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1.
Effect of Crop-Straw Derived Biochars on Pb(Ⅱ) Adsorption in Two Variable Charge Soils 总被引：1，自引：0，他引：1
Two variable charge soils were incubated with biochars derived from straws of peanut, soybean, canola, and rice to investigate the effect of the biochars on their chemical properties and Pb（II） adsorption using batch experiments. The results showed soil cation exchange capacity （CEC） and pH significantly increased after 30 d of incubation with the biochars added. The incorporation of the biochars markedly increased the adsorption of Pb（II）, and both the electrostatic and non-electrostatic adsorption mechanisms contributed to Pb（II） adsorption by the variable charge soils. Adsorption isotherms illustrated legume- straw derived biochars more greatly increased Pb（II） adsorption on soils through the non-electrostatic mechanism via the formation of surface complexes between Pb（II） and acid functional groups of the biochars than did non-legume straw biochars. The adsorption capacity of Pb（II） increased, while the desorption amount slightly decreased with the increasing suspension pH for the studied soils, especially in a high suspension pH, indicating that precipitation also plays an important role in immobilizing Pb（II） to the soils. 相似文献
2.
ZHANG Wei WANG Jin-jun ZHANG Zhong-ming QIN Zhen 《中国农业科学(英文版)》2007,6(11):1359-1368
The adsorption-desorption characteristics of chlorimuron-ethyl in soils were investigated to provide the basic data for evaluating the safety in field and the risk to water resource. The adsorption-desorption experiment was conducted by the batch equilibration and HPLC techniques; furthermore, data were analyzed with 5 mathematic models to describe the characteristics and mechanism of adsorption-desorption and translocation of the herbicide in soils. The results showed that the adsorption-desorption isotherms of chlorimuron-ethyl fitted for the Freundlich model well, and the physical reaction presents the main contribution during the adsorption-desorption process. The adsorption values （Kads-f） of chlorimuron-ethyl in 8 types of soil ranged from 0.798 to 6.891. The isotherms of 2# （Jiangxi clay） and 3# （Jiangxi sand loam） soils belong to the S-type curve, while the isotherms of another 6 type soils belong to the L-type isotherm. The results of desorption indicated that the hysteresis phenomena appeared during the desorption process, and the hysteresis coefficients （H） of the herbicides in 8 soils varied from 0.259-0.980. Furthermore, Kads-f and desorption values （Kads-f） increased with the OM （%） and the clay content increasing, while the values decreased with the soils pH increasing. The H values decreased with the OM and the clay content increasing, and increased with the soils pH increasing. It can be concluded that the low adsorption abilities of chlorimuron-ethyl in test soils and un-reversible adsorption existed in the process, which will induce the great translocation of the herbicide after application in field. It can be transported to ground or groundwater causing risk to environments. The physical and chemical properties of soils, including the OM, the clay content, and the pH of soil were the dominating factors during the adsorption-desorption. 相似文献
3.
Crop Yield and Soil Properties in the First 3 Years After Biochar Application to a Calcareous Soil 总被引：13，自引：0，他引：13
It remains unclear whether biochar applications to calcareous soils can improve soil fertility and crop yield. A long-term field experiment was established in 2009 so as to determine the effect of biochar on crop yield and soil properties in a calcareous soil. Five treatments were： 1） straw incorporation; 2） straw incorporation with inorganic fertilizer; 3）, 4） and 5） straw incorporation with inorganic fertilizer, and biochar at 30, 60, and 90 t ha-l, respectively. The annual yield of either winter wheat or summer maize was not increased significantly following biochar application, whereas the cumulative yield over the first 4 growing seasons was significantly increased. Soil pH, measured in situ, was increased by a maximum of 0.35 units after 2 yr following biochar application. After 3 yr, soil bulk density significantly decreased while soil water holding capacity increased with adding biochar of 90 t ha^-1. Alkaline hydrolysable N decreased but exchangeable K increased due to biochar addition. Olsen-P did not change compared to the treatment without biochar. The results suggested that biochar could be used in calcareous soils without yield loss or significant impacts on nutrient availability. 相似文献
4.
《农业科学学报》2016,(9)
In coastal regions, Bohai Gulf is one of the most affected areas by salinization. To study the effects of mocrosprinkler irrigation on the characteristics of highly saline sandy loam soil(ECe(saturated paste extract)=22.3 d S m~(–1); SAR(sodium adsorption ratio)=49.0) of North China, a laboratory experiment was conducted. Five water application intensity(WAI) treatments(1.7, 3.1, 5.3, 8.8, and 10.1 mm h~(–1)), five irrigation amount(IA) treatments(148, 168, 184, 201, and 223 mm) and three time periods of water redistribution(0, 24 and 48 h) were employed in the study. A compounding microsprinkler system was used for the WAI treatments, and a single microsprinkler was used for the IA treatments. The results indicated that, as soil depth increased, soil water content(θ) increased and then slightly decreased; with WAI and IA consistently increasing, the relatively moist region expanded and the average θ increased. Meanwhile, soil ECe increased as soil depth increased, and the zone with low soil salinity expanded as WAI and IA increased. Although the reduction of the average SAR was smaller than that of the average electrical conductivity of the ECe, these variables decreased in similar fashion as WAI and IA increased under microsprinkler irrigation. The average p H decreased as soil depth increased. Longer time periods of water redistribution led to lower salinity and slight expansion of the SAR zone. Considering the effects of leached salts in coastal saline soils, greater WAI and IA values are more advantageous under unsaturated flow conditions, as they cause better water movement in the soil. After leaching due to microsprinkler irrigation, highly saline soil gradually changes to moderately saline soil. The results provide theoretical and technological guidance for the salt leaching and landscaping of highly saline coastal environments. 相似文献
5.
LIU Jian-ling LIAO Wen-hua ZHANG Zuo-xin ZHANG Hai-tao WANG Xin-jun MENG Na 《中国农业科学(英文版)》2007,6(9):1107-1114
Phosphorus （P） applied from fertilizer and manure is important in increasing crop yield and soil fertility; however, excessive uses of phosphate fertilizer and manure may also increase P loss from agricultural soils, posing environmental impact. A long term experiment was conducted on a calcareous soil （meadow cinnamon） in Hebei Province, China, from 2003 to 2006 to investigate the effects of phosphate fertilizer and manure on the yield of Chinese cabbage, soil P accumulation, P sorption saturation, soluble P in runoff water, and P leaching. P fertilizer （P2O5） application at a rate of 360 kg ha^-1 or manure of 150 t ha^-1 significantly increased Chinese cabbage yield as compared to the unfertilized control. However, no significant yield response was found with excessive phosphate or manure application. Soil Olsen-P, soluble P, bioavailable P, the degree of phosphorus sorption saturation in top soil layer （0-20 cm）, and soluble P in runoff water increased significantly with the increase of phosphate fertilizer and manure application rates, whereas the maximum phosphorus sorption capacity （Qm） decreased with the phosphate fertilizer and manure application rates. Soil Olsen-P and soluble P also increased significantly in the sub soil layer （20-40 cm） with the high P fertilizer and manure rates. It indicates that excessive P application over crop demand can lead to a high environmental risk owing to the enrichment of soil Olsen-P, soluble P, bioavailable P, and the degree of phosphorus sorption saturation in agricultural soils. 相似文献
6.
Laboratory and field experiments were conducted to investigate the effects of water application intensity(WAI) on soil salinity management and the growth of Festuca arundinacea(festuca) under three stages of water and salt management strategies using microsprinkler irrigation in Hebei Province, North China. The soil water content(è) and salinity of homogeneous coastal saline soils were evaluated under different water application intensities in the laboratory experiment. The results indicated that the WAI of microsprinkler irrigation influenced the è, electrical conductivity(ECe) and p H of saline soils. As the WAI increased, the average values of è and ECe in the 0–40 cm profile also increased, while their average values in the 40–60 cm profile decreased. The p H value also slightly decreased as depth increased, but no significant differences were observed between the different treatments. The time periods of the water redistribution treatments had no obvious effects. Based on the results for è, ECe and p H, a smaller WAI was more desirable. The field experiment was conducted after being considered the results of the technical parameter experiment and evaporation, wind and leaching duration. The field experiment included three stages of water and salt regulation, based on three soil matric potentials(SMP), in which the SMP at a 20-cm depth below the surface was used to trigger irrigation. The results showed that the microsprinkler irrigation created an appropriate environment for festuca growth through the three stages of water and salt regulation. The low-salinity conditions that occurred at 0–10 cm depth during the first stage(-5 k Pa) continued to expand through the next two stages. The average p H value was less than 8.5. The tiller number of festuca increased as SMP decreased from the first stage to the third stage. After the three stages of water and salt regulation, the highly saline soil gradually changed to a low-saline soil. Overall, based on the salt desalinization, the microsprinkler irrigation and three stages of water and salt regulation could be successfully used to cultivate plants for the reclamation of coastal saline land in North China. 相似文献
7.
The total potassium(K)content of soils in Heilongjiang was relatively high in general and the available potassium content on soils was quite different for different soil types.The results of electro-ultra-filtration(EUF)analysis showed that the dark brown forest soils and the black soils in the northern part contained relatively high EUF-K,ranged from 12.5 to 15.7 mg per 100g soil.In the black soils in the southern part,the EUF-K ranged from 8 to 9mg per 100g soil.The albic and aeolian sandy soils contained low EUF-K,ranged from 3.2 to 4.8mg per 100g soil.Field experiment in 1982 indicated that potassium fertilizer in soils with medium or low EUF-K,increased soybean yield by 17%-34%,and obviously prevented the epidemic of meadow moth and soybean mosaic virus.Application of potassium fertilizer increased the protein and total sugar content of the plants,promoted transportation of nutrients,speeded up the growth of the plants,improved the resistance of crops to adverse conditions.Application of potassium fertilizer resulted in early maturity of crops(4-7 days earlier than cotrol),which had great significance for preventing crops from early frost damage.Hence,in order to keep nutrients balance in the soil and to increase soil fertility.potassium fertilizer or materials containing potassium must be applied to soils with medium and low EUF-K,such as black soils in the south part,ablic soils and aeolian sandy soils in Heilongjiang Province. 相似文献
8.
Effects of Soil Water Content on Cotton Root Growth and Distribution Under Mulched Drip Irrigation 总被引：1，自引：0，他引：1
HU Xiao-tan CHEN Hu WANG Jing MENG Xiao-bin CHEN Fu-hong 《中国农业科学(英文版)》2009,8(6):709-716
The relation between soil water content and the growth of cotton root was studied for the scheme of field water and cotton yield under mulched drip irrigation. Based on the field experiments, three treatments of soil water content were conducted with 90%, 75%θf, and 60%θf （θfis field water capacity）. Cotton roots and root-shoot ratio were studied with digging method, and the soil moisture was observed with TDR （time domain reflector）, and cotton yield was measured. The results indicated that the growth of cotton root accorded with Logistic growth curve in the three treatments, the cotton root grew quickly and its weight was very high under 75%θf because of the suitable soil water condition, while grew slowly and its weight was lower under 90%θf due to water moisture beyond the suitable condition, and the root weight was in between under 60%θf For the three water treatments, the cotton root weight decreased with soil depth, and decreased more significantly in deeper soil layer with the soil moisture increasing. And the ratio of cotton root weight in 0-30 cm soil layer to the total root weight was the highest under 75%θf. The cotton root system was distributed mainly in the soil of narrow row and wide row mulched with plastic film, and little in the soil outside plastic film. The weight of cotton root was the highest in the soil of narrow row or wide row mulched with plastic film under 75%θf. Root-shoot ratio decreased with the soil moisture increasing. The soil water content affected cotton yields, and cotton yield was the highest under 75%θf. The higher soil moisture level is unfavorable to the growth of cotton root system and yield of cotton under mulched drip irrigation. 相似文献
9.
Water erosion is the major reason for the loss of soil organic carbon in the Northeast China, which leads to the soil quality deterioration and adjacent water pollution. In this study, the effect of extraction temperature, pH value, and salt on the water extractable organic matter (WEOM) was determined by means of the UV absorbance, fluorescence excitation-emission matrix, and derived fluorescence indexes. In general, the carbon content and aromaticity of WEOM increased with the increasing of extraction temperature, with the exception that there was no significant difference in the amount at 0 and 20℃. More fluorophores, especially microbially-derived organic matter were extracted at high temperature. The pH values of extractant, including 5, 7, and 10, showed no effect on the carbon amount of WEOM, whereas the aromaticity and microbially-derived component gradually increased with the increasing of pH values. The fluorescence intensity of humic acid-like fluorophore was stronger in neutral and alkali condition than that in acidic condition. The addition of 10 mmol L-1 CaCl2 significantly decreased the carbon amount of recovered WEOM. Moreover, it significantly decreased the aromaticity of WEOM and the quantity of fulvic acid-like and humic acid-like fluorophores, whereas increased the percentage of tyrosine-like and tryptophan-like fluorophores in the total fluorophores and the amount of microbially-derived organic matter. Generally, 10 mmol L-1 KCl showed the same influence trend, but with low influence degree. 相似文献
10.
Soil phosphorus release to the water bodies in the upland fields of yellow soil areas and impacting factor was studied in Guizhou province. The results showed that the content of dissolved active P of surface runoff from various upland fields of yellow-soil were significantly different, which the concentrations of dissolved active P of runoff correlated with the contents of available-P, amorphous oxides of A1, and organic matter in the soils. The amount of soil phosphorus release to the water bodies affected by the level of applying P fertilizer and the process of corn growth, which with fertilizing from 150 to 900 kg P205 ha^-1 in the soil with high P level, the average contents of dissolved active P in the permeability-water of the soil increased from 0.020 mg L^-1 to 0.137 mg L^-1. The amount of soil phosphorus release to the water bodies also affected by environmental factor, which the amount of soil phosphorus release significantly increased under the conditions that temperature is 30℃-35℃, water/soil ratios is 15：1-25：1, submergence-time by water is 12-18 h and pH value of acid rains is 3.82-3.73. 相似文献
11.
通过弃耕砂田人工造林试验,并且以相邻的农作物砂田和原生地裸地为对照,对弃耕砂田造林地土壤水分生态进行观测研究,结果表明:在整个观测期内,弃耕砂田灌木造林地0～40 cm层土壤含水量平均为12.6%,与农作物砂田、原生地裸地含水量相比,分别高出9.5%和40.7%,这说明弃耕砂田的保水效果虽较新砂田有所下降,但较原生地裸地仍具有较好的水分保持能力;在整个生长期内,弃耕砂田灌木造林地土壤水分变化虽有上下波动,但总体呈下降趋势,7月份达到最低.而经过8～9月雨季后,土壤含水量得到补充而快速增加;与对照相比,弃耕砂田灌木造林地土壤含水量在(0～10 cm)与农作物砂田和原生地裸地差异不大,但在10～40 cm层的土壤含水量均高于农作物砂田和原生地裸地.观测研究初步表明,弃耕砂田具有植被恢复与利用必要的水分基础条件. 相似文献
12.
干旱区不同土地类型下甜高粱叶片光合特性和水分利用效率 总被引：3，自引：0，他引：3
【目的】了解旱区甜高粱的光合特性和水分利用效率对不同土地类型的适应机制。【方法】在河西走廊中部绿洲区,选择壤土地、盐碱地和沙荒地3种不同土地类型,于拔节期对甜高粱的气体交换参数进行测定与分析。【结果】不同土地类型下甜高粱净光合速率的日变化均呈“单峰型”,无“光午休”现象。与壤土地相比,盐碱地和沙荒地甜高粱叶片净光合速率和水分利用效率均有所降低,3种土地类型甜高粱的净光合速率分别为(30.75±4.31)、(25.31±4.43)和(23.71±3.86)μmolCO2?m-2?s-1,叶片水分利用效率分别为(5.42±0.98)、(4.34±0.55)和(3.08±0.31)μmolCO2?mmol-1H2O,田间水平水分利用效率分别为3.48、3.21和 2.17 kg?m-3,但盐碱地与壤土地差异性不显著。沙荒地甜高粱的叶片蒸腾速率最高,表明甜高粱通过增加蒸腾速率来降低其叶片的温度,进而适应这种高温强光的气候条件。【结论】从解决能源与生态危机和节约土地资源角度出发,在西北盐碱地和沙荒地等边际土地更有利于甜高粱的长久发展,同时在边际性土地上要获得更高的生物学产量和水分利用效率,须对其土壤的理化性质或者栽培措施进行改善,进而取得高产、节水效果。 相似文献
13.
为了探讨泗礁沙滩碎波带浮游动物的种类组成及其季节变化,2010年8月至2011年8月每月大潮期间,在泗礁沙滩碎波带设置8个站点,以浮游Ⅰ型生物网共采集到浮游动物67种,浮游幼虫10类,共计77个种类。浮游动物中甲壳动物最多,共56种,占总种数的72.73%,其中枝角类3种,桡足类43种,其他甲壳动物10种。此外,毛颚动物4种,水母类7种。优势种为小拟哲水蚤(Paracalanus parvus)、强额拟哲水蚤(Paracalanus crassirostris)、背针胸刺水蚤(Centropages dorsispinatus)等13种,其中四季皆为优势种的仅小拟哲水蚤和强额拟哲水蚤2种。泗礁沙滩碎波带浮游动物大致可分为4个生态类群,分别为河口半咸水生态类群(2种),近海暖温生态类群(2种),近海暖水生态类群(52种)和大洋广布生态类群(5种)。结果表明,泗礁沙滩碎波带浮游动物受盐度、温度、潮汐和外海水团等环境因素影响,海洋性浮游动物最多,季节变化显著,夏季优势种最多(10种),冬季最少(4种),平均密度春季最高(1 557.021个/网),冬季最低(87.875个/网)。 相似文献
14.
15.
在进行基础资料调查和数据分析的基础上,通过计算不同水源不同节水灌溉方式的年收入、支出、年净效益和投资回收期等,得到不同水源在不同灌溉方式下的年净效益平均值,完成节水灌溉方式经济适宜性的评价分析;以灌水均匀度作为技术适宜性评价指标,适宜性评价结合3种灌溉水源(地面水、浅井水、深井水),3种作物模型(粮食作物、经济作物、林果),3种地形地貌(1/1 000～3 000、1/100～1 0001、/10～100)5,种土壤质地(砂质、砂壤质、壤质、粘壤质、粘质),完成节水灌溉方式技术适宜性评价分析;根据调查资料整理和总结,得出群众对各种灌溉方式的评价结果,完成节水灌溉方式的社会适宜性评价分析;运用模糊综合评价法实现节水灌溉方式的适宜性评价。并且以典型灌区为实例,对构建的综合评价指标和决策集及建立的节水灌溉方式评价数学模型进行验证,完成了节水灌溉方式的优选。 相似文献
16.
利用粉煤灰改良风沙土物理性质的研究 总被引：1，自引：0，他引：1
[目的]研究粉煤灰改良风沙土物理性质的有效性。[方法]在测量供试样品的粒径范围、土壤比重、容重,孔隙度的基础上,对风沙土添加不同用量的粉煤灰并调控测试条件,研究了不同土壤样品的比重、容重,孔隙度及水分物理性质的变化情况。[结果]风沙土中掺入粉煤灰使风沙土黏粒含量增多,土壤容重、孔隙度降低,风沙土与粉煤灰最优的添加率为30％。30％添加率可有效改良土壤物理性状,土壤透水性与持水性约1：2,孔隙度为50％-60％,具有壤土的特点,其含水率较沙土有明显提高,渗透性不断升高,有效水分滞留时间增加。[结论]该研究为利用粉煤灰改良风沙土物理性质提供参考。 相似文献
17.
为探索同一物种在不同生态区域钙组分特征的差异,选择我国北方沙地重要建群种油蒿(Artemisia ordosica)为研究对象,采集了内蒙古杭锦旗、乌审旗、阿拉善左旗以及宁夏盐池县和陕西榆林市榆阳区不同沙地类型、不同生长阶段的油蒿样品,利用连续组分法测定分析了油蒿的钙组分特征.结果表明,在油蒿的不同器官中,叶水溶性钙和醋酸溶性钙均显著高于枝和根,叶与根盐酸溶性钙均显著高于枝.在不同生态区域,降水量较多的地区油蒿体内水溶性钙含量较多,降水量较少的地区油蒿体内盐酸溶性钙含量较高.分析得知,降水条件较好的地区较高的水溶性钙主要体现在油蒿的叶中,而降水条件较差的地区较高的盐酸溶性钙主要体现在油蒿的叶和根中.油蒿在不同生长阶段钙组分没有显著差异,但不同类型沙地上油蒿的钙组分却有显著差异.可见,不同生态区域的油蒿,生境条件越好体内水溶性钙含量越高,生境条件越差体内盐酸溶性钙含量越高. 相似文献
18.
[目的]针对我国北方砂壤土水分利用效率低的特点,通过室内模拟试验研究了砂壤土表层添加不同黏粒量对砂壤土湿润锋进程、累计入渗量、土壤剖面含水率的影响,分析了土壤中黏粒添加量对砂壤土水分运动影响和机制,旨在为砂壤土工程改良提供理论依据和实践指导.[方法]通过室内土柱模拟试验,设置常规对照（CK）以及2％、5％、10％和20％4个掺黏量,定水头条件下研究不同掺黏量对砂壤土水分入渗特征的影响.[结果]砂壤土表层掺黏后,显著减小了湿润锋进程.随着土壤表层掺黏量的增加,湿润锋下移速率、入渗速率逐渐减慢,累计入渗量减少.湿润锋、累计入渗量与时间之间符合幂函数关系.[结论]在入渗过程中,土壤表层掺黏能显著增加土壤对外界水分的蓄积量,提高土壤的储水量. 相似文献
19.
土壤水分常数是评价土壤改良效果的主要指标。文章通过研究不同掺粘量对砂壤土水分常数的影响及机理分析。旨在为内蒙古旱作农业砂壤土改良、扩蓄、提高生产力提供有力的科技支撑和理论依据。研究表明：砂壤土掺粘后土壤的饱和导水率明显下降,当掺粘量为5％时,饱和导水率降低约为砂壤土的36％;田间持水量、毛管持水量、饱和含水量和萎蔫含水量随着粘粒含量的增加而增加;土壤有效含水率随着掺粘量的增加呈现出先增加后降低的趋势。 相似文献
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[目的]研究高吸水树脂在沙质土壤中的保水效果。[方法]以江苏省徐州地区黄河故道砂质土为对象,丙烯酸酯系列高吸水性树脂为保水材料进行了相关试验。[结果]添加土壤质量0.2%～0.4%的高吸水树脂可延长砂质土壤灌溉后的脱水期。脱水期间持水量高于10%的天数达42 d,明显高于对照组从饱和含水量降至10%左右持水量时16 d的脱水天数。在二次灌水不搅动土层的情况下保水效果好于首次灌水。[结论]高吸水性树脂与土壤混合施用有重复吸水保水效果。 相似文献