The rapid population increase in China from 556.7 to 1226.7 million during the past 50 years means China has one-sixth of the world’s population. This population growth has imposed high pressures on Chinese agriculture. Crop production and productivities have more than doubled, for example mean maize yields have increased from 1.54 to 3.91 t ha-1 from 1960 to 1998. Despite this, food shortages remain major problems. These pressures have also led to intensive cultivation of sloping lands, making China the country with the most serious soil erosion problems in the world. Yunnan Province, south-west China, has some 70% of its total of 6.53 million hectares of cultivated fields located on sloping land, most of which suffers from soil erosion. Furthermore, traditional downslope cultivation of these upland fields produces increased soil loss and runoff and threatens agricultural sustainability. Crop yields on sloping land in these areas have decreased by 30-60% in the last century because of soil erosion and in 50-100 years most topsoil may have been removed. There is an urgent need to develop more productive and sustainable cropping systems and the dual aims of this project were to investigate ways of increasing productivity of maize on sloping land, while conserving soils. This investigation was carried out in Wang Jia Catchment (25028’N,102053’E), selected as a representative area of fragile slopes in Yunnan Province. Five treatments (1) Traditional + Downslope planting (control), (2) Traditional + Contour planting, (3) Traditional + Contour + Straw mulch, (4) Minimum tillage + Contour + Straw mulch and (5) Traditional + Contour + Polythene mulch, were selected for evaluation and established on replicated field plots in 1998 and 1999. An additional experiment in 1999 investigated the effects of irrigation on crop yield. Although there were variations during the growing season and between years, straw mulch with contour planting increased soil moisture (0-20 cm depth) and was associated with lower soil temperatures. Polythene mulch improved soil moisture retention when applied after early season rainfall or irrigation and caused increases in soil surface temperature of up to 4-50C. These increases in soil moisture and temperature were associated with increases in Green Leaf Area Index, Green Leaf Area Duration and standing biomass. Grain yield was increased up to 51.6%, compared to un-mulched plots. Straw mulch increases in yield 14.0 and 20.7% (nonirrigated treatment), compared with the control in 1998 (5.0 versus 4.3 t ha-1) and 1999 (6.2 versus 5.3 t ha-1), respectively. Furthermore, straw mulch appeared to be beneficial for maintaining soil fertility and improving soil structure. Irrigation improved early vegetative growth and final yields when early season rainfall was unreliable and maize grain yield increased by 39.5 to 59.6% in 1999, compared with the corresponding non-irrigated treatments. Polythene mulch and contour planting combined with early irrigation produced the highest maize yields. The results are compared with other published work, including research in erosion plots, where the effectiveness of mulches in reducing runoff and erosion has been evaluated. A cultivation technique combining polythene mulch, straw mulch, contour planting and early season irrigation is considered likely to be highly effective for increasing productivity and improving soil conservation on sloping land. This project is part of a larger programme, which aims to establish and evaluate a demonstration model at a catchment scale for more sustainable crop production systems in the highlands of South-East Asia.

No description available.

There has been little research conducted regarding the agricultural machinery market in China. However, current data suggest that this demand is dramatically increasing. This dissertation endeavors to generally define the current demand of the agricultural machinery market in China. There has been research conducted on multiple factors of the agricultural machinery market in China, such as land tenure rights, rural migration, government agricultural policies, and others. Through the use of limited quantitative data, market demand is analyzed and defined. By means of a qualitative case study of a successful multinational corporation, Deere & Co., how the demand is being met for agricultural machinery in China is also discussed. This case study also contributes to defining market demand for agricultural machinery in China. Through the use of this mixed-method research, key components of the Chinese agricultural machinery market are identified and analyzed. Challenges within this market are discussed, along with how Deere & Co.'s Chinese operations have dealt with these challenges. This corporation's experience in the Chinese market brings benefit to any company seeking to better understand the workings of the agricultural machinery market in China.

Cette thèse est une évaluation du potentiel d'atténuation technique et économique global dans l'agriculture Chinoise et des conditions nécessaires à la formation d’un prix du carbone dans ce secteur. Le champ de recherche inclut les émissions venant de terres cultivées et en particulier celles liées à l'utilisation d'engrais azotés synthétiques. Il s'articule autour de la construction d'une courbe de coûts marginaux de réduction (MACC), qui offre un cadre rationnel pour combiner les données biophysiques et économiques afin de refléter les coûts d'atténuation. Cet outil permet d'agréger le potentiel d'atténuation découlant de l'application d'un sous-ensemble de mesures coût-efficacité en dessus d'un niveau de référence désignée. Une analyse des politiques climatiques chinoises révèle que l'agriculture est presque absente de la stratégie nationale d'atténuation. Nous avons donc l'intention d’examiner la faisabilité du point de vue technique, économique et politique, d’intégrer l'agriculture dans les politiques domestiques d’atténuation. En premier lieu, la tendance et les méthodes de calcul des émissions sont évaluées afin de déterminer une approche rigoureuse permettant de construire des scénarios de référence à partir de prévisions des activités ‘business-as-usual’ pour 2020. Deuxièmement, nous identifions neuf mesures d'atténuation des sols cultivés, nous évaluons leur taux d'abattement et leur applicabilité future au-delà du scénario de base pour obtenir un potentiel total d'atténuation techniquement faisable. Leur traduction en potentiel économique est alors faite en comparant les coûts de mise en œuvre des différentes options d'atténuation relatives aux pratiques agricoles conventionnelles. Les résultats des MACC montrent que l’agriculture offre un potentiel d'atténuation important, qui pourrait compenser environ un tiers des émissions de référence et dont un tiers pourrait être réalisé au coût négatif pour les agriculteurs. Nous examinons enfin l’utilisation des instruments économiques pour réduire les émissions au moindre coût dans le secteur agricole. Compte tenu des obstacles institutionnels, comportementaux et sociaux, nous suggérons fortement d’engager une réforme dans le système des subventions d'engrais afin d'envoyer un signal politique clair aux agriculteurs. L’utilisation de l’intensité du carbone comme référence normalisée est recommandé pour améliorer et élargir l'accès aux projets de compensation, et peut aussi préparer le terrain pour un possible programme expérimental d'échange de quotas d’émissions dans l'agriculture. En cohérence avec la priorité de protéger la sécurité alimentaire en Chine, des études de cas sur la production régionale de céréales sont introduites dans toutes ces étapes, y compris l'analyse de l'intensité des gaz à effet de serre de la production dans chaque province, le potentiel régional de réduction des émissions liées à l'utilisation d’engrais azotés ainsi que la disparité de coûts de mise en œuvre dans certaines régions. / This thesis is an evaluation of the overall technical and economic mitigation potential in China agriculture and the conditions of putting a carbon price in this sector. The research scope is cropland emissions and particularly those related to synthetic nitrogen fertilizer use. The thesis is articulated around the construction of a bottom-up marginal abatement cost curve (MACC) which offers a rational framework for combining biophysical and economic data to reflect mitigation costs. This tool allows the aggregation of the mitigation potential arising from the application of a subset of cost-effective measures above a notional baseline level. An analysis of Chinese climate policies reveals that agriculture is nearly absent in the current national mitigation strategy. We therefore intend to assess the technical, economic and political feasibility of integrating agriculture into domestic mitigation policies. In the first place, the emissions trends and calculation methods are assessed to determine a rigorous approach to build baseline scenarios from projected business-as-usual activities to 2020. Secondly, we identify nine cropland mitigation measures, evaluate their abatement rates and future applicability beyond the baseline scenario to conclude a total feasible technical mitigation potential. The translation to the economic potential is then made by comparing the implementation costs of different mitigation options relative to conventional farming practices. The MACC results show that agriculture provides significant mitigation potential to be able to offset about one-third of baseline emissions and realisation of one-third of the potential is cost-negative for farmers. We finally examine the conditions of using economic instruments to reduce emissions at the lowest cost for the agricultural sector. Given the institutional, behaviour and socials obstacles, we strongly suggest a reform in agriculture fertilizer subsidies to send a clear political signal from central planning. Scaling-up offset projects using carbon intensity as the standardized baseline is recommended and can prepare the grounds for a possible experimental emission trading programme in agriculture. In light with the top priority of safeguarding food security in China, cases studies on regional cereal production are carried out in all these steps, including the analysis of provincial greenhouse gas intensity of production, regional abatement potential related to synthetic nitrogen fertilizer use as well as implementation cost disparities in certain regions.