Cangmai 6005 is a national wheat variety approved by Cangzhou Academy of Agriculture and Forestry Sciences,which has the characteristics of drought resistance,salt tolerance,high yield and stable yield. According to t...Cangmai 6005 is a national wheat variety approved by Cangzhou Academy of Agriculture and Forestry Sciences,which has the characteristics of drought resistance,salt tolerance,high yield and stable yield. According to the characteristics of dry-alkali land in Cangzhou City and the variety characteristics,the new cultivation technique was completed.展开更多
The objective of the study reported here was to determine whether LANDSAT TM images could be used to quantify changes in land-use and ecosystem services in Yuanmou County. The sizes of six land use/land cover (LUCC)...The objective of the study reported here was to determine whether LANDSAT TM images could be used to quantify changes in land-use and ecosystem services in Yuanmou County. The sizes of six land use/land cover (LUCC) categories were estimated in Yuanmou County according to the LANDSAT TM images in the summer of 1986 and 2005. Coefficients published by Xie Gaodi and co-workers in 2003 were used to value changes in ecosystem services delivered by each land use/land cover category, and the ecosystem services sensitivity analysis was conducted to determine the effect of manipulating these coefficients on the estimated values. The important results are summarized as followings. (1) The estimated size of cultivated land, pasture land, water area and unused land decreased by 6.39%, 1.35%, 2.25% and 10.67% respectively between 1986 and 2005. By contrast, the estimated size of forest land and construction land increased by about 2.23% and 71.15% respectively between 1986 and 2005. (2) The total ecosystem services value (EVS) of the study area increased from 2 142 132 609.46 yuan to 2 146 416 621.00 yuan, with the net increase of 4 284 011.54 yuan during the 20-year time period. (3) The coefficient sensitivity (CS) of the study are less than unity in all cases (CS 〈 1). This indicates that the total ecosystem values estimated for the study area are relatively inelastic with respect to the ecosystem service coefficients. While this implies that our estimates are robust and the coefficient is reasonable, highly under or over valued coefficients can substantially affect the veracity of estimated changes in ecosystem service values overtime even when the CS are less than unity(CS 〈 1).展开更多
The study, conducted at the Research Farm of the College of Agriculture, University of Tabriz in 2021, focused on the effects of various nitrogen-fixing bacterial isolates, biofertilizers containing nitrogen and phosp...The study, conducted at the Research Farm of the College of Agriculture, University of Tabriz in 2021, focused on the effects of various nitrogen-fixing bacterial isolates, biofertilizers containing nitrogen and phosphorus, as well as iron and zinc foliar applications on mustard growth under rainfed conditions. The results indicated that biofertilizers, whether used alone or in combination with chemical fertilizers, produced comparable grain and oil outputs compared to chemical fertilizers alone. Additionally, the application of iron and zinc through foliar spraying significantly enhanced both grain and oil production. These findings suggest that integrating nitrogen-fixing bacteria and biofertilizers could reduce reliance on chemical nitrogenous fertilizers, leading to decreased production expenses, improved product quality, and minimized environmental impact. This study highlights the potential for sustainable agricultural practices in dry land farming as a viable alternative to traditional chemical-intensive methods. Substituting chemical nitrogenous fertilizers with nitrogen-fixing bacteria or biofertilizers could result in cost savings in mustard grain and oil production while promoting environmental sustainability.展开更多
The desertification process is rapidly developing at present and 61.5% of the land area in the zone are already desertified.Among the desertified lands, 26.9% are seriously desertified, 25% most seriously desertified ...The desertification process is rapidly developing at present and 61.5% of the land area in the zone are already desertified.Among the desertified lands, 26.9% are seriously desertified, 25% most seriously desertified and 47.4% are the lands where desertification is under way. They are caused by over-reclamation for farming, over-grazing, unreasonable collection of firewood,the destruction of vegetation and the misuse of water resources. Under the ecological environment in semi-arid zone,the degraded environment process possesses the ability of restoring to its original status as soon as the interruption of excessive human activities are eliminated. The fencing- and-self-cultivating method is an effective measure adopted universally in semi-arid zone to cure the desertified lands.The desertified lands can be readjusted and controlled easily if other controlling measures are supplemented. The fundamental ways to control desertification are to utilize rationally the resources, to readjust the existing展开更多
The developmental tendency of dry land farming technologies in the semiarid area of China were reviewed based on the overview of recent progress in dry land farming researches from China and oversea. It was emphasized...The developmental tendency of dry land farming technologies in the semiarid area of China were reviewed based on the overview of recent progress in dry land farming researches from China and oversea. It was emphasized that conservation tillage, limited irrigation, genetic modification and chemical control are the important aspects for the dry land farming research and development of the future. In addition, some consid-展开更多
The dynamics of soil organic carbon(SOC)in cropland is one of the central issues related to both soil fertility and environmental safety. However, little information is available at county level regarding the spatiote...The dynamics of soil organic carbon(SOC)in cropland is one of the central issues related to both soil fertility and environmental safety. However, little information is available at county level regarding the spatiotemporal variability of SOC in the southwestern mountainous region of China. Thus, this study aimed to explore spatiotemporal changes of SOC in the cultivated soil layer of dry land in Mojiang County,Yunnan Province, China. Data were obtained from the second national soil survey(SNSS) of 1985 and soil tests for fertilizer application carried out by the Mojiang Agricultural Bureau in 2006. The ANOVA test was applied to determine any significant differences between the datasets, while semivariogram analysis was performed on geostatistics via an ordinary Kriging method in order to map spatial patterns of soil organic carbon density(SOCD). The results revealed that SOCD in the cultivated soil layer significantly decreased from 3.93 kg m^(-2) in 1985 to 2.89 kg m^(-2) in 2006, with a total soil organic carbon stock(SOCS) decrease of 41.54×10~4 t over the same period. SOCS levels fell most markedly in yellow-brown soil at a rate of51.52%, while an increase of 8.70% was found in the analysed latosol. Geostatistical analysis also showed that the recorded changes in SOCD between 1985 and2006 were spatially structured. The decreasing trend might be attributed to the combined action of intense cultivation, major crop residue removal without any protective tillage measures, unreasonable fertilization and natural climatic diversity inducing a large decrease in SOC in the studied cultivated dry land region of Mojiang County. Therefore, management measures such as protective tillage should be undertaken in order to enhance soil C sequestration.展开更多
A number of remotely sensed land cover datasets with spatial resolutions ~〈 1 km have recently become available or are in the process of being mapped. The application of these higher resolution and more up-to-date la...A number of remotely sensed land cover datasets with spatial resolutions ~〈 1 km have recently become available or are in the process of being mapped. The application of these higher resolution and more up-to-date land cover datasets in chemical transport models (CTMs) is expected to improve the simulation of dry deposition and biogenic emissions of non-methane volatile organic compounds (NMVOCs), which affect ozone and other secondary air pollutants. In the present study, we updated the land cover dataset in the nested-grid GEOS-Chem CTM with the 1 km resolution GLC2000 land cover map and examined the resulting changes in the simulation of surface ozone and sulfate over China in July 2007. Through affecting the dry deposition velocities of ozone and its precursors, using GLC2000 in the dry deposition module can decrease the simulated surface ozone by 3% (up to 6 ppb) over China. Simulated surface sulfate shows an increase of 3% in northwestern China and a decrease of 1% in northern China. Applying GLC2000 in the biogenic emissions of the NMVOC module can lead to a 0.5--4.5 ppb increase in simulated surface ozone over East China, mainly driven by the larger cove~:age of broadleaf trees in East China in the GLC2000 dataset. Our study quantifies the large sensitivity to land cover dataset~ with different spatial resolutions and time periods of simulated secondary air pollutants over China, supporting ongoing research efforts to produce high resolution and dynamically updated land cover datasets over China, as well as for the globe.展开更多
Dry land crops such as sorghums (grain sorghum, promising feedstocks for fuel ethanol production. The major issue sweet sorghum and forage sorghum) have been identified as for using the sweet sorghum as feedstock is...Dry land crops such as sorghums (grain sorghum, promising feedstocks for fuel ethanol production. The major issue sweet sorghum and forage sorghum) have been identified as for using the sweet sorghum as feedstock is its stability at room temperature. At room temperature, the sweet sorghum juice could lose from 40% to 50% of its fermentable sugars from 7 to 14 days No significant sugar content and profile changes were observed in juice stored at refrigerator temperature in two weeks. Ethanol fermentation efficiencies of fresh and frozen juice were high (-93%). Concentrated juice (≥25% sugar) had significantly lower efficiencies and large amounts of fructose left in finished beer; however, winery yeast strains and novel fermentation techniques may solve these problems. The ethanol yield from sorghum grain increased as starch content increased. No linear relationship between starch content and fermentation efficiency was found. Key factors affecting the ethanol fermentation efficiency of sorghum include starches and protein digestibility, amylose-lipid complexes, tannin content, and mash viscosity. Life cycle analysis showed a positive net energy value (NEV) = 25 500 Btu/gal ethanol. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) were used to determine changes in the structure and chemical composition of sorghum biomasses. Dilute sulfuric acid pretreatment was effective in removing the hemicellulose from biomasses and exposing the cellulose for enzymatic hydrolysis. Forage sorghum lignin had a lower syringyl/guaiacyl ratio and its pretreated biomass was easier to hydrolyze. Up to 72% hexose yield and 94% pentose yield were obtained by using a modified steam explosion with 2% sulfuric acid at 140℃ for 30 min and enzymatic hydrolysis with cellulase.展开更多
Based on the observed soil water data from experimental site located in southeast of Shanxi Province, the physical characteristics of soil water, crop effect on soil moisture, and the field water circulation pattern w...Based on the observed soil water data from experimental site located in southeast of Shanxi Province, the physical characteristics of soil water, crop effect on soil moisture, and the field water circulation pattern were studied by using the water balance method. The results suggested that soil water deficit often exists in fields of these areas. From May to June, the amount of water deficit in bare land rises to the maximum (232 8 mm) and falls to the minimum (66 6 mm) from August to September. By comparison, because of crop transpiration, both soil water deficit and dry soil layer in cultivated land are 15 1—40 4 mm more and 20—70 mm deeper respectively than those of bare land. Crops mainly planted in these areas have a relatively weak utilization ability to soil water. Winter wheat has the highest utilization ability to soil water among the crops planted in these areas. The soil water utilization ability of winter wheat is 26 2%—30 6% and winter wheat can use soil water that lies in soil layer below a depth of over 200 cm. Spring corn and millet can only consume soil water with the maximum ability of 13 4% and the deepest layer of 0—50 cm or 0—100cm, which shows that the soil water utilization ability of winter wheat is higher than that of spring crops. After crop is ripe, more than 41% of available soil water remains unused in field. So, increasing soil water storage and improving crop utilization ability to soil water by adopting efficient agrotechnique measures are the main ways for improving agricultural productivity in dry farming areas of Northern China.展开更多
The lower Ili River Basin is located in semi-arid area, and the annual rainfall is 177mm. Therefore, the irrigation is inevitable for agriculture. Large-scale irrigated agriculture had been developed since 1960's in ...The lower Ili River Basin is located in semi-arid area, and the annual rainfall is 177mm. Therefore, the irrigation is inevitable for agriculture. Large-scale irrigated agriculture had been developed since 1960's in the lower parts of the river and the total irrigated area is about 32 000 hm2. In the project area, the paddy rice-upland crop rotation has been practiced. Due to the domestic water use for hydropower and agriculture as well as water use among riparian countries, the deficit of water for agriculture in the lower part has been concerned. The authors, therefore, conducted the field survey and water balance analysis of the Akdara irrigation project in the lower Ill River Basin in order to assess the land and water uses. Moreover, the impact of the water use on water environment to the basin was analyzed. The following results were obtained as following (1) the groundwater level in the irrigated district varied from 1.5 m to 3.5 m through year. (2) 1970's groundwater level was drastically raised from 8 m to 3 m and the groundwater had been recharged in this period. (3) Water use efficiency of agriculture, which is the ratio of total evapotranspiration to the total water withdrawal was as low as 0.23.展开更多
The phenological phase, plant height, filler number, nutritional composition, yield and stem/leaf ratio of three oat (Arena sativa) varieties (lines) in winter dry land of Hunan were studied. The result shows that...The phenological phase, plant height, filler number, nutritional composition, yield and stem/leaf ratio of three oat (Arena sativa) varieties (lines) in winter dry land of Hunan were studied. The result shows that the three oat varieties were greatly different in plant height, nutritional composition, yield and stem/leaf ratio. Baiyan 7 had the best performance, with the plant height, tiller number and fresh yield of 101.67cm, 7.6 tiller/plant and 70.15 t/hm2 respectively ; the crude protein content of dry matter of Baiyan 7 was 32.63% ; the leaf weight per tiller of Baiyan 7 accounted for 31.6% of single tiller weight, while those of Baiyan 8 and Baiyan 2 accounted for 31.3% and 29.2%, respectively. The single tiller weight of oat could be estimated/calculated by the model/formula Y = 0.043 7X - 2.89 ( R2 = 0.913 4, P 〈 0.01 ), where Y is the single tiller weight ( g ) and X is the plant height (cm). Comprehensive analysis showed that Baiyan 7 had higher yields and stem/leaf ratio. Thus, Baiyan 7 is more suitable for planting as a winter-spring forage in the winter dry land of Hunan.展开更多
Hibridization is one of breeding strategy to increase productivity of crop including physic nut (Jatropha curcas Linn.). This study aimed to obtain information productivity per hectare and seed oil content of 11 numbe...Hibridization is one of breeding strategy to increase productivity of crop including physic nut (Jatropha curcas Linn.). This study aimed to obtain information productivity per hectare and seed oil content of 11 numbers of physic nut hybrids and their parental in four dry lands. The research was conducted in four dry land: Kalipare-Malang, Oro-oro Pule-Kejayan Pasuruan, Kedung Pengaron-Pasuruan and Jorongan-Leces Probolinggo. The materials used in this research are the eleven result numbers of physic nut hybrids, they are SP38XHS49, SP8XHS49, SP8XSP16, SP8XSP38, SP33XHS49, SM35XHS49, SM35XSP38, IP1AXHS49, IP1AXSP38, IP1PXHS 49, IP1PXSP38, and their parental, they are HS49, SP16, SP38, SP8, SP33, SM35, IP1A, IP1P, IP3P. Observation was done during the plants’ generative phase, on the second harvest. The results showed that SP38XHS49 hybrid on Kedung Pengaron, produces the highest seeds dry weight per hectare (1170 kg/ha) with 62.33 gram of dry weight of 100 seeds and the oil content is 32.56%. The highest average of dry seed productions from all planting sites achieved on the crossing between SP38XHS49 (658.75 kg/hectare) and followed by SP8XHS49 (607.5 kg/hectare). If the comparison of the four locations, the highest average productivity of physic nut achieved on location Jorongan, Leces, Probolinggo. In general, the data proves that the hybrid result from the crossing shows the higher production level compare to their parental. The dry weight of 100 seeds produced ranged from 54.03 grams to 68.29 grams. Of all four planting sites, it shows that the highest 100 seeds dry weight achieved by the crossing between IP1P-XHS49 which is 64.63 grams. The seed oil content ranged from 27.04 to 35.24 percent. The highest average of seed oil content achieved by the crossing between SM35XSP38 (32.035%).展开更多
Climate change and human activities are increasingly linked with the extinction of species globally. In semi-arid regions, these pressures threaten the natural distribution and ecology of species. The threat that the ...Climate change and human activities are increasingly linked with the extinction of species globally. In semi-arid regions, these pressures threaten the natural distribution and ecology of species. The threat that the shea butter tree (<em>Vitellaria paradoxa</em> subsp. <em>nilotica</em>) faces from human activity is well researched yet the sensitivity of its distribution to climate change remains barely known. We set out to assess the potential distribution of <em>Vitellaria</em> under different climate change scenarios using a MaxEnt. A current distribution model was first developed using only biophysical variables of soil type, temperature, precipitation, land use type, and elevation. This model was then projected onto two global warming scenarios (RCP 4.5 & RCP 8.5) for 2050 and 2070 using multi-model averages (BCC-CSM, CSM4, and MIROC5) derived from three general circulation models. Reductions are seen in distribution area across the landscape with soil type being the most important variable. These results draw useful implications for conservation of <em>Vitellaria</em> in that they show how it is vulnerable is to a changing climate as its natural range is mostly reduced. Since climate change is important in the distribution of the shea butter tree, the areas with highest suitability in this study can be used in establishing the Shea butter tree sustainable use zones/area within the Kidepo Critical Landscape (KCL), Uganda.展开更多
The aim of this study was to assess Acacia senegal trees’ characteristics as well as evaluate the carbon stock under a variety of ages in the El Demokeya forest in Sudan, where the Gum Arabic belt is located. 12 samp...The aim of this study was to assess Acacia senegal trees’ characteristics as well as evaluate the carbon stock under a variety of ages in the El Demokeya forest in Sudan, where the Gum Arabic belt is located. 12 sample plots, in 2021 were randomly distributed to represent the entire area of the forest prior to the required measurements. The sample was designed as squire plots with one hectare. In each sample plot, all trees were counted, their height (m), and Diameters Breast Height (DBH in cm), respectively. The results showed the highest number of trees per ha at age 20 years old and the lowest number at age 47 years, while the highest values of DBH and volume were found at age 47 years old. As a result, the maximum and minimum values of the aboveground biomass were found in the age 47 years old and 16 years, accounting for 19.87 tons and 1.9 tons respectively. Thus, the amount of carbon stock was 11.92 tons/ha in the 35-years-old and 1.19 tons/ha in the 21-year stands. Furthermore, the average carbon stock in all plots was estimated as 18.70 tons/ha and hence the total carbon stock in the El Demokeya forest is equal to 620.11 tons. Conclusively, the characteristics of trees, amount of aboveground biomass and carbon stock in the El Demokeya forest varied among the uneven-aged plantation groups. The study recommends and encourages the protection of A. senegal in order to increase the carbon sink as well as protect the environment in the era of climatic changes.展开更多
River basins in the drylands of Sub-Saharan Africa have traditionally been utilized for pastoral livelihoods under communal land tenure. Communities in West Pokot in Kenya have continued to experience increased precip...River basins in the drylands of Sub-Saharan Africa have traditionally been utilized for pastoral livelihoods under communal land tenure. Communities in West Pokot in Kenya have continued to experience increased precipitation and temperature as a result of climate variability and change. This study aimed at assessing the impact of climate variability and change at micro-basin level in order to address research and policy gaps on climate change and food security as policy arena shifts from centralized to decentralized governance in Kenya. Primary quantitative data was collected from 387 households’ perceptions of climate variability and change and its implications on food security were measured. Food security index score was calculated. The annual rainfall trend over Suam river basin for the period (1981-2020), was characterized by a linearly increasing annual rainfall trend. Mann Kendall test Z-statistics and Tau were at 2.3578 and 0.0720 respectively. The basin experienced the highest rainfall variability during the first decade (1981-1990) with the highest coefficient of rainfall variation noted at 11.5%. The highest temperature was recorded in the third decade (2001-2010) and fourth decade (2011-2020) at 27.0 and 28.2 degrees Celsius respectively. However, the overall index score for food security was 55.78 with food availability scoring the highest index, mean (SD) of 63.41 (36.52). This was attributed to households’ practice of both nomadic pastoralism and agro-pastoralism activities. Climate variability and change, have resulted in increased amount of rainfall received providing for opportunity investment in rain water harvesting to support both pastoralism and agro-pastoralism production to enhance food security.展开更多
基金Supported by National Key Research and Development Program of China(2017YFD0100600)
文摘Cangmai 6005 is a national wheat variety approved by Cangzhou Academy of Agriculture and Forestry Sciences,which has the characteristics of drought resistance,salt tolerance,high yield and stable yield. According to the characteristics of dry-alkali land in Cangzhou City and the variety characteristics,the new cultivation technique was completed.
基金the National Natural Science Foundation of China (30470297)the "Western Light" Talents Training Program of Chinese Academy of Sciences 2005 (C20609090)
文摘The objective of the study reported here was to determine whether LANDSAT TM images could be used to quantify changes in land-use and ecosystem services in Yuanmou County. The sizes of six land use/land cover (LUCC) categories were estimated in Yuanmou County according to the LANDSAT TM images in the summer of 1986 and 2005. Coefficients published by Xie Gaodi and co-workers in 2003 were used to value changes in ecosystem services delivered by each land use/land cover category, and the ecosystem services sensitivity analysis was conducted to determine the effect of manipulating these coefficients on the estimated values. The important results are summarized as followings. (1) The estimated size of cultivated land, pasture land, water area and unused land decreased by 6.39%, 1.35%, 2.25% and 10.67% respectively between 1986 and 2005. By contrast, the estimated size of forest land and construction land increased by about 2.23% and 71.15% respectively between 1986 and 2005. (2) The total ecosystem services value (EVS) of the study area increased from 2 142 132 609.46 yuan to 2 146 416 621.00 yuan, with the net increase of 4 284 011.54 yuan during the 20-year time period. (3) The coefficient sensitivity (CS) of the study are less than unity in all cases (CS 〈 1). This indicates that the total ecosystem values estimated for the study area are relatively inelastic with respect to the ecosystem service coefficients. While this implies that our estimates are robust and the coefficient is reasonable, highly under or over valued coefficients can substantially affect the veracity of estimated changes in ecosystem service values overtime even when the CS are less than unity(CS 〈 1).
文摘The study, conducted at the Research Farm of the College of Agriculture, University of Tabriz in 2021, focused on the effects of various nitrogen-fixing bacterial isolates, biofertilizers containing nitrogen and phosphorus, as well as iron and zinc foliar applications on mustard growth under rainfed conditions. The results indicated that biofertilizers, whether used alone or in combination with chemical fertilizers, produced comparable grain and oil outputs compared to chemical fertilizers alone. Additionally, the application of iron and zinc through foliar spraying significantly enhanced both grain and oil production. These findings suggest that integrating nitrogen-fixing bacteria and biofertilizers could reduce reliance on chemical nitrogenous fertilizers, leading to decreased production expenses, improved product quality, and minimized environmental impact. This study highlights the potential for sustainable agricultural practices in dry land farming as a viable alternative to traditional chemical-intensive methods. Substituting chemical nitrogenous fertilizers with nitrogen-fixing bacteria or biofertilizers could result in cost savings in mustard grain and oil production while promoting environmental sustainability.
文摘The desertification process is rapidly developing at present and 61.5% of the land area in the zone are already desertified.Among the desertified lands, 26.9% are seriously desertified, 25% most seriously desertified and 47.4% are the lands where desertification is under way. They are caused by over-reclamation for farming, over-grazing, unreasonable collection of firewood,the destruction of vegetation and the misuse of water resources. Under the ecological environment in semi-arid zone,the degraded environment process possesses the ability of restoring to its original status as soon as the interruption of excessive human activities are eliminated. The fencing- and-self-cultivating method is an effective measure adopted universally in semi-arid zone to cure the desertified lands.The desertified lands can be readjusted and controlled easily if other controlling measures are supplemented. The fundamental ways to control desertification are to utilize rationally the resources, to readjust the existing
基金supported by the Major State Basic Research Development Program of People’s Republic of China(G1999011708).
文摘The developmental tendency of dry land farming technologies in the semiarid area of China were reviewed based on the overview of recent progress in dry land farming researches from China and oversea. It was emphasized that conservation tillage, limited irrigation, genetic modification and chemical control are the important aspects for the dry land farming research and development of the future. In addition, some consid-
基金supported as a special project by the Agriculture Ministry of China(Grant No.201503119)the Natural Science Foundation of China(Grant No.41471232)
文摘The dynamics of soil organic carbon(SOC)in cropland is one of the central issues related to both soil fertility and environmental safety. However, little information is available at county level regarding the spatiotemporal variability of SOC in the southwestern mountainous region of China. Thus, this study aimed to explore spatiotemporal changes of SOC in the cultivated soil layer of dry land in Mojiang County,Yunnan Province, China. Data were obtained from the second national soil survey(SNSS) of 1985 and soil tests for fertilizer application carried out by the Mojiang Agricultural Bureau in 2006. The ANOVA test was applied to determine any significant differences between the datasets, while semivariogram analysis was performed on geostatistics via an ordinary Kriging method in order to map spatial patterns of soil organic carbon density(SOCD). The results revealed that SOCD in the cultivated soil layer significantly decreased from 3.93 kg m^(-2) in 1985 to 2.89 kg m^(-2) in 2006, with a total soil organic carbon stock(SOCS) decrease of 41.54×10~4 t over the same period. SOCS levels fell most markedly in yellow-brown soil at a rate of51.52%, while an increase of 8.70% was found in the analysed latosol. Geostatistical analysis also showed that the recorded changes in SOCD between 1985 and2006 were spatially structured. The decreasing trend might be attributed to the combined action of intense cultivation, major crop residue removal without any protective tillage measures, unreasonable fertilization and natural climatic diversity inducing a large decrease in SOC in the studied cultivated dry land region of Mojiang County. Therefore, management measures such as protective tillage should be undertaken in order to enhance soil C sequestration.
基金supported by the National HighTechnology Research and Development Program of China(Grant No.2009AA122005)the Beijing Nova Program(Grant No.Z121109002512052)
文摘A number of remotely sensed land cover datasets with spatial resolutions ~〈 1 km have recently become available or are in the process of being mapped. The application of these higher resolution and more up-to-date land cover datasets in chemical transport models (CTMs) is expected to improve the simulation of dry deposition and biogenic emissions of non-methane volatile organic compounds (NMVOCs), which affect ozone and other secondary air pollutants. In the present study, we updated the land cover dataset in the nested-grid GEOS-Chem CTM with the 1 km resolution GLC2000 land cover map and examined the resulting changes in the simulation of surface ozone and sulfate over China in July 2007. Through affecting the dry deposition velocities of ozone and its precursors, using GLC2000 in the dry deposition module can decrease the simulated surface ozone by 3% (up to 6 ppb) over China. Simulated surface sulfate shows an increase of 3% in northwestern China and a decrease of 1% in northern China. Applying GLC2000 in the biogenic emissions of the NMVOC module can lead to a 0.5--4.5 ppb increase in simulated surface ozone over East China, mainly driven by the larger cove~:age of broadleaf trees in East China in the GLC2000 dataset. Our study quantifies the large sensitivity to land cover dataset~ with different spatial resolutions and time periods of simulated secondary air pollutants over China, supporting ongoing research efforts to produce high resolution and dynamically updated land cover datasets over China, as well as for the globe.
基金Supported by National Research Initiative of the USDA Cooperative State Research, Education and Extension Service (2004-35504-14808)
文摘Dry land crops such as sorghums (grain sorghum, promising feedstocks for fuel ethanol production. The major issue sweet sorghum and forage sorghum) have been identified as for using the sweet sorghum as feedstock is its stability at room temperature. At room temperature, the sweet sorghum juice could lose from 40% to 50% of its fermentable sugars from 7 to 14 days No significant sugar content and profile changes were observed in juice stored at refrigerator temperature in two weeks. Ethanol fermentation efficiencies of fresh and frozen juice were high (-93%). Concentrated juice (≥25% sugar) had significantly lower efficiencies and large amounts of fructose left in finished beer; however, winery yeast strains and novel fermentation techniques may solve these problems. The ethanol yield from sorghum grain increased as starch content increased. No linear relationship between starch content and fermentation efficiency was found. Key factors affecting the ethanol fermentation efficiency of sorghum include starches and protein digestibility, amylose-lipid complexes, tannin content, and mash viscosity. Life cycle analysis showed a positive net energy value (NEV) = 25 500 Btu/gal ethanol. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) were used to determine changes in the structure and chemical composition of sorghum biomasses. Dilute sulfuric acid pretreatment was effective in removing the hemicellulose from biomasses and exposing the cellulose for enzymatic hydrolysis. Forage sorghum lignin had a lower syringyl/guaiacyl ratio and its pretreated biomass was easier to hydrolyze. Up to 72% hexose yield and 94% pentose yield were obtained by using a modified steam explosion with 2% sulfuric acid at 140℃ for 30 min and enzymatic hydrolysis with cellulase.
文摘Based on the observed soil water data from experimental site located in southeast of Shanxi Province, the physical characteristics of soil water, crop effect on soil moisture, and the field water circulation pattern were studied by using the water balance method. The results suggested that soil water deficit often exists in fields of these areas. From May to June, the amount of water deficit in bare land rises to the maximum (232 8 mm) and falls to the minimum (66 6 mm) from August to September. By comparison, because of crop transpiration, both soil water deficit and dry soil layer in cultivated land are 15 1—40 4 mm more and 20—70 mm deeper respectively than those of bare land. Crops mainly planted in these areas have a relatively weak utilization ability to soil water. Winter wheat has the highest utilization ability to soil water among the crops planted in these areas. The soil water utilization ability of winter wheat is 26 2%—30 6% and winter wheat can use soil water that lies in soil layer below a depth of over 200 cm. Spring corn and millet can only consume soil water with the maximum ability of 13 4% and the deepest layer of 0—50 cm or 0—100cm, which shows that the soil water utilization ability of winter wheat is higher than that of spring crops. After crop is ripe, more than 41% of available soil water remains unused in field. So, increasing soil water storage and improving crop utilization ability to soil water by adopting efficient agrotechnique measures are the main ways for improving agricultural productivity in dry farming areas of Northern China.
基金Supported by Global COE Program (Global Center of Excellence for Dryland Science) Funded by MEXT"Historical Interactions between the Multi-Cultural Societies and the Natural Environment in a Semi-Arid Region in Central Eurasia" Project Funded by Research Institute for Humanity and Nature, Japan
文摘The lower Ili River Basin is located in semi-arid area, and the annual rainfall is 177mm. Therefore, the irrigation is inevitable for agriculture. Large-scale irrigated agriculture had been developed since 1960's in the lower parts of the river and the total irrigated area is about 32 000 hm2. In the project area, the paddy rice-upland crop rotation has been practiced. Due to the domestic water use for hydropower and agriculture as well as water use among riparian countries, the deficit of water for agriculture in the lower part has been concerned. The authors, therefore, conducted the field survey and water balance analysis of the Akdara irrigation project in the lower Ill River Basin in order to assess the land and water uses. Moreover, the impact of the water use on water environment to the basin was analyzed. The following results were obtained as following (1) the groundwater level in the irrigated district varied from 1.5 m to 3.5 m through year. (2) 1970's groundwater level was drastically raised from 8 m to 3 m and the groundwater had been recharged in this period. (3) Water use efficiency of agriculture, which is the ratio of total evapotranspiration to the total water withdrawal was as low as 0.23.
基金Key Technology Research for Development and Efficient Cultivation and Utilization of Forage Mulberry(2013SZ03)
文摘The phenological phase, plant height, filler number, nutritional composition, yield and stem/leaf ratio of three oat (Arena sativa) varieties (lines) in winter dry land of Hunan were studied. The result shows that the three oat varieties were greatly different in plant height, nutritional composition, yield and stem/leaf ratio. Baiyan 7 had the best performance, with the plant height, tiller number and fresh yield of 101.67cm, 7.6 tiller/plant and 70.15 t/hm2 respectively ; the crude protein content of dry matter of Baiyan 7 was 32.63% ; the leaf weight per tiller of Baiyan 7 accounted for 31.6% of single tiller weight, while those of Baiyan 8 and Baiyan 2 accounted for 31.3% and 29.2%, respectively. The single tiller weight of oat could be estimated/calculated by the model/formula Y = 0.043 7X - 2.89 ( R2 = 0.913 4, P 〈 0.01 ), where Y is the single tiller weight ( g ) and X is the plant height (cm). Comprehensive analysis showed that Baiyan 7 had higher yields and stem/leaf ratio. Thus, Baiyan 7 is more suitable for planting as a winter-spring forage in the winter dry land of Hunan.
文摘Hibridization is one of breeding strategy to increase productivity of crop including physic nut (Jatropha curcas Linn.). This study aimed to obtain information productivity per hectare and seed oil content of 11 numbers of physic nut hybrids and their parental in four dry lands. The research was conducted in four dry land: Kalipare-Malang, Oro-oro Pule-Kejayan Pasuruan, Kedung Pengaron-Pasuruan and Jorongan-Leces Probolinggo. The materials used in this research are the eleven result numbers of physic nut hybrids, they are SP38XHS49, SP8XHS49, SP8XSP16, SP8XSP38, SP33XHS49, SM35XHS49, SM35XSP38, IP1AXHS49, IP1AXSP38, IP1PXHS 49, IP1PXSP38, and their parental, they are HS49, SP16, SP38, SP8, SP33, SM35, IP1A, IP1P, IP3P. Observation was done during the plants’ generative phase, on the second harvest. The results showed that SP38XHS49 hybrid on Kedung Pengaron, produces the highest seeds dry weight per hectare (1170 kg/ha) with 62.33 gram of dry weight of 100 seeds and the oil content is 32.56%. The highest average of dry seed productions from all planting sites achieved on the crossing between SP38XHS49 (658.75 kg/hectare) and followed by SP8XHS49 (607.5 kg/hectare). If the comparison of the four locations, the highest average productivity of physic nut achieved on location Jorongan, Leces, Probolinggo. In general, the data proves that the hybrid result from the crossing shows the higher production level compare to their parental. The dry weight of 100 seeds produced ranged from 54.03 grams to 68.29 grams. Of all four planting sites, it shows that the highest 100 seeds dry weight achieved by the crossing between IP1P-XHS49 which is 64.63 grams. The seed oil content ranged from 27.04 to 35.24 percent. The highest average of seed oil content achieved by the crossing between SM35XSP38 (32.035%).
文摘Climate change and human activities are increasingly linked with the extinction of species globally. In semi-arid regions, these pressures threaten the natural distribution and ecology of species. The threat that the shea butter tree (<em>Vitellaria paradoxa</em> subsp. <em>nilotica</em>) faces from human activity is well researched yet the sensitivity of its distribution to climate change remains barely known. We set out to assess the potential distribution of <em>Vitellaria</em> under different climate change scenarios using a MaxEnt. A current distribution model was first developed using only biophysical variables of soil type, temperature, precipitation, land use type, and elevation. This model was then projected onto two global warming scenarios (RCP 4.5 & RCP 8.5) for 2050 and 2070 using multi-model averages (BCC-CSM, CSM4, and MIROC5) derived from three general circulation models. Reductions are seen in distribution area across the landscape with soil type being the most important variable. These results draw useful implications for conservation of <em>Vitellaria</em> in that they show how it is vulnerable is to a changing climate as its natural range is mostly reduced. Since climate change is important in the distribution of the shea butter tree, the areas with highest suitability in this study can be used in establishing the Shea butter tree sustainable use zones/area within the Kidepo Critical Landscape (KCL), Uganda.
文摘The aim of this study was to assess Acacia senegal trees’ characteristics as well as evaluate the carbon stock under a variety of ages in the El Demokeya forest in Sudan, where the Gum Arabic belt is located. 12 sample plots, in 2021 were randomly distributed to represent the entire area of the forest prior to the required measurements. The sample was designed as squire plots with one hectare. In each sample plot, all trees were counted, their height (m), and Diameters Breast Height (DBH in cm), respectively. The results showed the highest number of trees per ha at age 20 years old and the lowest number at age 47 years, while the highest values of DBH and volume were found at age 47 years old. As a result, the maximum and minimum values of the aboveground biomass were found in the age 47 years old and 16 years, accounting for 19.87 tons and 1.9 tons respectively. Thus, the amount of carbon stock was 11.92 tons/ha in the 35-years-old and 1.19 tons/ha in the 21-year stands. Furthermore, the average carbon stock in all plots was estimated as 18.70 tons/ha and hence the total carbon stock in the El Demokeya forest is equal to 620.11 tons. Conclusively, the characteristics of trees, amount of aboveground biomass and carbon stock in the El Demokeya forest varied among the uneven-aged plantation groups. The study recommends and encourages the protection of A. senegal in order to increase the carbon sink as well as protect the environment in the era of climatic changes.
文摘River basins in the drylands of Sub-Saharan Africa have traditionally been utilized for pastoral livelihoods under communal land tenure. Communities in West Pokot in Kenya have continued to experience increased precipitation and temperature as a result of climate variability and change. This study aimed at assessing the impact of climate variability and change at micro-basin level in order to address research and policy gaps on climate change and food security as policy arena shifts from centralized to decentralized governance in Kenya. Primary quantitative data was collected from 387 households’ perceptions of climate variability and change and its implications on food security were measured. Food security index score was calculated. The annual rainfall trend over Suam river basin for the period (1981-2020), was characterized by a linearly increasing annual rainfall trend. Mann Kendall test Z-statistics and Tau were at 2.3578 and 0.0720 respectively. The basin experienced the highest rainfall variability during the first decade (1981-1990) with the highest coefficient of rainfall variation noted at 11.5%. The highest temperature was recorded in the third decade (2001-2010) and fourth decade (2011-2020) at 27.0 and 28.2 degrees Celsius respectively. However, the overall index score for food security was 55.78 with food availability scoring the highest index, mean (SD) of 63.41 (36.52). This was attributed to households’ practice of both nomadic pastoralism and agro-pastoralism activities. Climate variability and change, have resulted in increased amount of rainfall received providing for opportunity investment in rain water harvesting to support both pastoralism and agro-pastoralism production to enhance food security.