The effect of atmospheric aerosols and regional haze from air pollution on the yields of rice and winter wheat grown in China is assessed. The assessment is based on estimates of aerosol optical depths over China, the effect of these optical depths on the solar irradiance reaching the earth’s surface, and the response of rice and winter wheat grown in Nanjing to the change in solar irradiance. Two sets of aerosol optical depths are presented: one based on a coupled, regional climate/air quality model simulation and the other inferred from solar radiation measurements made over a 12-year period at meteorological stations in China. The model-estimated optical depths are significantly smaller than those derived from observations, perhaps because of errors in one or both sets of optical depths or because the data from the meteorological stations has been affected by local pollution. Radiative transfer calculations using the smaller, model-estimated aerosol optical depths indicate that the so-called “direct effect” of regional haze results in an ≈5–30% reduction in the solar irradiance reaching some of China’s most productive agricultural regions. Crop-response model simulations suggest an ≈1:1 relationship between a percentage increase (decrease) in total surface solar irradiance and a percentage increase (decrease) in the yields of rice and wheat. Collectively, these calculations suggest that regional haze in China is currently depressing optimal yields of ≈70% of the crops grown in China by at least 5–30%. Reducing the severity of regional haze in China through air pollution control could potentially result in a significant increase in crop yields and help the nation meet its growing food demands in the coming decades.

https://www.pnas.org/content/pnas/96/24/13626.full.pdf

Case study of the effects of atmospheric aerosols and regional haze on agriculture: an opportunity to enhance crop yields in China through emission controls?

Cultivated land and food supply in China.

[1] Large-scale assessments of the potential for food production and its impact on biogeochemical cycling require the best possible information on the distribution of cropland. This information can come from ground-based agricultural census data sets and/ or spaceborne remote sensing products, both with strengths and weaknesses. Official cropland statistics for China contain much information on the distribution of crop types, but are known to significantly underestimate total cropland areas and are generally at coarse spatial resolution. Remote sensing products can provide moderate to fine spatial resolution estimates of cropland location and extent, but supply little information on crop type or management. We combined county-scale agricultural census statistics on total cropland area and sown area of 17 major crops in 1990 with a fine-resolution land-cover map derived from 1995–1996 optical remote sensing (Landsat) data to generate 0.5� resolution maps of the distribution of rice agriculture in mainland China. Agricultural census data were used to determine the fraction of crop area in each 0.5� grid cell that was in single rice and each of 10 different multicrop paddy rice rotations (e.g., winter wheat/ rice), while the remote sensing land-cover product was used to determine the spatial distribution and extent of total cropland in China. We estimate that there were 0.30 million km 2 of paddy rice cropland; 75% of this paddy land was multicropped, and 56% had two rice plantings per year. Total sown area for paddy rice was 0.47 million km 2 . Paddy rice agriculture occurred on 23% of all cultivated land in China. INDEX TERMS: 0315 Atmospheric Composition and Structure: Biosphere/atmosphere interactions; 1615 Global Change: Biogeochemical processes (4805); KEYWORDS: paddy rice, maps, China, multicropping rotation, Landsat

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Combining remote sensing and ground census data to develop new maps of the distribution of rice agriculture in China

China's 8 challenges to water resources management in the first quarter of the 21st Century

Simulation of changes in the spatial pattern of land use in China

This statistical bulletin consists of 285 tables of agricultural statistics for the People's Republic of China. The statistics cover land use, population, labor force, gross value of agricultural output, agricultural investment, crop production, crop sown area, state procurement, livestock inventory and slaughter, animal product output, input production and use, costs of production, consumption of agricultural commodities, selected retail price indices and mixed average procurement prices for selected agricultural crops, and finally, quantity and value of imports and exports of selected commodities. Data are presented for the national level and, when available, the provincial level as well.

Agricultural Statistics of the People's Republic of China, 1949-90

China's demand for grain is likely to outpace domestic supplies in the next 10 years, according to ERS projections. By the year 2005, China will become a net importer of 32 million metric tons of grain annually. In the last two decades, China's grain trade has expanded dramatically, both as a buyer and a seller. Both China and the United States are major grain producers. How the grain trade between the two nations develops will be important to both agricultural economies. It is doubtful that China's farmers will be able to produce enough grain to keep pace with population gains and increased demand for feed grains to produce meat, eggs, and milk products for consumers.

Frederick W. Crook

Papers

Agricultural Statistics of the People's Republic of China, 1949-90

The future of China's grain market

Planning and Statistical Systems in China's Agriculture

Agricultural statistics of the People's Republic of China, 1949-86

Agriculture in the United States and the People's Republic of China, 1967-71