Policies to support economic and environmental goals at farm and regional scales: Outcomes for rice farmers in Southern India depend on their resource endowment

Improving water use and nitrogen efficiencies is of overall importance to society at large - to conserve scarce water resources and prevent environmental pollution. Efficient cultivation practices for rice which had no yield penalty were not adopted by farmers because of the open access to water free of charge. Well-chosen combinations of policy measures are thus needed to stimulate adoption of new cultivation practices. We developed a multi-objective linear programming (MGLP) model to explore the impact of: (i) modified rice cultivation including water-saving irrigation on farm profit; (ii) water pricing and water quota government policies on adoption of modified rice cultivation by farmers; (iii) a combination of (i) and (ii) to achieve the objectives of both farmers and society at large, and (iv) to study the trade-offs between income, water and nitrogen use. The analysis was carried out on four rice-based farm types for the state of Tamil Nadu, South India. Model results showed that observed farm profit of all four farm types could be increased using current practices simply by optimizing land use for specific crops. Adoption of modified rice cultivation further increased farm profit. Water-saving practices were selected only when water pricing was introduced. Farm profits were reduced even at low water prices but were compensated by farmers through adoption of modified rice cultivation. The combination of policies that stimulate adoption of modified rice cultivation was effective in achieving both increased farm income and water savings. The required water prices differed across farm types and seasons and impacted poor resource-endowed farmers the most. Providing water quotas could protect the poor resource-endowed farmers. The model helped to identify the optimal water price and water quota for each farm type to achieve both the objectives of farmers and society at large. Opportunities for reducing water use and avoiding environmental pollution at acceptable profits are available for all farm types, but need to be tailored to the farmers’ resource endowments.     

Introducing greenhouse gas mitigation as a development objective in rice-based agriculture: II. Cost–benefit assessment for different technologies,regions and scales

New tools for land use analysis including detailed cost–benefit assessments are needed to integrate resource management for enhancing farmers’ income and mitigating greenhouse gas (GHG) emissions. The paper comprises an assessment of GHG emissions and economic returns under different mitigation technologies in three rice growing regions in Asia, i.e., Ilocos Norte province (Philippines), Zhejiang province (China) and Haryana state (India). Site-specific data on soil, climate and socio-economics were integrated in the previously developed spreadsheet model TechnoGAS (Technical Coefficient Generator for Mitigation Technologies of Greenhouse Gas Emissions from Agricultural Sectors). Three baseline technologies that differed in terms of inorganic/organic N supply have been compared to different mitigation technologies in form of Marginal Abatement Cost Curves (MACCs). For the baseline technology of inorganic N (urea) fertilization, amendment with phosphogypsum and nitrification inhibitors are the most promising mitigation options resulting in shadow prices of less than US$10 per ton of carbon dioxide equivalent (CE). Assuming a mix of urea and farm yard manure for the baseline, we have tested several options including different irrigation patterns and husk used as fossil fuel. Mid-season drainage had a better cost–benefit ratio (ca. US$20 per t CE) than alternate flooding, but was less profitable than husk utilization (ca. US$4 per t CE). Assuming high organic inputs, biogas technology is, in most cases, the preferable option (ca. US$10 per t CE). Finally, we compiled regional abatement cost curves for selected administrative units using the outcome from regional optimization models. Implementing the three most promising technologies required US$6000 for Dingras municipality, Ilocos Norte, in the Philippines (ca. 10³ ha of rice land potentially providing emission savings of ca. 3000 t CE), US$50,000 for Pujiang county in China (ca. 10⁴ ha providing ca. 27,000 t CE), and US$1.2 million for Karnal district in India (ca. 10⁵ ha providing ca. 220,000 t CE).     

Integration of bio-physical and economic models to analyze management intensity and landscape structure effects at farm and landscape level

We present an integrated spatially explicit land use modeling framework, which integrates two key components of agricultural systems, the bio-physical production system and the management system, by coupling the bio-economic farm optimization model FAMOS[space], the crop rotation model CropRota, and the bio-physical process model EPIC (Environmental Policy Integrated Climate). The integrated modeling framework has been developed to analyze the cost-effectiveness of selected agri-environmental program (AEP) measures. We also focus on the landscape development and therefore include a detailed representation of landscape elements such as fields or orchard meadows in our analysis. An indicator set represents all main environmental AEP objectives, i.e. preservation of water and soil resources, mitigation of climate change, protection of biodiversity, maintenance of cultural landscapes as well as farm income support. The integrated modeling framework is applied to 20 farms in the Austrian ‘Mostviertel’ region, which are selected from the Integrated Administration and Control System (IACS) of the European Union. The cost-effectiveness of AEP measures is assessed under different premium levels. The implementation of the AEP clearly affects environmental quality in a positive way. Nitrogen rates are reduced, landscape elements can be sustained, and the landscape becomes more diverse. The program also increases farm gross margins on average. However, the cost-effectiveness ratios (CER) are declining with increasing premium levels. The results indicate that the cost-effectiveness of AEP measures can be improved by spatial targeting.     

Response of vegetative growth and fruit development to regulated deficit irrigation at different growth stages of pear-jujube tree

In order to investigate the response of vegetative growth, fruit development and water use efficiency to regulated deficit irrigation at different growth stages of pear-jujube tree (Zizyphus jujube Mill.), different water deficit at single-stage were treated on field grown 7-year old pear-jujube trees in 2005 and 2006. Treatments included severe (SD), moderate (MD) and low (LD) water deficit treatments at bud-burst to leafing (I), flowering to fruit set (II), fruit growth (III) and fruit maturation (IV) stages. Compared to the full irrigation (control), different water deficit treatments at different growth stages reduced photosynthesis rate (P_n) slightly and transpiration rate (T_r) significantly, thus it improved leaf water use efficiency (WUE_L, defined as the ratio of P_n to T_r) by 2.7-26.1%. After the re-watering, P_n had significant compensatory effect, but T_r was not enhanced significantly, thus WUE_L was improved by 31.4-42.2%. I-SD, I-MD, II-SD and II-MD decreased new shoot length, new shoot diameter and panicle length by 8-28%, 13-23% and 10-31%, respectively. Simultaneously, they reduced leaf area index (LAI) and pruning amount significantly. Flowering of pear-jujube tree advanced by 3-8 days in the water deficit treatments at stage I, Furthermore, SD and MD at stage I increased flowers per panicle and final fruit set by 18.9-40.5% and 15.5-36.6%, respectively. After a period of re-watering, different water deficit treatments at different growth stages improved the fruit growth rate by 15-30% without reduction of the final fruit volume. Compared to the control, I-MD, I-SD, I-LD, I-MD and I-SD treatments increased fruit yield by 13.2-31.9%, but reduced water consumption by 9.7-17.5%, therefore, they enhanced water use efficiency at yield level (WUE_Y, defined as ratio of fruit yield to total water use) by 17.3-41.4%. Therefore, suitable period and degree of water deficit can reduce irrigation water and restrain growth redundancy significantly, and it optimize the relationship between vegetative growth and reproductive growth of pear-jujube trees, which maintained or slightly increased the fruit yield, thus water use efficiency was significantly increased.