河南省降雨侵蚀力时空变异特征     

吴明作  何瑞珍  安树青  杨喜田  张军 《中国水土保持科学》2012,10(3):22-28

利用河南省119个气象台站自建站始至2003年的逐日降雨量资料,计算其所代表县(市)的逐年与平均降雨侵蚀力,并利用GIS等工具分析河南省降雨侵蚀力的时空变异特征。结果表明:河南省多年年均降雨侵蚀力总体趋势是由北向南递增,最大值出现在南部的新县、鸡公山、商城与桐柏、平舆,其值均超过7 000 MJ.mm/(hm2.h.a);河南省多年年均降雨侵蚀力排序结果可分为5个区域等级,基本与等值线一致;河南省各地的降雨侵蚀力在不同年份变异较大,FFT(快速傅立叶变换)表明无明显的年际周期性规律;河南省降雨侵蚀力的年内变化趋势表现为单峰型,侵蚀主要发生在7—9月份,集中度在北部区域均超过60%;河南省降雨侵蚀力与年侵蚀性降雨量或年侵蚀性降雨量和逐日侵蚀性降雨量之间存在极显著的线性相关性,相关系数分别为0.967 2和0.994 2。  相似文献   

硒的价态与浓度水平对6种植物种子发芽和根际生长的影响     

毛晖  王朝辉  Graham Lyons  Glenn McDonald 《农业环境保护》2011,(10):1958-1965

本文研究了硒的价态（Se6＋和Se4＋）和浓度水平（0～100mgSe·L-1）对6种植物（大麦、小麦、花椰菜、萝卜、苜蓿和欧芹）种子萌发和根际生长特性的影响。结果表明,低浓度硒（〈1mgSe·L-1）对种子发芽促进作用不明显,而高浓度硒（〉4mgSe·L-1）则有显著抑制作用,不同种子对硒的抗性表现不同。根长和芽长的测定结果表明,低浓度对花椰菜和小麦种子生长具有显著促进作用,对欧芹种子表现出抑制作用。较高浓度（1～4mg·L-1）即对花椰菜、苜蓿和欧芹的根生长表现出抑制作用,高浓度对小麦、大麦和萝卜根生长有抑制作用,且使芽生长受到抑制的硒浓度高于根生长。比较价态,低硒时六价对花椰菜生长的促进作用显著高于四价,高硒时小麦和苜蓿对硒的抗性表现为六价硒强于四价硒,其余科属差异不显著。不同科属对硒的抗性为禾本科小麦和大麦最强,十字花科花椰菜和萝卜次之,豆科苜蓿较差,伞形科欧芹最差。  相似文献   

Impact of land use on nitrogen concentration in groundwater and river water     

Seiko Yoshikawa  Hidehiro Takahashi  Yasuko Sasada  Hidetoshi Mochizuki 《Soil Science and Plant Nutrition》2013,59(6):898-909

Abstract

The aim of this study was to evaluate the impact of land use on nitrate nitrogen (NO₃-N) in shallow groundwater (G-N) and total nitrogen (N) in river water (R-N). The study area consisted of 26 watersheds (1342 km²) covering 72% of Kagawa Prefecture in Japan. We estimated G-N specific concentrations, which showed the magnitude of the upland fields, paddy fields, forests and urban land-use contributions to watershed-mean G-N. G-N specific concentrations were gained as partial regression coefficients using a multiple regression analysis of the watershed-mean G-N concentrations and the land-use ratios in each of the 26 watersheds. The results showed that the G-N specific concentration, which was gained as the partial regression coefficient for the multiple regression analysis, was 15.2 mg L^?1, 10.3 mg L^?1, 2.3 mg L^?1 and 2.5 mg L^?1 for the upland fields, paddy fields, forests and urban land-use types, respectively. R-N pollution load runoff to the river mouth was calculated by multiplying R-N specific concentration (previously reported) by river flow at the river mouth. Similarly, G-N pollution load arrival to groundwater was calculated by multiplying G-N specific concentration by the groundwater flow. The R-N pollution load runoff was 19.3 kg ha^?1 y^?1, 7.7 kg ha^?1 y^?1, 1.7 kg ha^?1 y^?1 and 7.6 kg ha^?1 y^?1, while the G-N pollution load arrival was 7.3 kg ha^?1 y^?1, 5.0 kg ha^?1 y^?1, 1.1 kg ha^?1 y^?1 and 1.2 kg ha^?1 y^?1, for upland fields, paddy fields, forests and urban areas, respectively. These results showed that the N in river water and groundwater was derived mainly from runoff and leaching from croplands. Therefore, the relationships between watershed-mean non-absorbed, applied nitrogen (NAA-N: nitrogen applied to cropland via fertilizer and manure without being absorbed by crops), R-N concentration and watershed-mean G-N concentration were investigated. A curvilinear correlation was observed between NAA-N and R-N concentrations (r² = 0.68) except for one small, high-density, urban watershed, and a weak linear correlation was observed between NAA-N and G-N concentrations (r² = 0.42).  相似文献   

Influence of Nitrate:Ammonium Ratios on Growth and Elemental Concentration in Two Azalea Cultivars     

《Journal of plant nutrition》2013,36(12):2503-2520

Abstract

Rooted cuttings of Rhododendron canescens “Brook” and Rhododendron austrinum were grown in sand culture with a modified Hoagland's solution under greenhouse conditions. The effect of varying ammonium:nitrate (NO₃ ^?:NH₄ ⁺) ratios (100:0, 75:25, 50:50, 25:75, 0:100) on growth, chlorophyll content, plant quality, and elemental tissue concentration were determined. With NO₃ ^? as the nitrogen (N) form, both azalea cultivars exhibited less vegetative growth, lower overall plant quality, with leaves showing visual chlorotic symptoms in comparison to plants receiving NH₄ ⁺ as the N‐form. Leachate pH was highest with NO₃ ^? as the predominate N‐form and decreased significantly with each increment of NH₄ ⁺. With both azalea cultivars, N‐form significantly influenced uptake and utilization of essential plant nutrients. Leaf concentrations of N, potassium (K), calcium (Ca), sulfur (S), boron (B), and molybdenum (Mo) were highest with NO₃ ^?‐N. Leaf elemental concentrations of phosphorous (P), magnesium (Mg), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) increased as NH₄ ⁺ supplied more of the N‐ratio. Significant differences in Mg, Mn, and Zn were observed between species. Results from this study show that foliar N concentration is not an accurate indicator of plant growth response. Further investigations are needed to determine if foliarchlorosis and low growth rates observed with NO₃ ^? fed plants due to an Fe deficiency, to low nitrate reductase (NR) activity in the leaves, or to a combination of these factors.  相似文献   

生物通风法修复柴油污染土壤模拟实验研究   总被引：2，自引：1，他引：2  

刘沙沙  陈志良  董家华  彭晓春  徐玉新 《土壤》2014,46(2):339-346

通过生物通风技术修复不同柴油浓度污染土壤的土柱模拟实验,研究了各土柱中土壤总石油烃(total petroleum hydrocarbon,TPH)的去除规律,并对影响柴油去除效果的因素进行了分析,结果表明:①经过3个月的生物通风后,初始柴油浓度为5(柱Ⅰ)、10(柱Ⅱ)、20(柱Ⅲ)、40(柱Ⅳ)g/kg的土柱柴油去除率为ⅡⅠⅣⅢ,柱Ⅱ的修复效果最佳,半衰期为60.05天,TPH最终去除率达65.3%;②挥发和生物降解作用影响土柱中柴油的去除,由于重力引起的向下迁移作用只对柴油在土柱中的空间分布产生影响,三者共同作用决定各土柱不同取样口柴油的去除规律;③在实验过程中,各土柱土壤pH变化不大,初始柴油浓度越高土柱水分损失率越小;有效磷和速效氮含量均有所降低,柱Ⅲ降低率最大,分别为58.27%和31.87%,柱Ⅰ最小;土柱上层土壤中的酶活性要低于下层,过氧化氢酶和脱氢酶活性均呈现出先升高后降低的趋势。实验结果为研究各土柱中柴油的生物降解规律提供了依据。  相似文献   

蚯蚓与黑麦草相互作用对土壤中荧蒽去除的影响   总被引：1，自引：0，他引：1  

JING Yong-Ping  LIU Man-Qiang  YIN Qi-Peng  LI Hui-Xin  HU Feng 《土壤圈》2013,23(4):523-531

Earthworms can promote the bioremediation of contaminated soils through enhancing plant growth and microorganism development. The individual and combined effects of earthworms and ryegrass (Lolium multiflorum Lam.) on the removal of fluoranthene from a sandy-loam alluvial soil were investigated in a 70-d microcosm experiment. The experiment was set up in a complete factorial design with treatments in four replicates: without earthworms or ryegrass (control, CK), with earthworms only (E), with ryegrass only (P), and with both earthworms and ryegrass (EP). The residual fluoranthene, microbial biomass C, and polyphenol oxidase activity in the soil changed significantly (P<0.01) with time. In general, the residual concentration of fluoranthene in the soil decreased sharply from 71.8-88.7 to 31.7-37.4 mg kg 1 in 14 d, and then decreased gradually to 19.7-30.5 mg kg 1 on the 70th d. The fluoranthene concentration left in the soil was the least with both earthworms and ryegrass, compared to the other treatments at the end of the experiment. Half-life times of fluoranthene in the E, P, and EP treatments were 17.8%-36.3% smaller than that of CK. More fluoranthene was absorbed by earthworms than ryegrass. However, the total amounts of fluoranthene accumulated in both the ryegrass and earthworms were small, only accounting for 0.01%-1.20% of the lost fluoranthene. Therefore, we assumed that microbial degradation would play a dominant functional role in fluoranthene removal from soil. We found that earthworms significantly increased microbial biomass C and polyphenol oxidase activity (P<0.01) in the presence of ryegrass at the end of the experiment. Furthermore, microbial biomass C and polyphenol oxidase activity were significantly (P<0.05) and negatively related to the residual fluoranthene concentration. This implied that earthworms might promote the removal of fluoranthene from soil via stimulating microbial biomass C and polyphenol oxidase activity.  相似文献   

CO₂浓度升高和施氮对冬小麦光合面积及粒叶比的影响     

许育彬  沈玉芳  李世清 《中国生态农业学报》2013,21(9):1049-1056

利用开顶式气室和盆栽方法, 以冬小麦品种"小偃6号"和"小偃22"为供试材料, 在2种CO₂浓度(375 μL·L^-1和750 μL·L^-1)和3个施氮水平[0、0.15 g(N)·kg^-1(土)和0.30 g(N)·kg ^-1(土)]下分析了小麦抽穗期绿色叶片、非叶光合器官(茎鞘、穗、芒)的形态和光合面积以及粒叶比对CO₂浓度升高和施氮的反应。结果表明, 施氮有助于小麦叶和非叶光合器官伸长和增宽(粗), 增加其光合面积、穗粒数、穗粒重、粒数叶比和粒重叶比。与背景CO₂浓度(375 μL·L^-1)相比, CO₂浓度升高对叶片和茎节长度、茎叶和芒光合面积具有明显的正向效应(P<0.05), 但对叶宽、茎节直径、穗面积影响不明显(P>0.05), 使"小偃6号"和"小偃22"单茎光合面积分别增加8.1%~15.1%和2.8%~13.2%, 且均以0.30 g(N)·kg^-1(土)施氮水平下增幅最大。CO₂浓度升高后, 穗粒数和粒数叶比在3个施氮水平下均不同程度增加, 其中2个品种粒数叶比分别在0.30 g(N)·kg^-1(土)和0.15 g(N)·kg^-1(土)施氮水平下增加最明显, 增幅分别为44.2%和41.4%; 穗粒重和粒重叶比在不施氮时下降, 在施氮时显著增加, 其中2个品种粒重叶比平均增幅分别为43.6%和20.7%。由于芒面积远小于其他源器官面积, 在单茎光合面积中所占比例较小(3%左右), 因此认为CO₂浓度升高主要通过促进小麦茎叶伸长生长来增加光合面积, 同时提高单位叶面积库承载力和物质调运能力, 改善源库关系, 增加氮素供应有利于小麦源库生长对CO₂浓度升高的反应。  相似文献   

土壤溶液浓度的野外测定方法研究     

何雨江  时磊 《水土保持通报》2013,(6):213-215,221

为寻求一种野外快速有效测定土壤溶液浓度的方法,于新疆自治区南疆地区开展了田间试验。利用负压计监测土壤水分,在土壤达到饱和时,在相同深度分别借助土钻和土壤水提取器同时取土样和土壤水样,利用电导率仪测定土壤电导率(EC1:5)和饱和土壤电导率(ECe),使用火焰光度计和滴定法测定土壤水溶液浓度(C),并利用SPSS17.0软件对实测数据进行线性回归分析及检验。结果表明,南疆砂壤土条件下,EC1:5值在0~10000μS/cm范围内,EC1:5与土壤总盐含量呈显著线性关系土壤ECe可用土壤EC1:5进行推算,二者关系系数可以根据饱和重量含水量确定在土壤达到饱和,EC1:5在0~3000μS/cm时,土壤溶液浓度与EC1:5呈显著线性关系。因此,通过野外测得土壤样品的EC1:5,并确定其适用条件后,根据相关关系可直接计算得到ECe和C。  相似文献   

Nitrogen Uptake and Use Efficiency in Upland Rice under Two Nitrogen Sources     

《Communications in Soil Science and Plant Analysis》2012,43(4):461-469

Upland rice is an important crop in South America, including Brazil. Nitrogen (N) is one of the most yield-limiting nutrients in upland rice production in Brazil. A greenhouse experiment was conducted to evaluate N uptake and use efficiency as influenced by N sources. The soil used in the experiment was an Oxisol. The N sources were ammonium sulfate and urea, and N rates were 0, 50, 100, 150, 300, and 400 mg kg^?1 of soil. Nitrogen concentrations in the root, shoot, and grain were significantly influenced by N sources. The N rate and N source significantly influenced the N uptake in root, shoot, and grain. Similarly, nitrogen rate by N source interaction was also significant for N uptake in the root, shoot, and grain, indicating N source has a significant influence on uptake of N. Overall, concentration (content per unit dry weight) of N was greater in the grain, followed by root and shoot. Agronomical efficiency, apparent recovery efficiency, and utilization efficiency of N were significantly influenced by N rate and varied with N sources. However, physiological and agrophysiological efficiencies were only influenced significantly by N sources. Overall, N recovery efficiency was 33% for ammonium sulfate and 37% for urea. Hence, the large amount of N lost from soil–plant system may be by denitrification or voltilization.  相似文献   

Influence of total soluble salt concentration on growth and elemental concentration of winged bean seedlings,Psophocarpus tetragonolobus (L.) DC.     

《Communications in Soil Science and Plant Analysis》2012,43(9):1009-1018

Abstract

Winged bean (Psophocarpus tetragonolobus) (L.) DC) seedlings of the accession TPT‐1, were grown in a greenhouse with graded, balanced total soluble salt (TSS) concentrations. After 4.5 days, plant height increased quadratically, with a maximum (149 cm) at 3000 ppm TSS. Seedlings were shortest at 1000 and 10,000 ppm TSS, 44.0 and 79.0 cm, respectively. Fresh weight of shoots increased quadratically with greatest weight, 29.03 g, at 5000 ppm TSS. Percent dry matter increased linearly with increasing TSS. Concentration of N, K and P increased quadratically with an increase in the TSS concentration in the growth medium. Concentration of Ca decreased quadratically with increasing TSS. Among the micronutrients, Fe and Mo concentration was quadratic, both elements were highest in the seedlings at 1000 and 10,000 ppm TSS rates. Concentrations of Mn and Zn increased linearly with increasing TSS. Winged bean seedlings at the 1000 to 3000 ppm TSS rates had spindly stems and a sparse, yellow foliage, typical for winged bean seedlings observed in the field during the first 4 to 5 weeks of growth. Seedlings at the 4000 and 5000 ppm TSS rates had sturdy stems and an abundant green foliage. At higher TSS concentrations, 5000 to 10,000 ppm TSS, seedlings had short intermodes and dark green foliage.  相似文献