Simulation and prediction of shallow groundwater depth in the North China Plain based on regional periodic characteristics

2021 ◽  
Vol 80 (18) ◽  
Author(s):  
Long Sun ◽  
Yongbing Zhang ◽  
Haiyang Si ◽  
Tema Koketso Ealotswe ◽  
Lei Wei ◽  
...  
Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2416
Author(s):  
Ming Lei ◽  
Yuqian Zhang ◽  
Yuxuan Dang ◽  
Xiangbin Kong ◽  
Jingtao Yao

Agricultural water management is a vital component of realizing the United Nation’s Sustainable Development Goals because of water shortages worldwide leading to a severe threat to ecological environments and global food security. As an agro-intensified irrigation area, the North China Plain (NCP) is the most important grain basket in China, which produces 30%–40% of the maize and 60%–80% of the wheat for China. However, this area has already been one of the largest groundwater funnels in the world due to long-term over-exploitation of groundwater. Due to the low precipitation during the growing period, winter wheat requires a large amount of groundwater to be pumped for irrigation, which consumes 70% of the groundwater irrigation. To alleviate the overexploitation of groundwater, the Chinese government implemented the Winter Wheat Fallow Policy (WWFP) in 2014. The evaluation and summarization of the WWFP will be beneficial for improving the groundwater overexploitation areas under high-intensity irrigation over all the world. So far, there have been few attempts at estimating the effectiveness of this policy. To fill this gap, we assessed the planting area of field crops and calculated the evapotranspiration of crops based on remote-sensed and meteorological data in the key area—Hengshui. We compared the agricultural water consumption before and after the implementation of this policy, and we analyzed the relationship between changes in crop planting structure and groundwater variations based on geographically weighted regression. Our results showed the overall classification accuracies for 2013 and 2015 were 85.56% and 82.22%, respectively. The planting area of winter wheat, as the most reduced crop, decreased from 35.71% (314,053 ha) in 2013 to 32.98% (289,986 ha) in 2015. The actual reduction in area of winter wheat reached 84% of the target (26 thousand ha) of the WWFP. The water consumption of major crops decreased from 2.98 billion m3 of water in 2013 to 2.83 billion m3 in 2015, a total reduction of 146 million m3, and 88.43% of reduced target of the WWFP (166 million m3). The planting changes of winter wheat did not directly affect the change of shallow groundwater level, but ET was positively related to shallow groundwater level and precipitation was negatively related to shallow groundwater levels. This study can provide a basis for the WWFP’s improvement and the development of sustainable agriculture in high-intensity irrigation areas.


Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3426
Author(s):  
Haipeng Guo ◽  
Muzi Li ◽  
Lu Wang ◽  
Yunlong Wang ◽  
Xisheng Zang ◽  
...  

Groundwater is an irreplaceable resource for irrigation and drinking in the North China Plain, and the quality of groundwater is of great importance to human health and social development. In this study, using the information from 59 groups of groundwater samples, groundwater quality conditions for irrigation and drinking purposes in an agricultural region of the North China Plain were analyzed. The groundwater belongs to a Quaternary loose rock pore water aquifer. The depths of shallow groundwater wells are 20–150 m below the surface, while the depths of deep groundwater wells are 150–650 m. The sodium adsorption ratio (SAR), sodium percentage (%Na), residual sodium carbonate (RSC), magnesium hazard (MH), permotic index (PI) and electrical conductivity (EC) were selected as indexes to evaluate the shallow groundwater suitability for irrigation. What’s more, the deep groundwater suitability for drinking was assessed and the human health risk of excessive chemicals in groundwater was studied. Results revealed that SAR, Na% and RSC indexes indicated the applicability of shallow groundwater for agricultural irrigation in the study area. We found 57.1% of the shallow groundwater samples were located in high salinity with a low sodium hazard zone. The concentrations of fluorine (F−) in 79.0% of the deep groundwater samples and iodine (I−) in 21.1% of the deep groundwater samples exceeded the permissible limits, respectively. The total hazard quotient (HQ) values of fluorine in over half of the deep groundwater samples exceeded the safety limits, and the health risk degree was ranked from high to low as children, adult females and adult males. In addition to natural factors, the soil layer compression caused by groundwater over-exploitation increased the fluorine concentration in groundwater. Effective measures are needed to reduce the fluorine content of the groundwater of the study area.


2021 ◽  
Author(s):  
Jin He ◽  
Qijun Den ◽  
Xuejun Ma ◽  
Xiaosi Su ◽  
Xuemei Ma

Abstract This study sought to further the current understanding on the relationship between soil salinization and groundwater hydrochemical processes. To this effect, 33 soil samples and 64 shallow groundwater samples were collected in Cangzhou City, a coastal region of the North China Plain. Soil salinization showed clear patterns of zonation from inland to coastal areas. The no-salinization or mild-salinization with Cl-SO4 or SO4-Cl types were discovered in the west of Cang County farther from the sea; this was restricted by brackish groundwater with HCO3·SO4-Ca·Na type and the deep water table. With increasing proximity to the coastline, groundwater salinity increased soil salt content and salinization, the effects of which were mainly determined by specific Cl/Br ratios and the seawater mixing index in groundwater. The positive δ18O and δ2H content in groundwater was related to the strong evaporation of groundwater with a shallow water table, indicating that the high soil salinity directly affected relict seawater evaporation. The observed severe-salinization soil and high NO3− concentrations indicate that agricultural activities were non-negligible salt sources in areas close to the sea. The results have relevance in improving saline-alkali soil and utilization of soil resources in the coastal areas in the North China Plain.


Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-7 ◽  
Author(s):  
Yu Liu ◽  
Rong Ma

The Luan River catchment within the North China plain has been famous for the development of its iron mineral resources since the 1950s. At the same time, it is also the main grain-producing area, known as the granary of eastern Hebei Province. Groundwater plays an important role in this region, and thus, it is imperative for us to improve our understanding of the heavy metal groundwater contamination in this catchment. Therefore, a total of 144 groundwater samples were collected for chemical analysis from 16 operational private wells of local residents in the study area, over eight consecutive periods from December 2016 to May 2017. Each shallow groundwater sample was analyzed for 39 heavy metals including among others, As, B, Ba, Be, Cd, Cr, Cu, Fe, Li, Mn, Mo, Ni, Sb, Se, Sn, Sr, V, and Zn. However, subsequent analyses only focused on three heavy metals (Cd, Cr, and Ni) that exceeded the Groundwater Quality Standard III. Spatial and temporal variations of Cd, Cr, and Ni in the shallow groundwater were analyzed. Cr was found to have the highest concentrations, followed by Ni and Cd. A human health risk assessment was conducted where carcinogenic risks and Hazard Quotients (HQs) were evaluated separately. The results indicate that both the carcinogenic risks and HQs of Ni and Cr are higher than the recommended standard value. Therefore, the prevention and control of heavy metal contamination in the Luan River catchment should focus on Ni and Cr.


2020 ◽  
Vol 17 (8) ◽  
pp. 2245-2262 ◽  
Author(s):  
Quan Zhang ◽  
Huimin Lei ◽  
Dawen Yang ◽  
Lihua Xiong ◽  
Pan Liu ◽  
...  

Abstract. Carbon sequestration in agroecosystems has great potential to mitigate global greenhouse gas emissions. To assess the decadal trend of CO2 fluxes of an irrigated wheat–maize rotation cropland over the North China Plain, the net ecosystem exchange (NEE) with the atmosphere was measured by using an eddy covariance system from 2005 to 2016. To evaluate the detailed CO2 budget components of this representative cropland, a comprehensive experiment was conducted in the full 2010–2011 wheat–maize rotation cycle by combining the eddy covariance NEE measurements, plant carbon storage samples, and a soil respiration experiment that differentiated between heterotrophic and below-ground autotrophic respirations. Over the past decade (from 2005 to 2016), the cropland exhibited a statistically nonsignificant decreasing carbon sequestration capacity; the average of total NEE, gross primary productivity (GPP), and ecosystem respiration (ER), respectively, were −364, 1174, and 810 gC m−2 for wheat and −136, 1008, and 872 gC m−2 for maize. The multiple regression revealed that air temperature and groundwater depth showed pronounced correlations with the CO2 fluxes for wheat. However, in the maize season, incoming shortwave radiation and groundwater depth showed pronounced correlations with CO2 fluxes. For the full 2010–2011 agricultural cycle, the CO2 fluxes for wheat and maize were as follows: for NEE they were −438 and −239 gC m−2, for GPP 1078 and 780 gC m−2, for ER 640 and 541 gC m−2, for soil heterotrophic respiration 377 and 292 gC m−2, for below-ground autotrophic respiration 136 and 115 gC m−2, and for above-ground autotrophic respiration 128 and 133 gC m−2. The net biome productivity was 59 gC m−2 for wheat and 5 gC m−2 for maize, indicating that wheat was a weak CO2 sink and maize was close to CO2 neutral to the atmosphere for this agricultural cycle. However, when considering the total CO2 loss in the fallow period, the net biome productivity was −40 gC m−2 yr−1 for the full 2010–2011 cycle, implying that the cropland was a weak CO2 source. The investigations of this study showed that taking cropland as a climate change mitigation tool is challenging and that further studies are required for the CO2 sequestration potential of croplands.


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