- Zhaohai Bai(older publications) (1)
- Zhaohai Bai (5)
- Dave Chadwick (1)
- David Chadwick (1)
- Mengchu Guo (1)
- Petr Havlík (1)
- Chunsheng Hu (2)
- Shuqin Jin (1)
- Carolien Kroeze (3)
- Gerard L. Velthof (3)
- Stewart Ledgard (1)
- Shengli Li (1)
- Hongbin Liu (1)
- Xia Liu (1)
- Jie Lu (2)
- Shengji Luan (1)
- Jiafa Luo (1)
- Wenqi Ma (1)
- Lin Ma (6)
- Oene Oenema (2)
- Wei Qin (1)
- John R. Williams (1)
- Michael R.F. Lee (1)
- Maryna Strokal (3)
- Gerard Velthof (1)
- Mengru Wang (2)
- Sha Wei (1)
- Zhiguo Wu (1)
- Fusuo Zhang (2)
- Hao Zhao (1)
- Zhanqing Zhao (2)
Accumulation and leaching of nitrate in soils in wheat-maize production in China
Lu, Jie ; Bai, Zhaohai ; Velthof, Gerard L. ; Wu, Zhiguo ; Chadwick, David ; Ma, Lin - \ 2019
Agricultural Water Management 212 (2019). - ISSN 0378-3774 - p. 407 - 415.
Maize - Nitrate accumulation - Nitrate leaching - Soil - Wheat
Application rates of fertilizers in China often exceed crop requirements, resulting in high accumulation of nitrate (NO3) in the soil. Nitrate that has accumulated in soils is highly prone to leaching, directly threatening the quality of groundwater. A study was conducted to assess the magnitude of NO3 accumulation and leaching in China, to identify factors controlling NO3 accumulation and leaching, and to develop strategies that can be used to minimize NO3 leaching. Data were compiled from 212 studies conducted in China, amounting to 1077 observations of the NO3 content of the 0–100 cm soil profile in wheat and maize fields after harvest. Leaching of NO3 was significantly correlated with NO3 accumulation in the soil. NO3 leaching increased with 0.058 and 0.34 kg NO3-N ha−1 per season for wheat and maize, respectively, for every 1 kg ha-1 increase in NO3-N accumulation in 0–100 cm. This mainly related to lower precipitation during the wheat season and intensive rainfall in the maize season. Accumulation of NO3 in maize systems was 50% lower than for wheat when fertilized at the same rate, due to differences in rainfall between seasons. Soil NO3 accumulation was higher in heavy textured soils than in freely draining lighter textured soils, as most of NO3 leached out of 0–100 cm soil in lighter textured soils. Compared to flood irrigation, sprinkler irrigation increased NO3 accumulation by 17% and 152% for wheat and maize, respectively, due to lower irrigation and leaching rate. The level of nitrate accumulation in Chinese arable soils has become a significant hazard to drinking water, so good agricultural management is essential. Soil NO3 accumulation and leaching in China can be reduced by source and process control, such as reducing fertilizer application, using slow or controlled release forms of fertilizers, and regulating irrigation.
Agricultural nitrogen and phosphorus emissions to water and their mitigation options in the Haihe Basin, China
Zhao, Zhanqing ; Qin, Wei ; Bai, Zhaohai ; Ma, Lin - \ 2019
Agricultural Water Management 212 (2019). - ISSN 0378-3774 - p. 262 - 272.
Crop-livestock system - Haihe Basin - Nitrogen - NUFER - Phosphorus - Water pollution
Agricultural nitrogen (N) and phosphorus (P) emissions to water bodies remain largely unknown in China, mainly due to the lack of reliable data sources and quantification tools. In this study, we constructed a grid-based NUFER (NUtrient Flow in food chains, Environment and Resources use) model in order to quantify a high-resolution agricultural N and P emissions to water bodies in Haihe Basin in 2012, based on data collected from county-level statistics, farm interview, and spatial data of topography, climate, soil texture, and land use. We also explored the mitigation strategies in 2030 via scenario analysis. The results showed that total agricultural N emission to water bodies in Haihe Basin was 1079 Gg N in 2012, of which cropland contributed 54%; total agricultural P emission to water bodies was 208 Gg P, livestock contributed 78%. There were large spatial variations in agricultural N and P emissions. Overall, the plain areas accounted for around 80% of the total agricultural N and P emissions to water in 2012. The highest N and P emission intensities were 10 t N km−2 and 2 t P km−2, respectively. N and P emissions were significantly related to anthropogenic factors (such as the livestock density and cropland) in the plain areas; whereas in mountainous areas, both anthropogenic and natural factors (e.g., slope deviation and soil texture) significantly affected N and P emissions. Our scenario analysis suggests that agricultural N and P emissions can be reduced by up to 45% and 77%, respectively for N and P in 2030, via improved agricultural and environmental policies, technologies and managements. The prohibition of direct animal manure discharge to the water system seems to be the most effective measure to mitigate the emissions. Our study provided a high-resolution agricultural N and P emissions to the water bodies of Haihe Basin and identified the most effective options to reduce these emissions in highly intensified agricultural areas.
Designing Vulnerable Zones of Nitrogen and Phosphorus Transfers to Control Water Pollution in China
Bai, Zhaohai ; Lu, Jie ; Zhao, Hao ; Velthof, Gerard L. ; Oenema, Oene ; Chadwick, Dave ; Williams, John R. ; Jin, Shuqin ; Liu, Hongbin ; Wang, Mengru ; Strokal, Maryna ; Kroeze, Carolien ; Hu, Chunsheng ; Ma, Lin - \ 2018
Environmental Science and Technology 52 (2018)16. - ISSN 0013-936X - p. 8987 - 8988.
Global environmental costs of China's thirst for milk
Bai, Zhaohai ; Lee, Michael R.F. ; Ma, Lin ; Ledgard, Stewart ; Velthof, Gerard L. ; Ma, Wenqi ; Guo, Mengchu ; Zhao, Zhanqing ; Wei, Sha ; Li, Shengli ; Liu, Xia ; Havlík, Petr ; Luo, Jiafa ; Hu, Chunsheng ; Zhang, Fusuo - \ 2018
Global Change Biology 24 (2018)5. - ISSN 1354-1013 - p. 2198 - 2211.
Cattle feed - Greenhouse gas - Land use, nitrogen losses - Milk trade - Shared socio-economic pathways scenarios
China has an ever-increasing thirst for milk, with a predicted 3.2-fold increase in demand by 2050 compared to the production level in 2010. What are the environmental implications of meeting this demand, and what is the preferred pathway? We addressed these questions by using a nexus approach, to examine the interdependencies of increasing milk consumption in China by 2050 and its global impacts, under different scenarios of domestic milk production and importation. Meeting China's milk demand in a business as usual scenario will increase global dairy-related (China and the leading milk exporting regions) greenhouse gas (GHG) emissions by 35% (from 565 to 764 Tg CO 2eq ) and land use for dairy feed production by 32% (from 84 to 111 million ha) compared to 2010, while reactive nitrogen losses from the dairy sector will increase by 48% (from 3.6 to 5.4 Tg nitrogen). Producing all additional milk in China with current technology will greatly increase animal feed import; from 1.9 to 8.5 Tg for concentrates and from 1.0 to 6.2 Tg for forage (alfalfa). In addition, it will increase domestic dairy related GHG emissions by 2.2 times compared to 2010 levels. Importing the extra milk will transfer the environmental burden from China to milk exporting countries; current dairy exporting countries may be unable to produce all additional milk due to physical limitations or environmental preferences/legislation. For example, the farmland area for cattle-feed production in New Zealand would have to increase by more than 57% (1.3 million ha) and that in Europe by more than 39% (15 million ha), while GHG emissions and nitrogen losses would increase roughly proportionally with the increase of farmland in both regions. We propose that a more sustainable dairy future will rely on high milk demanding regions (such as China) improving their domestic milk and feed production efficiencies up to the level of leading milk producing countries. This will decrease the global dairy related GHG emissions and land use by 12% (90 Tg CO 2eq reduction) and 30% (34 million ha land reduction) compared to the business as usual scenario, respectively. However, this still represents an increase in total GHG emissions of 19% whereas land use will decrease by 8% when compared with 2010 levels, respectively.
The MARINA model (Model to Assess River Inputs of Nutrients to seAs) : Model description and results for China
Strokal, Maryna ; Kroeze, Carolien ; Wang, Mengru ; Bai, Zhaohai ; Ma, Lin - \ 2016
Science of the Total Environment 562 (2016). - ISSN 0048-9697 - p. 869 - 888.
Agriculture - Chinese seas - MARINA Nutrient model - River export of nutrients - Sub-basins - Urbanization
Chinese agriculture has been developing fast towards industrial food production systems that discharge nutrient-rich wastewater into rivers. As a result, nutrient export by rivers has been increasing, resulting in coastal water pollution. We developed a Model to Assess River Inputs of Nutrients to seAs (MARINA) for China. The MARINA Nutrient Model quantifies river export of nutrients by source at the sub-basin scale as a function of human activities on land. MARINA is a downscaled version for China of the Global NEWS-2 (Nutrient Export from WaterSheds) model with an improved approach for nutrient losses from animal production and population. We use the model to quantify dissolved inorganic and organic nitrogen (N) and phosphorus (P) export by six large rivers draining into the Bohai Gulf (Yellow, Hai, Liao), Yellow Sea (Yangtze, Huai) and South China Sea (Pearl) in 1970, 2000 and 2050. We addressed uncertainties in the MARINA Nutrient model. Between 1970 and 2000 river export of dissolved N and P increased by a factor of 2-8 depending on sea and nutrient form. Thus, the risk for coastal eutrophication increased. Direct losses of manure to rivers contribute to 60-78% of nutrient inputs to the Bohai Gulf and 20-74% of nutrient inputs to the other seas in 2000. Sewage is an important source of dissolved inorganic P, and synthetic fertilizers of dissolved inorganic N. Over half of the nutrients exported by the Yangtze and Pearl rivers originated from human activities in downstream and middlestream sub-basins. The Yellow River exported up to 70% of dissolved inorganic N and P from downstream sub-basins and of dissolved organic N and P from middlestream sub-basins. Rivers draining into the Bohai Gulf are drier, and thus transport fewer nutrients. For the future we calculate further increases in river export of nutrients. The MARINA Nutrient model quantifies the main sources of coastal water pollution for sub-basins. This information can contribute to formulation of effective management options to reduce nutrient pollution of Chinese seas in the future.
Alarming nutrient pollution of Chinese rivers as a result of agricultural transitions
Strokal, Maryna ; Ma, Lin ; Bai, Zhaohai ; Luan, Shengji ; Kroeze, Carolien ; Oenema, Oene ; Velthof, Gerard ; Zhang, Fusuo - \ 2016
Environmental Research Letters 11 (2016)2. - ISSN 1748-9326
agricultural transitions - China - integrated modeling - nutrient pollution - rivers
Transitions in Chinese agriculture resulted in industrial animal production systems, disconnected from crop production. We analyzed side-effects of these transitions on total dissolved nitrogen (TDN) and phosphorus (TDP) inputs to rivers. In 2000, when transitions were ongoing, 30%-70% of the manure was directly discharged to rivers (range for sub-basins). Before the transition (1970) this was only 5%. Meanwhile, animal numbers more than doubled. As a result, TDN and TDP inputs to rivers increased 2- to 45-fold (range for sub-basins) during 1970-2000. Direct manure discharge accounts for over two-thirds of nutrients in the northern rivers and for 20%-95% of nutrients in the central and southern rivers. Environmental concern is growing in China. However, in the future, direct manure inputs may increase. Animal production is the largest cause of aquatic eutrophication. Our study is a warning signal and an urgent call for action to recycle animal manure in arable farming.