1. Introduction
Coastal areas offer very favorable environmental conditions for agricultural production (crop, livestock, forestry, and fisheries) due to fertile soil and a substantial supply of water. Higher productivity contributes to improve livelihoods from agriculture and a more sustainable use of fisheries and wetlands. Sustainable yields can increase land availability for other sectors and reduce the clearing and drainage of wetlands. Appropriate agricultural development may increase demand for agricultural inputs, services, and product consumption, which contribute to stimulating the local economy [
1]. On the other hand, farming activities create many adverse impacts on the environment of coastal areas. Mangroves and swamp are encroached for cultivation land, resulting in habitat loss and the degradation of biodiversity. The application of fertilizers, pesticides, and agricultural effluent disposal lead to a higher risk of water pollution and lower fish yield, as reported in many coastal zones [
1,
2,
3,
4]. With spatial proximity to the coastline, agricultural production must include objectives regarding the improvement of farm productivity through environmentally friendly practices, the encouragement of advisory services and appropriate policies, and the maintenance of water flows as well as quality to support coastal resources [
1,
2,
5,
6,
7].
With over 3200 km of coastline, the agricultural production of Vietnam is currently based mainly on three distinct systems including shrimp aquaculture, rice-based cropping, and fisheries [
8]. Shrimp production has been encouraged by the government to raise income for culturists through increasing trading opportunities and employment in aquaculture production (seed supply, processing, and marketing). The culturing of shrimp in the coastal provinces in Vietnam is classified into four subsystems based on the level of technology applied, stocking density, and yield including extensive, improved–extensive, semi-intensive, intensive, and integrated [
8,
9]. Extensive is a traditional method that is based mainly on natural recruiting post-larvae from wild sources within ecosystems and obtaining less than 200 kg/ha/year. Semi-intensive involves some stocking of shrimp larvae from a hatchery; its natural productivity is enhanced (1000–2500 kg/ha/year) by some use of feeds and fertilizers. The intensive system relies on high stocking density with a heavy feeding rate and the application of aeration with a yield of 5000–7500 kg/ha/year [
8]. Between 2000–2006, semi-intensive and intensive systems were quickly expanded from 0.36 million ha to 0.7 million ha in almost exclusively the coastal provinces [
9]. In integrated systems, shrimp larvae and other marine life are managed in mangrove forests along coastlines, and the shrimp yield reaches 200–300 kg/ha/year [
9]. However, the development of shrimp production has caused environmental pollution, depleted water supplies, and created disease problems in many southern coastal provinces such as Soctrang, Baclieu, and Camau [
8,
9,
10,
11], as well as reduced the mangrove forest in northern coastal areas [
12,
13,
14]. On the social–economic front, shrimp systems in Vietnam are considered as having the potential for improving profitability, increasing trading opportunity, and producing more shrimp products, but there is a high level of risk and indebtedness [
11].
Along with the aquaculture sector, there is the diversification of cropping systems of rice and other plants in the coastlines of Vietnam. The double rice cropping of He Thu (summer–autumn) and Dong Xuan (winter–spring) have been practiced since the 1970s. Then, one crop of soybeans was transplantedin1988. He Thu rice is intercropped with second soybean cropping. Farmers grow fruit trees such as orange and sugar cane within rice fields in ditches and dikes. The mixed farming of rice and freshwater fish or shrimp has been also cultivated since the 1990s. The ditches surrounding a paddy field are used for raising fish such as tilapia, carp, or shrimp [
15]. The intensification of rice system involves a relatively low risk, less debt, and higher labor wages, but low income for farmers and an increased in use of agrochemicals [
11].
Different farming systems have interrelations with each other. For long-term development, one system should perform linkages with others without damaging the ecology [
16]. As a research conducted earlier by Gowing and Tuong [
8], the unregulated production of shrimp aquaculture and agriculture in the southern coastal zone of Vietnam creates friction between the farmers who derive their livelihoods from shrimp farming and those who depend on rice systems. The occurrence of conflicts between shrimp farmers, rice farmers, and local people whose livelihood maybe adversely affected by environmental impacts refer unsustainable perspectives for coastal areas [
8].
Xuan Thuy National Park (XTNP) is a largest coastal wetland in northern Vietnam that has three stages of ecological succession: (1) rice encroaches on sedge (
cyperaceae) and mangrove (1960–1985); (2) shrimp aquaculture encroaches on mangrove forest (1985–1995); and (3) mangrove forest encroaches on the sea (1995–present) [
17]. XTNP has a heterogeneity of farming systems with their evolution. Aquaculture land expands rapidly from 132 ha (1986) to 1561 ha (2013), while rice is the main nutrient source for all households, but slightly decreased from 2346 ha to 2232 ha during the above period [
17]. Diverse systems enhance diverse food production, but at the same time, there have been severe problems of development with uncontrolled policies. The depletion of water quality, mangrove fragmentation, and increasing vulnerable levels are challenges that have been recognized by many researchers [
13,
17,
18,
19,
20,
21,
22,
23]. As opined by many agricultural experts, analyzing the existing farming systems corresponding with social, economic, and biophysical parameters is an effective method for proposing activities to protect the soil and water and enhance food security, as well as secure other benefits for farm families [
24,
25,
26,
27,
28]. Understanding farming systems can contribute to creating appropriate interventions that involve social–economic and management technologies for each system. Currently, empirical information on manifold systems and the interrelations between them in this conservation site has been scant. Agricultural policy makers face a shortage of information for the evaluation of existing agricultural production with government targets. The present study focuses on predominant farming systems that generate main sources of income for locals living in the buffer zone. Currently, there are no people living in the core zone.
In the light of the above, the main aim of this research is to provide a comparative assessment of different farming systems in XTNP under the context of coastal zone development. Moreover, the research at hand has several specific objectives, including (1) describing existing farming systems and management practices, and (2) assessing farm performance and the interrelations between farming systems. The delineation of manifold farming systems is important to inform practical interventions and enhance economic viability as well as the coexistence of the systems in the area.
4. Recommendations
Based on observations during the field surveys, we envision some measurements for economic development under the context of environmental protection for coastal areas related to promoting marketing tools, diversifying income sources, better strategies of price, and adopting better farm management practices. The recommendations that are proposed for both farmers and local authorities are as follows:
4.1. Marketing Activities, Diversifying Income Sources, and Cost Strategies
For IAM farmers, marketing tools of conservation, processing, and packaging are underdeveloped and often sold to middlemen, resulting in low value-added products and price squeeze issues. Labeling IAM products with Vietnamese Office of Intellectual Property certificates and selling them to the final customers instead of middlemen would be attractive tools to raise prices and solve the price squeeze problem. A parallel drying process should be applied to preserve shrimps and seaweed longer and sell them during off-season months. Over the long term, a sustainable certification program or environmental friendly labeling scheme could be promoted for IAM products due to its value and preference in the markets.
As noted by the council [
72], monoculture can lead to an increase in soil erosion, pest damage, and chemical pollution. Bromley and Chavas [
73] concluded that the diversification of crops can help farmers deal with drops in profits if the price for one crop is lower than average in a given time. Thereby, in order to overcome the weaknesses of mono RB, this research recommends alternative rotational cropping and intercropping. Rotational cropping could be implemented between rice and legumes or watermelon, which are popularly grown in the Giaoan and Giaoxuan buffer communes. The intercropping of rice and fresh aquaculture (perch) is already successfully applied in the Giaolac communal buffer zone. These practical tools help farmers diversify income sources in a year. For mono ISH culture, simultaneously raising shrimps with some male tilapias in the tilapia–shrimp ponds, which has been already applied by one farmer in XTNP, should be widely introduced by other farmers. The advantages of tilapias in the shrimp–tilapia system have also been mentioned earlier by Yi and Fitzsimmons [
74]. It could be an alternative tool for reducing disease, using antibiotics, and improving water quality in ponds while at the same time enhancing economic returns for farmers.
The collective power of the farmers that belong to the three farming systems was relatively weak, as there have been no market farmer groups in the area. Hence, a farmers’ market association should be created in the area to increase the voice of smallholder farmers.
Appropriate cost strategies also help farmers gain a higher level of profitability. In the case of RB production, a lower cost of nitrogen dosage and precise fertilization can help reduce the input costs as well as EID. Moreover, an increased rate of IPM application could also contribute to reducing the cost of pesticides in the long term. Rotational cropping also contributes to better soil health and reduced fertilizer costs in the RB system. In the case of ISH, promoting probiotics, restraining antibiotics, and effective formulated feed use can help farmers reduce costs, achieve higher incomes, and reduce side effects on the environment. In the IAM system, maintaining more forest coverage would generate more natural food within the system and reduce the cost of additive rice bran and formulated feeds for farmers.
4.2. Environmentally Friendly Farming Practices and Management
Existing farm activities are still conducted toward a manner of profitability that may broaden the gap between development and conservation. Promoting better farming practices can contribute to achieving higher yields while at the same time ensuring environmental protection. This research revealed that IAM is more sustainable than ISH and RB since it is less dependent on purchased costs; however, its productivity was low. Hence, we propose maintaining more trees in IAM farms, as it can contribute to achieving sustainable production capacity and providing more places for migratory birds. An implication based on optimal proportion was initially suggested by T.D. Truong [
75], who indicated that mangrove coverage of approximately 60% could enable farmers to reach the highest level of output and profit.
The adoption of antibiotics and veterinary medicines in the ISH sector are the factors increasing the costs and high potential side effects for coastal wetland. More seriously, sludge and effluent disposal from ISH ponds are not monitored stringently by any institutions. Hence, the findings suggest that the implementation of best management practices (BMPs) in aquaculture would be a practical means for preventing negative impacts while ensuring economic efficiency in coastal aquaculture, as presented by Boyd [
76]. In addition, treated and recirculated pond sludge was another technical resolution—previously mentioned by Hossain [
77]—that can be considered another measure for the reduction of sewage pollution in the area. More importantly, water quality restriction regulations for shrimp aquaculture in Decree No.22/2014/TT-BNNPTNT approved by Ministry of Agriculture and Rural Development (MARD) [
78] should be assured for enforcement at the farm level in the site.
We have found an imbalanced use of synthetic fertilizers in surveyed RB systems. Hence, this research suggests that cooperation between XTNP management experts, the CPC, the CAB, and the CAC ought to be required and re-established in order to stringently control whether local farmers follow government standards. Furthermore, precision farming or precision agriculture concepts should be introduced step by step in the coastal conservation zone to monitor the excessive use of urea [
79]. Another challenge of RB culture is that farmers do not apply the IPM tool to protect the natural population. The pesticide runoff from the rice area has had documented effects on IAM (90.47%) and ISH (77.78%). According to the council [
80], IMP can improve financial performances by reducing the pesticide input cost, pest population, and crop damage by pests. Thus, ecologically-based IPM should be urgently implemented in the area to enhance habitats and species in the surrounding zones and use plants as natural pesticides. This is imperative to strictly control chemical pesticides, and therefore contributes to the successful coexistence of the three systems.
5. Conclusions
The main purpose of this study is to assess the dynamics of farming systems through the adoption of SCP analysis. Three main farming systems were analyzed in the coastal XTNP with a substantial focus on cropping and aquaculture production. We conclude by emphasizing the outstanding facets of diverse coastal systems reflecting farming practices, whole-farm performance, and interrelation among the systems.
ISH required the highest production cost with a heavy reliance on artificial inputs; however, it also gained the highest net sustainable returns and sustainable family income in comparison with the other systems. The RB sector was cultivated to ensure food security for households, but its cultivators had the least labor productivity. IAM depended the least on artificial inputs and produced various ranges of products.
The production systems are economically important for local inhabitants, but the problems that arise from their unsustainable practices are very concerning. The adoption of antibiotics and veterinary medicines without careful record keeping in the ISH were recognized as potential side effects for environment and human health. More seriously, sludge and sewage from ISH farms were released to public rivers, which impaired intake from water sources for ISH and IAM. In surveyed rice plots, the results indicated that 100% of the farmers used pesticides as well as chemical fertilizers. Moreover, there has been an imbalance and excessive utilization of synthesis fertilizers. Besides, farmers no longer applied IPM tools to protect the natural population. The pesticide run-off from rice has been claimed to have effects on both ISH and IAM farms.
Our further results have demonstrated that the spatial proximity of farm designation was associated with unsustainable management practices, resulting in a low linkage between systems. Hence, we propose some recommendations to address the weaknesses of production regarding environmental friendly practices. Moreover, marketing activities, diversifying income sources, and forming farmers’ market groups are necessary for economic development prospects.
However, this research has limitations related to assessing the social–economic and institutional elements of SCP in farming systems, as well as analyzing the factors influencing SCP, including market supply, demand, and public policy. This implies that future studies should focus on the subjects of corporate supply–demand and agricultural policies (regulation, taxes, subsidies, information provision, etc.) that affect SCP to provide broad view of sustainable development.