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1.
岩溶区和碎屑岩区林地和农田土壤氮矿化过程对比研究 总被引：1，自引：1，他引：0
通过15N标记法和MCMC氮素转化模型,研究了岩溶区（石灰性土壤）和碎屑岩区（红壤）林地和农田土壤易分解有机氮矿化（M易）、难分解有机氮矿化（M难）和总有机氮矿化（M总）速率。结果发现,土壤矿化速率受土壤类型和土地利用方式的显著影响。林地石灰性土壤M总（3.71 mg N/kg）显著低于林地红壤（5.57 mg N/kg）,石灰性土壤MNlab（1.81 mg N/kg）与MNrec（1.90 mg N/kg）相近,而红壤M易（4.60 mg N/kg）显著高于M难（0.96 mg N/kg）。林地变为农田后,石灰性土壤M总 显著提高,而红壤显著降低。与林地相比,岩溶区农田土壤M易提高了72.5%,而M难下降了33.7%。碎屑岩区农田土壤M易和M难分别降低至2.47和0.46 mg N/kg。岩溶区土壤CaO和MgO含量与M易呈显著负相关,而与M难呈显著正相关,表明岩溶区土壤钙镁含量是影响氮矿化速率的重要因素。 相似文献
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通过野外采样调查分析,运用地统计学方法,分析了北碚区土壤有机碳（SOC）的分布特征和表层土壤有机碳的影响因素。结果表明:空间上,从表土层到底土层SOC含量依次降低,且差异显著,降幅依次为35.02 %和47.12 %;时间上,与1984年第二次土壤普查相比,从表土层到底土层土壤有机碳的含量呈增加趋势,增加幅度分别为:4.36 %,31.92 %和14.74 %。对表层土壤有机碳的影响因素进行了分析,发现SOC含量随着土壤中全氮、碱解氮、黏粒含量的增加而增加;含有碎屑岩的碳酸盐岩比纯碳酸盐岩形成的土壤有机碳含量高;随着海拔的升高SOC含量增大,表现为:山顶(21.94 g/kg)＞平坝(19.53 g/kg)＞槽谷(15.60 g/kg)＞山腰(13.40 g/kg);不同土地利用方式下的SOC含量高低顺序为:林地(26.16 g/kg)＞草坡(21.95 g/kg)＞菜地(16.75 g/kg)＞果园(15.31 g/kg)＞耕地(12.85 g/kg)。传统的耕作方式容易造成SOC损失,建议在岩溶山地通过退耕还林还草、坡改梯、增施有机肥增加土壤有机碳;推广应用免耕、少耕、秸秆还田等耕作措施,增加农田土壤固碳能力。 相似文献
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新疆天山西部巩乃斯河谷积雪与森林/草地 覆盖条件下季节冻土特征分析 总被引：1，自引：0，他引：1
不同的覆盖条件下,季节冻土的特征会存在差异。为了分析积雪与森林/草地覆盖条件下季节冻土的特征,在新疆天山西部巩乃斯河上游的中国科学院天山积雪雪崩研究站的实验场地监测了森林-积雪,草地-积雪,以及草地覆盖条件下季节冻土的冻结深度,并对有无积雪覆盖条件下季节冻土发育过程中的土壤温度和土壤含水量进行了跟踪测量。结果表明：森林-积雪覆盖条件下季节冻土的冻结深度最浅,草地-积雪覆盖条件下次之,草地覆盖条件下最深。积雪的存在可以改变季节冻土的冻结深度,还会影响土壤温度和土壤含水量变化。在季节冻土的发育阶段,积雪的隔热作用使得有积雪覆盖条件下土壤温度和土壤含水量较高;在积雪消融阶段,由于积雪融水的补给,土壤含水量也相应地增加,积雪消失后由于蒸发的存在导致土壤含水量减少。 相似文献
4.
珠江三角洲平原广东省佛山市顺德区土壤-蔬菜系统中Pb的健康安全预测预警 总被引：4，自引：0，他引：4
分析珠江三角洲顺德区208个蔬菜地表层土样、114个蔬菜样Pb的全量和38个表层土样Pb的形态含量,结果表明,土壤Pb平均值为44.3mg/kg,77.5%的土壤Pb含量超过广东省土壤背景值,蔬菜Pb超标率为74.6%。用2007年蔬菜土壤Pb的累积速率(1.02mg/kg),预测未来10年土壤Pb含量变化趋势,并分别以150、270、300和8580(mg/kg)为阈值对土壤中Pb进行预警,2007—2017年超过150mg/kg的土壤面积比例有所增加,而超过270mg/kg、300mg/kg的土壤面积比例不变。蔬菜Pb与土壤Pb的全量或有效量之间均存在"高原模式"。蔬菜Pb的空间分布表明,3种蔬菜Pb的高浓度主要位于工业比较发达的城镇,这与土壤Pb的空间分布大体一致。经蔬菜途径吸收Pb的THQ靶标危害系数不超过0.4。不同区域、家庭经济收入水平的THQ排序:THQ高THQ城市THQ中THQ农村THQ低,表明经济收入水平高的家庭经蔬菜途径摄入Pb的健康风险最高。 相似文献
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为探寻干旱半干旱区棉花微咸水膜下滴灌灌溉制度,在南疆地区开展了田间试验,对比分析了水分胁迫及盐分胁迫处理棉花的产量及长势,探讨了膜下滴灌条件下棉花对水盐胁迫的响应。试验采用WDY-500A微电子叶面积测量仪测定叶面积,并进行人工测产,采用原子吸收仪和滴定法测定土壤盐分。结果表明,轮灌处理A(苗期灌淡水)产量最高,为5 427kg/ha,其次是处理C(花铃前期灌淡水),为4 819.5kg/ha;棉花生育期对水分亏缺的敏感性为:花铃前期>蕾期>花铃后期;对盐分胁迫的敏感性为:苗期>蕾期>花铃前期>花铃后期;灌水总量越大,棉花株高越高,叶面积指数也越大;某时段出现水分亏缺,该时段株高和叶面积指数增长幅度减小;越早给棉花灌溉淡水,棉花株高越高,叶面积指数越大;膜下滴灌条件下,淡水灌溉可以有效淋洗棉花根区土壤多余盐分,保证土壤环境安全,但是微咸水灌溉对棉花根区盐分淋洗效果不佳,且对土壤环境有一定的危险性,需在适当时期(如非生长期)采用较大灌水定额洗盐。 相似文献
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岩溶高原区农业地膜中邻苯二甲酸二乙基己酯的释放及其对覆膜土壤的影响 总被引：1，自引：0，他引：1
随着邻苯二甲酸酯类(PAEs)增塑剂在塑料大棚、地膜覆盖栽培技术中的广泛应用,我国农业土壤中已普遍存在邻苯二甲酸二乙基己酯(DEHP)污染问题。针对我国中西部岩溶高原区农业土壤中存在的DEHP环境问题,本文选取云南岩溶高原区的红壤及烟草地膜作为研究对象,通过田间试验模拟覆膜土壤环境,并采用气相色谱-质谱分析法检测农膜、土壤介质中DEHP含量,定量研究了地膜中DEHP的释放及其在覆膜土壤中的浓度分布特征。结果表明:覆盖于原状土壤上的地膜,其DEHP释放量最大,均值为13.57mg/kg;覆盖于加生物抑制剂土壤上的地膜,其DEHP释放量略高于未覆土壤地膜,前者DEHP平均值为10.83mg/kg,后者为10.77mg/kg;地膜中DEHP的释放表现为缓慢释放和集中陡升两个释放段,总体释放量随时间的延长而增加。两组覆膜土壤中DEHP的检出浓度范围分别为0.17～3.74mg/kg(原状土)、0.34～4.29mg/kg(加生物抑制剂土壤),在国内外覆膜农田土壤PAEs类化合物检出浓度范围内;土壤中DEHP含量具有随时间呈先增后减的变化规律。相关性分析表明土壤中DEHP主要来自于地膜中DEHP的释放。研究认为在短周期内岩溶高原红壤不会出现DEHP的累积,合理安排农作物的覆膜种植可有效削减土壤的有机污染。 相似文献
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选取桂林丫吉试验场岩溶石山坡面上典型覆盖土壤的两个单元体为对象,对其土壤剖面层含水量的分布变化、土壤蒸发速率大小及其相关影响因素进行分析研究,结果表明:(1)土壤剖面最大含水率层位于土壤底部与基岩的交界处,中间过渡层土壤含水量最少,表层土壤水分受外界因素影响而变化显著;(2)在夏季岩溶石山区地表蒸发强烈,直径10cm的土壤柱日蒸发量为5~12mL之间,夜蒸发量在0~3mL之间;(3)几天内决定地表土壤日蒸发量(y)大小的因素主要是太阳辐射(x2)和土壤温度(x4),其关系式可表示为:y=18.018+0.001x2-0.691x4。 相似文献
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长期施肥对土壤颗粒粘粒矿物组成及其演变特征的影响 总被引：1，自引：0，他引：1
在湖北省武穴市长期定位试验的基础上,取不同施肥处理(施氮磷钾处理/NPK,氮磷钾-秸秆配施处理/NPKS)和荒地(HD)的土样,分离其耕层土壤(0～20 cm)不同粒级(2000 nm与450～2000、100～450和25～100 nm三个粒级)的土壤颗粒,并分析各粒级颗粒中粘粒矿物组合和氧化物的差异,揭示不同施肥措施下农田土壤颗粒中粘粒矿物的变化特征。结果表明,不同施肥处理土壤粘粒矿物的组成一致,均以高岭石为主,并都含有蛭石、HIV(1.4 nm过渡矿物)和伊利石,且随颗粒粒径减小矿物从2:1型向1:1型过渡;与荒地土壤相比,施氮磷钾处理中伊利石和蛭石减少,HIV增加,而氮磷钾-秸秆配施处理中则是伊利石减少,蛭石和HIV增加。随粒径减小,3种土壤颗粒中SiO_2和Fe_2O_3含量逐渐降低,Al_2O_3含量逐渐增加,其中各粒级颗粒的硅铝率和硅铁铝率也逐渐降低;与荒地土壤比,施氮磷钾和氮磷钾-秸秆配施处理各粒级颗粒的元素组成无明显变化,而硅铝率和硅铁铝率却有明显提高。3种土壤颗粒中游离态铁、铝含量的顺序为HDNPKSNPK,与铁游离度的变化规律一致,但非晶形铁、铝含量和铁的活化度变化不明显。各形态铁、铝氧化物的含量均随粒径减小而逐渐增大,与铁的游离度和活化度的变化规律一致。 相似文献
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分析珠江三角洲顺德区208个蔬菜地表层土样、114个蔬菜样Pb的全量和38个表层土样Pb的形态含量,结果表明,土壤Pb平均值为44.3mg/kg,77.5%的土壤Pb含量超过广东省土壤背景值,蔬菜Pb超标率为74.6%。用2007年蔬菜土壤Pb的累积速率(1.02mg/kg),预测未来10年土壤Pb含量变化趋势,并分别以150、270、300和8580(mg/kg)为阈值对土壤中Pb进行预警,2007—2017年超过150mg/kg的土壤面积比例有所增加,而超过270mg/kg、300mg/kg的土壤面积比例不变。蔬菜Pb与土壤Pb的全量或有效量之间均存在“高原模式”。蔬菜Pb的空间分布表明,3种蔬菜Pb的高浓度主要位于工业比较发达的城镇,这与土壤Pb的空间分布大体一致。经蔬菜途径吸收Pb的THQ靶标危害系数不超过0.4。不同区域、家庭经济收入水平的THQ排序：THQ高>THQ城市>THQ中>THQ农村>THQ低,表明经济收入水平高的家庭经蔬菜途径摄入Pb的健康风险最高。 相似文献
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Plastic film mulching is widely employed to improve crop yields. Mulching for the entire crop growth period is a widespread practice. However, a shorter plastic film mulching duration is suggested for obtaining larger grain yield recently. To quantify the effects of plastic film mulching durations on soil erosion and nutrient losses, a three-treatment experiment with three replicates was constructed in field. The designed treatments were control (M0, non-mulched treatment), mulching from sowing to the end of the peanut pod-setting stage (M1) and pod-filling stage (M2). Plastic film mulching significantly increased the mean runoff and sediment yield. With film mulching, the mean runoff and soil losses among M1 and M2 treatments had no significant difference, and significantly larger than that in M0 treatment. After mulching removing, there were no significant differences between the mean runoff and soil losses of M0 and M1 treatments. Compared with the M2 treatment, the M0 treatment had significantly reduced mean runoff and soil losses of all the events. Non-mulching increased the total nitrogen (TN) and total phosphorus (TP) losses. The M0 treatment had the highest TN (23.0 mg m?2) and TP (3.02 mg m?2) losses in the three treatments. The M2 treatment significantly reduced the TN and TP losses. In conclusion, mulching from sowing to the end of pod-setting stage was suggested as the appropriate choice for the largest yield and less soil erosion. But, some soil conservation measurements should be taken in furrow areas to effectively reduce soil erosion, under the condition of film mulching. 相似文献
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Research on the effect of straw mulching on the soil moisture by field experiment in the piedmont plain of the Taihang Mountains 
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下载免费PDF全文 To reveal the influencing effect of the long-term straw mulching on the soil moisture, this paper employed the field experiment data in 2010 of a typical area of Taihang Mountains plain, observed the soil moisture dynamic regularities under different mulching patterns by virtue of depressimeter and neutron probe, analyzed the characteristics of soil water content and storage in different depths and seasons under the long-term straw mulching. The results showed that the long-term straw mulching can keep the soil moisture conservation of the deep, while decreased the shallow. (1) The long-term straw mulching can changed the type of soil water movement. If no straw mulching, the type is mainly evaporation-infiltration. And with straw mantle the type would change into infiltration. The number of zero flux plane would be reduced or absent. (2) The long-term straw mulching can increase the soil water reserves of the whole soil profile with the depth between 0 cm and 220 cm. But the soil water content of the layer from 30 cm to 80 cm decreased and the soil water content of the layer from 80 cm to 220 cm increased instead., The effect of soil moisture conservation on winter wheat is not obvious; (3) With no straw mulching, the depth of infiltration recharge by rainfall or irrigation is shallower than 80 cm. In a straw mulching, the influence depth is can extend to 120 cm; (4) With no straw mulching , there is a deep layer on the depth of 220 cm between March and June, while this layer will disappear with a long-term straw mulching. 相似文献
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Effects of straw mulching on soil evaporation during the soil thawing period in a cold region in northeastern China 总被引：1，自引：0，他引：1
To study the effect of straw mulching on soil water evaporation, it is necessary to measure soil water evaporation under different conditions of straw mulching during the soil thawing period. A field experiment was conducted in winter, and soil evaporation was measured using a microlysimeter on bare land (LD) and 4500 (GF4500), 9000 (GF9000) and 13500 \(\hbox {kg/hm}^{2}\) (GF13500) straw mulch. The influence of different quantities of straw mulch on soil water evaporation during the thawing period was analyzed using the Mallat algorithm, statistical analysis and information cost function. The results showed that straw mulching could delay the thawing of the surface soil by 3–6 d, decrease the speed at which the surface soil thaws by 0.40–0.80 cm/d, delay the peak soil liquid water content, increase the soil liquid water content, reduce the cumulative evaporation by 2.70–7.40 mm in the thawing period, increase the range of soil evaporation by 0.04–0.10 mm in the early stage of the thawing period, and reduce the range of soil evaporation by 0.25–0.90 mm in the late stage of the thawing period. Straw mulching could reduce the range of and variation in soil evaporation and can reduce the effect of random factors on soil evaporation. When the amount of straw mulch exceeded 9000 \(\hbox {kg/hm}^{2}\), the effect of increasing the amount of straw mulch on daily soil water evaporation was small. 相似文献
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基于膜下滴灌特有的"膜中"、"膜间"、"膜边"、"膜外"微区环境,利用2011—2013年田间对比试验方法获取的5 960个数据,运用柯布-道格拉斯模型,构建膜下滴灌环境土壤层次、灌水定额、土壤水分、气温、蒸发综合因素与土壤水盐关系及影响效应分析模型.结果表明,在气候干旱、蒸发强烈灌区,地膜覆盖与滴灌结合的地表介面灌溉形式下,土壤水盐具有水平方向由"膜中"向"膜边"地表裸露区定向迁移,垂直方向土壤水盐则由下向上层运移且趋于"膜外"边界积累的趋势,尤其是气温与蒸发因素交互作用,推进膜下滴灌土壤水盐在地膜覆盖与土壤裸露区域空间运移,研究结果进一步揭示了膜下滴灌"土壤水盐定向迁移"形成机理,为膜下滴灌土壤水盐地表排放模式应用提供了依据. 相似文献
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Study on Movement Evolution Law of Soil Water in Condition of Agronomic Water Saving Irrigation 下载免费PDF全文
下载免费PDF全文 Fresh water supplied are often limited in mainland China, reducing agricultural productivity. However the use of straw mulch is the main management technique for agronomic water saving. This paper investigates the movement of soil water under straw mulch compared to a non-mulch test plot. Results demonstrated that straw mulch effected soil water movement primarily during drought periods and throughout shallow soil (i.e. depths of less than 200 cm). The soil moisture and soil water potential at the mulch test plot in drought period are both higher than that of contrast test plot, and along with increasing soil depth, the straw mulch effect weakens. When evaporation is dominated by surface evaporation, straw mulch will effectively restrict the evaporation of soil water; when evaporation dominated by vegetation transpiration, the straw mulch promotes the transpiration of vegetation. In drought periods, straw mulch is not effective for deep soil water infiltration, but is advantageous for soil water utilization of mid- and shallow- soils (0-120 cm), however the infiltration speed rate of straw mulch point during high water period is higher than that of contrast plot. This paper highlights the importance of good management practices of agricultural land in order to limit soil water losses, which is essential when water is such a limited resource. 相似文献
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通过对陕北毛乌素沙地不同农业措施土壤水分的观测分析,揭示出沙区土壤水分受补(灌)水量与农业措施如地下衬垫与地表覆盖的双重影响与控制,地下衬膜和地表覆膜抑渗、抑蒸保墒效应促进了土壤--作物--大气连续体系中水分有效循环,增加了耕层土壤贮水量,加大植物可利用的土层水分,从而使苜蓿增产,并可节水32%～40%,为沙区推广地下衬垫(膜)与地表覆盖(膜)节水技术提供科学依据. 相似文献
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A. Siczek M. Frąc J. Wielbo D. Kidaj 《International Journal of Environmental Science and Technology》2018,15(4):755-764
The importance of flavonoids in rhizosphere–legumes symbiosis has been recognized as critical. However, the limited data are available about their impact on soil microbial communities. In rhizosphere, it remains unclear whether flavonoids, mulch or their joint effects influence on soil microbial diversity and enzymes activity. Therefore, in this study, the effects of flavonoids and straw mulching on soil microbial functional diversity, fungi abundance and enzymes activity (dehydrogenases, protease, acid phosphomonoesterase) in pea rhizosphere were evaluated. The field study was conducted in Lublin, Poland (51°15′N, 22°35′E), on a Haplic Luvisol. Flavonoids were applied on pea seeds and after sowing soil surface was covered with straw mulch. In soil rhizosphere sampled three times during the vegetative period of pea were determined: dehydrogenases, protease and acid phosphomonoesterase activities, metabolic potential of soil bacteria, microbes number and predominant fungal species. The results showed that dehydrogenases and protease activities were significantly increased with time during pea growing season. Significant increase in dehydrogenases activity was observed after flavonoids and mulch influence. There was no impact of studied factors on acid phosphomonoesterase. The effects of flavonoids and mulch on biodiversity indices were related to sampling terms. Straw mulching increased potentially antagonistic fungi in pea rhizosphere. The results of this study can be useful in understanding the effects of flavonoids and mulch on microbial activity and dynamics in pea rhizosphere which is very important in soil quality and crop production. 相似文献
18.
覆膜时期及方式的选择对玉米的产量有很大影响,为得到玉米栽培试验的最优方案,开展秋覆膜、顶凌覆膜、春覆膜、早春揭膜覆膜、全膜二膜、以半膜(CK)为对照方式等六种不同覆膜时间及方式下对玉米产量的研究,结果显示,以早春接膜覆新膜增收增产最明显,亩产量901.2 kg,亩纯收入为1 537.4元,投产比为3.2,比半膜(CK)亩产量高出224.1 kg,亩纯收入高出495.2元,半膜的产投比仅为1.8,因此,在秋覆膜全膜双垄沟播技术的基础上,提倡早春揭膜覆新膜。 相似文献
19.