Increasing salt-affected agricultural land due to low precipitation, high surface evaporation, irrigation with saline water, and poor cultural practices has triggered the interest to understand the influence of salt o...Increasing salt-affected agricultural land due to low precipitation, high surface evaporation, irrigation with saline water, and poor cultural practices has triggered the interest to understand the influence of salt on nitrous oxide （N20） and carbon dioxide （CO2） emissions from soil. Three soils with varying electrical conductivity of saturated paste extract （ECe） （0.44-7.20 dS m-1） and sodium adsorption ratio of saturated paste extract （SARe） （1.1-27.7）, two saline-sodic soils （S2 and S3） and a non-saline, non-sodic soil （S1）, were incubated at moisture levels of 40%, 60%, and 80% water-filled pore space （WFPS） for 30 d, with or without nitrogen （N） fertilizer addition （urea at 525μg g-1 soil）. Evolving CO2 and N20 were estimated by analyzing the collected gas samples during the incubation period. Across all moisture and N levels, the cumulative N20 emissions increased significantly by 39.8% and 42.4% in S2 and S3, respectively, compared to S1. The cumulative CO2 emission from the three soils did not differ significantly as a result of the complex interactions of salinity and sodicity. Moisture had no significant effect oi1 N20 emissions, but cumulative CO2 emissions increased significantly with an increase in moisture. Addition of N significantly increased cumulative N20 and CO2 emissions. These showed that saline-sodic soils can be a significant contributor of N20 to the environment compared to non-saline, non-sodic soils. The application of N fertilizer, irrigation, and precipitation may potentially increase greenhouse gas （N20 and CO2） releases from saline-sodic soils.展开更多
Salinization and sodicity are obstacles for vegetation reconstruction of coastal tidal flat soils. A study was conducted with flue gas desulfurization（FGD）-gypsum applied at rates of 0, 15, 30, 45 and 60 Mg/ha to re...Salinization and sodicity are obstacles for vegetation reconstruction of coastal tidal flat soils. A study was conducted with flue gas desulfurization（FGD）-gypsum applied at rates of 0, 15, 30, 45 and 60 Mg/ha to remediate tidal flat soils of the Yangtze River estuary.Exchangeable sodium percentage（ESP）, exchangeable sodium（ExNa）, p H, soluble salt concentration, and composition of soluble salts were measured in 10 cm increments from the surface to 30 cm depth after 6 and 18 months. The results indicated that the effect of FGD-gypsum is greatest in the 0–10 cm mixing soil layer and 60 Mg/ha was the optimal rate that can reduce the ESP to below 6% and decrease soil p H to neutral（7.0）. The improvement effect was reached after 6 months, and remained after 18 months. The composition of soluble salts was transformed from sodic salt ions mainly containing Na~＋, HCO_3^-＋ CO_3^（2-）and Cl-to neutral salt ions mainly containing Ca^（2＋）and SO_4^（2-）. Non-halophyte plants were survived at 90%. The study demonstrates that the use of FGD-gypsum for remediating tidal flat soils is promising.展开更多
The net photosynthetic rate of flag leaves and influencing factors under saline sodic soil conditions were investigated at the full heading stage of rice.The net photosynthetic rate of rice leaves showed a double-peak...The net photosynthetic rate of flag leaves and influencing factors under saline sodic soil conditions were investigated at the full heading stage of rice.The net photosynthetic rate of rice leaves showed a double-peak curve in a day in both non-saline sodic and saline sodic soil treatments.The first peak of the net photosynthetic rate appeared at 9:00-10:00 and 9:00 in the saline sodic and non-saline sodic soil treatments,respectively,whereas the second peak both at 14:00.The midday depression of the net photosynthetic rate always appeared regardless of non-saline sodic or saline sodic soil conditions.In addition,the net photosynthetic rate significantly decreased in all day under saline sodic conditions compared with that under non-saline sodic conditions.Some differences were observed in correlation characters between the net photosynthetic rate and all influencing factors during 9:00-13:00.Under non-saline sodic conditions,the diurnal changes of the net photosynthetic rate in a day were mainly caused by stomatal conductance,and the limitation value and the stomatal factors served as determinants;whereas under saline sodic stress,the diurnal changes of the net photosynthetic rate in a day were mainly caused by non stomatal factors including light intensity and air temperature.展开更多
The objective of this work is to determine changes of surface properties of a bentonite after acid activation, using hydrochloric acid solutions (HCl) at room temperature. XRD, FX, FTIR, MEB, and BET analyses of the s...The objective of this work is to determine changes of surface properties of a bentonite after acid activation, using hydrochloric acid solutions (HCl) at room temperature. XRD, FX, FTIR, MEB, and BET analyses of the samples have been carried out to examine the structure of bentonite before and after acid activation. It is found that the raw bentonite is composed of dioctahedral montmorillonite with predominant quantity and certain amounts of quartz, albite and illite, etc. It has an cation exchange capacity (CEC) of 74.32 meq/g which allows it to be characterized as typical sodium bentonite. The changes, at low acid concentrations, are the result from from cation exchange (exchangeable cations with H+ ions). Differences of surface area at high acid concentrations (0.25 - 0.4 M) were caused by structural changes and partial decomposition of the samples. Data of surface area measurements have showed that with increase of concentration of hydrochloric acid, the surface area increased. The maximum value (837.11 m2/g) was reached by the sample activated with 0.4 M HCl. By against, activation with higher concentration (0.6 M) caused a decrease in the surface area.展开更多
Objective The Cenozoic Indo-Asian collision caused significant crustal shortening and plateau uplift in the central Tibet. The extrusion tectonic model has been widely accepted to explain the strike-slip faults around...Objective The Cenozoic Indo-Asian collision caused significant crustal shortening and plateau uplift in the central Tibet. The extrusion tectonic model has been widely accepted to explain the strike-slip faults around the Tibetan Plateau. Previous studies indicate that the lower crust flow is the main drive force of the extrusion tectonics. Whether mantle extrusion process occurred during the Cenozoic uplift is a major problem to be addressed, which is significant for understanding the uplift mechanism and tectonic evolution of the Tibetan Plateau.展开更多
Sodic soils are typically located in semi-arid to arid climates. However, sodic soils in continental humid climates are rare. As with sodic soils in dry climates, sodic soils in wetlands pose management difficulties f...Sodic soils are typically located in semi-arid to arid climates. However, sodic soils in continental humid climates are rare. As with sodic soils in dry climates, sodic soils in wetlands pose management difficulties for agriculture, forestry, or wild-life habitat. The typical practice of gypsum application is problematic given inability to provide drainage. Natraqualfs located in southeastern Missouri present an acid argillic horizon superimposed on a natric horizon, where the exchangeable sodium percentage and an alkaline reaction are characteristic attributes. Ferrolysis is an active soil process that is slowly degrading the natric horizon because of exchangeable Al<sup>3+</sup> and H<sup>+</sup> generation and re-stabilization of the soil structure, permitting leaching of the sodium.展开更多
For centuries, reclamation of sodic soils has been an essential part of cropping practices in several parts of the world. Parallel to increasing population, the need for new cropland constantly re-evaluates land suita...For centuries, reclamation of sodic soils has been an essential part of cropping practices in several parts of the world. Parallel to increasing population, the need for new cropland constantly re-evaluates land suitability concepts. Therefore, the importance of sodic soils as potential croplands is increasing worldwide. Although theoretically farmers can choose from a wide variety of reclamation options, according to profitability, business plans, and human and financial resources, in practice, few reclamation methods are applied at large scale. This article touches on the early history, 20th Century intensive research, and current trends of sodic soil reclamation. New approaches such as leaching, chemical amendments, addition of organic material, and biological and microbial improvements are discussed, and also brand-new approaches are reviewed. The early history is reviewed using historical books, the achievements of the last hundred years using basic technical literature, mostly books, and the current approaches of our time with fresh publications, mostly papers and two very recent conferences published in English.展开更多
Ten multipurpose tree species, Terminalia arjuna, Azadirechta indica, Prosopis juliflora, Pongamia pinnata, Casuarina equisetifolia, Prosopis alba, Acacia nilotica, Eucalyptus tereticornis, Pithecellobium dulce and Ca...Ten multipurpose tree species, Terminalia arjuna, Azadirechta indica, Prosopis juliflora, Pongamia pinnata, Casuarina equisetifolia, Prosopis alba, Acacia nilotica, Eucalyptus tereticornis, Pithecellobium dulce and Cassia siamea, were raised in a monoculture tree cropping system on the sodic soil of Gangetic alluvium in north India （26° 47° N： 80°46′ E） for 10 years to evaluate the biomass and bio-energy production. The soil was compact, sodic and impervious to water associated with nutrient deficiency or toxicity. Maximum plant height was recorded with E. tereticornis followed by C.equisetifolia and P. juliflora. A. nilotica performed better than the other species in terms of diameter at breast height （DBH） with a basal area of 13.04 m^2·ha^-1, followed by P. juliflora and C. equisetifolia. P. juliflora and A. nilotica produced nearly similar biomass of 56.50 and 50.75 Mg·ha^-1, respectively, at 10 years; whereas, A. indica, P. pinnata, C. siamea and P. alba did not perform well. P. juliflora scored maximum in net biomass production and nutrient demand. Nutrient （N, P, K, Ca, and Mg） concentrations were higher in leaf component of P. juliflora. However, in woody components, there was little variation between the species. N removal for production of one ton of wood was lowest in Acacia nilotica, P in T. arjuna, K in P. dulce and Ca and Mg in P. juliflora. P. juliflora gave the highest energy production of 1267.75 GJ.ha^-1 followed by A. nilotica with 1206 GJ.ha^-1 and the lowest ofA. indica （520.66 GJ.ha^-1）.展开更多
Sodic soils have immense productivity potential, if managed through proper technology interventions. Biocompost is prepared by composting pressmud (a sugar industry byproduct) received from cane juice filtration and s...Sodic soils have immense productivity potential, if managed through proper technology interventions. Biocompost is prepared by composting pressmud (a sugar industry byproduct) received from cane juice filtration and spent wash received from distilleries through microbial aerobic decomposition and can be used to reclaim sodic soils. Field experiments were conducted during the wet season of 2011 and 2012 to study the effect of incorporation of biocompost in sodic soil with four treatments: T1—Control, T2—Biocompost at 2 t ha-1, T3—Biocompost at 4 t ha-1 and T4—Biocompost at 6 t ha-1. The two promising salt tolerant rice varieties preferred by farmers, Narendra usar 3 and NDR 359 were used as test crops, which can produce yields ranging between 2-4 t ha-1 in soil having a pH range of 9.2 to 10.5. Among the different doses of biocompost tested, application of biocompost at 6 t ha-1 registered highest yields, enabled by a higher biomass, ear bearing tiller (EBT), and grain fertility in both varieties. Narendra usar 3 was more responsive to treatments even at lower doses of biocompost than NDR 359, but NDR 359 yielded slightly higher than Narendra usar 3 in all treatments. Soil health was also improved evidently on better fertility and low soil pH and EC at harvest. Thus, biocompost can be considered as a commercially viable, environmentally acceptable and practically enforceable option for improving the crop productivity and soil fertility status.展开更多
The Indus Plains of Pakistan lies between 23°to 37°latitude and 61°to 76°longi-tude in the northern hemisphere. The total Canal Commanded Area (CCA) is about 13.50million hectares of which 11.21 mi...The Indus Plains of Pakistan lies between 23°to 37°latitude and 61°to 76°longi-tude in the northern hemisphere. The total Canal Commanded Area (CCA) is about 13.50million hectares of which 11.21 million hectares are cultivated. At present, 103 millionacre-feet river flow is diverted into irrigation canals. In addition, 42 million acre feet of thegroundwater are being pumped through 257697 tubewells to supplement the canal supplies.展开更多
The most important task in leaching practices is assessment of water quantity required for leaching of saline and saline-sodic soils. Therefore, reliable estimation of the required leaching water quantity is vital for...The most important task in leaching practices is assessment of water quantity required for leaching of saline and saline-sodic soils. Therefore, reliable estimation of the required leaching water quantity is vital for reducing soil salinity to a desirable level. The present study aimed to investigate desodification of saline and sodic soils in central area of Khuzestan Province. Consequently, a large area of 3216 ha with S4A3 salinity/sodicity class in Khuzestan, Iran, was selected to obtain the required data. This experiment was conducted with two treatments and tree replicates. In the first treatment, the experiment was conducted by applying just 100 cm water depth in four 25 cm intervals. In the second treatment, 5000 kg/ha Sulfuric Acid was applied prior to salt leaching together with leaching water. The intermittent ponding method was conducted with double rings in a rectangular array. The required physical and chemical analyses were performed on the collected data. The leaching water was supplied from Shotait River. Four mathematical models were applied to the collected experimental data to derive a suitable empirical model. The results for large scale applications indicated that the proposed logarithmic model can estimate the capital leaching requirement much than the previously proposed models.展开更多
文摘Increasing salt-affected agricultural land due to low precipitation, high surface evaporation, irrigation with saline water, and poor cultural practices has triggered the interest to understand the influence of salt on nitrous oxide （N20） and carbon dioxide （CO2） emissions from soil. Three soils with varying electrical conductivity of saturated paste extract （ECe） （0.44-7.20 dS m-1） and sodium adsorption ratio of saturated paste extract （SARe） （1.1-27.7）, two saline-sodic soils （S2 and S3） and a non-saline, non-sodic soil （S1）, were incubated at moisture levels of 40%, 60%, and 80% water-filled pore space （WFPS） for 30 d, with or without nitrogen （N） fertilizer addition （urea at 525μg g-1 soil）. Evolving CO2 and N20 were estimated by analyzing the collected gas samples during the incubation period. Across all moisture and N levels, the cumulative N20 emissions increased significantly by 39.8% and 42.4% in S2 and S3, respectively, compared to S1. The cumulative CO2 emission from the three soils did not differ significantly as a result of the complex interactions of salinity and sodicity. Moisture had no significant effect oi1 N20 emissions, but cumulative CO2 emissions increased significantly with an increase in moisture. Addition of N significantly increased cumulative N20 and CO2 emissions. These showed that saline-sodic soils can be a significant contributor of N20 to the environment compared to non-saline, non-sodic soils. The application of N fertilizer, irrigation, and precipitation may potentially increase greenhouse gas （N20 and CO2） releases from saline-sodic soils.
基金supported by the National Public Project of Environmental Protection(No.201109023)the Shanghai Agricultural Committee(No.2012-2-1)
文摘Salinization and sodicity are obstacles for vegetation reconstruction of coastal tidal flat soils. A study was conducted with flue gas desulfurization（FGD）-gypsum applied at rates of 0, 15, 30, 45 and 60 Mg/ha to remediate tidal flat soils of the Yangtze River estuary.Exchangeable sodium percentage（ESP）, exchangeable sodium（ExNa）, p H, soluble salt concentration, and composition of soluble salts were measured in 10 cm increments from the surface to 30 cm depth after 6 and 18 months. The results indicated that the effect of FGD-gypsum is greatest in the 0–10 cm mixing soil layer and 60 Mg/ha was the optimal rate that can reduce the ESP to below 6% and decrease soil p H to neutral（7.0）. The improvement effect was reached after 6 months, and remained after 18 months. The composition of soluble salts was transformed from sodic salt ions mainly containing Na~＋, HCO_3^-＋ CO_3^（2-）and Cl-to neutral salt ions mainly containing Ca^（2＋）and SO_4^（2-）. Non-halophyte plants were survived at 90%. The study demonstrates that the use of FGD-gypsum for remediating tidal flat soils is promising.
文摘The net photosynthetic rate of flag leaves and influencing factors under saline sodic soil conditions were investigated at the full heading stage of rice.The net photosynthetic rate of rice leaves showed a double-peak curve in a day in both non-saline sodic and saline sodic soil treatments.The first peak of the net photosynthetic rate appeared at 9:00-10:00 and 9:00 in the saline sodic and non-saline sodic soil treatments,respectively,whereas the second peak both at 14:00.The midday depression of the net photosynthetic rate always appeared regardless of non-saline sodic or saline sodic soil conditions.In addition,the net photosynthetic rate significantly decreased in all day under saline sodic conditions compared with that under non-saline sodic conditions.Some differences were observed in correlation characters between the net photosynthetic rate and all influencing factors during 9:00-13:00.Under non-saline sodic conditions,the diurnal changes of the net photosynthetic rate in a day were mainly caused by stomatal conductance,and the limitation value and the stomatal factors served as determinants;whereas under saline sodic stress,the diurnal changes of the net photosynthetic rate in a day were mainly caused by non stomatal factors including light intensity and air temperature.
文摘The objective of this work is to determine changes of surface properties of a bentonite after acid activation, using hydrochloric acid solutions (HCl) at room temperature. XRD, FX, FTIR, MEB, and BET analyses of the samples have been carried out to examine the structure of bentonite before and after acid activation. It is found that the raw bentonite is composed of dioctahedral montmorillonite with predominant quantity and certain amounts of quartz, albite and illite, etc. It has an cation exchange capacity (CEC) of 74.32 meq/g which allows it to be characterized as typical sodium bentonite. The changes, at low acid concentrations, are the result from from cation exchange (exchangeable cations with H+ ions). Differences of surface area at high acid concentrations (0.25 - 0.4 M) were caused by structural changes and partial decomposition of the samples. Data of surface area measurements have showed that with increase of concentration of hydrochloric acid, the surface area increased. The maximum value (837.11 m2/g) was reached by the sample activated with 0.4 M HCl. By against, activation with higher concentration (0.6 M) caused a decrease in the surface area.
基金supported by the National Natural Science Foundation of China (grant No.41072052)
文摘Objective The Cenozoic Indo-Asian collision caused significant crustal shortening and plateau uplift in the central Tibet. The extrusion tectonic model has been widely accepted to explain the strike-slip faults around the Tibetan Plateau. Previous studies indicate that the lower crust flow is the main drive force of the extrusion tectonics. Whether mantle extrusion process occurred during the Cenozoic uplift is a major problem to be addressed, which is significant for understanding the uplift mechanism and tectonic evolution of the Tibetan Plateau.
文摘Sodic soils are typically located in semi-arid to arid climates. However, sodic soils in continental humid climates are rare. As with sodic soils in dry climates, sodic soils in wetlands pose management difficulties for agriculture, forestry, or wild-life habitat. The typical practice of gypsum application is problematic given inability to provide drainage. Natraqualfs located in southeastern Missouri present an acid argillic horizon superimposed on a natric horizon, where the exchangeable sodium percentage and an alkaline reaction are characteristic attributes. Ferrolysis is an active soil process that is slowly degrading the natric horizon because of exchangeable Al<sup>3+</sup> and H<sup>+</sup> generation and re-stabilization of the soil structure, permitting leaching of the sodium.
基金Under the auspices of CAS President’s International Fellowship Initiative Project(No.2019VCA0014)Hungarian National Research,Development and Innovation Office Foundation(No.K124290)。
文摘For centuries, reclamation of sodic soils has been an essential part of cropping practices in several parts of the world. Parallel to increasing population, the need for new cropland constantly re-evaluates land suitability concepts. Therefore, the importance of sodic soils as potential croplands is increasing worldwide. Although theoretically farmers can choose from a wide variety of reclamation options, according to profitability, business plans, and human and financial resources, in practice, few reclamation methods are applied at large scale. This article touches on the early history, 20th Century intensive research, and current trends of sodic soil reclamation. New approaches such as leaching, chemical amendments, addition of organic material, and biological and microbial improvements are discussed, and also brand-new approaches are reviewed. The early history is reviewed using historical books, the achievements of the last hundred years using basic technical literature, mostly books, and the current approaches of our time with fresh publications, mostly papers and two very recent conferences published in English.
文摘Ten multipurpose tree species, Terminalia arjuna, Azadirechta indica, Prosopis juliflora, Pongamia pinnata, Casuarina equisetifolia, Prosopis alba, Acacia nilotica, Eucalyptus tereticornis, Pithecellobium dulce and Cassia siamea, were raised in a monoculture tree cropping system on the sodic soil of Gangetic alluvium in north India （26° 47° N： 80°46′ E） for 10 years to evaluate the biomass and bio-energy production. The soil was compact, sodic and impervious to water associated with nutrient deficiency or toxicity. Maximum plant height was recorded with E. tereticornis followed by C.equisetifolia and P. juliflora. A. nilotica performed better than the other species in terms of diameter at breast height （DBH） with a basal area of 13.04 m^2·ha^-1, followed by P. juliflora and C. equisetifolia. P. juliflora and A. nilotica produced nearly similar biomass of 56.50 and 50.75 Mg·ha^-1, respectively, at 10 years; whereas, A. indica, P. pinnata, C. siamea and P. alba did not perform well. P. juliflora scored maximum in net biomass production and nutrient demand. Nutrient （N, P, K, Ca, and Mg） concentrations were higher in leaf component of P. juliflora. However, in woody components, there was little variation between the species. N removal for production of one ton of wood was lowest in Acacia nilotica, P in T. arjuna, K in P. dulce and Ca and Mg in P. juliflora. P. juliflora gave the highest energy production of 1267.75 GJ.ha^-1 followed by A. nilotica with 1206 GJ.ha^-1 and the lowest ofA. indica （520.66 GJ.ha^-1）.
文摘Sodic soils have immense productivity potential, if managed through proper technology interventions. Biocompost is prepared by composting pressmud (a sugar industry byproduct) received from cane juice filtration and spent wash received from distilleries through microbial aerobic decomposition and can be used to reclaim sodic soils. Field experiments were conducted during the wet season of 2011 and 2012 to study the effect of incorporation of biocompost in sodic soil with four treatments: T1—Control, T2—Biocompost at 2 t ha-1, T3—Biocompost at 4 t ha-1 and T4—Biocompost at 6 t ha-1. The two promising salt tolerant rice varieties preferred by farmers, Narendra usar 3 and NDR 359 were used as test crops, which can produce yields ranging between 2-4 t ha-1 in soil having a pH range of 9.2 to 10.5. Among the different doses of biocompost tested, application of biocompost at 6 t ha-1 registered highest yields, enabled by a higher biomass, ear bearing tiller (EBT), and grain fertility in both varieties. Narendra usar 3 was more responsive to treatments even at lower doses of biocompost than NDR 359, but NDR 359 yielded slightly higher than Narendra usar 3 in all treatments. Soil health was also improved evidently on better fertility and low soil pH and EC at harvest. Thus, biocompost can be considered as a commercially viable, environmentally acceptable and practically enforceable option for improving the crop productivity and soil fertility status.
文摘The Indus Plains of Pakistan lies between 23°to 37°latitude and 61°to 76°longi-tude in the northern hemisphere. The total Canal Commanded Area (CCA) is about 13.50million hectares of which 11.21 million hectares are cultivated. At present, 103 millionacre-feet river flow is diverted into irrigation canals. In addition, 42 million acre feet of thegroundwater are being pumped through 257697 tubewells to supplement the canal supplies.
文摘The most important task in leaching practices is assessment of water quantity required for leaching of saline and saline-sodic soils. Therefore, reliable estimation of the required leaching water quantity is vital for reducing soil salinity to a desirable level. The present study aimed to investigate desodification of saline and sodic soils in central area of Khuzestan Province. Consequently, a large area of 3216 ha with S4A3 salinity/sodicity class in Khuzestan, Iran, was selected to obtain the required data. This experiment was conducted with two treatments and tree replicates. In the first treatment, the experiment was conducted by applying just 100 cm water depth in four 25 cm intervals. In the second treatment, 5000 kg/ha Sulfuric Acid was applied prior to salt leaching together with leaching water. The intermittent ponding method was conducted with double rings in a rectangular array. The required physical and chemical analyses were performed on the collected data. The leaching water was supplied from Shotait River. Four mathematical models were applied to the collected experimental data to derive a suitable empirical model. The results for large scale applications indicated that the proposed logarithmic model can estimate the capital leaching requirement much than the previously proposed models.
