气湿度13．4％,节约灌溉用水36．7％,而且能促使作物早熟,提高作物产量,减少作物病害,降低生产成本,是目前日光温室理想的灌溉技术。     

Effect of Irrigation Type on Inoculum Density of Macrophomina phaseolina in Melon Fields in Arizona

Charcoal rot, caused by Macrophomina phaseolina, has become increasingly problematic for melon growers using subsurface drip irrigation in Arizona; but has rarely been observed in fields with furrow irrigation. Since the relationship between increasing incidence of charcoal rot on melon and irrigation type is unknown, studies were initiated to determine the effects of edaphic factors on inoculum density. Soil samples were collected once from fields irrigated by subsurface drip, with and without plastic mulch, and by furrow at 10, 20 and 30 cm depths. Samples were analysed for percentage soil moisture, pH, salinity and inoculum density. Percentage soil moisture was significantly higher at 20 and 30 cm depths in the furrow‐irrigated field compared with the drip‐irrigated field with plastic mulch, but not in the field without plastic mulch. Average minimum and maximum temperatures and inoculum density were significantly lower at all three depths in the furrow‐irrigated field compared with both types of drip irrigation. pH was significantly higher in the furrow‐irrigated field compared with both types of drip irrigation at 20 and 30 cm depths but not at 10 cm depth. Differences in inoculum densities of M. phaseolina suggest that drip irrigation may contribute to higher disease incidences.     

Seasons of birth and marriage in two Chinese localities

Data from two rural Chinese settings suggest that an ecological variable — the reliability of food supply — may exert a more decisive influence on birth seasonality than time of marriage or attributes of temperature, rainfall, or workload. First births seem to be especially important for patterns of seasonality; comparison between villages suggests that a periodic but reliable source of food may encourage a seasonal distribution of first births, the effect of which might be to protect the mother and/or her newborn infant. It is the periodicity of first births that may give aggregate birth figures the appearance of seasonality.This paper is based on fieldwork conducted by Myron L. Cohen (Columbia) and myself and is part of a larger, continuing study of the social and economic attributes of a particular Chinese regional system. Fieldwork and initial data analysis were funded by the National Science Foundation with supplementary support for further data analysis provided by the Research Foundation of the City University of New York. A debt of gratitude is due the Institute of Ethnology, Academia Sinica (Taiwan) and the Joint Commission on Rural Reconstruction (Taiwan) for encouragement and sponsorship in the field. I am particularly grateful to my colleagues Carol R. and Melvin Ember, and Gregory Johnson for the generous statistical and critical assistance they provided during analysis of the data from Meinung. I am also indebted to Arthur Wolf (Stanford) and to Margery Wolf for suggestions and criticisms offered after reading an early version of the present paper.     

保墒灌溉对渠灌类型区冬小麦产量构成及生理特性的影响

以传统耕作栽培方式为对照,研究了5种保墒灌溉栽培方式下冬小麦产量构成的差异,并对冬小麦灌浆期旗叶叶绿素含量、MDA含量、SOD含量、水分利用效率进行了研究。结果显示:不同保墒灌溉栽培方式对冬小麦均有增产作用,平均增产13.46%,穗长平均增加7.15%,不孕小穗数平均降低21.78%,结实小穗平均增加11.42%,穗粒数平均增加10.82%,千粒重平均增加11.05%。保墒灌溉栽培方式的冬小麦灌浆期旗叶叶绿素含量降低减缓,MDA含量降低、SOD含量增高,水分利用效率平均提高24.03%。结果表明,以免耕留茬方式增产幅度最大,水分利用效率最高。     

Aeschynomene as green manure for rice

The widely accepted application of the fertilizers via the irrigation stream (fertigation) has necessitated the development of suitable techniques to help research in estimating the fertilizer requirements of crops. This paper describes a simple, inexpensive, and precise system tested for three years in field experiments, in which various levels of a fertilizer could be supplied simultaneously. The same system could also be used when irrigating simultaneously various crops with different fertilizer requirements from a single concentrated fertilizer solution, using only one fertigator.     

世界上可以用海水灌溉的盐生植物资源

报道了世界上可以利用海水灌溉的盐生植物种类及其生活型 、植物类型、分布、光合途径、耐盐水平和用途。此类植物有１６８种,分属３２科,一些用途不明的布盐能力达到适应海水的植物没有列入,例如粉藻科、眼有科、水龟科等,约有６０余种。     

基于20 cm蒸发皿蒸发量制定的华北地区温室黄瓜滴灌灌水制度

试验分别于2013和2014年在中国农业科学院新乡综合试验基地进行,以20 cm蒸发皿蒸发量（E_p -20）为灌水依据,设置5种水面蒸发系数（K_cp1:0.25;K_cp2:0.5;K_cp3:0.75;K_cp4:1.0;K_cp5:1.25）代表5种灌水水平,分析了不同水量（I_r）对温室黄瓜滴灌耗水量（ET）、产量、品质以及水分利用效率（WUE）的影响,探讨了以E_p -20制定温室滴灌灌水计划的可行性.结果表明：温室滴灌黄瓜整个生育期内的耗水量在129~314 mm,耗水量随着灌水量的增加而增加.当灌水量超过0.75E_p 20时,各处理之间的产量无差异,平均单果质量、单株瓜条数和平均瓜长对灌水量的响应均存在一个阈值（0.75E_p 20）;品质方面,可溶性固形物、维生素C和可溶性糖含量均随着灌水量的增加而降低,而可溶性蛋白质含量为：K_cp2＞K_cp3＞K_cp4＞K_cp1＞K_cp5;采用修正后的Penman Monteith公式计算温室滴灌黄瓜参考蒸发蒸腾量所得结果与E_p -20呈极显著线性相关关系.可见,在华北地区日光温室黄瓜的滴灌灌水制度选用0.75倍的20 cm蒸发皿水面蒸发量作为灌水依据简单可行.     

Field screening of barley cultivars to soil salinity using a sprinkler and a drip irrigation system

The establishment of proper agronomical practices and plant breeding programs for saline environments is limited by the lack of adequate field screening methods. We assessed the relationships between leaf ion concentration and grain yield in a set of barley cultivars and compared their ranking for salinity tolerance established with a triple-line-source (TLS) sprinkler system, where the absorption of salts is through the leaves and the roots, with that obtained with a drip-irrigation (DI) system, where the absorption of salts is only through the roots. The saline solution in both systems was made up of sodium and hydrated calcium chloride (1:1 w/w). Except for the highest saline treatments, direct leaf absorption of toxic Na⁺ and Cl^- was minor or negligible, but it was substantial for Ca²+. Irrespective of barley cultivar and leaf age, the accumulation of Cl^- in the TLS was 1.5–2.5 times greater than Na⁺. There was no significant correlation between grain yield and leaf sap ion concentration among eighteen barley cultivars. Thus, leaf ion concentrations should not be used as screening tools in breeding programs for increasing salinity tolerance in barley. The highest-yielding cultivars under non-saline conditions were also most productive under moderately saline conditions, though not under high-saline conditions. Although grain yields of the eighteen barley cultivars in the TLS were substantially lower than in the DI, the salinity tolerances estimated in both systems were significantly correlated (P < 0.05), indicating that the simple and inexpensive TLS irrigation system could be successfully used in screening for salinity tolerance in barley.     

喷灌条件下耕作方式和亏缺灌溉对麦后移栽棉产量和水分利用的影响

探明耕作方式和亏缺灌溉对麦后移栽棉产量和水分利用的效应,对于建立麦后移栽棉的适宜耕作方式及灌溉制度十分重要.在大田条件下设置了翻耕和免耕2种耕作方式(灌水定额均为45 mm)及相应减小50％灌水定额的亏缺灌溉,分析了不同耕作方式和亏缺灌溉对棉花耗水规律、籽棉产量、水分利用效率和纤维品质的影响.结果表明:与翻耕相比,免耕减少了棉田20.3％的棵间土壤蒸发;不论何种耕作方式,亏缺灌溉在不影响棉花产量和纤维品质的同时,有效降低了耗水量,提高了水分利用效率.在喷灌条件下,灌水定额为22.5 mm的免耕耕作方式,不仅可有效降低麦后移栽棉田间无效棵间土壤蒸发,还可实现节水、优质、高产的有效统一.     

基于恒水位蒸发皿蒸发量的膜下滴灌棉花灌溉指标

为探索新疆膜下滴灌棉花简易方便的高效灌溉指标,于2008-2009年在乌鲁木齐开展了2个生长季的人工控水试验.在棉花蕾期和花铃期均设2个灌水周期和2个灌水水平,分析了不同水分处理对棉花产量、耗水量和水分利用效率的影响.结果表明: 各处理的棉花耗水过程与蒸发皿蒸发量具有较高的相关性,高产棉田\[2008年处理T₄(蕾期和花铃期灌水周期分别为10和7 d,相应灌水定额分别为30.0和37.5 mm)和2009年处理T₁(蕾期和花铃期灌水周期均为7 d,相应灌水定额分别为22.5和37.5 mm)\]苗期、蕾期、花铃期和吐絮期的蒸发皿-作物系数(K_p)分别为0.29～0.30、0.52～0.53、0.74～0.88和0.19～0.20;2008年处理T₄的产量(5060 kg·hm^-2)和水分利用效率(1.00 kg·m^-3)最高,2009年处理T₁的产量(4467 kg·hm^-2)和水分利用效率(0.99 kg·m^-3)最高;蕾期蒸发皿7和10 d的平均累积蒸发量分别为40～50和60～70 mm,花铃期蒸发皿7 d的累积蒸发量为40～50 mm.在新疆棉区灌45 mm出苗水、苗期和吐絮期不灌水,蕾期和花铃期当蒸发皿蒸发量达到45～65和45 mm时开始灌溉,灌水定额通过阶段累积蒸发量与蒸发皿-作物系数K_p(蕾期、初花期、盛花期和末花期分别取0.5、0.75、0.85和0.75)相乘确定时,在获得高产的同时可节约灌溉水资源,提高水分利用效率,可以作为当地膜下滴灌棉田简易方便的高效灌溉指标.     

小麦灌水时期与灌水量对花后果聚糖积累与转运及水分利用效率的影响

于2004-2005年和2005-2006年冬小麦生长季,在山东泰安和兖州进行田间试验,研究不同灌水时期和灌水量处理对冬小麦开花后倒二节间果聚糖积累与转运和水分利用效率的影响.结果表明：全生育期不灌水促进了灌浆后期倒二节间贮藏果聚糖向籽粒的转运.在拔节期和开花期各灌水60 mm,可提高开花后旗叶的光合速率和同化物输入籽粒量及其对籽粒的贡献率,拔节期、开花期和灌浆期各灌水60 mm或拔节期和开花期各灌水90 mm,灌浆后期旗叶的光合速率显著降低,营养器官花前贮藏同化物转运量及其对籽粒的贡献率升高,花后同化物输入籽粒量及其对籽粒的贡献率降低,灌浆后期倒二节间的聚合度（DP）≥4、DP=3果聚糖滞留量增加,不利于果聚糖向籽粒的转运.两个生长季中,拔节期和开花期各灌水60mm处理的小麦籽粒产量较高,水分利用效率最高.拔节期、开花期和灌浆期各灌水60 mm或拔节期和开花期各灌水90 mm,小麦籽粒产量无显著变化,水分利用效率降低.     

棉花节水灌溉气象等级指标

干旱是我国棉区主要的气象灾害,构建棉花不同发育期节水灌溉气象等级指标对于优化农田灌溉、指导农业生产具有十分重要的现实意义。论文基于农田水分平衡原理,利用全国347个地面气象观测站1961~2008年逐日气象资料、89个农业气象观测站1993~2008年（其中26个站为1980~2008年）逐旬土壤湿度、灌溉量、逐年作物产量等资料,结合FAO-1979作物产量-水分关系函数,针对全国棉区播种-现蕾、现蕾-开花、开花-吐絮和全生育期的水分亏缺率、水分亏缺量与减产率之间的关系,构建棉花不同发育期和全生育期节水灌溉气象等级指标。除发育时段不同外,其他在研究站点的选择、选取的因素等方面完全一致。结果表明：棉花全生育期节水灌溉气象Ⅰ~Ⅲ级水分亏缺率(D)和水分亏缺量（辅助指标）指标分别为：15%≤D＜30%、30%≤D＜45%、≥45%和1~2水、2~4水、≥4水;播种-现蕾为20%≤D＜40%、40%≤D＜50%、≥50%和0.5水、1水、＞1水;现蕾-开花为20%≤D＜35%、35%≤D＜45%、≥45%和0.5水、1水、＞1水;开花-吐絮为20%≤D＜35%、35%≤D＜50%、≥50%和1水、1~2水、＞2水。     

农田灌溉对印度区域气候的影响模拟

为满足人类对粮食的需求,全球灌溉农田面积迅速扩张,农田灌溉对区域气候的影响引起广泛地关注。利用区域环境系统集成模式(RIEMS2.0)和最新的土地利用变化资料,选取农田灌溉面积最大的印度区域作为研究区域,进行雨养农田和灌溉农田的对比试验,探讨农田灌溉对区域气候的影响。结果表明:(1)农田灌溉使得印度区域年平均气温降低1.4℃,年平均降水率增加0.35mm/d。农田灌溉对印度区域气候的影响存在明显的季节波动,季风前期及6月份该区域气候对下垫面变化的响应最为敏感;7-9月各气候要素变化较小。(2) 农田灌溉使得印度区域地表净辐射增加,且地表净辐射在潜热通量和感热通量之间的分配发生了较大的改变,潜热通量增加,感热通量减少;对地表起冷却作用;同时由于土壤湿度增加,蒸散作用增强,大气中水汽含量增加,潜热不稳定能量增加,导致对流性降水增加。     

高浓度臭氧对蒙古栎叶片酚类物质含量和总抗氧化能力的影响

采用开顶箱(OTC)法,研究了高浓度臭氧(80±8 nmol·mol^-1)熏蒸处理对蒙古栎叶片 中总酚、类黄酮、单宁及丙二醛(MDA)含量的影响,使用1,1-二苯基苦基苯肼(DPPH) 法测定了蒙古栎叶片的总抗氧化能力.结果表明:蒙古栎叶片中总酚、类黄酮、缩合单宁和MDA的含量都有所增加,其中总酚和缩合单宁含量分别增加了48.17%和26.77%,差异显著（P<0.05）;类黄酮和MDA含量分别增加了24.66%和5.26%,差异不显著(P＞0.05);蒙古栎叶片总抗氧化能力显著增强(P<0.05),且与叶片中总酚和缩合单宁含量呈显著的正相关关系.     

Analysis of soil moisture variations in an irrigated orchard root zone

Soil moisture and suction head in an irrigated orchard were continuously monitored by time domain reflectometry (TDR) probes and gypsum blocks, respectively, during and between successive irrigation events. On each side of the trees in the plot, two 30-cm long probes were installed vertically 10 cm below the soil surface (denoted as shallow) and another two probes were installed vertically 40 cm below the soil surface (denoted as deep). The variation in moisture content measured by the TDR probes between successive irrigation events was qualitatively divided into four stages: the first was during water application; the second initiated when irrigation stopped and the moisture content in the layer sharply decreased, mainly due to free drainage. The succeeding moderate soil-moisture decrease, caused by the simultaneous diminishing free drainage and root uptake, was the third stage. During the fourth stage, moisture depletion from the layer was solely by root uptake. The slopes of moisture content variation with time throughout this stage enabled the monitoring of water availability to the plant. The range of moisture content variations and moisture depletion rates between subsequent irrigation events was higher in the shallow (10–40 cm) than in the deeper (40–70 cm) layer. Irrigation nonuniformity and spatial variability of soil hydraulic properties contributed to the unevenness of the moisture distribution in the soil profile. However, as soon as moisture content within a layer reached field capacity, namely the free drainage had stopped, irrigation uniformity had a negligible effect on water flux to the plant roots. The measured data indicate that soil moisture is fully available to the plant as long as the momentary moisture flux from the soil bulk to the soil–root interface can replenish the moisture being depleted to supply, under non-stressed conditions, the atmospheric water demand. This flux is dominated by the local momentary value of the soil's bulk hydraulic conductivity, K _r, and it stays constant for a certain range of K _r values, controlled by the increasing root suction. A decrease in water availability to the plant appears for longer irrigation intervals as a break in the constant soil-moisture depletion rate during stage 4. This break is better correlated to a threshold K _r value than to threshold values of moisture content or suction. Therefore, it is suggested that moisture content or suction used to measure water availability or to control irrigation first be alibrated by K _r() or K _r() curves, respectively.