[Objective] The aim of this study was to study the influence of plants on the soil moisture content under different fertilization.[Method] Using sainfoin,sweet clover,Astragalus adsurgens,alfalfa,ryegrass,little flowe...[Objective] The aim of this study was to study the influence of plants on the soil moisture content under different fertilization.[Method] Using sainfoin,sweet clover,Astragalus adsurgens,alfalfa,ryegrass,little flower,white clover as experimental material,this study explored the effects of soil moisture on the improvement of soil quality.[Result] Results showed that the soil moisture content of different plants follows as:sainfoin 〉sweet clover 〉Astragalus adsurgens 〉alfalfa perennial ryegrass 〉small crown 〉white clover,and the average moisture content reached 24.13% which was 2.45% higher than that of control group.At planting white clover,sweet clover,under the condition of 7 kinds of crops,in the treatments without fertilizer and with organic fertilizer,soil moisture content of soil in 0-20 cm grew significantly.[Conclusion] The application of organic fertilizer and growing of plants would improve soil moisture in abandoned fields,enhance the ability of soil water supply,and improve soil fertility.展开更多
Sloping and mountainous olive production systems are widespread, occupying large parts of the Mediterranean landscape prone to water erosion. Soil erosion, runoff, and soil water content patterns over a three-year per...Sloping and mountainous olive production systems are widespread, occupying large parts of the Mediterranean landscape prone to water erosion. Soil erosion, runoff, and soil water content patterns over a three-year period were monitored in erosion plots on a mountainside with rainfed olive (Olea europaea cv. Picual) trees under: 1) non-tillage with barley strips of 4 m width (BS); 2) non-tillage with native vegetation strips of 4 m width (NVS); and 3) non-tillage without plant strips (NT). The erosion plots, located in Lanjaron (Granada, south-eastern Spain), on a 30% slope, were 192 m2 in area. For assessing soil water dynamics in real-time and near-continuous soil water content measurements, multisensor capacitance probes were installed in the middle of plant strips and beneath the olive tree at five soil depths (10, 20, 30, 50, and 100 cm). The highest erosion and runoff rates were measured under NT, with a mean of 17.3 Mg ha-1 year-1 and 140.0 mm year-1, respectively, over the entire study period. The BS and NVS with respect to the NT reduced erosion by 71% and 59% and runoff by 95% and 94%, respectively. In general, greater available soil water content was found under BS than NVS and NT, especially beneath the olive tree canopies. These results supported the recommendation of non-tillage with barley strips in order to reduce erosion and to preserve soil water for trees in traditional mountainous olive-producing areas, where orchards cover vast tracts of land.展开更多
Through a simulation test conducted with soil columns (61.8cm in diameter) in field condition,effect of crop planting upon the regulation of salt-water dynamics in soils was studied by monitoring of salt-water dynamic...Through a simulation test conducted with soil columns (61.8cm in diameter) in field condition,effect of crop planting upon the regulation of salt-water dynamics in soils was studied by monitoring of salt-water dynamics in situ,using soil salinity sensors and tensiometers.The results indicated that the amount of water absorbed by crops from the soil was generally larger than the decrement of water consumption from soil surface evaporation reduced by the crop covering the soil surface and improving the soil structure,therefore,under the conditions of crop growing and non-irrigation,water content in soil profile was less than that without crop growing,and the gradient of negative pressure of soil water in soil profile especially in the root zone was enlarged,thus causing the water flowing from subsoils into root zone and increasing the groundwater moving upwards into soil layer via capillary rise,so that the groundwater evaporation increased.Consequently,under the condition of crop growing,the salt was mainly accumulated towards the root zone rather than to the top soil.the accumulating rate of salt in groundwater via capillary rise of soil water to subsoils was increased thereby.展开更多
Hydrological regime has been widely recognized as one of the major forces determining vegetation distribution in seasonally flooded wetland. Poyang Lake, the largest freshwater lake in China, has been encountering dra...Hydrological regime has been widely recognized as one of the major forces determining vegetation distribution in seasonally flooded wetland. Poyang Lake, the largest freshwater lake in China, has been encountering dramatic changes in hydrological conditions in last decade, which greatly influenced the wetland vegetations. To explore the relationships between hydrology and vegetation distri- bution, water-table depth, soil moisture, species composition, diversity and biomass were measured at a seasonally flooded wetland section at Wucheng National Nature Reserve. Three plant communities, Artemisia capillaris, Phragmites australis and Carex cineras- cens communities, were examined which are zonally distributed from upland to lakeshore with decreasing elevation. Canonical corre- spondence analysis (CCA), spearmen correlation and logistic regression were adopted to analyze the relationships between vegetation characteristics and hydrological variables of water-table depth and soil moisture. Results show that significant hydrological gradient exist along the wetland transect. Water-table demonstrates a seasonal variation and is consistently deepest in A. capillaris community (ranging from q).5 m above ground to +10.3 m below ground), intermediate in P. australis community (-2.6 m to +7.8 m) and shallow- est in C. cinerascens community (-4.5 m to +6.1 m). Soil moisture is lowest and most variable in A. capillaris community, highest and least variable in P. australis community, and intermediate and moderate variable in C. cinerascens community. The CCA ordination indicated that variables of water-table depth and soil moisture are strongly related to community distribution, which explained 81.7% of the vegetation variations. Species diversity indices are significantly positively correlated with soil moisture and negatively correlated with moisture variability, while above- and belowground biomass are positively correlated with moisture. Above- and belowground biomass present Gaussian models along the gradient of average water-table depth in growing season, while species diversity indices show bimodal patterns. The optimal average water-table depths for above- and belowground biomass are 0.8 m and 0.5 m, respectively, and are 2.2 m and 2.4 m for species richness and Shannon-Wiener indices, respectively. Outcomes of this work improved the under- standings of the relationship between hydrology and vegetation.展开更多
In this paper, the hydraulic resistances and capacitances were evaluated. based on the development of non-(?) model of water flow in the soil-plant system and the simulating experiment work.The results show that the m...In this paper, the hydraulic resistances and capacitances were evaluated. based on the development of non-(?) model of water flow in the soil-plant system and the simulating experiment work.The results show that the mean hydraulic resistance in the soil-plant system is 6.79×109 MPa·S·m-3; the mean hydraulic capacitance in the system is 5.2×107m3·MPa-1. In the components of hydraulic capacitance in the system, the capacitance in soil (81.8×10-6m3·MPa ) is the biggest and its variability with suii water potential is extremely strong, the capacitance in plant (5.3×10-7m3·MPa-1) is much smaller than that in soil, and the capacitance in shoots (15.5×10-7m3·2MPa-1) is bigger than that in roots (8.4×10-7m3·2MPa-1). An interesting result is that the capacitance in plant is almost equivalent to that in the soil-plant system.展开更多
Interaction between soil water and nutrients plays an important role in sustainable crop management in semi-arid environments.On the basis of a field experiment conducted from 2000 to 2003,this study examined the coup...Interaction between soil water and nutrients plays an important role in sustainable crop management in semi-arid environments.On the basis of a field experiment conducted from 2000 to 2003,this study examined the coupled effects of irrigation and fertilizers on maize growth and yield in a semi-arid region of northeastern China.In terms of plant productivity,nitrogen fertilizer had the most significant effect followed by irrigation and phosphate levels.The combined application of nutrients and irrigation exerted a synergistic effect on the grain yield of maize plants.Regression analysis indicated that optimal levels of nitrogen and phosphate,in addition to adequate irrigation,could greatly improve the efficiency of grain production.Similarly,optimization of soil nutrient availability substantially increased water use efficiency.These suggested that for the most efficient and sustainable crop production,irrigation and nutrient management should be based on a quantitative understanding of water/nutrients interaction,particularly in semi-arid and arid regions.展开更多
Superabsorbents such as cross-linked PAM (polyacrylamides) are frequently used to increase water availability to plants. Commercial PAM providers suggest that besides its increasing water availability, PAMs also inc...Superabsorbents such as cross-linked PAM (polyacrylamides) are frequently used to increase water availability to plants. Commercial PAM providers suggest that besides its increasing water availability, PAMs also increase nutrient availability to plants. To test this premise, four application rates (0.0 g·kg^-1, 0.33 g·kg^-1, 1.66 g·kg^-1, 3.33 g·kg^-1 and 6.66 g·kg^-1) ofa PAM were mixed with sandy and loamy soils to evaluate its effect on nutrient leaching and retention in these soils. Miscible displacements of chloride were conducted on columns of PAM-soil mixtures and results were evaluated by an equilibrium CDE (convection dispersion equation) model. Increasing the PAM rates up to 1.66 g·kg^-1 resulted in increased early appearance and dispersive transport of chloride in sand. In addition, increasing the PAM rates gradually caused increased tailing of the breakthrough curves of chloride in both soils. These suggested that PAM increased preferential transport of chloride while it increased retention of chloride in soils. Effect of PAM on preferential transport and retardation of CI was greater in sand than loam.展开更多
Based on the geochemical data obtained from the national project about the prevention and control of soil contamination, this paper explored the properties of soil chemical elements in Huanghuaihai Plain, Shandong Pro...Based on the geochemical data obtained from the national project about the prevention and control of soil contamination, this paper explored the properties of soil chemical elements in Huanghuaihai Plain, Shandong Province. The results showed that among the grade-one nutritive elements in soil, organic matter, nitrogen and phosphorus were relatively deficient while potassium was rich. Meanwhile, as the grade-two nutritive elements, calcium oxide and magnesium oxide were relatively short and sulfur’s content was abundant. About the other beneficial and trace nutri-tive elements, iron oxide, manganese, molybdenum and boron were deficient, but the content of chlorine was high, hardly lack. The main barriers to improving land productivity were soil salinization and soil heavy metal contamination. The values of soil integrated fertility index that most of the soil in the study area is middle-lower fertilized. Specifical y, the low fertility area and lower fertility area are 6 1604 and 1 244 km2 respectively, occupying about 97.43% and 1.97% of the total area. The moderate fertility soil has an area of 172 km2, occupying about 0.27% of the total area. The higher fertility soil covers an area of 128 km2, while the high fertility area of only 76 km2. This article proposed scientific fertilization, elimination of soil obsta-cle, remediation of heavy-metal-contaminated soil and other effective measures to improve land productivity according to the basic investigation results, which provides a good technological support for the planning and development of good-quality and high-benefit agriculture.展开更多
Architectural plasticity of clonal plants may enhance exploitation of soil moisture heterogeneity by the plants. The plasticity of clonal architecture in response to soil moisture in the stoloniferous herb, Duchesne...Architectural plasticity of clonal plants may enhance exploitation of soil moisture heterogeneity by the plants. The plasticity of clonal architecture in response to soil moisture in the stoloniferous herb, Duchesnea indica Focke, was investigated in an experiment with different soil moisture contents as treatments, i.e. 40%, 60%, 80%, 100% of the maximum moisture content of soil (MMCS). As soil moisture content increased, the spacer length, ramet density, branching intensity and branching angle of D. indica plants changed by quadratic curve. And the optimum habitat for the plants was at 80% of the MMCS. This architectural plasticity in D. indica was simulated through the Dynamic Logistic Model. The imitative effect was statistically satisfactory. Its architectural plasticity observed here may allow the species to show foraging behavior in its habitat where soil moisture is patchily distributed.展开更多
The interaction of Pb Cd can be observed not only in the uptake process of elements by plants and in their influence on the growth, but also in rhizosphere. The changes in extractable Cd and Pb concentrations in the ...The interaction of Pb Cd can be observed not only in the uptake process of elements by plants and in their influence on the growth, but also in rhizosphere. The changes in extractable Cd and Pb concentrations in the rhizosphere soil of rice plants, root exudates from wheat and wheat plant and their complexing capacity with Pb and Cd were investigated under different Pb and Cd treatments. Results showed that the concentration of extractable Cd in the rhizosphere of rice in red soil was markedly increased by Pb Cd interaction. It increased by 56% in the treatment with Pb and Cd added against that in the treatment with only Cd added in soil. The considerable differences in both composition and amount of root exudate from wheat and rice were found among different treatments. Pb and Cd might be complexed by root exudates. The concentrations of free Pb and Cd in the solution were increased markedly by adding root exudate from wheat and decreased by that from rice due to Pb Cd interaction. The distribution patterns of Pb and Cd in roots were affected by Pb Cd interaction, which accelerated transport of Pb into internal tissue and retarded accumulation of Cd in external tissue.展开更多
Effect of different shading levels (no-shading, 80% shading, and 40% shading) on photosynthetic and stomatal responses in cotton leaves were investigated under conditions of different soil water contents in summer mid...Effect of different shading levels (no-shading, 80% shading, and 40% shading) on photosynthetic and stomatal responses in cotton leaves were investigated under conditions of different soil water contents in summer midday. All cotton leaves exhibited similar basic responses to shading, including decreased net photosynthetic rates, a tendency to decrease in transpiration rates, and increased stomatal conductance and intercellular CO2 concentration. The leaf conductance of 80% shaded and 40% shaded plants increased by 28% and 16.7% compared with no-shaded plants at high water, respectively, but the net photosynthetic rates of 80% shaded and 40% shaded plants declined by 50% and 14.73%, respectively. Results showed that combined effect of soil moisture and shading on photosynthetic and stomatal responses in cotton leaves was very remarkable.展开更多
Here we use an analytical method to determine δ^13C in local plants and organic matter in the soils above Furong cave, Chong- qing, China. We also monitored d13C in dissolved inorganic carbon (DIC) of drip water, ...Here we use an analytical method to determine δ^13C in local plants and organic matter in the soils above Furong cave, Chong- qing, China. We also monitored d13C in dissolved inorganic carbon (DIC) of drip water, δ^13C of active deposits under the drip waters, and the concentration of air CO2 (PCO2). Based on these, we preliminarily studied the transportation characteristics of stable carbon isotope (^13C) in cave system of the subtropical karst area. The average δ^13C value of 27 local plant samples, which belong to 16 families, was -32% and the weighted δ^13C for surface dry biomass was -33%0. We found that for 54 soil samples collected from 5 soil profiles, δ^13C of soil organic matters was -22%o, which could be attributed to the different trans- portation rates of stable carbon isotopes during the decomposition of plants and organic matters in soils. The relatively lighter 12C tended to transfer into gaseous CO2, which made the relatively heavier ^13C concentrated in the soils. On the basis of moni- toring of DIC- δ^13C in drip waters from July 2009 to June 2010, we found that values in winter months were heavier and values in summer months were lighter in general, the reason of which was that in summer months, both the temperature and the hu- midity were comparatively higher, resulted in more CO2 with lighter δ^13C generated from organic matters decomposition and plants respiration. The average DIC- δ^13C value was -11%o, about 11%o heavier than the δ^13C of organic matters in soils, which proved that part of DIC in cave drip water was sourced from dissolution of inorganic carbonate (host rock, with heavier δ^13C. As for the δ^13C of active deposits at five drip water sites in Furong cave, they had almost the same variation with relatively light values. In other words, these active speleothems were deposited at equilibrium conditions for isotopic fractionation. These results suggest that the carbon isotopic information of speleothems could be used to track the evolution of local vegetation in certain situations.展开更多
Biological characteristics of methane emission were compared among Oryza sativa, Panicum crus-galli andCyperus difformis grown on paddy soil. The order of the amounts of methane emitted was P. crus-galli > O. sativ...Biological characteristics of methane emission were compared among Oryza sativa, Panicum crus-galli andCyperus difformis grown on paddy soil. The order of the amounts of methane emitted was P. crus-galli > O. sativa >C. difformis, with the former two 11 and 8 times as much as that of the latter, respectively. And it was just opposite tothat of the methane-forming activities of roots of the three plants. The diurnal changes of methane emission of thethree plants were relatively consistent with valleys during 11:00-14:00 and midnight and peaks during 8:00-11: 00,14:00- 20:00 and about 5:00 early morning. The methanogenic activites in rhizospheric soils were higher than those innonrhizospheric soils with P. crus-galli and O. sativa, but not with C. difformis. The pathways of methane release ofP. crus-galli and O . sativa were probably through the top gaps near the junctions of nodal plate and leaf sheath, how-ever in C. difformistopgaps from which methane could escape into atmosphere were not found.展开更多
A study on the effect of Pb-Cd interaction on plant growth and on the chemistry of elements in plants was conducted under greenhouse condition with red soil-wetland rice system in different growth stage. The results s...A study on the effect of Pb-Cd interaction on plant growth and on the chemistry of elements in plants was conducted under greenhouse condition with red soil-wetland rice system in different growth stage. The results showed that Pb-Cd interactions on growth and metal uptake varied with different growth stageS and chemical compounds added. The plant height and the root weight were markedly affected by Pb-Cd interiction in the young stage but not in the ripening stage of rice at the treatments of PbCl_2 and CdCl_2 added. However, the weight of rice straw in the ripening stage was significantly effected by Pb-Cd interaction with the treatments of Pb(OAc)_2 and CdCl_2. The chemistry of elements in plants also depended on Pb-Cd interaction in varying degrees on account of different plant parts and growth stage. It seems that Pb-Cd interaction occurred not only in roots but also in other parts of wetland rice.展开更多
On basis of aquatic and riverside-aquatic plants collection of O.V. fomina botanical garden is conducted research of ontogenesis, ecology, phenology, carpogenesis, biomorphology, life forms, adaptatations, of this gr...On basis of aquatic and riverside-aquatic plants collection of O.V. fomina botanical garden is conducted research of ontogenesis, ecology, phenology, carpogenesis, biomorphology, life forms, adaptatations, of this group's plants, peculiarities of their cultivation and application in conditions of temperate zone of Ukraine. Special values in research have ancient genera and species, which include representatives ofNymphaeaceae salisb, and trapaceae Dumort. families, 22 species, 6 varieties, 1 hybrid, 30 cultivars of which are presented in collection of garden in open and covered soil. For the first time in covered soil of two conservatories ecological modeling was conducted. Placement of plants is done in form of 5 models of artificial ecotopes, in 155 abatises. Four ecobiomorphological groups based on rhizome system were determined for Nymphaeaceae, among which conditionally-rhizome and conditionally-stolone are provided for the first time.展开更多
Kuwait is located in hyper arid desert environment. This geographical location and irrational human activities accelerate the expansion of land degradation problem. In order to rehabilitate the degraded areas it is ne...Kuwait is located in hyper arid desert environment. This geographical location and irrational human activities accelerate the expansion of land degradation problem. In order to rehabilitate the degraded areas it is necessary to use soil and water resources in sustainable manner. Owing to these reasons it is essential to use appropriate methods based on the scientific diagnostics of the problem. It is compulsory to identify, specify and test different efficient, cost-effective and environment friendly sound sustainable sand control measures such as, semi-circular bunds, square micro catchment and checker board palm leaves to rehabilitate degraded lands in Liyah refilled quarries. To evaluate the impact of rehabilitation method through mulching with date palm leaves soil samples were collected (control and rehabilitation sites with square micro catchment) prior to the implementation plan and post completion of the project (three years). In this study will be highlighted on detail the results of using square micro catchment and with short brief descriptions on other water harvesting techniques. The results showed an improvement of physical soil properties after the application of these techniques. Soil fertility increased through increasing the quantity of fine and very fine sand. The soil moisture at the surface soil increased from 0.085% to 1.62% after the treatment. The untreated soil has high bulk density about 2 g/cm3 and low porosity about 27%. However, after the soil was ploughed and mulched the bulk density decreased to 0.03 g/cm3. And porosity improved 98%. This study conserved the irrigation water through reducing the proportion of soil evaporation, in addition to the creation of optimum condition for plant growth. The aim of this study was to analyze the effect of using organic mulch date palm leaves with water harvesting techniques on the physical and biological properties of degraded soil in Liyah area.展开更多
Salinity of soils or water poses an increasing threat to food production due to climate change. Plant breeding programs were applied to improve salt tolerance in new wheat genotypes to overcome this problem. The aim o...Salinity of soils or water poses an increasing threat to food production due to climate change. Plant breeding programs were applied to improve salt tolerance in new wheat genotypes to overcome this problem. The aim of this research work is to estimate the realized improvement in salt tolerance of the selected genotypes through plant breeding programs. The comparison experiments were conducted in salinized soils at two locations for two years as compared with two local cultivars. All the selected genotypes derived from F2 populations after six cycles of exposure to high salinity level were tested for salt tolerance during all growth stage. At harvest stage, seed yield and its components were studied for the comparison. Results showed that there were significant differences between all selected genotypes and local eultivars in their overall sensitivities to soil salinity. All selected genotypes were superior in seed yield and its components at maturity to those of the local cultivars at the two location and years. Clearly, all the selected genotypes exhibited more than twice seed yield/m2 compared with that obtained from local cultivars. The results also indicated that there were differences among selected genotypes in their responses to soil salinity between locations and years, but not significant. Important thing is significant improvement in selected genotypes was achieved in their salt tolerance through six cycles of screening and selection to high salinity level. The conclusion is a strong possibility to improve salt tolerant genotypes of wheat with high salt tolerance through plant breeding programs.展开更多
Plum is the major fruit species in the area of North Montenegro. Over a long period of growing in this region, autochthonous cultivars adapted, and have been achieving satisfactory results, despite poor growing condit...Plum is the major fruit species in the area of North Montenegro. Over a long period of growing in this region, autochthonous cultivars adapted, and have been achieving satisfactory results, despite poor growing conditions. A study conducted over a period of three years in a North Montenegro region included in situ identification of autochthonous plum cultivars. Observation and recording of their phenological and pomological traits were performed using International Board for Plant Genetic Resources (IBPGR) and International union for the Protection of New Varieties of plants (UPOV) methodologies. Eighteen cultivars derived from Prunusdomestica L. and two cultivars derived from P. insititia L. were identified. Flowering started between March 26th and April 12th and fruit ripening between 13th of July (Petrovaca) and 18th September (Trnovaca). Fruit weight ranged from 6.65 g ± 0.235 g to 53.88 g ± 0.654 g respectively and stone weight from 0.16 g ±0.003 g to 2.20 g ± 0.711 g. The cultivars were classified as being extremely small in terms of fruit size, except for cvs Crvenadurgulja (big fruit size). Rounded fruit shape and light green ground color were dominant. Skin color ranged from amber to black. Yellow green was a dominant flesh color and medium flesh firmness predominated. The fruits of the above cultivars could be processed, particularly into plum brandy, or they could be used fresh or dried. The selected plum cultivars can be used in breeding programmes, as rootstocks as well as in further disease related systematic studies under field and laboratory conditions.展开更多
基金Supported by the"Twelfth Five-Year Plan"of the National Science and Technology(2011BAD31B01)~~
文摘[Objective] The aim of this study was to study the influence of plants on the soil moisture content under different fertilization.[Method] Using sainfoin,sweet clover,Astragalus adsurgens,alfalfa,ryegrass,little flower,white clover as experimental material,this study explored the effects of soil moisture on the improvement of soil quality.[Result] Results showed that the soil moisture content of different plants follows as:sainfoin 〉sweet clover 〉Astragalus adsurgens 〉alfalfa perennial ryegrass 〉small crown 〉white clover,and the average moisture content reached 24.13% which was 2.45% higher than that of control group.At planting white clover,sweet clover,under the condition of 7 kinds of crops,in the treatments without fertilizer and with organic fertilizer,soil moisture content of soil in 0-20 cm grew significantly.[Conclusion] The application of organic fertilizer and growing of plants would improve soil moisture in abandoned fields,enhance the ability of soil water supply,and improve soil fertility.
基金Project supported by the European Union (No.EU QLK5-CT2002-01841)
文摘Sloping and mountainous olive production systems are widespread, occupying large parts of the Mediterranean landscape prone to water erosion. Soil erosion, runoff, and soil water content patterns over a three-year period were monitored in erosion plots on a mountainside with rainfed olive (Olea europaea cv. Picual) trees under: 1) non-tillage with barley strips of 4 m width (BS); 2) non-tillage with native vegetation strips of 4 m width (NVS); and 3) non-tillage without plant strips (NT). The erosion plots, located in Lanjaron (Granada, south-eastern Spain), on a 30% slope, were 192 m2 in area. For assessing soil water dynamics in real-time and near-continuous soil water content measurements, multisensor capacitance probes were installed in the middle of plant strips and beneath the olive tree at five soil depths (10, 20, 30, 50, and 100 cm). The highest erosion and runoff rates were measured under NT, with a mean of 17.3 Mg ha-1 year-1 and 140.0 mm year-1, respectively, over the entire study period. The BS and NVS with respect to the NT reduced erosion by 71% and 59% and runoff by 95% and 94%, respectively. In general, greater available soil water content was found under BS than NVS and NT, especially beneath the olive tree canopies. These results supported the recommendation of non-tillage with barley strips in order to reduce erosion and to preserve soil water for trees in traditional mountainous olive-producing areas, where orchards cover vast tracts of land.
文摘Through a simulation test conducted with soil columns (61.8cm in diameter) in field condition,effect of crop planting upon the regulation of salt-water dynamics in soils was studied by monitoring of salt-water dynamics in situ,using soil salinity sensors and tensiometers.The results indicated that the amount of water absorbed by crops from the soil was generally larger than the decrement of water consumption from soil surface evaporation reduced by the crop covering the soil surface and improving the soil structure,therefore,under the conditions of crop growing and non-irrigation,water content in soil profile was less than that without crop growing,and the gradient of negative pressure of soil water in soil profile especially in the root zone was enlarged,thus causing the water flowing from subsoils into root zone and increasing the groundwater moving upwards into soil layer via capillary rise,so that the groundwater evaporation increased.Consequently,under the condition of crop growing,the salt was mainly accumulated towards the root zone rather than to the top soil.the accumulating rate of salt in groundwater via capillary rise of soil water to subsoils was increased thereby.
基金National Natural Science Foundation of China(No.41371062)Collaborative Innovation Center for Major Ecological Security Issues of Jiangxi Province and Monitoring Implementation(No.JXS-EW-00)+1 种基金National Basic Research Program of China(No.2012CB417003)Science Foundation of Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences(No.NIGLAS2012135001)
文摘Hydrological regime has been widely recognized as one of the major forces determining vegetation distribution in seasonally flooded wetland. Poyang Lake, the largest freshwater lake in China, has been encountering dramatic changes in hydrological conditions in last decade, which greatly influenced the wetland vegetations. To explore the relationships between hydrology and vegetation distri- bution, water-table depth, soil moisture, species composition, diversity and biomass were measured at a seasonally flooded wetland section at Wucheng National Nature Reserve. Three plant communities, Artemisia capillaris, Phragmites australis and Carex cineras- cens communities, were examined which are zonally distributed from upland to lakeshore with decreasing elevation. Canonical corre- spondence analysis (CCA), spearmen correlation and logistic regression were adopted to analyze the relationships between vegetation characteristics and hydrological variables of water-table depth and soil moisture. Results show that significant hydrological gradient exist along the wetland transect. Water-table demonstrates a seasonal variation and is consistently deepest in A. capillaris community (ranging from q).5 m above ground to +10.3 m below ground), intermediate in P. australis community (-2.6 m to +7.8 m) and shallow- est in C. cinerascens community (-4.5 m to +6.1 m). Soil moisture is lowest and most variable in A. capillaris community, highest and least variable in P. australis community, and intermediate and moderate variable in C. cinerascens community. The CCA ordination indicated that variables of water-table depth and soil moisture are strongly related to community distribution, which explained 81.7% of the vegetation variations. Species diversity indices are significantly positively correlated with soil moisture and negatively correlated with moisture variability, while above- and belowground biomass are positively correlated with moisture. Above- and belowground biomass present Gaussian models along the gradient of average water-table depth in growing season, while species diversity indices show bimodal patterns. The optimal average water-table depths for above- and belowground biomass are 0.8 m and 0.5 m, respectively, and are 2.2 m and 2.4 m for species richness and Shannon-Wiener indices, respectively. Outcomes of this work improved the under- standings of the relationship between hydrology and vegetation.
文摘In this paper, the hydraulic resistances and capacitances were evaluated. based on the development of non-(?) model of water flow in the soil-plant system and the simulating experiment work.The results show that the mean hydraulic resistance in the soil-plant system is 6.79×109 MPa·S·m-3; the mean hydraulic capacitance in the system is 5.2×107m3·MPa-1. In the components of hydraulic capacitance in the system, the capacitance in soil (81.8×10-6m3·MPa ) is the biggest and its variability with suii water potential is extremely strong, the capacitance in plant (5.3×10-7m3·MPa-1) is much smaller than that in soil, and the capacitance in shoots (15.5×10-7m3·2MPa-1) is bigger than that in roots (8.4×10-7m3·2MPa-1). An interesting result is that the capacitance in plant is almost equivalent to that in the soil-plant system.
基金supported by the National High Technology Research and Development Program (863 Program) of China(No.2002AA2Z4321-02)
文摘Interaction between soil water and nutrients plays an important role in sustainable crop management in semi-arid environments.On the basis of a field experiment conducted from 2000 to 2003,this study examined the coupled effects of irrigation and fertilizers on maize growth and yield in a semi-arid region of northeastern China.In terms of plant productivity,nitrogen fertilizer had the most significant effect followed by irrigation and phosphate levels.The combined application of nutrients and irrigation exerted a synergistic effect on the grain yield of maize plants.Regression analysis indicated that optimal levels of nitrogen and phosphate,in addition to adequate irrigation,could greatly improve the efficiency of grain production.Similarly,optimization of soil nutrient availability substantially increased water use efficiency.These suggested that for the most efficient and sustainable crop production,irrigation and nutrient management should be based on a quantitative understanding of water/nutrients interaction,particularly in semi-arid and arid regions.
文摘Superabsorbents such as cross-linked PAM (polyacrylamides) are frequently used to increase water availability to plants. Commercial PAM providers suggest that besides its increasing water availability, PAMs also increase nutrient availability to plants. To test this premise, four application rates (0.0 g·kg^-1, 0.33 g·kg^-1, 1.66 g·kg^-1, 3.33 g·kg^-1 and 6.66 g·kg^-1) ofa PAM were mixed with sandy and loamy soils to evaluate its effect on nutrient leaching and retention in these soils. Miscible displacements of chloride were conducted on columns of PAM-soil mixtures and results were evaluated by an equilibrium CDE (convection dispersion equation) model. Increasing the PAM rates up to 1.66 g·kg^-1 resulted in increased early appearance and dispersive transport of chloride in sand. In addition, increasing the PAM rates gradually caused increased tailing of the breakthrough curves of chloride in both soils. These suggested that PAM increased preferential transport of chloride while it increased retention of chloride in soils. Effect of PAM on preferential transport and retardation of CI was greater in sand than loam.
基金Supported by Multi-goal Geochemical Survey in Laoling-Hekou Regions,Shandong Province of National Soil Survey and Pollution Prevention(GZTR20060104)~~
文摘Based on the geochemical data obtained from the national project about the prevention and control of soil contamination, this paper explored the properties of soil chemical elements in Huanghuaihai Plain, Shandong Province. The results showed that among the grade-one nutritive elements in soil, organic matter, nitrogen and phosphorus were relatively deficient while potassium was rich. Meanwhile, as the grade-two nutritive elements, calcium oxide and magnesium oxide were relatively short and sulfur’s content was abundant. About the other beneficial and trace nutri-tive elements, iron oxide, manganese, molybdenum and boron were deficient, but the content of chlorine was high, hardly lack. The main barriers to improving land productivity were soil salinization and soil heavy metal contamination. The values of soil integrated fertility index that most of the soil in the study area is middle-lower fertilized. Specifical y, the low fertility area and lower fertility area are 6 1604 and 1 244 km2 respectively, occupying about 97.43% and 1.97% of the total area. The moderate fertility soil has an area of 172 km2, occupying about 0.27% of the total area. The higher fertility soil covers an area of 128 km2, while the high fertility area of only 76 km2. This article proposed scientific fertilization, elimination of soil obsta-cle, remediation of heavy-metal-contaminated soil and other effective measures to improve land productivity according to the basic investigation results, which provides a good technological support for the planning and development of good-quality and high-benefit agriculture.
文摘Architectural plasticity of clonal plants may enhance exploitation of soil moisture heterogeneity by the plants. The plasticity of clonal architecture in response to soil moisture in the stoloniferous herb, Duchesnea indica Focke, was investigated in an experiment with different soil moisture contents as treatments, i.e. 40%, 60%, 80%, 100% of the maximum moisture content of soil (MMCS). As soil moisture content increased, the spacer length, ramet density, branching intensity and branching angle of D. indica plants changed by quadratic curve. And the optimum habitat for the plants was at 80% of the MMCS. This architectural plasticity in D. indica was simulated through the Dynamic Logistic Model. The imitative effect was statistically satisfactory. Its architectural plasticity observed here may allow the species to show foraging behavior in its habitat where soil moisture is patchily distributed.
文摘The interaction of Pb Cd can be observed not only in the uptake process of elements by plants and in their influence on the growth, but also in rhizosphere. The changes in extractable Cd and Pb concentrations in the rhizosphere soil of rice plants, root exudates from wheat and wheat plant and their complexing capacity with Pb and Cd were investigated under different Pb and Cd treatments. Results showed that the concentration of extractable Cd in the rhizosphere of rice in red soil was markedly increased by Pb Cd interaction. It increased by 56% in the treatment with Pb and Cd added against that in the treatment with only Cd added in soil. The considerable differences in both composition and amount of root exudate from wheat and rice were found among different treatments. Pb and Cd might be complexed by root exudates. The concentrations of free Pb and Cd in the solution were increased markedly by adding root exudate from wheat and decreased by that from rice due to Pb Cd interaction. The distribution patterns of Pb and Cd in roots were affected by Pb Cd interaction, which accelerated transport of Pb into internal tissue and retarded accumulation of Cd in external tissue.
基金Project (No. 49725102) supported by the National Outstanding Youth Science Foundation of China.
文摘Effect of different shading levels (no-shading, 80% shading, and 40% shading) on photosynthetic and stomatal responses in cotton leaves were investigated under conditions of different soil water contents in summer midday. All cotton leaves exhibited similar basic responses to shading, including decreased net photosynthetic rates, a tendency to decrease in transpiration rates, and increased stomatal conductance and intercellular CO2 concentration. The leaf conductance of 80% shaded and 40% shaded plants increased by 28% and 16.7% compared with no-shaded plants at high water, respectively, but the net photosynthetic rates of 80% shaded and 40% shaded plants declined by 50% and 14.73%, respectively. Results showed that combined effect of soil moisture and shading on photosynthetic and stomatal responses in cotton leaves was very remarkable.
基金supported by Open Foundation of the Karst Dynamics Laboratory,China (Grant Nos.GKN0842008 and KDL2008-08)National Natural Science Foundation of China (Grant Nos.40802035,41030103,41172165 and 40971122)+1 种基金Open Foundation of the State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,CAS,China (Grant No. SKLLQG0907)Key Project of Special Research Foundation of Southwest University,China (Grant Nos. XDJK2009B016 and XDJK2009C106)
文摘Here we use an analytical method to determine δ^13C in local plants and organic matter in the soils above Furong cave, Chong- qing, China. We also monitored d13C in dissolved inorganic carbon (DIC) of drip water, δ^13C of active deposits under the drip waters, and the concentration of air CO2 (PCO2). Based on these, we preliminarily studied the transportation characteristics of stable carbon isotope (^13C) in cave system of the subtropical karst area. The average δ^13C value of 27 local plant samples, which belong to 16 families, was -32% and the weighted δ^13C for surface dry biomass was -33%0. We found that for 54 soil samples collected from 5 soil profiles, δ^13C of soil organic matters was -22%o, which could be attributed to the different trans- portation rates of stable carbon isotopes during the decomposition of plants and organic matters in soils. The relatively lighter 12C tended to transfer into gaseous CO2, which made the relatively heavier ^13C concentrated in the soils. On the basis of moni- toring of DIC- δ^13C in drip waters from July 2009 to June 2010, we found that values in winter months were heavier and values in summer months were lighter in general, the reason of which was that in summer months, both the temperature and the hu- midity were comparatively higher, resulted in more CO2 with lighter δ^13C generated from organic matters decomposition and plants respiration. The average DIC- δ^13C value was -11%o, about 11%o heavier than the δ^13C of organic matters in soils, which proved that part of DIC in cave drip water was sourced from dissolution of inorganic carbonate (host rock, with heavier δ^13C. As for the δ^13C of active deposits at five drip water sites in Furong cave, they had almost the same variation with relatively light values. In other words, these active speleothems were deposited at equilibrium conditions for isotopic fractionation. These results suggest that the carbon isotopic information of speleothems could be used to track the evolution of local vegetation in certain situations.
文摘Biological characteristics of methane emission were compared among Oryza sativa, Panicum crus-galli andCyperus difformis grown on paddy soil. The order of the amounts of methane emitted was P. crus-galli > O. sativa >C. difformis, with the former two 11 and 8 times as much as that of the latter, respectively. And it was just opposite tothat of the methane-forming activities of roots of the three plants. The diurnal changes of methane emission of thethree plants were relatively consistent with valleys during 11:00-14:00 and midnight and peaks during 8:00-11: 00,14:00- 20:00 and about 5:00 early morning. The methanogenic activites in rhizospheric soils were higher than those innonrhizospheric soils with P. crus-galli and O. sativa, but not with C. difformis. The pathways of methane release ofP. crus-galli and O . sativa were probably through the top gaps near the junctions of nodal plate and leaf sheath, how-ever in C. difformistopgaps from which methane could escape into atmosphere were not found.
文摘A study on the effect of Pb-Cd interaction on plant growth and on the chemistry of elements in plants was conducted under greenhouse condition with red soil-wetland rice system in different growth stage. The results showed that Pb-Cd interactions on growth and metal uptake varied with different growth stageS and chemical compounds added. The plant height and the root weight were markedly affected by Pb-Cd interiction in the young stage but not in the ripening stage of rice at the treatments of PbCl_2 and CdCl_2 added. However, the weight of rice straw in the ripening stage was significantly effected by Pb-Cd interaction with the treatments of Pb(OAc)_2 and CdCl_2. The chemistry of elements in plants also depended on Pb-Cd interaction in varying degrees on account of different plant parts and growth stage. It seems that Pb-Cd interaction occurred not only in roots but also in other parts of wetland rice.
文摘On basis of aquatic and riverside-aquatic plants collection of O.V. fomina botanical garden is conducted research of ontogenesis, ecology, phenology, carpogenesis, biomorphology, life forms, adaptatations, of this group's plants, peculiarities of their cultivation and application in conditions of temperate zone of Ukraine. Special values in research have ancient genera and species, which include representatives ofNymphaeaceae salisb, and trapaceae Dumort. families, 22 species, 6 varieties, 1 hybrid, 30 cultivars of which are presented in collection of garden in open and covered soil. For the first time in covered soil of two conservatories ecological modeling was conducted. Placement of plants is done in form of 5 models of artificial ecotopes, in 155 abatises. Four ecobiomorphological groups based on rhizome system were determined for Nymphaeaceae, among which conditionally-rhizome and conditionally-stolone are provided for the first time.
文摘Kuwait is located in hyper arid desert environment. This geographical location and irrational human activities accelerate the expansion of land degradation problem. In order to rehabilitate the degraded areas it is necessary to use soil and water resources in sustainable manner. Owing to these reasons it is essential to use appropriate methods based on the scientific diagnostics of the problem. It is compulsory to identify, specify and test different efficient, cost-effective and environment friendly sound sustainable sand control measures such as, semi-circular bunds, square micro catchment and checker board palm leaves to rehabilitate degraded lands in Liyah refilled quarries. To evaluate the impact of rehabilitation method through mulching with date palm leaves soil samples were collected (control and rehabilitation sites with square micro catchment) prior to the implementation plan and post completion of the project (three years). In this study will be highlighted on detail the results of using square micro catchment and with short brief descriptions on other water harvesting techniques. The results showed an improvement of physical soil properties after the application of these techniques. Soil fertility increased through increasing the quantity of fine and very fine sand. The soil moisture at the surface soil increased from 0.085% to 1.62% after the treatment. The untreated soil has high bulk density about 2 g/cm3 and low porosity about 27%. However, after the soil was ploughed and mulched the bulk density decreased to 0.03 g/cm3. And porosity improved 98%. This study conserved the irrigation water through reducing the proportion of soil evaporation, in addition to the creation of optimum condition for plant growth. The aim of this study was to analyze the effect of using organic mulch date palm leaves with water harvesting techniques on the physical and biological properties of degraded soil in Liyah area.
文摘Salinity of soils or water poses an increasing threat to food production due to climate change. Plant breeding programs were applied to improve salt tolerance in new wheat genotypes to overcome this problem. The aim of this research work is to estimate the realized improvement in salt tolerance of the selected genotypes through plant breeding programs. The comparison experiments were conducted in salinized soils at two locations for two years as compared with two local cultivars. All the selected genotypes derived from F2 populations after six cycles of exposure to high salinity level were tested for salt tolerance during all growth stage. At harvest stage, seed yield and its components were studied for the comparison. Results showed that there were significant differences between all selected genotypes and local eultivars in their overall sensitivities to soil salinity. All selected genotypes were superior in seed yield and its components at maturity to those of the local cultivars at the two location and years. Clearly, all the selected genotypes exhibited more than twice seed yield/m2 compared with that obtained from local cultivars. The results also indicated that there were differences among selected genotypes in their responses to soil salinity between locations and years, but not significant. Important thing is significant improvement in selected genotypes was achieved in their salt tolerance through six cycles of screening and selection to high salinity level. The conclusion is a strong possibility to improve salt tolerant genotypes of wheat with high salt tolerance through plant breeding programs.
文摘Plum is the major fruit species in the area of North Montenegro. Over a long period of growing in this region, autochthonous cultivars adapted, and have been achieving satisfactory results, despite poor growing conditions. A study conducted over a period of three years in a North Montenegro region included in situ identification of autochthonous plum cultivars. Observation and recording of their phenological and pomological traits were performed using International Board for Plant Genetic Resources (IBPGR) and International union for the Protection of New Varieties of plants (UPOV) methodologies. Eighteen cultivars derived from Prunusdomestica L. and two cultivars derived from P. insititia L. were identified. Flowering started between March 26th and April 12th and fruit ripening between 13th of July (Petrovaca) and 18th September (Trnovaca). Fruit weight ranged from 6.65 g ± 0.235 g to 53.88 g ± 0.654 g respectively and stone weight from 0.16 g ±0.003 g to 2.20 g ± 0.711 g. The cultivars were classified as being extremely small in terms of fruit size, except for cvs Crvenadurgulja (big fruit size). Rounded fruit shape and light green ground color were dominant. Skin color ranged from amber to black. Yellow green was a dominant flesh color and medium flesh firmness predominated. The fruits of the above cultivars could be processed, particularly into plum brandy, or they could be used fresh or dried. The selected plum cultivars can be used in breeding programmes, as rootstocks as well as in further disease related systematic studies under field and laboratory conditions.