Our results demonstrate experimentally what has long been argued anecdotally, that farmers respond to price incentives . For organizations looking to provide contracts to farmers, this result is encouraging because it implies that they can provide strong incentives to farmers without undertaking the costs of providing training and input loans. By far the most binding constraint to expansion for ESOP is the need to raise sufficient capital to provide input loans to farmers at planting. Our results demonstrate that much of this expense may be unnecessary and ESOP could potentially expand the number of farmers it contracts with, and thus its throughput, by offering farmers a guaranteed price. With a price guarantee delivering secure market access, farmers can use the contract as collateral to rent in more land and obtain loans for inputs, improving outcomes for both parties and contributing to more rapid rural transformation.Since the plastics industry first flourished in the 1950s, global plastic production has steadily increased, reaching 368 million tons in 2019 . However, poor management of plastic waste means that it is frequently washed into the oceans, where it accumulates and disperses on a global scale, showing a great resilience . Studies estimate that the amount of plastic floating on the sea surface is between 93,000 and 236,000 tons, representing approximately 5000 to 50,000 billion fragments, 92% of which are micro-particles of plastic , also called “micro-plastics” . These micro-plastics can enter the marine environment by several pathways .
The majority of MP found in the oceans are secondary MP produced by the fragmentation of larger plastic debris under a combination of environmental factors . Primary MP, in contrast, are those directly released into the environment as micro-sized particles . Micro-plastics have been reported in all major oceans and seas including the Pacific , Atlantic and Indian Oceans , as well as the Southern Ocean , Arctic polar waters , Antarctica , and the Mediterranean and North Seas . They have been found everywhere, from populated coastal environments to the most remote areas . Their ubiquitous nature in all environmental matrices, from surface water,down through the water column to the sediments,grow table including in marine biota,as their small sizes make them easily taken up by a wide range of organisms . In French Polynesia , pearl-farming is the second most important economic activity, based on the trade of pearl and mother-of-pearl . It also contributes to the social development of the territory by being widespread across 23 remote islands and atoll lagoons. However, pearl-farming is associated with a specific source of plastic pollution. The inventory carried out by Andr´efou¨et et al. in the atoll lagoon of Ahe revealed thousands of tons of plastic pearl-farming gears . Rearing structures and equipment of these types are accumulating over time in pearl-farming lagoons. They may fragment into smaller particles, which then add to MP entering the lagoons from other anthropogenic pressures and from the South Pacific subtropical gyre . This situation is worsened by the semi-enclosed environments of some of these lagoons, which could favour MP accumulation.Pearl-farming could thus be causing a risk to itself through plastic pollution, with a potential impact of MP on the suspension filter-feeding pearl oyster Pinctada margaritifera. Indeed, exposure using polystyrene microbeads demonstrated a dose-dependent effect on the energy balance and dose-specific transcriptomic disruption to gene expression in P. margaritifera. However, these effects were only observed in experimental controlled conditions that do not properly represent the complexity of the environment.
Furthermore, concentrations tested were not ecologically relevant since no environmental surveys had been performed in pearl-farming lagoons. To date, only one study has demonstrated the presence of MP in French Polynesia waters, using a 50 µm-plankton net in front of a public beach in Moorea, where they reached 0.74 MP m–2 . There was, therefore, a strong need to evaluate and characterize MP pollution in pearl-farming lagoons. The aim of the present study was to evaluate MP contamination in pearl-farming atoll lagoons of French Polynesia with low population and tourism. We investigated MP concentration, composition and spatial distribution in surface water and the water column , as well as in the tissue of cultivated pearl oysters. Our study addressed two main aspects: the distributions and concentrations of MP in the compartments investigated; the identification of polymer types and relative abundance, in so far as the main characteristics of MP contamination could be related to those of local macroplastic pollution sources such as the widely distributed pearl-farming gears. The data produced should facilitate decision making for local government policies to assess and anticipate this emerging risk for pearl-farming sustainability in French Polynesia.Its agricultural sector is particularly susceptible to various damages caused by climate change . Close to 40 percent of the country’s total land area is agricultural land. The agriculture sector accounts for 24 percent of Vietnam’s GDP, 20 percent of total exports, and over 70 percent of total employment . Using integrated or multi-sector modeling, Arndt et al. estimated the economic cost of climate change in Vietnam and concluded that the annual GDP growth rate would decline by about 1%–2%. Even so, they found that the negative impacts on agriculture and roads would be modest by 2050. They further showed that adopting appropriate preemptive actions to climate change would bring positive results. Agriculture is an important pillar of the Vietnamese economy. Rice farming, which uses two-thirds of the country’s rural labor, produces 30 percent of the country’s total agricultural production value . Vietnam is also one of the largest rice exporters in the world .
More than half of Vietnam’s rice production and about 90 percent of the rice exports come from the Mekong River Delta.However, this low-lying area faces some of the worst impacts of climate change and is therefore seen to ‘‘severely compromise’’ the country’s future rice production . Recent studies have shown that ongoing climate change has had significant impacts on rice production and the livelihoods of farmers in the region. The most serious effect is caused by saltwater intrusion during the Winter– Spring crop season . In the 2015/16 W-S crop season, MRD farmers suffered great losses from saltwater intrusion as rice paddy production fell by 11.2 percent in comparison with the 2014/15 W-S crop season . The problem is likely to continue in the future. The sea level in 2050 is projected to be between 25 cm and 30 cm higher than the 2000 level, which will likely result in salinity intrusion of >4g/l up to 50–60 km from the mouths of the Mekong River affecting about 30,000 hectares of agricultural area . Local authorities have intervened to protect MRD farmers against drought and salinity intrusion. Assistance includes adjusting seasonal schedules, managing water resources, adjusting cultivation techniques, diversifying and changing crops, applying new varieties, and self-learning to protect crops and cut economic losses . Previous studies provided empirical evidence on the effectiveness of adaptation strategies as well as the factors that influence the rice farmers’ choice among various adaptation strategies . However, the benefits of such solutions were not properly controlled in the past comparative studies. Specifically, the following problems can be cited. First, studies that used a binary indicator to measure the cope-with climate-change solutions failed to quantify the costs or control the farmer’s response process. Second, the impact of each strategy on income and productivity could not be separated as the studies aggregated many coping solutions. Third, the use of annual outcome indicators such as costs, profits, and productivity could not identify the effect of a single-response strategy in each crop season since the seasonal weather factor is not controlled.
To avoid these problems, we investigate the role of an adjusted cropping calendar in the rice production of MRD farmers facing saltwater intrusion. We focused on the relationship between early planting and the production and welfare of MRD rice farmers during the 2019/20 W-S crop season. This strategy is based on the following considerations. First, Nguyen and Ho , Nguyen et al. , and Nguyen and Nguyen found that farmers’ adaptation strategies against climate change significantly affect their farm income. Because farmers are highly resource conscious when making climate adaptation decisions, a comparative study is required to gauge the change in farmers’ welfare under different adaptation strategies. Second, Lu et al. argued that the timing of sowing needs to be predicted appropriately to avoid risks and achieve maximum yields. In 2018, the Ministry of Agriculture and Rural Development of Vietnam instructed the provinces in the MRD coastal areas to apply Climate-Smart Maps and Adaptation Plans 1 to adjust the rice planting calendar during the 2019/20 W-S crop season to minimize saltwater intrusion brought by the 2019 El Niño . In 2019, ebb flow table experts predicted that saltwater intrusion in the MRD would start earlier and that the salinity level would be higher than those in the 2015/16 dry season. The Department of Crop Production issued Official Document No. 1252/TT-VPNN directing the MRD to adjust its planting calendar in the 2019/20 W-S crop season. Coastal areas of the MRD, including Long An, Kien Giang, and Soc Trang provinces, were advised to plant rice from early October to early November in 2019. This created an opportunity for a natural experiment for the current study. To the best of our knowledge, this is the first study to examine the impacts of the adjusted cropping calendar on the welfare of rice farming households in the 2019/20 W-S crop season.
To determine the effect of early planting in response to saltwater intrusion, a total of 1176 rice farmers in three MRD provinces were randomly selected as research participants. Then propensity score matching was applied to match 412 early-planter farmers with 764 non early planters ,comparing the rice farming income and rice yield of the two groups. We found that early planting increased rice farming income by VND 8.62–8.77 million per hectare and rice production by 2.51–2.59 tons per hectare during the 2019/20 W-S crop season. Our findings suggest that during salinity years, advancing the rice cropping calendar to early planting can increase the production and income of rice farmers. This confirms the significant benefits of crop calendar adjustment in areas exposed to the risk of saltwater intrusion. The result also corroborates the robustness of a ‘‘planned’’ response to climate change risks in agricultural production . It is also consistent with the framework for agricultural climate change adaptation advocated by Ozor et al. and the process model of private proactive climate change adaptation presented by Grothmann and Patt . The paper proceeds as follows. Section 2 presents an overview of the study site and rice cropping practice in the MRD. Section 3 describes the sample and the methodology. Section 4 reports and discusses the results. Section 5 concludes the paper. MRD farmers practice either two or three rice cropping systems. Normally, the Winter–Spring crop season is from November to February, the Summer–Autumn rice season is from April to July, and the Autumn–Winter rice season is from August to November. In normal years with no drought or high salinity, MRD rice farmers start planting in middle to late December for the W-S crop season. Rice farmers can move the planting calendar forward, particularly for the W-S season, whenever unfavorable environmental conditions such as drought and high salinity necessitate it Nguyen . For early planting, the DCP calendar recommends planting within the month of October during the W-S season, which is the season most affected by drought and salinity. Nguyen found that rice farmers in Long An, Kien Giang, and Soc Trang, especially those practicing the two-cropping system, define ‘‘early planting’’ as starting the planting period by mid-November. Considering this, we define early planting for the 2019/20W-Scrop season as planting rice by 15 November 2019 at the latest provided that this is the last cropping of the 2019/20 crop year. If the farmer planted before 15 November 2019 but had another cropping extending from late November to February 2020, he or she was considered a non-early planter for the 2019/20 W-S crop season.The target sample size of the treatment group was 384.