The influence of phosphate fertilizer application levels and cultivars on cadmium uptake by Komatsuna (Brassica rapa L. var. perviridis)

Cadmium (Cd) is a common impurity in phosphate fertilizers and application of phosphate fertilizer may contribute to soil Cd accumulation. Changes in Cd burdens to agricultural soils and the potential for plant Cd accumulation resulting from fertilizer input were investigated in this study. A field experiment was conducted on Haplaquept to investigate the influence of calcium superphosphate on extractable and total soil Cd and on growth and Cd uptake of different Komatsuna (Brassica rapa L. var. perviridis) cultivars. Four cultivars of Komatsuna were grown on the soil and harvested after 60 days. The superphosphate application increased total soil Cd from 2.51 to 2.75?mg?kg^?1, 0.1?mol?L^?1 hydrochloric acid (HCl) extractable Cd from 1.48 to 1.55?mg?kg^?1, 0.01?mol?L^?1 HCl extractable Cd from 0.043 to 0.046?mg?kg^?1 and water extractable Cd from 0.0057 to 0.0077?mg?kg^?1. Cd input reached 5.68?g?ha^–1 at a rate of 240?kg?ha^–1 superphosphate fertilizer application. Superphosphate affected dry-matter yield of leaves to different degrees in each cultivar. ‘Nakamachi’ produced the highest yield in 2008 and ‘Hamami No. 2’ in 2009. Compared with the control (no phosphate fertilizer), application of superphosphate at a rate of 240?kg?ha^–1 increased the Cd concentration in dry leaves by 0.14?mg?kg^?1 in ‘Maruha’, 1.03?mg?kg^?1 in ‘Nakamachi’, 0.63?mg?kg^?1 in ‘SC8-007’ in 2008, and by 0.19?mg?kg^?1 in Maruha’, 0.17?mg?kg^?1 in ‘Hamami No. 2’, while it decreased by 0.27?mg?kg^?1 in ‘Nakamachi’ in 2009. Field experiments in two years demonstrated that applications of different levels of calcium superphosphate did not influence Cd concentration in soil and Komatsuna significantly. However, there was a significant difference in Cd concentration of fresh and dry Komatsuna leaves among four cultivars in 2008 and 2009. The highest Cd concentration was found in the ‘Nakamachi’ cultivar (2.14?mg?kg^?1 in 2008 and 1.91?mg?kg^?1 in 2009). The lowest Cd concentration was observed in the ‘Maruha’ cultivar (1.51?mg?kg^?1?dry weight (DW)) in 2008 and in the ‘Hamami No. 2’ cultivar (1.56?mg?kg^?1?DW) in 2009. A decreasing trend in Cd concentration was found in ‘Nakamachi’, followed by ‘SC8-007’, ‘Hamami No. 2’ and ‘Maruha’ successively. It is necessary to consider a low-uptake cultivar for growing in a Cd polluted soil. In these two years’ results, ‘Maruha’ cultivar was the lowest Cd uptake cultivar compared to the others.     

Decadal changes in the rice-cropping system in the Ayeyarwady Delta using a large archive of satellite imagery from 1981 to 2020

In the last 40 years, the rice-cropping system has considerably changed in the Ayeyarwady Delta. The large archive of satellite imagery provides a history of how land and water resource managements have changed in the face of growing populations, resource demand, and climate change. This study aimed to assess the decadal changes in the rice-cropping system in the Ayeyarwady Delta by using the large archive of satellite imagery for the last 40 years (1981???2020). The long-term NDVI dataset provided various information on rice cultivation. Signal processing techniques were used to detect on the historical changes in the rice-cropping system, and the impact of climate change was assessed by using trend analysis. Until the 1980s, single-cropping of summer rice was dominant in the Delta. To enhance the grain yield of rice, the irrigation facilities were introduced in 1992 under an initiative of the Myanmar government. As a result, the annual cropping intensities increased from 1.087?±?0.390 in the 1980s to 1.422?±?0.499 in the 2010s. The information on historical change in the rice-cropping system would be useful to consider the practical and cost-effective utilization of remaining land and water resources. Moreover, the trend analysis of NDVI time-series showed negative trends in coastal areas. This indicates that the rice production in coastal areas has been constrained by the saline intrusion. The salt-affected areas are expected to expand under future climate change scenarios. Government support is highly required for sustainable rice production in the Delta.

     

Optimum insurance contract of flood damage index insurance for rice farmers in Myanmar

Climate change is an underlying cause of many extreme events such as enormous cyclones and erratic torrential rains. These phenomena threaten farmers in coastal regions of Myanmar. Self-insurance through means such as crop diversification is insufficient for sustainable farm management. Weather index insurance (WII) is receiving much attention because of its low management costs. An optimum WII contract for flood damage using rainfall as the index has been proposed for rice farmers in coastal regions. According to the model, an insurance payment demand function is derived by solving the expected utility maximization problem. The utility function of the contract is specified as constant relative risk aversion type. The production function is specified as Cobb–Douglas type. By substituting real average data of rice production of farmers into this function, the optimum insurance payment and premium are obtained. Changes in insurance compensation by payments according to an increase in the price of rice, rainfall, and degree of risk aversion are investigated. Results suggest that if an average farmer pays around 41.5 US dollars per year, then farm management will be optimally stabilized under the flood risk.

     

Sulfated cholecystokinin‐8 increases ghrelin secretion but does not affect oxyntomodulin in Holstein steers

The effect of appetite regulatory hormone cholecystokinin (CCK) on the secretions of oxyntomodulin (OXM) and ghrelin, and the effect of ghrelin on the secretions of CCK and OXM were studied in ruminants. Eight Holstein steers, 7 months old, 243 ± 7 kg body weight (BW), were arranged in an incomplete Latin square design (8 animals × 4 treatments × 4 days of sampling). Steers were intravenously injected with 10 µg of sulfated CCK‐8/kg BW, 20 µg of acyl ghrelin/kg BW, 100 µg of des‐acyl ghrelin/kg BW or vehicle. Blood samples were collected from ?60 min to 120 min relative to time of injection. Plasma concentrations of ghrelin, sulfated CCK and OXM were measured by double‐antibody radioimmunoassay. Plasma acyl ghrelin was increased to peak level (428.3 ± 6 pg/mL) at 60 min after injection of CCK compared with pre‐injected levels (203.3 ± 1 pg/mL). These results showed for the first time, that intravenous bolus injection of CCK increased ghrelin secretion in ruminants. In contrast, injection of ghrelin did not change CCK secretion. Administration of ghrelin or CCK has no effect on plasma OXM concentrations. In conclusion, our results show that administration of CCK increased ghrelin secretion but did not affect OXM release in ruminants. Ghrelin did not affect the secretions of CCK and OXM.     

A Property-Rights Approach to Understanding Regulations and Practices in Community-Based Forest Management: Comparison of Three Systems in the Philippines

Decentralizing property rights from state control to user communities has encouraged people’s participation in forest management. Relatively few studies, however, examine the forest regulations required for exercising such property rights. To address this issue, Schlager and Ostrom’s ‘bundle of rights’ framework was used to examine various forms of property rights and regulations in three systems of community-based forest management. The field research was undertaken in the northern Philippines, using eight cases of community-based forest management at sites in the provinces of Nueva Vizcaya and Ifugao. Local communities were found to informally retain the authority to create locally crafted property rights and regulations in a central government-initiated program. While forest regulations and practices prescribed at the national level have improved forest conditions, the flow of forest benefits to communities has been limited because of decentralization without devolution of authority. A case study of a site initiated by a local government indicated that the transfer of responsibility from the central government to local government units can create more favourable conditions for the flow of forest benefits to communities. But due to a lack of clarity about devolution of cutting permits and about the locations of afforested critical watershed areas, authorized local users lose their authorization. When forest is managed traditionally, communities can have more assured rights than in government-initiated programs, particularly in relation to tree ownership. This is because individuals have the authority to devise collective-choice rights as well as operational rights.     

Measuring farmers’ preferences for weather index insurance in the Ayeyarwady Delta,Myanmar: a discrete choice experiment approach

Paddy and Water Environment - This study examines farmers’ preferences for weather index insurance (WII) in the Ayeyarwady Delta, Myanmar, using discrete choice experiments. It employs data...     

Factors affecting participation of user group members: comparative studies on two types of community forestry in the Dry Zone, Myanmar

Drawing on the example of community forestry in Myanmar’s Dry Zone area, this paper conceptualizes and empirically assesses key factors for obtaining the participation of user group members, with emphasis on the implementation stage. More specifically, the study clarifies the commonalities and differences in influential factors between two types of community forestry: agroforestry and natural forest types. Field data were collected by semi-structured interviews with 54 households in four selected user groups, by key informant interviews, by informal interviews, and by direct observations. Our analysis was conducted in accordance with a framework in which selected social/institutional, economic, and physical factors affect participation. The results show that social/institutional factors are the most influential factors in both types, while economic factors are directly related to participation of user groups in the agroforestry type alone. Results indicated that preconditions, such as selection of leaders, should be considered in accordance with the local context in which the people have a shared recognition of what confers legitimacy to leadership. We recommend collaboration of the Forest Department with user group members in providing information regarding the use and selling of forest products from agroforestry-type community forest, as well as frequent communication with user groups to provide incentives regarding property rights stability for future benefits to continue participation of user group members in managing the dry forest.