Drivers of Long-Term Land-Use Pressure in the Merguellil Wadi, Tunisia, Using DPSIR Approach and Remote Sensing

Increasing land use pressure is a primary force for degradation of agricultural areas. The drivers for these pressures are initiated by a series of interconnected processes. This study presents a novel methodology to analyze drivers of changing land use pressure and the effects on society and landscape. The focus was on characterizing these drivers and relate them to land use statistics obtained from geospatial data from the important semiarid Merguellil Wadi between 1976 and 2016. Cause-and-effect relationships between different drivers of land use change were analyzed using the DPSIR approach. Results show that during the 40-year period cultivated land increased and wetland areas decreased substantially. Drivers for change were pressure from economic development, cultivation practices, and hydro-agricultural techniques. This leads to stress on water and soil resulting in soil erosion, poverty increase, and rural exodus. We show that hydro-agricultural techniques adapted to the semiarid climate, allocation of land property rights, resource allocation, and improved marketing of agricultural products can help rural residents to diversify their economy, and thus better preserve the fragile semiarid landscape. Results of this study can be used to ensure sustainable management of water and soil resources in areas with similar climate and socio-economic conditions.

The formation of a Kinh traditional village in Huế in early modern Vietnam

This article traces the transformation of Huế from an open migrant society to a closed community from the seventeenth through nineteenth centuries through an examination of the village documents of Thanh Phước in Thừa Thiên Huế province. In Thanh Phước, the expansion of cultivated land reached its limits around the end of the seventeenth century. Subsequently, continuous population pressure resulted in the emergence of social groups with closed and fixed membership called làng and dòng họ after the eighteenth century. A significant feature of this social development was that the patrilineal kinship favoured by Confucianism was used to protect the vested interests of the earliest inhabitants of the village and their descendants. This indicates that the penetration of Confucianism among the common people and the development and stagnation of agriculture in early modern Vietnam were mutual, complementary phenomena.

The temporal and spatial scales of arable land loss and its impact in Guangxi, China: A Commentary

Cropland abandonment because of rural depopulation or policy interventions has become a key issue in Chinese mountainous areas. One such region is the Guangxi Karst Mountainous Area (GKMA), a zone where more than 59% of total land area is hilly and arable land of a commercially viable size is almost non-existent. The rugged terrain and land fragmentation in upland karst areas result in the scarcity of land suitable for cultivation. Although depopulation and declining agriculture since 2000 within the GKMA have led to vast areas of abandoned cropland, the spatiotemporal distribution that underlies this pattern as well as its causes remain little understood. Geomorphic features also bring about differences in the distribution of settlements. Settlements with different degrees of distribution are accompanied by spatial differences in cultivated land resources, which lead to differences in the sufficiency of cultivated land resources. In this paper we provide an overview of the magnitude of the problem of arable land loss. settlements and analyze the spatial distribution and the spatial agglomeration of the cultivated land.

Geological Resource Planning and Environmental Impact Assessments Based on GIS

The purpose is to study the geological resource planning and environmental impact assessments based on the geographic information system (GIS). In this study, the land resources of Yinan County in southeastern Shandong Province are taken as the research object. Based on a GIS, the current situation of land resource development is analyzed, land resource planning is carried out, and environmental impact mitigation measures are evaluated and analyzed through the environmental impact. The results obtained depict the distribution of cultivated land; the development area is 1617.31 hm2, of which 577.32 hm2 is cultivated land, 30.43 hm2 is garden land, 399.66 hm2 is forest land, 40.87 hm2 is urban and rural construction land, 10.11 hm2 is traffic water conservancy and other construction land, and 558.92 hm2 is natural reserve land. In the layout of the construction land, the development area is 841.94 hm2, of which 175.44 hm2 is cultivated land, 47.88 hm2 is garden land, 100.54 hm2 is forest land, 0.1 hm2 is other agricultural land, 90.45 hm2 is urban and rural construction land, 3.66 hm2 is traffic water conservancy and other construction land, 11.33 hm2 is water area, and 412.54 hm2 is natural reserve land. The impact of the implementation of planning on most indicators is positive and beneficial, while the impact of negative indicators is relatively small. It is revealed that the implementation of the plan has little impact on most of the ecological environment indicators. Construction and cultivated land development further improve the level of urbanization. In the process of planning implementation, corresponding measures should be taken to slow down or eliminate the negative development of the ecological environment.

Estimation of Cultivated Land Quality Based on Soil Hyperspectral Data

Efficient monitoring of cultivated land quality (CLQ) plays a significant role in cultivated land protection. Soil spectral data can reflect the state of cultivated land. However, most studies have used crop spectral information to estimate CLQ, and there is little research on using soil spectral data for this purpose. In this study, soil hyperspectral data were utilized for the first time to evaluate CLQ. We obtained the optimal spectral variables from dry soil spectral data using a gradient boosting decision tree (GBDT) algorithm combined with the variance inflation factor (VIF). Two estimation algorithms (partial least-squares regression (PLSR) and back-propagation neural network (BPNN)) with 10-fold cross-validation were employed to develop the relationship model between the optimal spectral variables and CLQ. The optimal algorithms were determined by the degree of fit (determination coefficient, R2). In order to estimate CLQ at the regional scale, HuanJing-1A Hyperspectral Imager (HJ-1A HSI) data were transformed into dry soil spectral data using the linkage model of original soil spectral reflectance to dry soil spectral reflectance. This study was conducted in the Guangdong Province, China and the Conghua district within the same province. The results showed the following: (1) the optimal spectral variables selected from the dry soil spectral variables were 478 nm, 502 nm, 614 nm, 872 nm, 966 nm, 1007 nm, and 1796 nm. (2) The BPNN was the optimal model, with an R2(C) of 0.71 and a normalized root mean square error (NRMSE) of 12.20%. (3) The results showed the R2 of the regional-scale CLQ estimation based on the proposed method was 0.05 higher, and the NRMSE was 0.92% lower than that of the CLQ map obtained using the traditional method. Additionally, the NRMSE of the regional-scale CLQ estimation base on dry soil spectral variables from HJ-1A HSI data was 2.00% lower than that of the model base on the original HJ-1A HSI data.

Comparison of Crop Evapotranspiration and Water Productivity of Typical Delta Irrigation Areas in Aral Sea Basin

The intensity of agricultural activities and the characteristics of water consumption affect the hydrological processes of inland river basins in Central Asia. The crop water requirements and water productivity are different between the Amu Darya and Syr Darya river basins due to the different water resource development and utilization policies of Uzbekistan and Kazakhstan, which have resulted in more severe agricultural water consumption of the Amu Darya delta than the Syr Darya delta, and the differences in the surface runoff are injected into the Aral Sea. To reveal the difference in water resource dissipation, water productivity, and its influencing factors between the two basins, this study selected the irrigation areas of Amu Darya delta (IAAD) and Syr Darya delta (IASD) as typical examples; the actual evapotranspiration (ETa) was retrieved by using the modified surface energy balance algorithm for land model (SEBAL) based on high spatial resolution Landsat images from 2000 to 2020. Land use and cover change (LUCC) and streamflow data were obtained to analyze the reasons for the spatio-temporal heterogeneity of regional ETa. The water productivity of typical crops in two irrigation areas was compared and combined with statistical data. The results indicate that: (1) the ETa simulated by the SEBAL model matched the crop evapotranspiration (ETc) calculated by the Penman–Monteith method and ground-measured data well, with all the correlation coefficients higher than 0.7. (2) In IAAD, the average ETa was 1150 mm, and the ETa had shown a decreasing trend; for the IASD, the average ETa was 800 mm. The ETa showed an increasing trend with low stability due to a large amount of developable cultivated land. The change of cultivated land dominated the spatio-temporal characteristics of ETa in the two irrigation areas (3). Combined with high spatial resolution ETa inversion results, the water productivity of cotton and rice in IAAD was significantly lower than in IASD, and wheat was not significantly different, but all were far lower than the international average. This study can provide useful information for agricultural water management in the Aral Sea region.