This study aimed to investigate whether saline silt and sandy loam coastal soils could be reclaimed by micro-sprinkler irrigation.The experiments were run using moderately salt-tolerant tall fescue grass.Micro-sprinkl...This study aimed to investigate whether saline silt and sandy loam coastal soils could be reclaimed by micro-sprinkler irrigation.The experiments were run using moderately salt-tolerant tall fescue grass.Micro-sprinkler irrigation in three stages was used to regulate soil matric potential at a 20-cm soil depth.Continued regulation of soil water and salt through micro-sprinkler irrigation consistently resulted in an increasingly large low-salinity region.The application of the three stages of soil wateresalt regulation resulted in an absence of salt accumulation throughout the soil profile and the conversion of highly saline soils into moderately saline soils.There were increases in the plant height,leaf width,leaf length,and tiller numbers of tall fescue throughout the leaching process.The results showed that micro-sprinkler irrigation in three soil water and salt regulation stages can be used to successfully cultivate tall festuca in highly saline coastal soil.This approach achieved better effects in sandy loam soil than in silt soil.Tall fescue showed greater survival rates in sandy loam soil due to the rapid reclamation process,whereas plant growth was higher in silt soil because of effective water conservation.In sandy loam,soil moisture should be maintained during soil reclamation,and in silt soil,soil root-zone environments optimal for the emergence of plants should be quickly established.Micro-sprinkler irrigation can be successfully applied to the cultivation of tall fescue in coastal heavy saline soils under a three-stage soil wateresalt regulation regime.展开更多
Soil salinity has become a major constraint to rice productivity in the coastal region of Bangladesh, which threatened food security. Therefore, field experiment was conducted at salt stressed Shyamnagor Upazilla of S...Soil salinity has become a major constraint to rice productivity in the coastal region of Bangladesh, which threatened food security. Therefore, field experiment was conducted at salt stressed Shyamnagor Upazilla of Satkhira district to improve the soil salinity status, sustainable rice production and suppression of global warming potentials. Selected soil amendments viz. trichocompost, tea waste compost, azolla compost and phospho-gypsum (PG) were applied in the field plots one week prior to rice transplanting. In addition, proline solution (25 mM) was applied on the transplanted rice plants at active vegetative stage. Gas samples from the paddy field were collected by Closed Chamber technique and analyzed in by Gas Chromatograph. The 25% replacement of chemical fertilizer (i.e., 75% NPKS) with trichocompost, tea waste compost, Azolla compost and Phospho-gypsum amendments increased grain yield by 4.7% - 7.0%, 2.3% - 7.1% 11.9% - 16.6% and 9.5% - 14.2% during dry boro rice cultivation, while grain yield increments of 5.0% - 7.6%, 2.3% - 10.2%, 12.8% - 15.3% and 10.2% - 15.3% were recorded in wet Aman season respectively, compared to chemically fertilized (100% NPKS) field plot. The least GWPs 3575 and 3650 kg CO<sub>2</sub> eq./ha were found in PG Cyanobacterial mixture with proline (T10) and tea waste compost with proline (T8) amended rice field, while the maximum GWPs 4725 and 4500 kg CO<sub>2 </sub>eq./ha were recorded in NPKS fertilized (100%, T2) and NPKS (75%) with Azolla compost (T5) amended plots during dry boro rice cultivation. The overall soil properties improved significantly with the selected soil amendments, while soil electrical conductivity (EC), soil pH and Na+ cation in the amended soil decreased, eventually improved the soil salinity status. Conclusively, phospho-gypsum amendments with cyanobacteria inoculation and proline solution (25 mM) application could be an effective option to reclaim coastal saline soils, sustaining rice productivity and reducing global warming potentials.展开更多
Laboratory and field experiments were conducted to investigate the effects of water application intensity（WAI） on soil salinity management and the growth of Festuca arundinacea（festuca） under three stages of water...Laboratory and field experiments were conducted to investigate the effects of water application intensity（WAI） on soil salinity management and the growth of Festuca arundinacea（festuca） under three stages of water and salt management strategies using microsprinkler irrigation in Hebei Province, North China. The soil water content（è） and salinity of homogeneous coastal saline soils were evaluated under different water application intensities in the laboratory experiment. The results indicated that the WAI of microsprinkler irrigation influenced the è, electrical conductivity（ECe） and p H of saline soils. As the WAI increased, the average values of è and ECe in the 0–40 cm profile also increased, while their average values in the 40–60 cm profile decreased. The p H value also slightly decreased as depth increased, but no significant differences were observed between the different treatments. The time periods of the water redistribution treatments had no obvious effects. Based on the results for è, ECe and p H, a smaller WAI was more desirable. The field experiment was conducted after being considered the results of the technical parameter experiment and evaporation, wind and leaching duration. The field experiment included three stages of water and salt regulation, based on three soil matric potentials（SMP）, in which the SMP at a 20-cm depth below the surface was used to trigger irrigation. The results showed that the microsprinkler irrigation created an appropriate environment for festuca growth through the three stages of water and salt regulation. The low-salinity conditions that occurred at 0–10 cm depth during the first stage（-5 k Pa） continued to expand through the next two stages. The average p H value was less than 8.5. The tiller number of festuca increased as SMP decreased from the first stage to the third stage. After the three stages of water and salt regulation, the highly saline soil gradually changed to a low-saline soil. Overall, based on the salt desalinization, the microsprinkler irrigation and three stages of water and salt regulation could be successfully used to cultivate plants for the reclamation of coastal saline land in North China.展开更多
Soil salinization or alkalization is a form of soil desertification. Coastal saline-alkali soil represents a type of desert and a key system in the network of ecosystems at the continent-ocean interface. Tamarix chine...Soil salinization or alkalization is a form of soil desertification. Coastal saline-alkali soil represents a type of desert and a key system in the network of ecosystems at the continent-ocean interface. Tamarix chinensis is a drought-tolerant plant that is widely distributed in the coastal saline-alkali soil of Bohai Bay, China. In this study, we used 454 pyrosequencing techniques to investigate the characteristics and distribution of the microbial diversity in coastal saline-alkali soil of the T. chinensis woodland at Bohai Bay. A total of 20,315 sequences were obtained, representing 19 known bacterial phyla and a large proportion of unclassified bacteria at the phylum level. Proteobacteria, Acidobacteria and Actinobacteria were the predominant phyla. The coverage of T. chinensis affected the microbial composition. At the phylum level, the relative abundance of y-Proteobacteria and Bacteroidetes decreased whereas Actinobacteria increased with the increasing coverage of T. chinensis. At the genus level, the proportions of Steroidobacter, Lechevalieria, Gp3 and Gp4 decreased with the increase of the vegetation coverage whereas the proportion of Nocardioides increased. A cluster analysis showed that the existing T. chinensis changed the niches for the microorganisms in the coastal saline-alkali soil, which caused changes in the microbial community. The analysis also distinguished the microbial community structure of the marginal area from those of the dense area and sparse area. Furthermore, the results also indicated that the distance to the seashore line could also affect certain groups of soil bacteria in this coastal saline-alkali soil, such as the family Cryomorphaceae and class Flavobacteria, whose population decreased as the distance increased. In addition, the seawater and temperature could be the driving factors that affected the changes.展开更多
In coastal regions, Bohai Gulf is one of the most affected areas by salinization. To study the effects of mocrosprinkler irrigation on the characteristics of highly saline sandy loam soil（ECe（saturated paste extract...In coastal regions, Bohai Gulf is one of the most affected areas by salinization. To study the effects of mocrosprinkler irrigation on the characteristics of highly saline sandy loam soil（ECe（saturated paste extract）=22.3 d S m^–1; SAR（sodium adsorption ratio）=49.0） of North China, a laboratory experiment was conducted. Five water application intensity（WAI） treatments（1.7, 3.1, 5.3, 8.8, and 10.1 mm h^–1）, five irrigation amount（IA） treatments（148, 168, 184, 201, and 223 mm） and three time periods of water redistribution（0, 24 and 48 h） were employed in the study. A compounding microsprinkler system was used for the WAI treatments, and a single microsprinkler was used for the IA treatments. The results indicated that, as soil depth increased, soil water content（θ） increased and then slightly decreased; with WAI and IA consistently increasing, the relatively moist region expanded and the average θ increased. Meanwhile, soil ECe increased as soil depth increased, and the zone with low soil salinity expanded as WAI and IA increased. Although the reduction of the average SAR was smaller than that of the average electrical conductivity of the ECe, these variables decreased in similar fashion as WAI and IA increased under microsprinkler irrigation. The average p H decreased as soil depth increased. Longer time periods of water redistribution led to lower salinity and slight expansion of the SAR zone. Considering the effects of leached salts in coastal saline soils, greater WAI and IA values are more advantageous under unsaturated flow conditions, as they cause better water movement in the soil. After leaching due to microsprinkler irrigation, highly saline soil gradually changes to moderately saline soil. The results provide theoretical and technological guidance for the salt leaching and landscaping of highly saline coastal environments.展开更多
Soil is the essential part for agricultural and environmental sciences,and soil salinity and soil water content are both the important influence factors for sustainable development of agriculture and ecological enviro...Soil is the essential part for agricultural and environmental sciences,and soil salinity and soil water content are both the important influence factors for sustainable development of agriculture and ecological environment.Digital camera,as one of the most popular and convenient proximal sensing instruments,has its irreplaceable position for soil properties assessment.In this study,we collected 52 soil samples and photographs at the same time along the coast in Yancheng City of Jiangsu Province.We carefully analyzed the relationship between soil properties and image brightness,and found that soil salt content had higher correlation with average image brightness value than soil water content.From the brightness levels,the high correlation coefficients between soil salt content and brightness levels concentrated on the high brightness values,and the high correlation coefficients between soil water content and brightness levels focused on the low brightness values.Different significance levels(P)determined different brightness levels related to soil properties,hence P value setting can be an optional way to select brightness levels as the input variables for modeling soil properties.Given these information,random forest algorithm was applied to develop soil salt content and soil water content inversion models using randomly 70%of the dataset,and the rest data for testing models.The results showed that soil salt content model had high accuracy(R_(v)^(2)=0.79,RMSE_(v)=12 g/kg,and RPD_(v)=2.18),and soil water content inversion model was barely satisfied(R_(v)^(2)=0.47,RMSE_(v)=3.04%,and RPD_(v)=1.38).This study proposes a method of modeling soil properties with a digital camera.Combining unmanned aerial vehicle(UAV),it has potential popularization and application value for precise agriculture and land management.展开更多
This research is based on the U8 (43) uniform table to conduct uniform experiments for improving saline soil. Different proportions of saline soil and silt, with a composted residue of marine fish and seashells that w...This research is based on the U8 (43) uniform table to conduct uniform experiments for improving saline soil. Different proportions of saline soil and silt, with a composted residue of marine fish and seashells that was mixed with sawdust and cow dung, were chosen as the assembly factors. The improvement coefficients for available nitrogen phosphorus of the mixed salt mud and for the production of tall fescue hay were adopted as the characterization values. According to the causal relations that were previously established by 64 types of permutations and combinations, the optimal assembly scheme with maximum characterization values was determined. The results indicate that the artificial soil that consisted of saline soil and silts in a ratio of 8:2;sea fish waste, shellfish trash and sawdust in a ratio of 5:4:1;and 8 kg of cow dung (10 wt%) is the best among the 64 types of composting treatments. Under the improved conditions, the predictive values of the increasing coefficients of valid nitrogen and valid phosphorus in the soil are 1.99 and 1.93, respectively;the predictive value of the tall fescue in a unit area production is 238.83 g·m-2. Its error accuracy is more than 99.82%. All of the above results indicate that utilizing the saline soil improvement media, which is composed of Haihe river silts, fish and shellfish slag, cow dung, and other wastes, provides a new option for saline soil improvement.展开更多
Various calibration methods have been propounded to determine profiles of apparent bulk soil electrical conductivity (ECa) and soil electrical conductivity of a saturated soil paste extract (ECe) or a 1:5 soil water e...Various calibration methods have been propounded to determine profiles of apparent bulk soil electrical conductivity (ECa) and soil electrical conductivity of a saturated soil paste extract (ECe) or a 1:5 soil water extract (EC1:5) using an electromagnetic induction instrument (EM38). The modeled coefficients, one of the successful and classical methods hitherto, were chosen to calibrate the EM38 measurements of the inverted salinity profiles of characteristic coastal saline soils at selected sites of Xincao Farm, Jiangsu Province, China. However, this method required three parameters for each depth layer. An integration approach, based on an exponential decay profile model, was proposed and the model was fitted to all the calibration sites. The obtained model can then be used to predict EC1:5 at a certain depth from electromagnetic measurements made using the EM38 device positioned in horizontal and vertical positions at the soil surface. This exponential decay model predicted the EC1:5 well according to the results of a one-way analysis of variance, and the further comparison indicated that the modeled coefficients appeared to be slightly superior to, but not statistically different from, this exponential decay model. Nevertheless, this exponential decay model was more significant and practical because it depended on less empirical parameters and could be used to perform point predictions of EC1:5 continuously with depth.展开更多
Background:Tall wheatgrass is a perennial salt-tolerant bunchgrass,which is a promising candidate for establishing a“Coastal Grass Belt”in China,particularly in the coastal saline–alkaline soils surrounding the Boh...Background:Tall wheatgrass is a perennial salt-tolerant bunchgrass,which is a promising candidate for establishing a“Coastal Grass Belt”in China,particularly in the coastal saline–alkaline soils surrounding the Bohai Sea.Methods:Seven harvesting treatments were performed to explore the optimal harvesting time and frequency for tall wheatgrass in coastal area.The dry matter yield(DMY)and forage nutritional values were investigated for each cut.The correlation between harvesting time and frequency thereof among the investigated traits was also determined.Results:The results showed that the two-cut on June 18 and October 29 produced the highest DMY.Another two-cut on May 26 and October 29 produced a relatively high crude protein(CP)yield.The DMY,contents of neutral detergent fiber(NDF),acid detergent fiber(ADF),and crude cellulose(CC)as well as CP yield were positively correlated to plant height,while the CP content and the relative feed value(RFV)were negatively correlated to plant height.The accumulating growing degree days,accumulated precipitation,and sunshine duration were positively correlated with plant height,DMY,contents of NDF,ADF,and CC as well as CP yield,but negatively correlated with CP content and RFV for the first cut.Conclusions:The two-cut treatment at the end of May and October may be suitable for tall wheatgrass in the“Coastal Grass Belt”targeted area.展开更多
探究不同有机物料投入对滨海盐碱地土壤理化性质及玉米生长发育的调控作用,为滨海盐碱地夏玉米生产提供理论依据。试验于2021-2022年夏玉米生长季在山东省滨州市无棣县滨海盐碱型农田进行。有机物料类型及用量分别为腐植酸(3000 kg hm^(...探究不同有机物料投入对滨海盐碱地土壤理化性质及玉米生长发育的调控作用,为滨海盐碱地夏玉米生产提供理论依据。试验于2021-2022年夏玉米生长季在山东省滨州市无棣县滨海盐碱型农田进行。有机物料类型及用量分别为腐植酸(3000 kg hm^(–2), HA)、生物炭(15,000 kg hm^(–2), BC)、生物有机肥(15,000 kg hm^(–2), BO),以不添加有机物料为对照(CK),探究0~40 cm土层土壤容重、总孔隙度、田间持水量、pH值、电导率及总有机碳含量的变化,分析不同有机物料投入对玉米地上部干物质积累和产量形成的影响。结果表明,腐植酸、生物炭和生物有机肥的施用均可在一定程度上改善盐碱土理化性质。3种有机物料连续处理能有效降低表层土壤容重,增加土壤总孔隙度和田间持水量;可显著降低0~10cm土层pH,分别平均降低0.17、0.08和0.20。连续施用2年后,腐植酸显著降低0~40cm土层电导率,平均降低32.74%;3种有机物料显著增加0~20 cm土层中总有机碳的含量,其中生物炭处理能显著增加57.99%。腐植酸和生物有机肥处理显著增加夏玉米地上部干物质积累量和产量;连续使用2年后腐植酸处理产量显著增加了11.01%,表现较好。综上所述,本试验条件下腐植酸施用后能改善土壤物理结构、降低0~10 cm土层pH、提高土壤中有机碳含量、显著降低土壤电导率,促进夏玉米地上部干物质积累、提高籽粒产量,且连续施用2年后较CK增加纯收益。故而腐植酸可作为改良滨海盐碱地土壤理化性状、促进夏玉米生长发育的有机物料。生物有机肥的施用可改善土壤理化性状,但仍需进行定位试验以验证其长期经济效应。展开更多
硅是作物生长的有益元素,有助于缓解作物遭受的盐胁迫。本试验以大田试验种植的登海605为试验材料,分别于小喇叭口期(V9)、大喇叭口期(V12)和抽雄期(VT)进行喷施硅制剂(8 g L^(–1) Si O_(2))处理,并以同期喷施等量清水为对照,旨在探讨...硅是作物生长的有益元素,有助于缓解作物遭受的盐胁迫。本试验以大田试验种植的登海605为试验材料,分别于小喇叭口期(V9)、大喇叭口期(V12)和抽雄期(VT)进行喷施硅制剂(8 g L^(–1) Si O_(2))处理,并以同期喷施等量清水为对照,旨在探讨不同时期叶面喷施硅制剂对滨海盐碱地夏玉米叶片光合性能及籽粒产量的影响,为滨海盐碱地夏玉米抗逆增产提供理论依据。结果表明,与对照相比,不同时期喷施叶面硅制剂,均能够显著增加盐碱地夏玉米叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性,降低丙二醛(MDA)含量,缓解光合器官的损伤和光合色素的降解;V9、V12、VT期叶面喷施硅制剂处理R6期,叶面积指数2年平均分别提高6.28%、7.16%、6.66%,2023年R3期叶绿素含量分别提高6.62%、7.52%、7.47%。喷施硅制剂提高了叶片净光合速率(P_(n))、蒸腾速率(T_(r))、气孔导度(G_(s))以及胞间CO_(2)浓度(C_(i));V9、V12、VT期叶面喷施硅制剂处理R3期P_n两年平均分别提高11.64%、11.73%、16.39%。光合速率提升促进了干物质积累及其向籽粒的转运,R6期干物质积累量分别提高8.46%、8.88%、9.67%,穗粒数和千粒重显著提高,最终籽粒产量在2022年和2023年分别提升了7.24%、10.47%、12.94%和6.23%、7.99%、11.25%;综上,本试验条件下,滨海轻中度盐碱地夏玉米生产过程中以VT期喷施叶面硅制剂的增产效果最佳,主要是缓解了氧化胁迫、提升了光合性能、促进了干物质积累与转运。展开更多
基金supported by the China Scholarship Council(Grant No.201906715015)the Priority Academic Development Program of Jiangsu Higher Education Institutions.
文摘This study aimed to investigate whether saline silt and sandy loam coastal soils could be reclaimed by micro-sprinkler irrigation.The experiments were run using moderately salt-tolerant tall fescue grass.Micro-sprinkler irrigation in three stages was used to regulate soil matric potential at a 20-cm soil depth.Continued regulation of soil water and salt through micro-sprinkler irrigation consistently resulted in an increasingly large low-salinity region.The application of the three stages of soil wateresalt regulation resulted in an absence of salt accumulation throughout the soil profile and the conversion of highly saline soils into moderately saline soils.There were increases in the plant height,leaf width,leaf length,and tiller numbers of tall fescue throughout the leaching process.The results showed that micro-sprinkler irrigation in three soil water and salt regulation stages can be used to successfully cultivate tall festuca in highly saline coastal soil.This approach achieved better effects in sandy loam soil than in silt soil.Tall fescue showed greater survival rates in sandy loam soil due to the rapid reclamation process,whereas plant growth was higher in silt soil because of effective water conservation.In sandy loam,soil moisture should be maintained during soil reclamation,and in silt soil,soil root-zone environments optimal for the emergence of plants should be quickly established.Micro-sprinkler irrigation can be successfully applied to the cultivation of tall fescue in coastal heavy saline soils under a three-stage soil wateresalt regulation regime.
文摘Soil salinity has become a major constraint to rice productivity in the coastal region of Bangladesh, which threatened food security. Therefore, field experiment was conducted at salt stressed Shyamnagor Upazilla of Satkhira district to improve the soil salinity status, sustainable rice production and suppression of global warming potentials. Selected soil amendments viz. trichocompost, tea waste compost, azolla compost and phospho-gypsum (PG) were applied in the field plots one week prior to rice transplanting. In addition, proline solution (25 mM) was applied on the transplanted rice plants at active vegetative stage. Gas samples from the paddy field were collected by Closed Chamber technique and analyzed in by Gas Chromatograph. The 25% replacement of chemical fertilizer (i.e., 75% NPKS) with trichocompost, tea waste compost, Azolla compost and Phospho-gypsum amendments increased grain yield by 4.7% - 7.0%, 2.3% - 7.1% 11.9% - 16.6% and 9.5% - 14.2% during dry boro rice cultivation, while grain yield increments of 5.0% - 7.6%, 2.3% - 10.2%, 12.8% - 15.3% and 10.2% - 15.3% were recorded in wet Aman season respectively, compared to chemically fertilized (100% NPKS) field plot. The least GWPs 3575 and 3650 kg CO<sub>2</sub> eq./ha were found in PG Cyanobacterial mixture with proline (T10) and tea waste compost with proline (T8) amended rice field, while the maximum GWPs 4725 and 4500 kg CO<sub>2 </sub>eq./ha were recorded in NPKS fertilized (100%, T2) and NPKS (75%) with Azolla compost (T5) amended plots during dry boro rice cultivation. The overall soil properties improved significantly with the selected soil amendments, while soil electrical conductivity (EC), soil pH and Na+ cation in the amended soil decreased, eventually improved the soil salinity status. Conclusively, phospho-gypsum amendments with cyanobacteria inoculation and proline solution (25 mM) application could be an effective option to reclaim coastal saline soils, sustaining rice productivity and reducing global warming potentials.
基金supported by the National High-Technology R&D Program of China (2013 BAC02B02 and 2013BAC02B01)the National Science Foundation for Young Scientists of China (51409126)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions, China (1033000001)the Action Plan for Development of Western China of Chinese Academy of Sciences (KZCX 2-XB3-16)
文摘Laboratory and field experiments were conducted to investigate the effects of water application intensity（WAI） on soil salinity management and the growth of Festuca arundinacea（festuca） under three stages of water and salt management strategies using microsprinkler irrigation in Hebei Province, North China. The soil water content（è） and salinity of homogeneous coastal saline soils were evaluated under different water application intensities in the laboratory experiment. The results indicated that the WAI of microsprinkler irrigation influenced the è, electrical conductivity（ECe） and p H of saline soils. As the WAI increased, the average values of è and ECe in the 0–40 cm profile also increased, while their average values in the 40–60 cm profile decreased. The p H value also slightly decreased as depth increased, but no significant differences were observed between the different treatments. The time periods of the water redistribution treatments had no obvious effects. Based on the results for è, ECe and p H, a smaller WAI was more desirable. The field experiment was conducted after being considered the results of the technical parameter experiment and evaporation, wind and leaching duration. The field experiment included three stages of water and salt regulation, based on three soil matric potentials（SMP）, in which the SMP at a 20-cm depth below the surface was used to trigger irrigation. The results showed that the microsprinkler irrigation created an appropriate environment for festuca growth through the three stages of water and salt regulation. The low-salinity conditions that occurred at 0–10 cm depth during the first stage（-5 k Pa） continued to expand through the next two stages. The average p H value was less than 8.5. The tiller number of festuca increased as SMP decreased from the first stage to the third stage. After the three stages of water and salt regulation, the highly saline soil gradually changed to a low-saline soil. Overall, based on the salt desalinization, the microsprinkler irrigation and three stages of water and salt regulation could be successfully used to cultivate plants for the reclamation of coastal saline land in North China.
基金funded by the National Natural Science Foundation of China(31470544,41271265)a special financial grant from the China Postdoctoral Science Foundation(2013T60900)the Science and Technology Projects in Gansu Province(1304NKCA135)
文摘Soil salinization or alkalization is a form of soil desertification. Coastal saline-alkali soil represents a type of desert and a key system in the network of ecosystems at the continent-ocean interface. Tamarix chinensis is a drought-tolerant plant that is widely distributed in the coastal saline-alkali soil of Bohai Bay, China. In this study, we used 454 pyrosequencing techniques to investigate the characteristics and distribution of the microbial diversity in coastal saline-alkali soil of the T. chinensis woodland at Bohai Bay. A total of 20,315 sequences were obtained, representing 19 known bacterial phyla and a large proportion of unclassified bacteria at the phylum level. Proteobacteria, Acidobacteria and Actinobacteria were the predominant phyla. The coverage of T. chinensis affected the microbial composition. At the phylum level, the relative abundance of y-Proteobacteria and Bacteroidetes decreased whereas Actinobacteria increased with the increasing coverage of T. chinensis. At the genus level, the proportions of Steroidobacter, Lechevalieria, Gp3 and Gp4 decreased with the increase of the vegetation coverage whereas the proportion of Nocardioides increased. A cluster analysis showed that the existing T. chinensis changed the niches for the microorganisms in the coastal saline-alkali soil, which caused changes in the microbial community. The analysis also distinguished the microbial community structure of the marginal area from those of the dense area and sparse area. Furthermore, the results also indicated that the distance to the seashore line could also affect certain groups of soil bacteria in this coastal saline-alkali soil, such as the family Cryomorphaceae and class Flavobacteria, whose population decreased as the distance increased. In addition, the seawater and temperature could be the driving factors that affected the changes.
基金supported by the National High-Tech R&D Program of China(2013 BAC02B02 and 2013BAC02B01)the National Science Foundation for Young Scientists of China(51409126,31300530,51409124)Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),China
文摘In coastal regions, Bohai Gulf is one of the most affected areas by salinization. To study the effects of mocrosprinkler irrigation on the characteristics of highly saline sandy loam soil（ECe（saturated paste extract）=22.3 d S m^–1; SAR（sodium adsorption ratio）=49.0） of North China, a laboratory experiment was conducted. Five water application intensity（WAI） treatments（1.7, 3.1, 5.3, 8.8, and 10.1 mm h^–1）, five irrigation amount（IA） treatments（148, 168, 184, 201, and 223 mm） and three time periods of water redistribution（0, 24 and 48 h） were employed in the study. A compounding microsprinkler system was used for the WAI treatments, and a single microsprinkler was used for the IA treatments. The results indicated that, as soil depth increased, soil water content（θ） increased and then slightly decreased; with WAI and IA consistently increasing, the relatively moist region expanded and the average θ increased. Meanwhile, soil ECe increased as soil depth increased, and the zone with low soil salinity expanded as WAI and IA increased. Although the reduction of the average SAR was smaller than that of the average electrical conductivity of the ECe, these variables decreased in similar fashion as WAI and IA increased under microsprinkler irrigation. The average p H decreased as soil depth increased. Longer time periods of water redistribution led to lower salinity and slight expansion of the SAR zone. Considering the effects of leached salts in coastal saline soils, greater WAI and IA values are more advantageous under unsaturated flow conditions, as they cause better water movement in the soil. After leaching due to microsprinkler irrigation, highly saline soil gradually changes to moderately saline soil. The results provide theoretical and technological guidance for the salt leaching and landscaping of highly saline coastal environments.
基金Under the auspices of the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA28110301,XDA2306040303)National Natural Science Foundation of China(No.41807001,41977424)Natural Science Foundation of Jilin Province(No.20200201026JC)。
文摘Soil is the essential part for agricultural and environmental sciences,and soil salinity and soil water content are both the important influence factors for sustainable development of agriculture and ecological environment.Digital camera,as one of the most popular and convenient proximal sensing instruments,has its irreplaceable position for soil properties assessment.In this study,we collected 52 soil samples and photographs at the same time along the coast in Yancheng City of Jiangsu Province.We carefully analyzed the relationship between soil properties and image brightness,and found that soil salt content had higher correlation with average image brightness value than soil water content.From the brightness levels,the high correlation coefficients between soil salt content and brightness levels concentrated on the high brightness values,and the high correlation coefficients between soil water content and brightness levels focused on the low brightness values.Different significance levels(P)determined different brightness levels related to soil properties,hence P value setting can be an optional way to select brightness levels as the input variables for modeling soil properties.Given these information,random forest algorithm was applied to develop soil salt content and soil water content inversion models using randomly 70%of the dataset,and the rest data for testing models.The results showed that soil salt content model had high accuracy(R_(v)^(2)=0.79,RMSE_(v)=12 g/kg,and RPD_(v)=2.18),and soil water content inversion model was barely satisfied(R_(v)^(2)=0.47,RMSE_(v)=3.04%,and RPD_(v)=1.38).This study proposes a method of modeling soil properties with a digital camera.Combining unmanned aerial vehicle(UAV),it has potential popularization and application value for precise agriculture and land management.
文摘This research is based on the U8 (43) uniform table to conduct uniform experiments for improving saline soil. Different proportions of saline soil and silt, with a composted residue of marine fish and seashells that was mixed with sawdust and cow dung, were chosen as the assembly factors. The improvement coefficients for available nitrogen phosphorus of the mixed salt mud and for the production of tall fescue hay were adopted as the characterization values. According to the causal relations that were previously established by 64 types of permutations and combinations, the optimal assembly scheme with maximum characterization values was determined. The results indicate that the artificial soil that consisted of saline soil and silts in a ratio of 8:2;sea fish waste, shellfish trash and sawdust in a ratio of 5:4:1;and 8 kg of cow dung (10 wt%) is the best among the 64 types of composting treatments. Under the improved conditions, the predictive values of the increasing coefficients of valid nitrogen and valid phosphorus in the soil are 1.99 and 1.93, respectively;the predictive value of the tall fescue in a unit area production is 238.83 g·m-2. Its error accuracy is more than 99.82%. All of the above results indicate that utilizing the saline soil improvement media, which is composed of Haihe river silts, fish and shellfish slag, cow dung, and other wastes, provides a new option for saline soil improvement.
基金Project supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (No. KZCX2-YW-406-3)the National Key Basic Research Support Foundation (NKBRSF) of China (No. 2005CB121108).
文摘Various calibration methods have been propounded to determine profiles of apparent bulk soil electrical conductivity (ECa) and soil electrical conductivity of a saturated soil paste extract (ECe) or a 1:5 soil water extract (EC1:5) using an electromagnetic induction instrument (EM38). The modeled coefficients, one of the successful and classical methods hitherto, were chosen to calibrate the EM38 measurements of the inverted salinity profiles of characteristic coastal saline soils at selected sites of Xincao Farm, Jiangsu Province, China. However, this method required three parameters for each depth layer. An integration approach, based on an exponential decay profile model, was proposed and the model was fitted to all the calibration sites. The obtained model can then be used to predict EC1:5 at a certain depth from electromagnetic measurements made using the EM38 device positioned in horizontal and vertical positions at the soil surface. This exponential decay model predicted the EC1:5 well according to the results of a one-way analysis of variance, and the further comparison indicated that the modeled coefficients appeared to be slightly superior to, but not statistically different from, this exponential decay model. Nevertheless, this exponential decay model was more significant and practical because it depended on less empirical parameters and could be used to perform point predictions of EC1:5 continuously with depth.
基金Strategic Priority Research Program of the Chinese Academy of Sciences,Grant/Award Number:XDA26040105。
文摘Background:Tall wheatgrass is a perennial salt-tolerant bunchgrass,which is a promising candidate for establishing a“Coastal Grass Belt”in China,particularly in the coastal saline–alkaline soils surrounding the Bohai Sea.Methods:Seven harvesting treatments were performed to explore the optimal harvesting time and frequency for tall wheatgrass in coastal area.The dry matter yield(DMY)and forage nutritional values were investigated for each cut.The correlation between harvesting time and frequency thereof among the investigated traits was also determined.Results:The results showed that the two-cut on June 18 and October 29 produced the highest DMY.Another two-cut on May 26 and October 29 produced a relatively high crude protein(CP)yield.The DMY,contents of neutral detergent fiber(NDF),acid detergent fiber(ADF),and crude cellulose(CC)as well as CP yield were positively correlated to plant height,while the CP content and the relative feed value(RFV)were negatively correlated to plant height.The accumulating growing degree days,accumulated precipitation,and sunshine duration were positively correlated with plant height,DMY,contents of NDF,ADF,and CC as well as CP yield,but negatively correlated with CP content and RFV for the first cut.Conclusions:The two-cut treatment at the end of May and October may be suitable for tall wheatgrass in the“Coastal Grass Belt”targeted area.
文摘探究不同有机物料投入对滨海盐碱地土壤理化性质及玉米生长发育的调控作用,为滨海盐碱地夏玉米生产提供理论依据。试验于2021-2022年夏玉米生长季在山东省滨州市无棣县滨海盐碱型农田进行。有机物料类型及用量分别为腐植酸(3000 kg hm^(–2), HA)、生物炭(15,000 kg hm^(–2), BC)、生物有机肥(15,000 kg hm^(–2), BO),以不添加有机物料为对照(CK),探究0~40 cm土层土壤容重、总孔隙度、田间持水量、pH值、电导率及总有机碳含量的变化,分析不同有机物料投入对玉米地上部干物质积累和产量形成的影响。结果表明,腐植酸、生物炭和生物有机肥的施用均可在一定程度上改善盐碱土理化性质。3种有机物料连续处理能有效降低表层土壤容重,增加土壤总孔隙度和田间持水量;可显著降低0~10cm土层pH,分别平均降低0.17、0.08和0.20。连续施用2年后,腐植酸显著降低0~40cm土层电导率,平均降低32.74%;3种有机物料显著增加0~20 cm土层中总有机碳的含量,其中生物炭处理能显著增加57.99%。腐植酸和生物有机肥处理显著增加夏玉米地上部干物质积累量和产量;连续使用2年后腐植酸处理产量显著增加了11.01%,表现较好。综上所述,本试验条件下腐植酸施用后能改善土壤物理结构、降低0~10 cm土层pH、提高土壤中有机碳含量、显著降低土壤电导率,促进夏玉米地上部干物质积累、提高籽粒产量,且连续施用2年后较CK增加纯收益。故而腐植酸可作为改良滨海盐碱地土壤理化性状、促进夏玉米生长发育的有机物料。生物有机肥的施用可改善土壤理化性状,但仍需进行定位试验以验证其长期经济效应。
文摘硅是作物生长的有益元素,有助于缓解作物遭受的盐胁迫。本试验以大田试验种植的登海605为试验材料,分别于小喇叭口期(V9)、大喇叭口期(V12)和抽雄期(VT)进行喷施硅制剂(8 g L^(–1) Si O_(2))处理,并以同期喷施等量清水为对照,旨在探讨不同时期叶面喷施硅制剂对滨海盐碱地夏玉米叶片光合性能及籽粒产量的影响,为滨海盐碱地夏玉米抗逆增产提供理论依据。结果表明,与对照相比,不同时期喷施叶面硅制剂,均能够显著增加盐碱地夏玉米叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性,降低丙二醛(MDA)含量,缓解光合器官的损伤和光合色素的降解;V9、V12、VT期叶面喷施硅制剂处理R6期,叶面积指数2年平均分别提高6.28%、7.16%、6.66%,2023年R3期叶绿素含量分别提高6.62%、7.52%、7.47%。喷施硅制剂提高了叶片净光合速率(P_(n))、蒸腾速率(T_(r))、气孔导度(G_(s))以及胞间CO_(2)浓度(C_(i));V9、V12、VT期叶面喷施硅制剂处理R3期P_n两年平均分别提高11.64%、11.73%、16.39%。光合速率提升促进了干物质积累及其向籽粒的转运,R6期干物质积累量分别提高8.46%、8.88%、9.67%,穗粒数和千粒重显著提高,最终籽粒产量在2022年和2023年分别提升了7.24%、10.47%、12.94%和6.23%、7.99%、11.25%;综上,本试验条件下,滨海轻中度盐碱地夏玉米生产过程中以VT期喷施叶面硅制剂的增产效果最佳,主要是缓解了氧化胁迫、提升了光合性能、促进了干物质积累与转运。
