盐碱地栽植糖用甜菜与施肥

根据第二次土壤普查资料显示,内蒙古东四盟、市的中、重盐碱化和盐、碱土此类型荒地和耕地面积有81.9万hm^2,可开发栽植糖用甜菜,促进糖产业发展。通过研究、分析,参考国外糖用甜菜对养分的吸收和移出量,提出调整N∶P2O5=1∶0.375-0.400为1∶1.2,K2O和Mg O施用量为吸收和移出量的1/3,Zn按土壤含量适当施用,Mn、B按吸收和移出量补施,在施有机肥的基础上,参考施肥方案。

Initial Exploration on Effect of Saline-alkali Land Rebuilding and Utilization by Fenlong Cultivation

In order to explore the effect of Fenlong cultivation in rebuilding and uti- lization of saline-alkali land, the Fenlong tillage machine and Fenlong technology were invented and put into tests in the saline-alkali land from 2015-2016 in Xinjiang Autonomous Region and Shaanxi province, respectively. The results showed that in Xinjiang, the total salt content in the heavy saline-alkali soil decreased by 31.31% after one season of cotton planting using Fenlong, while cotton yield increased by 48.80%, and the soil salinity level was fallen from ＂severe＂ to ＂moderate＂ level. In Shaanxi, the total salt content in decreased by 42.73% after planting summer corn summer corn the mild saline-alkali land using Fenlong cultivation, while the corn yield increased by 34.83%, and the soil salinity degree was changed from ＂mild de- salination＂ to ＂normal farmland＂. At last, the paper provided the mechanism and reasons for desalination in soil and yield increase by Fenlong cultivation.

Cloning and Differential Gene Expression of Two Catalases in Suaeda salsa in Response to Salt Stress

Two different cDNA clones (Sscat1 and Sscat2) encoding catalase, the primary important H2O2-scavenging enzyme, were isolated from a AZap-cDNA library constructed from a 400 mmol/L NaCl-treated library of Suaeda salsa ( L.) Pall aerial tissue. Sscat1 (1.7 kb) contains a full open reading frame of 492 amino acids and Sscat2 (1.1 kb) is a partial clone. BLAST analysis indicates that the two clones share 71.9% identity in nucleotide sequence and 75% identity in deduced amino acid sequence within the last 287 amino acid residues of Sscat1. Southern blotting analysis showed that Sscat1 is multicopy in S. salsa genome, while Sscat2 is a single copy gene. Northern blotting analysis showed a rapid increase in the steady-level of both genes in roots after 48 It salt treatment, but only Sscat1 was induced in salinity treated leaves. Time-course analysis carried out in leaves confirmed that Sscat1 was induced by salt stress, in contrast to Sscat2. These implied that the expression of Sscat1 and Sscat2 genes are differentially regulated in S. salsa. The activity of total catalase is dramatically increased in response to salt stress.

Isolation of S-adenosylmethionine Synthetase Gene from Suaeda salsa and Its Differential Expression Under NaCl Stress

AdoMet plays numerous roles of being the major methyl-group donor in trans-methylation reactions. To gain insight into the possible functions of the AdoMet protein of Suaeda salsa L. in response to salt stress, S adenosylmethionine synthetase gene (SAMS2) was analyzed. We isolated SAMS2 cDNA clone (AF321001) from a lambda -Zap cDNA library constructed from the halophyte S. salsa Pall aerial tissue treated with 400 mmol/L NaCl. SsSAMS2 was found to encode a S-adenolyl-L-methionine synthetase enzyme (AdoMet synthetase). The fragment was 1 531 bp with an open reading frame of 395 amino acids, the calculated molecular weight was about 43 kD. SsSAMS2 showed the highest homology to SAMS2 gene of Catharanthus roseus G. Don., with 93% identity in deduced amino acid sequence. Southern blotting analysis showed that SsSAMS2 might be a two-copy gene in S. salsa genome. Northern blot indicated that the cDNA was up-regulated by salt and other stresses. Enzyme activity assay indicated that the activity of SAMS2 increased under NaCl stress.

Effect of K^+ Nutrition on Growth and Activity of Leaf Tonoplast V-H^+-ATPase and V-H^+-PPase of Suaeda salsa Under NaCl Stress

Suaeda salsa L. seedlings grown in Hoagland nutrient solution were treated with different concentrations of NaCl combined with two levels of K + (12 μmol/L and 6 mmol/L) to study the K + nutrition effect on plant growth and leaf tonoplast V-H +-ATPase and V-H +-PPase activity. Increase of K + supply in the culture solution markedly increased the fresh weight, dry weight and K + content of S. salsa plants. Western blot analysis showed that the leaf V-H +-ATPase of S. salsa was at least composed of A,B,C,D,E and c subunits, and their expression decreased with the increase of NaCl concentration under K + starvation (12 μmol/L K +), but increased under normal K + application (6 mmol/L K +). Leaf V-H +-PPase molecular weight was about 72.6 kD and its expression increased as NaCl concentration increased under both high or low levels of K + concentration in nutrient solution. There was a positive correlation between of V-H +-ATPase or V-H +-PPase activity and the amounts of their expression. Results in this study suggest that K + nutrition plays an important role in the salt tolerance of S. salsa, and K + is involved in the regulation of V-H +-ATPase or V-H +-PPase activity under salt stress.

Simulation Study on the Alkalized-salinized Grassland Ecosystem in the Songnen Plain

Using Object-oriented design and a new programming language JAVA, a physically-based model was built to simulate the hydrological, alkalization/de-alkalization and salinization/desalinization processes in soil. Furthermore, a process-based model was built to evaluate the dynamics of four herbaceous ecosystems (including dynamics of above-ground biomass, below-ground biomass, and litter biomass), each dominated by Aneurolepidium chinense (Trin.) Kitag., Chloris virgata Sw., Puccinellia tenuiflora (Turcz.) Scribn. et Merr. and Suaeda glauca Bunge. This model is a daily-time step model, suitable for simulating hydrological, alkalization/de-alkalization and salinization/desalinization processes of heterogeneous soil, and growth dynamics of different grassland communities. With climatic data and experimental data of Changling Experimental Site in Jilin Province, the soil moisture content (in 1991, 1996, 1997 and 1998), soil salt concentration, exchangeable cation percentage and pH in soil and growth dynamics of these four sorts of grassland communities (in 1991) were simulated and the results were verified to be in accord with observed data.

Study on the Landscaping Technologies for Coastal Saline-Alkali Land in Tanghai County of Tangshan City

Tanghai County is one of the counties in Tangshan City with the highest saline-alkali degree, with 80% of its land being covered by saline-alkali soils. Through studying landscaping technologies for coastal saline-alkali land in Tanghai County, 3 dominant modes for landscaping engineering in such land were summarized as shallow underground pipe desalination technology, banding soil replacement technology and hole membrane soil replacement technology, which are different in application scope and also in cost (respectively 260, 210 and 170 yuan). 3 landscaping measures were also proposed, including promotion of suitable plant cultivation technologies, application of saline-alkali tolerant plants and biological improvement of soils. To explore economic and practical planting patterns for saline-alkali land, low-cost landscaping tests were conducted from the perspectives of improving landscaping engineering mode and optimizing landscaping measures, and the results showed that it was practical to apply low-cost landscaping patterns, and comprehensive ecological measures should be adopted to realize the sustained utilization of soil.

Application Research of Restoration Materials on Degraded Land

[Objective] The paper aimed at researching on the ecological remediation materials and related technologies in degraded land.[Method] Pointing at the specific reasons for degradation of soil moisture and fertility conditions,the ecological remediation materials and related technologies for soil moisture had been studied using layered silicates as substrate materials and using straw turnover as the method.The application research had been carried out in degraded cultivated land,compacted land,saline-alkali soil and laboratory of nine provinces and regions on 26 species and 48 varieties.[Result] The materials and related technologies are environment-friendly in formula,processing,application with no hidden trouble as secondary pollution,which can be used for the restoration of positive balance of soil moisture conditions（water,fertilizer,gas,and heat）,establishment of the core of a stable circle and improving food production steadily.The materials are more suitable for plant growth than chemical fertilizers,applying of which helps plants obtain better adversity resistance.[Conclusion] The ecological remediation materials for soil moisture can reduce the application of chemical fertilizers effectively and improve the production and quality of crops remarkably.

Dynamic Changes of Nitrogen in Saline-alkaline Paddy Field and Its Potential Environmental Impacts

[Objective] The paper was to study the dynamic changes of nitrogen in saline-alkaline paddy field and its potential environment impacts. [Method] With typical sodic saline-alkaline paddy fields of Songnen Plain as study object,field test method was used to explore the dynamic changes was strong alkof nitrogen in paddy field of the region and its potential impact on environment. [Result] The soil in test regionaline with high CEC and C/N ratios,as well as poor preserving capacity of fertilizer. During the two-year field experiment,the indicators of salinization fluctuated. Initially,the concentrations of total nitrogen and ammonia nitrogen reached their maximum values,then decreased over time as a result of heavy rain. The maximum of nitrate concentration appeared later than those of total nitrogen and ammonia nitrogen. Ammonia volatilization accounted for 18.9%-28.8% of the nitrogen loss. The total nitrogen concentration in surface water was higher than the national Class Ⅲ surface water environmental quality standard. The concentration of ammonia from the recession flow of agricultural field was considerably high,which would potentially threaten the fishery in the downstream of Chagan Lake. [Conclusion] The study provided theoretical basis for saline-alkaline soil management and conservation of water and fishery resources.

The Characteristics of Spatial Distribution of Saline-alkali Wasteland in Datong Basin, Northern China

[Objective] Saline-alkali wasteland is a kind of land use type that formed by soil salinization and secondary salinization. To study the causes of spatial distri- bution of saline-alkali wasteland could be used as reference for the amelioration and is significant for developing the reserved land with great potential. [Method] The re- search set a total of 1 729 sampling points in the study area of 34 433 hm2. Spa- tial analyses were used to find out the causes of saline-alkali wasteland in Datong basin from four factors： topography, geology, hydrology and soil. DEM and land use data were used to calculate distribution index of topography, and distribution of the total salinity （TS） and pH was analyzed by means of IDW interpolation. [Result] The results showed that saline-alkali wasteland was distributed on flat and low-lying ter- rains with poor drainage, which led to salt accumulation. 87% of saline-alkali wasteland was distributed on Quaternary Holocene alluvium whose performance of soil hydraulic conductivity was poor. TS value distribution was that in midstream re- gion was the highest, less in upstream region and the least in downstream region along the rivers, and TS value decreased when distance between saline-alkali wasteland and rivers increased. The major soil types in Datong basin were fluvo- aquic soil and saline soil. Both of the two soil types were of high TS value and pH value, and heavily salinized and strongly alkalized. [Conclusion] High groundwater table and the existence of two salt accumulation centers are the two causes of saline-alkali wasteland in Datong basin. The key to ameliorate saline-alkali waste- land is to descend the groundwater table and lessen salt accumulation.

Assessing Reclamation Levels of Coastal Saline Lands with Integrated Stepwise Discriminant Analysis and Laboratory Hyperspectral Data

At different times over the past 30 years in Zhejiang Province, China, the coastal tidelands have been successively enclosed and reclaimed for agricultural land use. The purpose of this work was to evaluate whether laboratory hyperspectral data might be used to estimate the physicochemical characteristics of these reclaimed saline soils. A coastal region of Shangyu City (Zhejiang Province), which was grouped into four subzones according to reclamation history, was used as the study area, and soil samples were collected in each subzone. Physicochemical analyses showed that the soils were characterized by high electrical conductivity and sand content with low organic matter; the longer the saline lands had been reclaimed, the lower were the electrical conductivity and sand content and the higher the organic matter content. These changing trends of soil chemical and physical properties were found in laboratory reflectance spectra of soil samples and their first-order derivative curves. Stepwise discriminant analysis (SDA) identified six salient spectral bands at 488, 530, 670, 880, 1400, and 1900 nm. Using derived discriminant functions for saline lands with different historical years of reclamation, classification revealed an overall accuracy from a self-test of 86.6% and from cross-validation of 89.3%. Therefore, as opposed to time-consuming field investigations, this study suggested that remotely sensed hyperspectral data could serve as a promising measure to assess the reclamation levels of coastal saline lands.

Delineation of Site-Specific Management Zones Based on Temporal and Spatial Variability of Soil Electrical Conductivity

A coastal saline field of 10.5 ha was selected as the study site and 122 bulk electrical conductivity (ECb) measurements were performed thrice in situ in the topsoil (0-20 cm) across the field using a hand held device to assess the spatial variability and temporal stability of the distribution of soil electrical conductivity (EC), to identify the management zones using cluster analysis based on the spatiotemporal variability of soil EC, and to evaluate the probable potential for site-specific management in coastal regions with conventional statistics and geostatistical techniques. The results indicated high coefficients of variation for topsoil salinity over all the three samplings. The spatial structure of the salinity variability remained relatively stable with time. Kriged contour maps, drawn on the basis of spatial variance structure of the data, showed the spatial trend of the salinity distribution and revealed areas of consistently high or consistently low salinity, while a temporal stability map indicated stable and unstable regions. On the basis of the spatiotemporal characteristics, cluster analysis divided the site into three potential management zones, each with different characteristics that could have an impact on the way the field was managed. On the basis of the clearly defined management zones it was concluded that coastal saline land could be managed in a site-specific way.

Dynamics of Saline-alkali Land and Its Ecological Regionalization in Western Songnen Plain, China

As the important reserve land resources for food production,saline-alkali land should play a significant role to ensure the national food security in the context of global food crisis. The western Songnen Plain is one of main distribution regions of saline-alkali land in China,with great potential in agricultural development. In this study,the extent,transformation,spatial distribution and temporal change of saline-alkali land in the western Songnen Plain during 1954–2005 were investigated by using remote sensing and GIS spatial analysis methods. Saline-alkali land change was detected from a temporal series of topographic maps in 1954,satellite images of Landsat MSS in 1976,Landsat TM/ETM in 1988,2000 and 2005 through artificial visual interpretation. The results indicated a significant expansion in saline-alkali land area and aggravation in salinization. The area of saline-alkali land had increased from 401.48×103 ha in 1954 to 1 097.45×103 ha in 2005. While the ratio of light,moderate and serious salinized land areas changed from 6.72︰2.92︰1.00 to 1.25︰1.06︰1.00 in the study period. Grassland,cropland,swampland and water body were the major land use and land cover types from which saline-alkali land transformed. And the secondary salinization occured mainly in Da′an City,Tongyu County,Changling County,Daqing City,Dorbod Mongolian Autonomous County and Zhaoyuan County. Finally,seven large ecoregions and 14 corresponding sub-ecoregions were delineated out based on spatio-temopral dynamic characteristics of saline-alkali land and geo-relational environmental attributes. According to the results,measures of amelioration and ways of development of saline-alkali land in the western Songnen Plain were put forward.

Restoration and Rational Use of Degraded Saline Reed Wetlands:A Case Study in Western Songnen Plain, China

The protection, restoration and sustainable use are key issues of all the wetlands worldwide. Ecological, agronomic, and engineering techniques have been integrated in the development of a structurally sound, ecologically beneficial engineering restoration method for restoring and utilizing a degraded saline wetland in the western Songnen Plain of China. Hydrological restoration was performed by developing a system of biannual irrigation and drainage using civil engineering measures to bring wetlands into contact with river water and improve the irrigation and drainage system in the wetlands. Agronomic measures such as plowing the reed fields, reed rhizome transplantation, and fertilization were used to restore the reed vegetation. Biological measures, including the release of crab and fish fry and natural proliferation, were used to restore the aquatic communities. The results of the restoration were clear and positive. By the year 2009, the reed yield had increased by 20.9 times. Remarkable ecological benefits occurred simultaneously. Vegetation primary-production capacity increased, local climate regulation and water purification enhanced, and biodiversity increased. This demonstration of engineering techniques illustrates the basic route for the restoration of degraded wetlands, that the biodiversity should be reconstructed by the comprehensive application of engineering, biological, and agronomic measures based on habitat restoration under the guidance of process-oriented strategies. The complex ecological system including reeds, fish and crabs is based on the biological principles of coexistence and material recycling and provides a reasonable ecological engineering model suitable for the sustainable utilization of degraded saline reed wetlands.

Regenerative Role of Soil Seed Banks of Different Successional Stages in A Saline-alkaline Grassland in Northeast China

Soil seed banks can act as a potential seed source for natural revegetation and restoration. However, in a saline-alkaline grassland, it remains unclear how the stages of vegetation succession affect the characteristics of soil seed banks and the potential of soil seed banks of different successional stages for vegetation restoration. In this study, seasonal changes of the soil seed bank, and seed production and dispersal dynamics along degradation successional gradients were investigated in a saline-alkaline grassland in Northeast China, where the dominant grass during the 1960 s, Leymus chinensis was replaced with the secondary successional order of Puccinellia chinampoensis, Chloris virgata, and Suaeda salsa, together with bare patches. It was found that the soil seed bank composition varied according to the changing vegetation and had the highest species richness(7–16) in the climax successional stage, but had a low S?rensen similarity(0.22–0.37) with the aboveground vegetation. There was a high seed density of the soil seed bank(21 062–62 166/m2 in August and December) and also high S?rensen similarity index values(0.47–0.60) in the secondary successional stages of P. chinampoensis, C. virgata, and S. salsa. In bare patches, there were many seeds in the soil seed bank and some seedlings also appeared in the aboveground vegetation, indicating the existence of a persistent soil seed bank. Seed density and species richness differed substantially among the different successional stages, which was related to the reproductive characteristics of the standing plants in vegetation communities. Due to the lack of propagules of perennial species, especially the climax species of L. chinensis, in the soil, the successful restoration of the degraded saline-alkaline grassland was not possible. The study proved that in a degraded saline-alkaline grassland dominated by biennial or annual species, the soil seed bank was important for the revegetation of the current dominant plants, but not for the restoration of the original target species. Therefore, it is necessary to induce seeds or other propagules of the target perennial species.

Quantitative Assessment of Impacts of Regional Climate and Human Activities on Saline-alkali Land Changes:A Case Study of Qian'an County,Jilin Province

Interdecadal and interannuat variations of saline-alkali land area in Qian＇an County, Jilin Province, China were comprehensively analyzed in this paper by means of satellite remote sensing interpretation, field flux observations and regional climate diagnosis. The results show that on the interannual scale, the impact of climate factors accounts for 71.6% of the total variation of the saline-alkali land area, and that of human activities accounts for 28.4%. Therefore the impact of climate factors is obviously greater than that of human activities. On the interdecadal scale, the impact of climate factors on the increase of the saline-alkali land area accounts for 43.2%, and that of human activities accounts for 56.8%. The impact of human activities on the variation of saline-alkali land area is very clear on the interdecadal scale, and the negative impact of human activities on the environment should not be negligible. Besides, changes in the area of heavy saline-alkali land have some indication for development of saline-alkali land in Qian＇an County.

Landscape Dynamics and Driving Factors in Da’an County of Jilin Province in Northeast China During 1956-2000

The landscape pattern of Da’an County, Northeast China has undergone significant changes since the 1950s as a result of climatic change and human activities. The aim of this paper is to quantitatively study landscape pattern and its spatial dynamics of Da’an County at the landscape level over the nearly 50-year span. Patch dynamics were examined ac-cording to land use and land cover change processes built from a series of images, as well as topographic maps, and tem-poral patterns built from landscape pattern metrics. The transition matrix of landscape patch types and changes of various landscape metrics were applied. The results showed that, from 1956 to 2000, the landscape within the study area had un-dertaken a complicated evolution in landscape structure and composition. The outstanding characteristic is that sa-line-alkali land increased and grassland decreased. As some smaller patches amalgamated, the heterogeneity of patch de-creased. All those changes were the synthetic result of both climatic and anthropogenic influences, but the predominant factor was different in different parts. In the southern part of the study area, the landscape pattern changes resulted from the modification of climate obviously, while in the northern part, the landscape pattern changes were mainly caused by human activities, such as the conversion between farmland and saline-alkali land. This phenomenon showed that human activities played more important role in the north than in the south of Da’an County.

A GIS-based Tupu Analysis of Dynamics of Saline-alkali Land in Western Jilin Province

Based on Tupu theory, this paper studied the dynamic changes, conversion modes, expansion intensity and landscape attributes of the saline-alkali lands in Changling County, Zhenlai County and Da'an City of the western Jilin Province in 1980-2000 with the help of GIS. The results show that the saline-alkali land rather sharply increased in Da'an during 1995-2000; the main conversion processes in the three counties were from grassland to saline-alkali land and from saline-alkali land to grassland; and the typical shapes, spatial expansion speed and mode, and landscape attributes of the saline-alkali land were different in the three counties, which were closely related to local topography, predominant wind orientation, water resources distribution, etc. The corresponding spatial expansion mode was marginality in Changling, random in Zhenlai and more kernels in Da'an, respectively. Landscape attributes also responded to the spatial-temporal dynamic changes of the saline-alkali land and the landscape indices of Da'an fluctuated greatly. The frame of this research may provide fundamental reference for landscape analysis and give some suggestions for regional sustainable development.

Land Use/Cover Changes and Environmental Consequences in Songnen Plain,Northeast China

The Songnen Plain in Northeast China,one of the key national bases of agricultural production,went through remarkable land use/cover changes in recent years.This study aimed to explore the long-term land use/cover changes and the effects of these changes on the environment.The Landsat-based analysis showed that,during 1986-2000,cropland,built-up land and barren land had increased,among which cropland had the largest increase of 9,198km2 with an increase rate of 7.5%.Woodland,grassland,water body and swampland had decreased correspondingly,among which grassland had the most dramatic decrease of 6,127km2 with a decrease rate of 25.6%.The transition matrix results revealed that grassland,woodland and swampland were the three main land use types converted to cropland.Climate warming created the potential environment for the conversion of grassland and swampland into cropland.Land resources policy made by central and provincial governments of China affected the pattern and intensity of land use.Land use/cover changes accompanied by climatic variation brought out a series of environmental consequences,such as sand desertification of land,land salinization and alkalinization,grassland degradation,and more frequent floods.Under this circumstance,optimized land use structure and restoration measures are needed.

Determination of photosynthetic parameters in two seawater-tolerant vegetables

It is difficult to determine the photosynthetic parameters of non-fiat leaves/green stems using photosynthetic instruments, due to the unusual morphology of both organs, especially for Suaeda salsa and Salicornia bigelovii as two seawater-tolerant vegetables. To solve the problem, we developed a simple, practical, and effective method to measure and calculate the photosynthetic parameters （such as PN, gs, E） based on unit fresh mass, instead of leaf area. The light/COftemperature response curves of the plants can also be measured by this method. This new method is more effective, stable, and reliable than conventional methods for plants with non-flat leaves. In addition, the relative notes on measurements and calculation of photosynthetic parameters were discussed in this paper. This method solves technical difficulties in photosynthetic parameter determination of the two seawater-tolerant vegetables and similar plants.