Linkage between soil salinization indicators and physicochemical properties in a long-term intensive agricultural coastal reclamation area, Eastern China

2019 ◽  
Vol 19 (11) ◽  
pp. 3699-3707 ◽  
Author(s):  
Xuefeng Xie ◽  
Lijie Pu ◽  
Ming Zhu ◽  
Yan Xu ◽  
Xiaohan Wang
2021 ◽  
Vol 13 (16) ◽  
pp. 8690
Author(s):  
Caiyao Xu ◽  
Lijie Pu ◽  
Fanbin Kong ◽  
Bowei Li

Coastal ecological protection and restoration projects aimed to restore and recover the ecological environment of coastal wetland with high-intensity human reclamation activity, while the integrity of the coastal wetland system with human reclamation activity and the ability of individual land use types to control the overall system were not fully considered. In this study, a six-stage land use conversion network was constructed by using a complex network model to analyze coastal land use dynamic changes in the coastal reclamation area located in eastern China from 1977 to 2016. The results showed that land use types had gradually transformed from being dominated by natural types to artificial types, and the speed of transformation was accelerating. The proportion of un-reclaimed area decreased from 93% in 1977 to 46% in 2007, and finally fell to 8% in 2014 and 2016. Tidal flat and halophytic vegetation were the main output land use types, while cropland, woodland and aquaculture pond were the main input land use types. Cropland had the highest value of betweenness centrality, which played a key role in land use change from 1992 to 2014. The land use system of the coastal reclamation area was the most stable in 2002–2007, followed by 1984–1992, and the most unstable in 2007–2014. The Chinese and local government should carry out some measures to improve the land use in coastal wetland ecosystems, including the allocation and integration of land use for production space, living space, and ecological space, and develop multi-functionality of land use to realize the coastal high-quality development and coastal ecological protection and restoration.


2014 ◽  
Vol 294 ◽  
pp. 411-417 ◽  
Author(s):  
Yan Xu ◽  
Lijie Pu ◽  
Ming Zhu ◽  
Jianguo Li ◽  
Meng Zhang ◽  
...  

2020 ◽  
pp. 181-191
Author(s):  
M. Tkachenko ◽  
N. Borys ◽  
Ye. Kovalenko

The research aims to establish the eff ectiveness of granular chalk use produced by «Slavuta-Calcium» Ltd. under growing Poliska–90 winter wheat variety, changing the physicochemical properties of grey forest soil and the wheat productivity. It also aims to establish optimal dosis of «Slavuta-Calcium» granular chalk as the meliorant and mineral fertilizer for grey forest soil in the system of winter wheat fertilization. In the temporary fi eld studies, various doses of nutrients N60–90–120P30–45–60K60–90–120 combined with «Slavuta–Calcium» granular chalk in a dose of Ca230–460–690 kg/ha of the active substance were studied against the background of secondary plowing of rotation products – soybean biomass that averaged 2.34 t/ha. Granular chalk is a modern complex highly eff ective meliorant with the content of Ca – 37.7 and Mg – 0.2 %, the mass fraction of carbonates (CaCO3 + MgCO3) makes at least 95 %. It is characterized by a high level of solubility when interacting with moisture in soil. It has a form of white granules, the mass fraction of 4.0–6.0 mm in size granules makes not less than 90 % and the one of 1.0 mm in size makes less than 5 %. Reactivity – 97 %. The granular chalk is advisable to apply on acidic soils, as a highly concentrated calcium-magnesium fertilizer, with the former as the dominant fertilizer, to optimize the physicochemical properties of the soil, as well as the plant nutrition system, in particular, increasing the availability of an element for assimilation by plants and as long-term ameliorants. The eff ectiveness of the use of mineral fertilizers, in particular acidic nitrogen on highly and medium acidic soils, after chemical reclamation is increased by 30–50 %, and slightly acidic by 15–20 %. The increase in productivity of crops from the combined eff ects of nutrients and chalk granulated is usually higher than when separately applied. The eff ectiveness of the integrated action of these elements is manifested in the growth of plant productivity and the quality of the resulting products, as well as the optimization of physical chemical properties and soil buff ering in the long term. In order to optimize the physicochemical properties of the arable layer of gray forest soil and the productive nutrition of agricultural crops, winter wheat, in particular, biogenic elements should be used in doses N60-90-120P30-45- 60K60-90-120 with granulated chalk «Slavuta-Calcium» in doses of Ca230-460-690 kg/ha of active substance. Granulated chalk obtained as a result of industrial grinding of solid sedimentary carbonate rocks of natural origin, subsequently under the infl uence of the granulation process of the starting material contains Ca and Mg carbonates of at least 95 %, dense granules which facilitates convenient mechanized application, as well as chalk suitable for accurate metered application on the quest map. Key words: granular chalk, gray forest soil, chemical reclamation, crop productivity.


2007 ◽  
Vol 12 (1) ◽  
pp. 46-50 ◽  
Author(s):  
Min-Hee Nam ◽  
Chang-Suk Kong ◽  
Soon-Sun Bak ◽  
Yang-Bong Lee ◽  
Sook-Hee Rhee ◽  
...  

2021 ◽  
Vol 13 (7) ◽  
pp. 1317
Author(s):  
Xiaodan Ma ◽  
Peng Yan ◽  
Tianliang Zhao ◽  
Xiaofang Jia ◽  
Jian Jiao ◽  
...  

The chemical composition dataset of Aerosol Reanalysis of NASA’s Modern-Era Retrospective Analysis for Research and Application, version 2 (MERRAero) has not been thoroughly evaluated with observation data in mainland China due to the lack of long-term chemical components data. Using the 5-year data of PM10 mass concentrations and chemical compositions obtained from the routine sampling measurements at the World Meteorological Organization the Global Atmosphere Watch Programme regional background stations, Jing Sha (JS) and Lin’An (LA), in central and eastern China, we comprehensively evaluate the surface PM10 concentrations and chemical compositions such as sulfate (SO42−), organic carbon (OC) and black carbon (BC) derived from MERRAero. Overall, the concentrations of PM10, SO42−, OC and BC from the MERRAero agreed well with the measurements, despite a slight and consistent overestimation of BC concentrations and a moderate and persistent underestimation of PM10 concentrations throughout the study period. The MERRAero reanalysis of aerosol compositions performs better during the summertime than wintertime. By considering the nitrate particles in PM10 reconstruction, MERRAero performance can be significantly improved. The unreasonable seasonal variations of PM10 chemical compositions at station LA by MERRAero could be causative factors for the larger MERRAero discrepancies during 2016–2017 than the period of 2011–2013.


Agriculture ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 211
Author(s):  
Tharani Gopalakrishnan ◽  
Lalit Kumar

Soil salinity is a serious threat to coastal agriculture and has resulted in a significant reduction in agricultural output in many regions. Jaffna Peninsula, a semi-arid region located in the northern-most part of Sri Lanka, is also a victim of the adverse effects of coastal salinity. This study investigated long-term soil salinity changes and their link with agricultural land use changes, especially paddy land. Two Landsat images from 1988 and 2019 were used to map soil salinity distribution and changes. Another set of images was analyzed at four temporal periods to map abandoned paddy lands. A comparison of changes in soil salinity with abandoned paddy lands showed that abandoned paddy lands had significantly higher salinity than active paddy lands, confirming that increasing salts owing to the high levels of sea water intrusion in the soils, as well as higher water salinity in wells used for irrigation, could be the major drivers of degradation of paddy lands. The results also showed that there was a dramatic increase in soil salinity (1.4-fold) in the coastal lowlands of Jaffna Peninsula. 64.6% of the salinity-affected land was identified as being in the extreme saline category. In addition to reducing net arable lands, soil salinization has serious implications for food security and the livelihoods of farmers, potentially impacting the regional and national economy.


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