Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resources
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陕北安塞县生态与经济系统耦合协调发展
No full text协调生态环境与社会经济的均衡发展，是实现县域可持续发展的重要因素。以延安市安塞县为对象，基于社会经济与生
态环境的数据，构建安塞县社会经济系统与生态环境系统的指标体系，利用熵权法计算社会-经济-环境综合评价指数，在此基
础上利用耦合协调度模型、剪刀差方法和耦合度模型分析了社会经济系统与生态环境系统的耦合协调状态、发展速度差异以及
耦合度演变趋势。结果表明:1996—2013 年间，安塞县社会经济系统综合评价指数稳定上升，自然生态系统综合水平呈现波动
下降趋势，前者发展速度总体上快于后者;耦合协调度指数由 0．33 增长至 0．59，反映了该区域社会经济与生态环境的关系不断
改善，较好地实现了二者的协调;剪刀差在 0． 032 水平范围内波动上升，说明二者发展趋势之间的差异逐渐增大;安塞县社会经
济与生态环境的耦合度分布于 45°＜β＜90° 范围内，二者处于协调发展阶段，耦合度 β 表现为先下降后上升，说明经济与环境之
间的矛盾开始显露。研究表明，安塞县应着力加强生态建设的固基和推进作用，缓解社会经济和生态环境的矛盾，实现二者的
协调发展。</p
夏剪强度对温室葡萄果实品质的影响
No full text以陕西广泛种植的“户太 8 号”葡萄为试材，在日光温室条件下通过测定不同夏剪强度下的一次果
及二次果果实品质(可溶性糖、可溶性蛋白质、维生素 C、可溶性固形物、可滴定酸、白藜芦醇和原花青素)，
综合评定葡萄果实对不同夏剪强度的反应，以期为温室葡萄栽培管理提供指导。结果表明:夏剪强度可明
显改变结果枝一次果及副梢萌发所结二次果的品质，且各品质指标之间差异较明显。在出现二次结实的
情况下，中梢修剪提高一次果的品质，但降低二次果品质;在禁止二次结实的情况下，长梢修剪的葡萄品质
较优，虽然短梢修剪的一次果果实口感和风味较差，但果实的保健价值更高。二次果的保健价值普遍优于
一次果，但风味品质普遍较差。</p
Spatial variability of soil water content and related factors across the Hexi Corridor of China
No full textSoil water is a key factor limiting ecosystem sustainability in arid and semi-arid areas of the Hexi Corridor of China, which is characterized by an ecological environment that is vulnerable to climate change. However, there is a knowledge gap regarding the large-scale spatial distribution of soil water in this region. The specific objectives of this study were to determine the spatial distribution patterns of soil water content (SWC) across the entire Hexi Corridor and identify the factors responsible for spatial variation of SWC at a regional scale. This study collected and analyzed SWC in the 0–100 cm soil profile from 109 field sampling sites (farmland, grassland and forestland) across the Hexi Corridor in 2017. We selected 17 factors, including land use, topography (latitude, longitude, elevation, slope gradient, and slope aspect), soil properties (soil clay content, soil silt content, soil bulk density, saturated hydraulic conductivity, field capacity, and soil organic carbon content), climate factors (mean annual precipitation, potential evaporation, and aridity index), plant characteristic (vegetation coverage) and planting pattern (irrigation or rain-fed), as possible environmental variables to analyze their effects on SWC. The results showed that SWC was 0.083 (±0.067) g/g in the 0–100 cm soil profile and decreased in the order of farmland, grassland and forestland. The SWC in the upper soil layers (0–20, 20–40 and 40–60 cm) had obvious difference when the mean annual precipitation differed by 200 mm. The SWC decreased from southeast to northwest following the same pattern as precipitation, and had a moderate to strong spatial dependence in a large effective range (75–378 km). The SWC showed a similar distribution and had no significant difference between soil layers in the 0–100 cm soil profile. The principal component analysis showed that the mean annual precipitation, geographical position (longitude and latitude) and soil properties (soil bulk density and soil clay content) were the main factors dominating the variance of environmental variables. A stepwise linear regression equation showed that plant characteristic (vegetation coverage) and soil properties (soil organic carbon content, field capacity and soil clay content) were the optimal factors to predict the variation of SWC. Soil clay content could better explain SWC variation in the deeper soil layers compared with other factors.</p
不同氮肥管理下春玉米地土壤硝态氮的淋溶阻控技术与阈值研究
No full text
摘要
肥料产业的发展促进了粮食增产，保证了粮食安全供给。由于人类持续向土地投入大量化学肥料，农业面源污染负面效应逐渐凸显，给人类生存健康带来潜在风险。未来农业向着绿色、环保方向发展，对于解决农业增产与环境的平衡问题具有重要的意义。黄土高原南部旱作农业区，土层深厚而疏松，暴雨频发，为农业面源污染提供了条件。因此，在该地区研究不同的氮肥管理措施下硝态氮的淋溶特征与阻控技术，对于提高作物产量和保护生态环境具有重要的指导意义。
本试验在黄土高原南部长武农业生态试验站进行，采用完全随机区组设计，半覆膜种植，供试作物为春玉米，品种为先玉335。设置4组试验处理，每组3个重复，分别为：（1）不同施氮量，施氮量分别为0、80、100、130、160、200、250kg/hm2；（2）总施氮200kg/hm2，设置缓控肥与普通尿素不同施用比例，比例分别为35%+65%、50%+50%、65%+35%；（3）施氮200kg/hm2时，设置硝化抑制剂不同添加浓度，分别为施氮量的1%、5%、10%、15%；（4）在施氮200、250kg/hm2的基础上，采用玉米秸秆深埋措施。在缓控肥与硝化抑制剂试验处理区，采取春玉米各生育期根层土壤，测定土壤硝态氮含量。在春玉米收获期采取土壤样品和植物样，分别测定土壤硝态氮含量和籽粒产量，以确定各种氮肥管理措施对土壤硝态氮淋溶及春玉米籽粒产量的影响。试验于2017—2018年开展2年，主要结果如下：
（1）适量的施氮量促进春玉米增产，同时可降低土壤硝态氮淋溶累积。在施氮范围0～250 kg/hm2内，春玉米籽粒产量呈现先增长后下降的趋势，经函数模拟分析，施氮为227 kg/hm2时产量可达到最大。施氮量在0～160 kg/hm2时，土壤硝态氮含量保持在较低的水平，不会引起大量淋溶累积。当施氮量超过160 kg/hm2时，淋溶至深层土壤的硝态氮显著增加，导致土层0—300累积量剧增。因此，引发土壤硝态氮淋溶累积的施氮阈值为160 kg/hm2。施氮量为200 kg/hm2时，植株总吸氮量、氮素利用效率达到最大。施氮量达到250 kg/hm2时，使春玉米籽粒产量和氮素利用效率存在一定程度降低。
（2）缓控肥的施用可有效阻控土壤硝态氮的淋溶下移，减少下层土壤硝态氮的累积。各处理中，缓控肥与普通尿素施用比例为50%+50%时，淋溶至深层的土壤硝态氮最少，对土壤硝态氮的淋溶阻控效果最佳，土层0—300cm硝态氮累积量降低37.39%。缓控肥的施用降低春玉米各生育期根层土壤硝态氮含量，各缓控肥处理之间，无明显差异。缓控肥的施用一定程度上降低了春玉米籽粒产量，主要由于缓控肥在春玉米生长前期阶段肥效释放较慢，与春玉米根系对氮素的吸收不同步，降低作物总吸氮量与氮素利用效率，进而降低产量。
（3）适量的硝化抑制剂对土壤硝态氮的淋溶下移起到有效的阻控作用，减少土层硝态氮的累积。随着硝化抑制剂添加量的增加，土壤硝态氮向深层土壤淋溶的风险系数增加，同时，土壤硝态氮的累积量有增加的趋势。硝化抑制剂添加量为施氮量的1%时，土层剖面硝态氮含量最低，土层0—300cm硝态氮累积量最低(与对照对比降低55.68%)。硝化抑制剂的施用使春玉米各生育期根层土壤硝态氮含量显著降低，不同量硝化抑制剂处理之间无显著性差异。与对照相比，添加硝化抑制剂对春玉米增产没有积极作用，但适量硝化抑制剂浓度对土壤硝态氮淋溶具有抑制作用。
（4）秸秆深埋对土壤硝态氮淋溶下移可以起到有效阻控作用，降低深层土壤硝态氮累积量。施氮为200 kg/hm2时，秸秆深埋使得土层0—300cm硝态氮总累积量降低25.29%。施氮为250 kg/hm2时，秸秆深埋使得土层0—300cm硝态氮总累积量降低5.49%。同等施氮条件下，秸秆深埋提高春玉米籽粒产量，促进植株对氮肥的有效吸收，提高作物的氮素利用效率。
综上所述，在黄土高原沟壑旱作农业区，在当地气候和试验管理条件下，经数学模拟分析，施氮量达到227.38 kg/hm2时，春玉米可获得最高产量，采用秸秆深埋措施可促进春玉米提高产量。控制施氮量、采用秸秆深埋、施用缓控肥可控制土壤硝态氮的淋溶累积。施氮量1%的硝化抑制剂添加量对土壤硝态氮淋溶下移有阻控效果。
关键词：春玉米；缓控肥；硝化抑制剂；秸秆深埋；土壤硝态氮；淋溶阈值
Abstract
The development of fertilizer industry has promoted the increase of grain production and ensured the supply of food security. As human beings continue to apply a large amount of chemical fertilizers in the land, the negative effects of agricultural non-point source pollution are gradually highlighted, which brings great risks to human survival and health. In the future, agriculture will develop at the direction of green and environmental protection, which is of great significance to solve the problem of balance between agricultural production increase and environment. In the dry farming area of the Loess Plateau, the soil layer is deep and the rainfall is uneven, which provides conditions for agricultural non-point source pollution. Therefore, taking different nitrogen management measures in this area has important guiding significance for improving grain crop yield and maintaining ecological environment security.
The experiment was carried out at Changwu State Key Agro-Ecological Station. Pioneer 335, a spring maize , was planted with halfplastic film mulching,the experiment was designed by completely randomized grouping.The experiment inclueded four treatments and three replicates, they were: (1) Different nitrogen application rates, 0, 80, 100, 130, 160, 200 , 250 kg/hm2 respectively; (2) On the basis of 200 kg/hm2 nitrogen application, we set up different application ratios of slow-controlled fertilizer and ordinary urea, which took up the proportion 35%+65%, 50%+50%, 65%+35% respectively; (3) When applying 200 kg/hm2 nitrogen, we set up different nitrification inhibitor concentration, The amount of nitrification inhibitor was 1%, 5%, 10% and 15% of total nitrogen application respectively. (4) Based on the application of 200 kg/hm2 and 250 kg/hm2 of nitrogen, Measures for straw deep buried was taken. In the experimental treatment zone of Slow-Controlled Fertilizer and nitrification inhibitor , we took root soil sample and measured soil nitrate nitrogen content during the growth period of spring maize. Soil and plant samples were taken during the harvest period of spring maize,and measured soil nitrate nitrogen content and grain yield, to confirm the effects of different nitrogen managements on soil nitrate nitrogen leaching and spring maize grain yield. The experiment was carried out from in 2017-2018 for two years. The main results are as follows:
(1) Appropriate amount of nitrogen application promoted the yield of spring maize and reduced soil nitrate nitrogen leaching and accumulation. The grain yield of spring maize increased at first and then decreased within the range of 0～250 kg/hm2 of nitrogen application, and functional simulation analysis showed that the maximum yield could be achieved when nitrogen application was 227 kg/hm2. Soil nitrate nitrogen content remained at a reasonable low level when nitrogen application within the range of 0～160 kg/hm2, which would not cause a large amount of leaching and accumulation. When the amount of nitrogen applied exceeded 160kg/hm2, the soil nitrate nitrogen leached into deep soil layer significantly, resulting in a sharp increase of soil nitrate nitrogen accumulation in the soil 0-300 layer. Therefore, the threshold of nitrogen application for soil nitrate nitrogen leaching and accumulation is 160 kg/hm2. When the nitrogen application rate was 200 kg/hm2, the total nitrogen uptake and nitrogen use efficiency of the plant reached the highest level. When the nitrogen application rate reached 250 kg/hm2, grain yield of spring maize and nitrogen use efficiency were reduced.
(2) The application of slow-controlled fertilizer can effectively control the leaching of soil nitrate nitrogen, and reduce the accumulation of soil nitrate nitrogen. Among all treatments, when slow-controlled fertilizer and ordinary urea application proportion was each half, the soil nitrate nitrogen leached into deep soil layer was the least, reached the best control effect. The application of slow-controlled fertilizer reduced soil nitrate nitrogen accumulation in 0-300 cm soil layer by 37.39%. The application of slow-controlled fertilizer reduced the root layer soil nitrate nitrogen content at different growth stages of Spring Maize, and there was no significant difference among all slow-controlled fertilizer treatments. The application of slow-controlled fertilizer reduced the grain yield of spring maize, mainly because slow-controlled fertilizer efficiency released slowly in the early stage of spring maize growth, which is not synchronized with nitrogen uptake by spring maize roots, and reduced the total nitrogen uptake and nitrogen use efficiency of crops, at last reducing the spring maize yield.
(3) Appropriate amount of nitrification inhibitors can effectively prevent the leaching of soil nitrate nitrogen and reduce the accumulation of soil nitrate nitrogen. With the increase of nitrification inhibitors dosage, the risk of soil nitrate nitrogen leaching to deep soil increased, and the accumulation of soil nitrate nitrogen tended to increase. The nitrate nitrogen content in soil profile was the lowest when the amount of nitrification inhibitor was 1% of nitrogen application, and the nitrate nitrogen accumulation in 0-300 cm soil layer was the lowest（Compared with the control, it decreased by 55.68%）. The application of nitrification inhibitors significantly reduced the nitrate nitrogen content in root layer of Spring Maize at growth stages,but there was no significant difference between different amount of nitrification inhibitor treatments. Compared with the treatment without nitrification inhibitor, adding nitrification inhibitor had no positive effect on the yield of spring maize, but appropriate concentration of nitrification inhibitor had inhibitory effect on soil nitrate nitrogen leaching.
(4) Straw deep buried can effectively control the leaching of soil nitrate nitrogen, and reduce the accumulation of soil nitrate nitrogen. When nitrogen application was 200 kg/hm2, the accumulation of soil nitrate nitrogen in 0-300 cm soil layer was reduced by 25.29% due to straw deep buried. When nitrogen application was 250kg/hm2, the accumulation of soil nitrate nitrogen in 0-300 cm soil layer was reduced by 5.49% due to straw deep buried. When apply the same amount of nitrogen, the measures of straw burying can effectively improve the grain yield of spring maize, promote the absorption of nitrogen by plants, and improve the nitrogen use efficiency of crops.
In summary, under the conditions of local climate and experimental management, the maximum yield of spring maize can be obtained when the amount of nitrogen applied reaches 227.38 kg/hm2 through mathematical simulation analysis in the dry farming area of the Loess Plateau. The measure of straw deep buried can promote the yield of spring maize. the measures of controlling the amount of nitrogen applied, deep burying of straw and using slow-controlled fertilizer can control the leaching and acc
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No full text沙层特性对沙盖黄土坡面产流产沙变化贡献的定量分析
No full text沙盖黄土坡面产流产沙方式独特，侵蚀过程复杂，量化降雨过程中该类坡面产流产沙变化影响因素贡献的大小对揭示其侵蚀机理具有重要的意义。本文基于室内模拟降雨试验，定量分析沙层厚度（2 cm, 5 cm和10 cm）和粒径组成（100%粒径≤0.25 mm、75%粒径≤0.25 mm +25%粒径﹥0.25mm、50%粒径≤0.25 mm +50%粒径﹥0.25 mm、未处理原沙和100%粒径﹥0.25 mm）在降雨过程中对产流产沙变化的影响和贡献。结果显示：沙层厚度增厚能明显延长产流时间，减少总产流量，增加总产沙量，增大降雨过程中产流产沙的变异性；随沙层粒径组成变粗，初始产流时间和产沙量无明显变化规律，产流量有增大趋势。沙层厚度、粒径组成及二者交互作用对初始产流时间变化的贡献率分别为68.03%，15.77%和3.85%。沙层厚度对降雨不同时段15 min产流量和不同历时总产流量的贡献率分别在23.89%～52.22%和41.10%～48.94%之间，对相应产沙的贡献率分别在29.19%～62.01%和13.53%～30.31%之间。整体上沙层粒径组成变化对产流产沙量变化的贡献率小于沙层厚度，且无明显规律。沙层厚度和粒径组成交互作用对产流量和降雨中前期产沙量的影响显著（p< 0.05），其对产流产沙变化的贡献率分别在13.12%～26.62%和3.22%～43.12%之间，不同降雨时段变化明显。研究结果说明，沙层厚度决定沙盖黄土坡面产流产沙过程，其和沙层粒径组成对产流产沙的影响和贡献随坡面沙层的侵蚀演化而动态变化，且二者的交互作用也不容忽视。</p
Stocks and Stoichiometry of Soil Organic Carbon,
No full textThe Loess Plateau is an important region for vegetation restoration in China; however, changes in soil organic carbon (SOC), soil nutrients, and stoichiometry after restoration in this vulnerable ecoregion are not well understood. Typical restoration types, including orchardland, grassland, shrubland, and forestland, were chosen to examine changes in the stocks and stoichiometry of SOC, soil total nitrogen (TN), and soil total phosphorus (TP) at different soil depths and recovery times. Results showed that SOC stocks first increased and then stabilized in orchardland, grassland, and shrubland at 0–30 cm depths, while in forestland, SOC stocks gradually increased. Soil TN stocks first increased and then decreased in orchardland, shrubland, and forestland with restoration age at 0–30 cm depths, while soil TP stocks showed little variation between restoration types; at the same time, the overall C:N, C:P, and N:P ratios increased with restoration age. In the later stages of restoration, the stocks of SOC and soil TN at 0–30 cm soil depths were still lower than those in natural grassland and natural forest. Additionally, the SOC, soil TN, and soil TP stocks and the C:N, C:P, ndN:Pratiosdecreasedwithsoildepth. heforestlandhadthehighestrateofchangeinSOCandsoil TN stocks, at 0–10 cm soil depth. These results indicate a complex response of SOC, soil TN, and soil TP stocks and stoichiometry to vegetation restoration, which could have important implications for understanding C, N, and P changes and nutrient limitations after vegetation restoration.</p