浅谈无人机遥感技术在土地整治项目中的应用

随着科学技术水平不断推进,计算机技术与遥感技术等有机结合,无人机遥感技术凭借其轻便、高效、精确的数字地形测绘技术被广泛应用于各类工程领域,本文结合土地整治项目对无人机遥感技术发展现状以及在土地整治项目中的应用优势和特点进行研究分析,并探讨了无人机遥感技术应用在土地整治项目中的优势和不足,无人机遥感技术虽能提供基础的数据资料和技术支持,但项目实施中仍要对部分区域进行必要的实地核查。     

涌泉根灌湿润体水氮运移特性试验研究

在陕北米脂山地微灌枣树示范基地原状土上进行了涌泉根灌肥液入渗试验,研究了湿润体特征值的变化规律及水氮运移特性.〖JP+1〗结果表明：涌泉根灌入渗能力随肥液质量浓度增大而增大,累积入渗量与入渗时间的关系符合Kostiakov模型;竖直剖面的水平和垂直方向上的湿润锋运移速度均随肥液质量浓度增大而增大,并与时间均呈良好的幂函数关系.肥液质量浓度越大,涌泉根灌相同时间内湿润体的湿润深度越深,相同位置处的土壤质量含水率越大.清水与不同肥液质量浓度的涌泉根灌土壤平均质量含水率分布规律类似,肥液质量浓度越大,相同土层深度的质量含水率越大.在一定施肥条件下,涌泉根灌肥液入渗相同深度处NO-3-N与NH+4-N质量比均随肥液质量浓度增大而增大,经过水分再分布,均于土层深度70 cm处接近本底值.     

2种水分生境下红砂叶片功能性状的响应及适应机制

干旱是中国西北荒漠生态系统的主要特点之一，干旱对植物的生长、发育、繁殖及分布等产生重要的影响。红砂是广泛分布在我国温带荒漠草原生态系统中的优势种和主要建群种之一，对多种环境胁迫尤其是干旱胁迫具有极强的耐受性。因此，研究红砂对不同水分生境的响应及适应机理有着重要的科学意义。对不同水分条件自然生境中(小红山地区和长流水地区)的红砂叶片形态、表皮微形态及超微结构进行分析，揭示红砂适应干旱胁迫的叶片形态结构特征。结果表明，随着生境中土壤含水量的降低，红砂叶片厚度增大，叶面积及气孔开度减小，角质层增厚，从而降低植物蒸散过程中体内水分的散失。表皮细胞面积减小，表皮细胞密度增大，细胞壁增厚，增加了表皮细胞弹性，有助于降低干旱胁迫下植物失水造成的机械损伤。与此同时，栅栏组织增厚，且细胞排列更加致密，海绵组织的厚度减小，在一定程度上促进叶片的光合作用进行。因此，红砂叶片的形态结构特点使其对干旱具有极强的耐受性。研究揭示了荒漠植物红砂的叶片形态结构对不同水分条件的响应，为理解荒漠植物对水分限制的响应机制提供数据支持。     

生物炭对砒砂岩与沙复配土壤理化性状及辣椒生长的影响

为探究生物炭对砒砂岩与沙复配土壤肥力提升和作物生长的影响。通过盆栽试验,研究不同添加量的生物炭对辣椒生物学性状、产量以及复配土壤理化性状的影响。结果表明:复配土比例为1∶1时,A2处理使茎叶鲜质量、干质量增加81.4%、80.5%,单果长、单果茎粗增加15.1%、21.0%,土壤有效磷含量增加11.08 mg·kg-1,对土壤pH和全盐量影响不大。复配土比例为1∶2时,B2处理下果实鲜质量、干质量增加39.7%、40.2%,茎叶鲜质量、干质量增加28.1%、29.5%、根鲜质量、干质量增加35.0%、22.0%,单果长、单果茎粗分别增加12.1%、13.0%,单株结果数增加119.8%,产量最高且土壤pH和盐分变化不大。复配土为1∶5时,添加生物炭对辣椒生长发育和产量积累产生抑制。因此,该试验条件下,建议1∶1和1∶2的复配土生物炭添加量为2%,1∶5的复配土不建议施用生物炭。     

涌泉根灌不同浓度肥液入渗特性及土壤湿润体模型研究

为了研究涌泉根灌肥液入渗特性及湿润体水氮运移的变化规律,在陕北米脂山地微灌枣树示范基地原状土上进行了涌泉根灌肥液入渗试验。结果表明:累积入渗量与入渗时间之间符合Kostiakov幂函数关系(R20.9,P0.01);涌泉根灌入渗能力与增渗效果均随肥液浓度增大而增大;水平湿润锋与竖直湿润锋运移距离均随肥液浓度增大而增大,且均与入渗时间呈显著的幂函数关系,水平方向和竖直方向的湿润锋运移距离的拟合值与实测值的相对误差在–3.84%～5.20%以内。肥液浓度的不同对于湿润体大小略有影响。提出了涌泉根灌肥液入渗湿润体内土壤含水率和NH_4~+-N浓度分布的数学模型,即在一定浓度范围内,单位含水率的变化可引起的肥液浓度变化,且模型的计算精度较高(模拟值与实测值相对误差在10%以内),并符合湿润体内土壤含水率和NH_4~+-N分布规律,可对不同位置处土壤含水率及NH_4~+-N含量进行估算。水分分布情况对肥液浓度条件敏感性较低,NH_4~+-N分布情况对肥液浓度条件敏感性较高。研究可为涌泉根灌水肥高效利用提供参考。     

Effect of Humic Acid on the Nitrate Removal by Strong Base Anion Exchanger Supported Nanoscale Zero-valent Iron Composite

To probe the effect of common coexist substances on the nitrate removal by polymeric resin supported nanoscale zero-valent iron composite (D201-nZVI), humic acid (HA) was added into the nitrate removal system to elaborate the different interactions between each two and among all in the system including HA, nitrate, and D201-nZVI. The results showed that the effect of HA on the reduction of nitrate by D201-nZVI was concentration-dependent. At low HA concentration (<?5 mg/L), HA coating formed by the HA adsorption on the surface of the nZVI particles enhanced the dispersion of the particles, which led to a more evenly distribution of nZVI particles in the solution, and thus a higher nitrate reduction activity. When HA concentration was increased to 5 mg/L or more, the competitive adsorption of HA and NO₃^? on the surfaces of the D201-nZVI dominated, and the nitrate removal rate and ammonia nitrogen production were decreased. When the HA concentration reached to a further high level (>?20 mg/L), HA acted as an electron shuttle to accelerate the reduction of Fe(III) to Fe(II) in the D201-nZVI, and thus the nitrate reduction rate was accordingly enhanced. The ammonia production increased by 24.8% at HA concentration of 40 mg/L as compared with that of the control (without addition of HA). This research elucidated the interaction of HA within different HA concentration in the complicate system of anions removal by organic support-nanoscale metal particle composite, which may shade some new light on the potential application of nanoscale zero-valent materials in the practical remediation of natural water.     

Natural vegetation restoration of Liaodong oak (Quercus liaotungensis Koidz.) forests rapidly increased the content and ratio of inert carbon in soil macroaggregates

The lack of clarity of how natural vegetation restoration influences soil organic carbon (SOC) content and SOC components in soil aggregate fractions limits the understanding of SOC sequestration and turnover in forest ecosystems. The aim of this study was to explore how natural vegetation restoration affects the SOC content and ratio of SOC components in soil macroaggregates (>250 μm), microaggregates (53-250 μm), and silt and clay (<53 μm) fractions in 30-, 60-, 90- and 120-year-old Liaodong oak (Quercus liaotungensis Koidz.) forests, Shaanxi, China in 2015. And the associated effects of biomasses of leaf litter and different sizes of roots (0-0.5, 0.5-1.0, 1.0-2.0 and >2.0 mm diameter) on SOC components were studied too. Results showed that the contents of high activated carbon (HAC), activated carbon (AC) and inert carbon (IC) in the macroaggregates, microaggregates and silt and clay fractions increased with restoration ages. Moreover, IC content in the microaggregates in topsoil (0-20 cm) rapidly increased; peaking in the 90-year-old restored forest, and was 5.74 times higher than AC content. In deep soil (20-80 cm), IC content was 3.58 times that of AC content. Biomasses of 0.5-1.0 mm diameter roots and leaf litter affected the content of aggregate fractions in topsoil, while the biomass of >2.0 mm diameter roots affected the content of aggregate fractions in deep soil. Across the soil profiles, macroaggregates had the highest capacity for HAC sequestration. The effects of restoration ages on soil aggregate fractions and SOC content were less in deep soil than in topsoil. In conclusion, natural vegetation restoration of Liaodong oak forests improved the contents of SOC, especially IC within topsoil and deep soil. The influence of IC on aggregate stability was greater than the other SOC components, and the aggregate stability was significantly affected by the biomasses of litter, 0.5-1.0 mm diameter roots in topsoil and >2.0 mm diameter roots in deep soil. Natural vegetation restoration of Liaodong oak forests promoted SOC sequestration by soil macroaggregates.     

Soft rock for improving crop yield in sandy soil in the Mu Us desert,China

Soft rock efficiently retains water because it is hard when dry but expands rapidly when wet, thus it can be used as a natural water retention agent. Therefore, soft rock can be blended with sandy soil to enhance the water-holding capacity of sandy land. Understanding how soft rock content in sandy soil affects corn growth (Zea mays L.) is essential for enhancing local agricultural production in the Mu Us Desert. The Root Zone Water Quality Model 2 was calibrated and validated based on 2-years of experimental data for composite soils prepared at three ratios of soft rock to sand (1:1, 1:2, and 1:5 v/v), and then used to estimate the water non-limiting potential yield (Yp) and the potential yield of a rainfed crop [Yp(r)], along with yield gap [YG(r)] of corn using the weather data from 1990 to 2013 in the Mu Us Desert. The mean simulated Yp(r) of corn in the compound soil at a ratio of 1:2 was significantly higher than that of the compound soil at 1:1 and 1:5 ratios, respectively. The mean simulated Yp(r)s of corn were 2.551, 3.527, and 2.924?Mg ha^?1 and the YG(r)s were 6.071, 5.096, and 5.698?Mg ha^?1 for 1:1, 1:2, and 1:5 ratios, respectively. The crop yield depends on the amount of soft rock added to the sandy soils.     

黄土丘陵沟壑区沟道造地土壤养分变化特征及评价

[目的] 研究黄土丘陵沟壑区治沟造地工程后沟道土壤养分的变化特征，为该区改进土地整治方法，采取合理耕种管理措施及提高养分资源利用率提供科学依据。[方法] 以陕西省延安市典型治沟造地项目区土壤为研究对象，采用统计分析方法，分别对项目区整治前、整治后2，3，6 a土壤有机质、全氮、有效磷、速效钾4个指标的变化特征进行分析，并采用物元模型对其进行综合评价。[结果] ①除速效钾外，研究区土壤养分含量普遍较低；沟道中土壤养分变异程度较大，属中等变异程度，土地整治后，沟道中各种养分变异系数有变小的趋势。②沟道土地整治后6 a时间内，随工程实施年限的增加，土壤有机质含量呈现出先减少后增加的趋势，6 a时含量低于整治前；土壤全氮和有效磷含量呈现先增加后减少的趋势，6 a时高于整治前；土壤速效钾含量持续降低。③沟道土地整治后3 a，土壤养分评价等级恢复到整治前水平，且有继续提高的潜力。[结论] 与坡面土地整治相比，黄土丘陵沟壑区沟道造地土壤养分恢复时间更短，可根据沟道不同位置土壤养分变异特征，调整沟道作物空间布局，实施不同程度和方法的管理措施，增加粮食产量。     

沙质河漫滩地土壤质量提升技术研究

【目的】研究沙质河漫滩地土壤质量提升技术,探索覆土改良措施对该地区土壤地力提升效益。【方法】通过对沙质河漫滩进行覆土,研究覆土材料的理化性质,进一步分析了其对土壤速效养分的影响。【结果】①覆土土壤田间持水率沙土高于黄土,黄土是沙土的1.88倍,表明黄土的保水特性远高于沙土。②通过水分特征曲线分析,黄土体积含水率高于沙土,黄土体积含水率在下降至14%以后趋于稳定,沙土饱和导水率在下降至5%以后趋于稳定,表明黄土持水性能高于沙土。③在水稻抽穗期和成熟期,表层土壤有效磷量显著高于底层,且差异显著。水稻成熟期土壤速效钾除表层量较高外,其余各土层量均较低,其中20～30 cm土层速效钾量较水稻抽穗期的量显著降低。④土壤有效磷与土壤有机质显著相关,与土壤黏粒量显著相关;有机质与土壤有效磷和速效钾著正相关。【结论】沙地覆盖黄土后土壤质量得到改善,土壤保水保肥能力显著提升。