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Food security in China affects the livelihood and well-being of one-fifth of the world population. Climate change is now affecting agriculture and food production in every country of the world. Here the authors present the IMPACT model results on yield, production, and net trade of major crops (wheat, rice, and maize) in China, and on daily calorie availability as an overall indicator of food security under climate change scenarios and socio-economic pathways in 2050. The obtained results show that wheat, maize, and rice yields will increase by 17%, 45%, and 15%, alongside price increases of 60%, 100%, and 40%, respectively, during 2010-2050. Crop production is projected to increase by 23%, 70%, and 3% reaching 123, 240, and 125 million tons for wheat, maize, and rice, respectively, in 2050. The results also show that China will remain a major importer of maize at 20 million tons per year, but turn from a net importer of rice (5 million tons per year in 2010) to a net exporter in 2020 (5-9 million tons per year by 2050), while becoming a self-sufficient consumer of wheat by 2050. The outcomes of calorie availability suggest that China will be able to maintain a level of at least 3,000 kilocalories per day through 2010-2050. Climate change has relatively little effect on calorie availability within a pathway scenario.The authors conclude that Chinese agriculture is relatively resilient to climate change. Chinese food security by 2050 will unlikely be compromised in the context of climate change. The major challenge to food security, however, will rise from increasing demand coupled with regional disparities in the adaptive capacity to climate change.

Standardization in the field of agro-geoinformation is imperative to support and simplify the sharing, usage and interoperability of agro-geoinformation of different sources. It is also a complex task that addresses multiple aspects encompassing data collection, data analysis, data management, system development, data sharing and information service. As such, a reference model is required to achieve this task in an integrated and consistent manner. The reference model for agro-geoinformation standards defined aim, emphasis, groups of standards and their relation. Using methods of system engineering and conceptual schema, this paper developed and brought forward a reference model for agro-geoinformation standards. The reference model consists of three levels — the base standard level, the general standard level, the profile and application standard level. The general standard consists of five groups including guidance standards, data or product standards, management standards, application system development standards and information service standards. The paper mainly set forth the standard composition and essentials of five groups. It put forward important principles and methods for building specific agricultural information standard profiles and application standards based on the base standard and the general standard. The reference model has guidance meaning for the field information standardization which focuses on information accumulation, application and service as well as establishment of agro-geoinformation standard system.

In 2003, the International Commission on Illumination (CIE) adopted 15 standard skies that cover a broad spectrum of the usual skies found in the world. Each sky represents a unique sky luminance distribution, which is the most effective way to classify the 15 CIE Standard Skies. However, luminance distributions for the whole sky vault are far from being widely available. Alternatively, the standard skies can be categorized by various climatic parameters but the criteria to distinguish individual skies are not always clear-cut and may lead to ambiguous results. The artificial neural networks (ANNs) represent a powerful tool for pattern recognition. This paper presents the work on the classification of the standard skies using a new form of neural network architecture, namely the probabilistic neural network (PNN), which is particularly apposite in classification problems. Five meteorological variables, viz. zenith luminance, global, direct-beam and sky-diffuse illuminance, and solar altitude are employed as input data. Totally, 9000 samples covering the time span between 1999 and 2005 are shuffled. The findings suggest that the PNN is an appropriate tool for sky classification. Copyright © 2009 Royal Meteorological Society

Soil organic carbon (SOC) contents in many farmlands have been depleted because of the long-term history of intensive cultivation in China. Chinese farmers are encouraged to adopt alternative management practices on their farms to sequester SOC. On the basis of the availability of carbon (C) resources in the rural areas in China, the most promising practices are (1) incorporating more crop residue in the soils and (2) resuming traditional manure fertilizer. By implementing the alternative practices, increase in SOC content has been observed in some fields. This paper investigates how the C sequestration strategies could affect nitrous oxide (N2O) and methane (CH4) emissions from the agricultural soils in six selected sites across China. A process-based model, denitrification-decomposition or DNDC, which has been widely validated against data sets of SOC dynamics and N2O and CH4 fluxes observed in China, was adopted in the study to quantify the greenhouse gas impacts of enhanced crop residue incorporation and manure amendment under the diverse climate, soil, and crop rotation conditions across the six agroecosystems. Model results indicated that (1) when the alternative management practices were employed C sequestration rates increased, however, N2O or CH4 emissions were also increased for these practices; and (2) reducing the application rates of synthetic fertilizer in conjunction with the alternative practices could decrease N2O emissions while at the same time maintaining existing crop yields and C sequestration rates. The modeling approach could help with development of spatially differentiated best management practices at large regional scales.

It is experienced the low temperature, rain, snow, cold weather never happened over the past 50 years in the South-China in 2008 year. The electricity, transportation, communication, house and farmland have been seriously damaged. It is very urgent to monitor disaster by using remote sensing images, assess and guide disaster relief. Optical and thermal infrared remote sensing is influenced much by atmospheric clouds, so the microwave data is the best choice to monitor and analyze the development of disaster. As the scope of the affected area is very large, passive microwave data AMSR-E is used to monitor the change of snow-area and the distribution of snow-depth (intensity). The application analysis indicates that passive microwave data can be well utilized to monitor changes in snow cover and the intensity distribution, and more study should be made further for mixed pixel including water.

The L1 band (1.58 GHz)on board GPS satellite is very suitable for monitoring the change of soil moisture. The research for retrieval of soil moisture from GNSS-R is just beginning. This paper makes an analysis by using simulation data from AIEM model and experiment data from SMEX02. The analysis for simulation data from AIEM model shows that scattering signal of GPS is influenced much by angle and roughness, so the retrieval algorithm should consider the angle and roughness. The analysis of experiment data in SMEX02 indicates that the average correlation coefficient is above 0.85 between soil moisture and GNSS-R SNR for a single field site, so the soil moisture can be accurately retrieved by GNSS-R for single site, and the retrieval algorithm should be built for single site under considering incidence angle.

This paper proposes a systematic definition of circular agriculture and describes its basic features and implications, with reference to the circular economy models of the Dupont Corporation, the Kalundborg Industrial Symbiosis of Denmark, the DSD recycling system of Germany and the recycling society of Ayacho, Japan. It further categorises prevailing models for the development of circular agriculture in China and analyses typical characteristics. The paper concludes with policy proposals and suggested strategies for the development of a circular economy in China’s agricultural sector.