黄土丘陵沟壑区山地果园集流高效利用技术研究

对黄土丘陵沟壑区山地果园集流节水利用的定位试验观测和分析的结果表明 :将果园修成“回”字形集水面 ,将超渗产流蓄贮 ,既可以减少果园水土流失 ,又能满足果树旱季用水 ;采用地膜覆盖、秸秆覆盖、绿色覆盖措施可以有效地减少地面蒸发 ,调节地表温度 ,增加土壤有机质 ,达到高效利用雨水资源的目的。该技术具有简便、实用、经济效益高的特点 ,适宜在生产中大力推广应用     

堆渣边坡生态棒护坡措施的水土保持效益

[目的]探究堆渣边坡生态棒防护措施的综合防护效果,为露天采石场裸露边坡的生态修复提供依据。[方法]利用人工降雨模拟试验,收集不同降雨强度下地表层和矿渣层的产流量、产沙量,并建立综合贡献度模型。[结果]随着坡度的增加地表层的径流总量和泥沙总量呈递增趋势,而矿渣层的径流总量和泥沙总量呈递减趋势,与径流总量相比泥沙总量变化趋势不明显;对照组与生态棒防护措施下,地表层的产流—产沙相关性均高于矿渣层;当降雨强度为30和120mm/h时,生态棒防护边坡在坡度为15°时具有较佳的防护效果,当降雨强度为60mm/h时,径流量和泥沙量受坡度变化的影响不显著。[结论]生态棒防护措施具有拦蓄坡面径流和泥沙的功能,与对照组相比可以更有效地防治坡面水土流失。     

岔巴沟流域泥沙输移比时空分异特征及影响因素

本文以团山沟单元小流域作为流域系统产沙的源地，将其它中小流域输沙模数与单元小流域侵蚀模数之比定义为泥沙输移比，系统的研究了岔巴沟流域次暴雨泥沙输移比的时空变化特征及降水水文影响因子和地貌形态因子的综合影响。研究发现，从长远来看，流域系统的侵蚀与产沙可达到平衡，但就次降雨或年度而言，流域系统经常处于泥沙滞留和滞留的泥沙重新侵蚀搬运的状态。降雨量、径流系数、降雨时间、水流平均含沙量能很好的表达岔巴沟各流域次暴雨泥沙输移比，在考虑地貌形态因子的影响后，得到了岔巴沟流域次暴雨泥沙输移比的降水水文因子与地貌形态因子关系的综合表达式。     

丘陵赤红壤降雨入渗产流模型及其变化特征

在分析南亚热带丘陵赤红壤降雨入渗和产流过程基础上 ,依据田间实测资料 ,建立了丘陵赤红壤降雨入渗产流数学模型 ,分析了南亚热带丘陵赤红壤地表径流的动态变化特征及其影响因素。结果表明 ,丘陵赤红壤区 ,4～ 9月每次降雨产生的径流量变化范围为 0 .2～ 5 1.0 4m m,径流率变化范围为 0 .5 6 %～ 47.5 8% ,10月至次年 3月一般不产生地表径流 ;地表径流量与降雨量拟合关系式为 R0 =0 .0 2 5 9.Pn1 .40 34 ,径流率与土壤表层初始含水量拟合关系式为 R′0 =9.8788W7.770 2 ,而降雨强度对径流量的影响要比降雨量、土壤表层初始含水量小得多。     

Grain yield increases in wheat and barley to nitrogen applied after transient waterlogging in the high rainfall cropping zone of western Australia

Nitrogen (N) is a major factor limiting grain production in the high rainfall zone (HRZ, 450–700 mm annual average rainfall of southwestern Australia (SWA). Transient waterlogging and leaching of applied N fertilizer are hazards faced in most years by crop producers. The major crops are wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), canola (Brassica napus L.) and lupin (Lupinus angustifiolius L.) grown in rotation. Two series of experiments involving, levels and timing of N fertilizer application and levels of plant population were done. The first series, in 2003–2004, consisted of 3 experiments in 3 growing seasons (early May to late-October) to measure the grain yield (GY) increase (response) of wheat and barley to various methods of N fertilizer application (methods of split N application were compared to N applied at sowing). The aim of the experiments was to determine the optimal N fertilizer application strategy for maximum GY and quality in situations where transient waterlogging was a frequent occurrence. The second series of four experiments, from 2007–2009, measured the GY of wheat sown at three levels of plant population to 4 levels of N applied after transient waterlogging (taken to be rainfall events in which >25 mm of rain was recorded in 24 to 48 hours).

Applying the N fertilizer after high rainfall and transient waterlogging (tactical N application) increased GY and protein percentage of grain compared to applying all of the N fertilizer at sowing. Where transient waterlogging was not frequent, applying the N after waterlogging was not always better than applying part of the N according to growth stage of the crop or according to fixed times after sowing. When the crop was water-logged three or more times, N uptake by the crop at anthesis and apparent fertilizer N recovery in the crop was substantially increased by applying the N after waterlogging compared to applying the entire N at sowing. This study found that a tactical N management strategy for the HRZ of SWA is to apply some N at sowing with subsequent applications made after heavy rainfall that leads to transient waterlogging. Split N fertilizer applied either according to time after sowing or to growth stage of the crop was equally effective for increasing GY in situations where waterlogging was less frequent.

The observation from these experiments, that grain yield increases due to splitting the N dose were associated with increases in ear numbers, lead to a further set of experiments where plant population was increased in conjunction with N applied after waterlogging events. The combined strategy of increased plant population with strategic N application decreased the amount of N required for maximum GY where more than 3 heavy rainfall events occurred in a growing season.

One practical outcome of this research is to indicate that farmers can withhold applications of N fertilizer after sowing in seasons when transient waterlogging does not occur.     

玉米茎秆汁液防治坡面土壤侵蚀的室内模拟试验

该文通过室内人工模拟降雨试验,研究了地表施加玉米茎秆汁液对降雨产流产沙强度的影响,旨在探索玉米茎秆汁液是否可以作为土壤改良剂来减少产流产沙强度。试验设计了2种玉米茎秆汁液的施加量(400和800 g)、4种施加浓度(10%、25%、50%和75%)和4种降雨强度(50、25、75、100 mm/h)。结果表明,各施加浓度和施加量的玉米茎秆汁液都能够减少降雨产流产沙强度,且相同条件下的产沙强度减小程度大于产流强度减小程度。当玉米茎秆汁液的施加量为400 g时,随着施加浓度从10%增加至25%、50%和75%,减流百分比分别为31.243%、31.685%、34.595%和39.475%,减沙百分比分别为23.167%、41.993%、37.918%和64.606%;当玉米茎秆汁液的施加量为800 g时,随着施加浓度从10%增加至25%、50%、75%,减流百分比分别为37.583%、56.433%、63.170%和76.360%,减沙百分比分别为48.214%、77.219%、88.572%和95.539%。当施加量和降雨强度相同时,产流产沙强度与施加浓度之间呈显著的指数函数递减关系,产沙强度随降雨强度的变化呈显著的幂函数递增关系。当施加量为400 g时,各施加浓度下的产流强度与降雨强度之间呈显著的线性函数递增关系,当施加量为800 g时,各施加浓度下的产流强度随降雨强度呈显著的指数函数递增关系。研究为水力侵蚀的防治提供了新思路,为水蚀荒漠化的防治提供了新方法。     

延河水沙变化分析

延河甘谷驿水文站以上水土流失面积５８９１ｋｍ２，年均侵蚀模数８０００ｔ／ｋｍ２。该流域自５０年代开展水土保持综合治理，截至１９８９年底止，已完成水土保持综合治理面积２５９３．６ｋｍ２，治理程度达４４％。采用水文法、水保法分析河流水沙变化，与非治理时段１９５６～１９６９年相比，治理期７０～８０年代年均减沙２６４０万ｔ，减少了４０％，其中降雨偏枯影响占８％，下垫面影响占９２％；治理期内年均减水０．４４亿ｍ３，减少了１７．５％，其中降雨影响占２３．８％，下垫面影响占７６．２％。在下垫面减沙减水中，水土保持措施的作用分别占７２．７％和５０．６％。     

不同雨强条件下红壤坡地养分流失特征研究

采用人工模拟降雨装置 ,对红壤坡地养分流失特征进行了试验研究 ,结果表明 :在雨强较大情况下 ,土壤养分以泥沙形式随径流迁移 ;当雨强较小时 ,随径流迁移的可溶态养分流失量占流失泥沙养分量的比例较高 ,土壤养分流失氮、磷、钾分别达到 5 3.12 % ,2 3.1% ,2 1.5 % ;不同形态的养分在流失泥沙中均有养分富集现象 ,但富集率各不相同 ;土壤养分流失量与雨强及泥沙流失量呈正相关关系。