Soil water dynamics and deep soil recharge in a record wet year in the southern Loess Plateau of China

Terrestrial water cycles are influenced by hydrologic and textural properties of the deep loess layer in the Loess Plateau. Analyses of soil water profile distributions are needed to understand the regional water cycle processes and to guide agricultural production and sustainability. The objective of this study was to quantify the extent of deep soil water recharge and soil water profile dynamics during 1987-2003, especially in a record wet year of 2003, in common cropping systems in a semiarid-subhumid region of the southern Loess Plateau. The Chinese Ecological Research Network (CERN) site and a long-term rotation experiment site in a flat tableland were selected for this study. Soil moisture profiles were measured by a neutron probe to a depth of 6 m in 2003. The precipitation of 954 mm at the Changwu County Meteorological Station in 2003 was 63.4% higher than the long-term average (584 mm), and was a record high since 1957. Although cropping systems affected deep soil water recharge, the persistent dry soil layer formed between 2- and 3-m depths in croplands, resulting from many years of intensive cropping, was fully replenished in all cropping systems in 2003. Further frequency analysis indicated that the desiccated layer between 2- and 3-m depths would be fully recharged at least once in about 10 years for all existing cropping systems excluding continuous alfalfa. This finding should alleviate concerns about the formation of a permanent deep-soil desiccation layer as well as its potential impact on the long-term sustainability of the existing intensive cropping systems in the region.     

黄土高原沙棘资源建设浅谈

经过各方的共同努力,沙棘资源建设已经取得了很大成绩,资源总量增长了一倍多,达2000多万亩,建设了一批试验示范区,取得了建设经验。大力发展沙棘,能够加速黄土高原水土流失的综合治理进程,是一项行之有效的重大举措。     

黄土高原地区雨水集蓄利用技术发展评述

通过对黄土高原地区雨水集蓄利用技术发展现状的全面分析 ,指出了目前该地区雨水集蓄利用技术推广应用中存在的主要问题 ,最后提出了发展本地区先进、高效、适用雨水集蓄利用技术的具体对策     

黄土高原丘陵沟壑区土壤水库调蓄能力分析

重建黄土高原土壤水库的调蓄功能是进行黄土高原生态环境治理的根本,而土壤水库的基本调蓄能力是对黄土高原土壤水库的定量描述.在对坡面果园土壤含水量定位观测的基础上,以含水量长期稳定土层为调节深度,得出阳坡土壤水库调节深度为300 cm,阴坡为450 cm,半阳坡和半阴坡介于二者之间;阳坡、阴坡、半阳坡和半阴坡坡面果园的调蓄能力分别为597.50、896.22、697.06和796.64 mm;土壤水库的调蓄量受调蓄能力及降水量的影响,丰水年主要受土壤水库调蓄能力影响,不同坡向间呈现出较大的差异性,以阴坡最大,阳坡最小,在年际之间也呈现出同样规律;枯水年土壤水库的调蓄能力主要受控于雨季降水量,坡向间差异不明显,其土壤水库蓄水有效性也表现为同样规律.     

夏闲覆盖和种植方式对黄土旱塬小麦产量及土壤水分的影响

【目的】充分利用夏闲期降水,提高旱地麦田土壤蓄水保墒能力,增产增收。【方法】通过3 a田间试验,研究了夏闲期秸秆残膜二元覆盖+垄膜沟播(JCLG)、夏闲期黑网膜覆盖+露地条播(HWLT)与夏闲期秸秆覆盖+露地条播(JLT)3种栽培措施对黄土旱塬冬小麦土壤水分及产量的影响。【结果】JCLG处理可显著提高小麦产量、生物量、降水生产效率,较JLT处理分别提高9.5%～35.1%,13.2%～42.2%,8.8%～35.6%。同时JCLG处理具有良好的休闲期蓄水效率,较JLT处理平均提高29.5%,平水年二者差异显著。HWLT处理也具有良好的水分休闲效率和增产效果,较JLT处理平均提高22.5%和18%。播前2 m土壤贮水量和耗水量、产量、生物量均呈极显著相关关系,一定程度上根据播前土壤贮水量来预测当地冬小麦产量。【结论】JCLG处理和HWLT处理2种覆盖种植方式均适宜在黄土旱塬乃至我国旱地麦区推广应用,且以夏闲期秸秆残膜二元覆盖+垄膜沟播(JCLG)方式效果更佳。     

黄土高原中部主要乡土树种生长过程分析

本文对黄土高原中部油松、侧柏、刺槐、沙棘、胡颓子和火炬树等乡土树种树高、胸径及材积生长量进行了测定,结果表明：研究区树高生长曲线分两种类型,以油松、侧柏等人工实生林为一种类型,即满足“慢一快一缓慢一稳降”生长规律,沙棘、火炬树等萌蘖林开始生长较快,之后逐渐降低并趋于稳定。6树种树高平均生长量为0．4518±0．2763...     

黄土高原中部不同类型区沙棘果实营养成分分析

本文对黄土高原中部(陕西省)沙棘分布较为集中,且具代表性的靖边县、黄龙县和陇县的沙棘果进行采样并分析了全果实粗蛋白、粗脂肪、鲜水分的含量及总酸度;果肉和果汁中维生素及糖类含量;沙棘果汁(原汁)中氨基酸含量;种子油的脂肪酸组成;鲜果肉油的脂肪酸组成等,为该区沙棘进一步的开发利用提供基础数据.     

沙棘在黄土高原农林复合生态系统中的应用

沙棘作为干旱、半干旱地区优良的多用途树种,除具有较高经济价值外,还具有较强的固氮改土、防风固沙和保持水土能力,因此被广泛用于黄土高原农林复合生态系统之中。目前,沙棘已在五大复合系统、多个结构类型中应用,形成了多种多样的复合模式。其中,沙棘＋杏十牧草的隔坡水平沟复合模式、沙棘＋苜蓿＋天然牧草的林牧复合模式、沙棘＋油松的防护林复合模式、沙棘＋甘草的林药复合模式及沙棘＋黑加仑＋油菜的庭院复合模式等均为黄土高原农林复合系统的典范。随着沙棘新品种的不断培育与引进,沙棘在农林复合生态系统中的应用将日益广泛。     

黄土高原中部主要引进树种生长过程分析

本文对黄土高原中部引进的奥地利黑松、美国黄松、美人松、欧洲赤松、欧洲黑松等16个树种,林分个体树高平均生长量曲线分两种类型,以欧洲黑松为代表的第一种类型,苗期生长较快,随着年龄的增加,树高平均生长量趋于减慢且逐渐稳定,另外一种类型满足正常的"慢—快—缓慢—稳中有降"的生长规律。树高年平均生长量为0.369±0.097m,以美国黄松和欧洲黑松的最高(0.535±0.052m),以铁杉的最低(0.251±0.044m);树高连年生长量平均值为0.387±0.104m,欧洲黑松的最高,华山松的最低,前者是后者的2.63倍;16树种胸径年平均生长量在林木整个生长过程中变化幅度较小,以美国黄松的最高(1.595±0.192cm),青扦的最低(0.363±0.088cm),二者相差近4倍,就乡土树种白皮松、华山松、金钱松、青扦、铁杉、樟子松(0.6048cm)与外来引进树种(0.8488cm)相比,国外引进树种的生长量远远高于国内引进树种。16树种胸径连年生长量平均值为0.7056±0.2570cm,美国黄松的最大(1.249±0.350cm),青扦的最小(0.376±0.241cm),外国引进树种高出乡土树种50.0%以上。     

黄土高原地区潜在腾发量模拟及时空变化

运用世界粮农组织推荐的Penman-Monteith方程和1980-2008年黄土高原不同经纬度18个气象站气象要素观测数据,研究了黄土高原地区不同气象站点参照腾发量的时空变化特征。结果表明：1980～2008年黄土高原参照腾发量年平均值为874．74～1129．79mm,并随着纬度从北到南和经度从东到西有逐渐增加的趋势;20多年间绝大部分研究点的E瓦呈逐年增加趋势,其变化倾向率为4．04～48．25mm／10a,无论包头、横山、绥德、延安、洛川、固原、环县和临汾等地降雨量逐年减少,还是东胜、榆林、民和、靖远、海原和长治等地降雨量逐年增加,可见黄土高原的干旱化正在加剧。黄土高原各气象站点的参照腾发量年内最大值均出现在6、7月;5～8月的ET0占全年的比重为52．9％～59．2％,比重随着纬度的增加而减少。     

黄土高原中部沙棘与秋胡颓子光合参数之异同

用LI-6400光合仪全面系统测定了黄土高原中部人工沙棘林和秋胡颓子林的各种光合生理指标,主要结果为:两树种叶片光强响应曲线暗呼吸速率、表观量子效率、最大光合速率、光补偿点及光饱和点数值分别为:-3.677μmol·CO2·m-2·s-1、-1.715μmol·CO2·m-2·s-1,0.0517mol·mol-1、0...     

Effects of rainfall harvesting and mulching technologies on water use efficiency and crop yield in the semi-arid Loess Plateau, China

In semi-arid areas, crop growth is greatly limited by water. Amount of available water in soil can be increased by surface mulching and other soil management practices. Field experiments were conducted in 2005 and 2006 at Gaolan, Gansu, China, to determine the influence of ridge and furrow rainfall harvesting system (RFRHS), surface mulching and supplementary irrigation (SI) in various combinations on rainwater harvesting, amount of moisture in soil, water use efficiency (WUE), biomass yield of sweet sorghum (Sorghum bicolour L.) and seed yield of maize (Zea mays L.). In conventional fields without RFRHS, gravel-sand mulching produced higher biomass yield than plastic-mulching or straw-mulching. In plastic-mulched fields, an increasing amount of supplemental irrigation was needed to improve crop yield. There was no effect of RFRHS without plastic-covered ridge on rainwater harvesting when natural precipitation was less than 5 mm per event. This was due to little runoff of rainwater from frequent low precipitation showers, and most of the harvested rainwater gathered at the soil surface is lost to evaporation. In the RFRHS, crop yield and WUE were higher with plastic-covered ridges than bare ridges, and also higher with gravel-sand-mulched furrows than bare furrows in most cases, or straw-mulched furrows in some cases. This was most likely due to decreased evaporation with plastic or gravel-sand mulch. In the RFRHS with plastic-covered ridges and gravel-sand-mulched furrows, application of 30 mm supplemental irrigation produced the highest yield and WUE for sweet sorghum and maize in most cases. In conclusion, the findings suggested the integrated use of RFRHS, mulching and supplementary irrigation to improve rainwater availability for high sustainable crop yield. However, the high additional costs of supplemental irrigation and construction of RFRHS for rainwater harvesting need to be considered before using these practices on a commercial scale.     

黄土高原区降雨与海洋表面温度的相关分析研究

研究了黄土高原区降雨时间序列和海洋表面温度的关系。采用谱分析法研究了降雨时间序列的频率特性,根据赤池信息系数确定了最优频率组合,并利用Fourer级数进行了降雨时间序列重构。降雨与海洋表面温度的相关分析表明,太平洋地区(东经150°,北纬15°)的海洋表面温度能够较好的预测黄土高原区3个月后的降雨。     

黄土高原中国沙棘克隆种群高度结构动态

为了解黄土高原中国沙棘种群演替规律,以人工林为材料、以高度替代年龄为手段,采用＂空间差异代替时间变化法＂和＂样地编年序列法＂对种群结构类型及其动态进行分析。结果表明：种群高度结构可划分为增长型、稳定型和衰退型,种群结构动态遵循增长型、稳定型、衰退型、恢复型、增长型的顺序变化过程。上述结果与种群年龄结构动态分析一致,两者都揭示了中国沙棘通过林窗更新恢复种群结构稳定性这一特殊而重要的事实。其中,克隆种群结构由增长型经过稳定型发展到衰退型,这一过程符合阳性树种的普遍演替规律。而在衰退型种群中,中国沙棘通过克隆繁殖调节恢复增长型种群结构则体现了克隆植物的特殊性。同时,克隆种群稳定性恢复的实现与克隆植物独有的＂生理整合＂及＂觅养行为＂等优越性密切相关。     

黄土丘陵区沙棘水土保持薪炭林土地生产潜力研究

本文对黄土丘陵区主要灌木水土保持薪炭林树种——沙棘(Hippophae rhamnoides Lo)的土地生产潜力进行了研究。应用Thornthwait Memorial模型估算了其土地气候生产潜力，揭示了沙棘在该地区实际存在的气候条件下可能达到的理论产量；实测了当前技术经济管理水平条件下所能达到的最高产量——现实生产潜力，分析了目前林业的现实生产潜力与气候生产潜力之间的差距，预示了其发展前景；从合理利用气候资源和充分发挥土地生产潜力角度，提出了沙棘应为当地水土保持薪炭林优选的灌木树种。其结果对该地区培育坡地水土保持薪炭林具有重要的实践指导意义。     

黄土高原坡面刺槐林土壤水分有效性分析

通过定位观测并引入土壤水分有效性标准,对黄土高原刺槐林不同地理位置、不同坡向和不同时期土壤储水量进行了分析,结果表明,由南向北,土壤储水量有效性递减,刺槐林0~600 cm土壤水分的有效性淳化和延安表现为中效,延安为轻度亏缺;米脂表现为难效,为中度亏缺。在不同坡向间阴坡土壤水分的有效性最高,阳坡最低,半阴坡和半阳坡介于二者之间;在1~8月份土壤水分的有效性逐渐降低,9~12月土壤水分得到恢复,有效性提高。     

宁夏黄土高原区滴灌青贮玉米灌溉参数试验研究

针对宁夏黄土高原区青贮玉米灌溉土地生产效率低、灌溉方式粗放、对产量影响不明确等技术问题,通过田间试验,分析不同土壤水分下限对滴灌青贮玉米株高、净光合速率、蒸腾速率、水分生产效率及产量的影响。结果表明:1青贮玉米株高增加量,处理F7最大,F8次之,F4最低;2日平均净光合速率,处理F7最高,为20.08μmol/(m~2·s),处理F1最低,为8.01μmol/(m~2·s);日平均蒸腾速率,处理F8最高,为3.57 mmol/(m\+2·s),处理F1最小,为1.71 mmol/(m~2·s);3处理F7产量最高,为89 724 kg/hm~2,处理F1最低,为57 136.5 kg/hm~2,同时,处理F7水分生产效率也达到最大值,为20.67 kg/m3;综合考虑作物产量和水分生产效率,滴灌青贮玉米土壤水分下限以处理F7为宜。     

黄土区五种土壤抗冲性试验分析

通过室内放水冲刷实验,分析了黄土高坡5种土壤在不同坡度下的下切冲刷过程及影响冲刷的坡度、水流特征以及水流含沙量等影响因素。结果表明,在流量为120 L/h条件下,5种土壤的抗冲系数均随着坡度的增大而降低,且呈现指数回归关系,决定系数R~2较高,土壤抗冲性大小依次为杨凌黏壤土延安砂质黏壤土周至黏壤土志丹砂质壤土靖边砂质壤土;5种土壤的抗冲系数和水流流速均呈现出负相关的线性变化规律;5种土壤的冲刷强度基本都随着坡度的增加而增加,随着冲刷时间的推移,冲刷强度逐渐减小,且坡度越大,前期的冲刷强度越大;5种土壤的抗冲系数与水流含沙量呈现出负相关的线性变化规律,决定系数R~2在0.857 7~0.957 5之间,随水流含沙量的变化,抗冲性越好的土壤其本身的抗冲系数变化越显著。     

陕北黄土高原降雨侵蚀力简易计算模型的比较研究

以位于陕北黄土高原的延安、榆林和横山3个气象站的月雨量数据和年雨量数据对Wischmeier、Renard、刘秉正等研究的7种降雨侵蚀力简易计算模型进行验证,将计算结果与陕北黄土高原降雨侵蚀力基准值进行对比,发现刘秉正提出的渭北地区R计算模型较其他模型与基准值比较接近。但是,由于该模型的相对偏差仍然较大,所以,对于陕北...     

Soil water dynamics and water use efficiency in spring maize (Zea mays L.) fields subjected to different water management practices on the Loess Plateau, China

Soil water supply is the main limiting factor to crop production across the Loess Plateau, China. A 2-year field experiment was conducted at the Changwu agro-ecosystem research station to evaluate various water management practices for achieving favorable grain yield (GY) with high water use efficiency (WUE) of spring maize (Zea mays L.). Four practices were examined: a rain-fed (RF) system as the control; supplementary irrigation (SI); film mulching (FM); and straw mulching (SM) (in 2008 only). The soil profile water storage (W) and the crop evapotranspiration (ET) levels were studied during the maize growing season, and the GY as well as the WUE were also compared. The results showed that mean soil water storage in the top 200 cm of the profile was significantly (P < 0.05) increased in the SI (380 mm in 2007, 411 mm in 2008) and SM (414 mm in 2008) compared to the FM (361 mm in 2007, 381 mm in 2008) and RF (360 mm in 2007, 384 mm in 2008) treatments. The soil water content was lower at the end of growing season than before planting in the 60-140 cm part of the profile in both the RF and FM treatments. Cumulative ET and average crop coefficiency (K_c) throughout the whole maize growing season were significantly (P < 0.05) higher in the SI (ET, 501 mm in 2007, 431 mm in 2008; K_c, 1.0 in 2007, 0.9 in 2008) treatment than in the other treatments. Both FM and SI significantly improved the GY. The WUE were increased significantly (23-25%; P < 0.05) under the FM treatment. It was concluded that both SI and FM are beneficial for improving the yield of spring maize on the Loess Plateau. However, FM is preferable because of the shortage of available water in the area.