INTRODUCTION
The issue of organic agriculture and organic fertilizers has never been a central topic during forums as it is today. These include International and National Conferences, titled: i) “Vietnam Organic Agriculture: Development and Integration” on 16 December, 2017 chaired by Hanoi Prime Minister; ii) Organic Agriculture Development with the topic: “Vietnam Organic Agricultural Development Solution” on 27 December, 2017 chaired by the Ministry of Agriculture and Rural Development in Ho Chi Minh City; iii) “Solutions for Promoting the Production and Consumption of Organic Agricultural Products” on 4 April, 2017; and iv) “Developing Organic Fertilizers” on 9 March, 2018 organized by the Ministry of Agriculture and Rural Development in Hanoi; as well as National Workshop on “Organic agriculture: Current Situation and Development Orientation” on 27 September, 2013, organized by the Association of Organic Agriculture and the Department of Crop Production in Ho Chi Minh City. Also, organic agriculture and organic fertilizer are included in the Crops Production and the Livestock law, which has just been approved by the XIV National Assembly at the 6th session on November 19, 2018 in Vietnam.
However, due to many factors, there has recently been an increasing trend on the role of organic agriculture and the use of organic fertilizer, considering that inorganic fertilizer causes to degrade soil fertility and groundwater as well as surface water pollution, increase greenhouse gas emissions and more seriously affecting the quality of agricultural products, consumer health and calling for the elimination of inorganic fertilizers. Nevertheless, it is important to remember the world still uses huge amounts of inorganic fertilizers, 187 million tons of N + P2O5 + K2O in 2018, while there is only 17 million tons of industrially produced organic fertilizer. Therefore, it is very important to properly and objectively determine the role of organic and inorganic fertilizers in order to have the most appropriate approach in agricultural production today.
INORGANIC OR ORGANIC FERTILIZER
The purpose of all production methods is to create products that are safe for human consumption, with minimal negative impact on the environment and maintain biodiversity for the next generation. Among the Asian countries, each country will prioritize the choice of production method that best suits its local conditions and other resources to achieve the highest efficiency.
A frequently asked question is whether inorganic or organic fertilizers are safer with regard to the quality of farm produce and the environment. First of all, we need to understand that, no matter what source is supplied, the nutrients must be converted to inorganic or ionic form so that the plants can absorb. Therefore, it is too simplistic to say that using inorganic fertilizers is not safe. If we followed this logic, perhaps, in developed countries where large-scale production by hydroponic methods in which almost 100% of nutrients are in inorganic form, there is no safe product.
History shows that, with a small population, just using low-yield indigenous crop varieties is enough to meet the needs of mankind for food. In many sites nutrients inherent in the soil are compensated by alluvium sediment every year, just rotation and organic compost fertilizers are adequate to meet the nutritional needs of plants (Doberman and Fairhurst, 2000). However, as the population increases, the area of agricultural land decreases due to urbanization, transportation and other needs, intensive pressure to increase productivity is inescapable. Hybrid and high-yielding rice varieties are developed, together with the crops intensity increases, making the inherent nutrition in the soil decline rapidly. In such situations the organic fertilizer alone cannot help balance the nutritional needs of the plants, and the use of chemical fertilizers has increased as an indispensable role (Table 1 and 2).
It can be said that chemical fertilizer-based agriculture began in 1909 when German scientists Fritz Harber and Carl Bosch (Reference) synthesized NH3 and commercially produced this fertilizer in 1914, leading to the gradual replacement of organic-based agriculture by inorganicbased since the mid-twentieth century. This shift was evident in China from 1949 to 1990 (Table 3). In Vietnam, inorganic-based fertilizer can probably be measured from June 1962, when the first super phosphate fertilizer was produced and developed rapidly since the late 80’s of the twentieth century.
Table 4 shows that, in the last 53 years, the world's land area for food crops has increased by only 1.16 times but the population has increased by 2.36 times. During the same period in Vietnam, the population increased by 5.4 times. This means the area of arable land per capita decreased by 50% on average. To meet the demand, this requires intensive farming to increase productivity by 2.75 times in the world and 3 times in Vietnam, of which intensive farming through chemical fertilizers plays a decisive role. Rice, the staple food crop in Asia, consuming 50~70% of the total chemical fertilizer also shows an increase in productivity over the past half a century by 2~3 times (Table 5). This is directly related to increasing inorganic fertilizer using.
Currently, countries with low agricultural land area per capita will use more inorganic fertilizers to intensify and increase productivity, except for some countries with economic difficulties. In contrast, countries with high agricultural land area per capita will use less inorganic fertilizer such as Australia and Russia, which mainly uses organic fertilizer and recycle plants residues in crop rotations, even cutting down crop production to stabilize the market with avoiding oversupply and also to improve soil fertility. Countries using a lot of inorganic fertilizers are China, Vietnam and South Korea with rates of 3~4 times higher than the world average. Because of Vietnam’s case, due to cultivation planting of many crops a year, the average amount of fertilizer per crop will be lower. In some developed countries, high inorganic fertilizer use has decreased in order to reduce the amount of fertilizer per unit area, such as Korea, from 412 kg/ha in 2002 to 369 kg/ha in 2015 (-11%); in Japan, the corresponding reduction from 333 to 223 kg/ha (-33%), in France use decreased from 211 to 169 kg/ha (-20%). Contrary to China, the amount of fertilizer increased over the same period from 377 to 506 kg/ha (+34.2%) and Vietnam increased from 305 to 439 kg/ha (+43.9%). In the US alone, the amount of fertilizer also increased by 22% from 112 to 137 kg/ha for the period 2002~2015 (Tables 4, 6). Considering the use of inorganic fertilizers in 4 developed countries representing 3 continents also shows the trend of increasing amount over time (Table 6).
To feed the growing population, each country can take one or more of the following measures: i) Increase the area through reclaiming new lands; ii) Increasing crop intensity; and iii) Intensifying cultivation (new varieties, fertilization, disease and insect pest management and application of appropriate irrigation measures). However, for Vietnam, land for agricultural production in general and food crops in particular has not only stopped increasing but is rapidly decreasing in both quantity and quality.
It can be clearly understood that the production of many crops in Vietnam has increased significantly in recent years especially food crops mainly due to increased crop yields. Bumb and Banante (1996) reported that productivity contributes over 80% of crop production, the remaining 20% is due to the increase in acreage. In Vietnam, it can be said that almost 100% of the increase in crop production is due to increased productivity. Take three representative large-scale crops, that consume a lot of fertilizer as an example, namely rice, maize and coffee. These three major crops covered 9.3 million ha of cultivation accounting for 61.6% of the total cultivated area of agricultural crops and consume over 80% of the national fertilizer use. From 1921~2018 (97 years), the rice cultivation area increased by 1.64 times; but output increased 7.08 times, thanks to an increase of 4.4 times productivity. With other crops also have the same rule: Maize yield increased by 4.1 times in 42 years; Coffee increased by 3.7 times in 28 years (Table 7).
According to 2018 statistics, Vietnam consumed 10.76 million tons of inorganic fertilizers of all kinds (valued at 2.75 billion USD), of which domestic production was 7.69 million tons and imported 4.42 million tons (Table 8).
However, the majority of domestically produced NPK fertilizers use other fertilizers as raw materials. The statistics on fertilizers supplied for agricultural production need to be standardized. According to AgroMonitor (2019), the amount of urea and DAP used for NPK production is 525,000 tons and 280,000 tons respectively, not counting the large quantities of Muriate of potash (MOP, KCl), Sulfate of ammonium (SA, (NH4)2SO4), Monoammonium phosphate (MAP), etc. Therefore, the actual use of fertilizers is around 8.5~9.0 million tons of all kinds and adequately meets the needs of 15 million ha of cultivation with a fertilizer level of around 600 kg of fertilizer/ha or 250~300 kg/ha of N+P2O5+K2O.
In addition, the two main agricultural production areas of Vietnam, the Red River Delta (RRD) and the Mekong River Delta (MRD), are no longer receiving all the sediments as it were before. Red river delta has not had alluvium for many years, while in MRD, floods tend to reduce. Nearly 90% of the years only have small and medium floods (Tran Minh Tuan, 2017). The amount of alluvium flowing through Tan Chau and Chau Doc gate on average from 1997 to 2016 decreased by 720,000 tons/year (2.3% yearly); and decrease by 46% during 20 years. Therefore, together with the increase of two or three rice varieties per year and the lack of alluvium also makes the demand for the increasing of organic fertilizers in Vietnam (Tran Minh Tuan, 2017).
In terms of the amount of organic fertilizer used, it is very unfortunate that countries now have almost no statistics. However, it can be said that in developed countries, the amount of organic fertilizer used is quite large, based on the number of heads of cattle and poultry and the area of food production. According to persistent market research, the size of the world's market for processed organic fertilizer in 2016 was only 17 million tons (valued at 5.57 billion USD), of which organic fertilizers of livestock waste origin (cattle manure, poultry, etc) reached 3.43 billion USD, the remaining is organic fertilizer originated from plant, mainly peat of low quality (Helen Gu, 2019). Europe is the most region that produces and uses organic fertilizer (38%), followed by Asia-Pacific (24%) and North America (21.8%). Currently, Belgium is the largest exporter of organic fertilizer with 1.15 million tons per year, followed by the Netherlands and the United States (Vinachem, 2015). Meanwhile, France is the largest market for processed organic fertilizer. Thus, Vietnam is also one of the world's leading producers of organic fertilizer with the market supply of over 1.2 million tons of organic fertilizer.
Currently, the CAGR (Compound Annual Growth Rate) of organic fertilizers is expected to grow at a rate of 7.1% per year (2 times higher than in the inorganic fertilizer sector) and reach a value of 10.23 billion USD by 2025. Of course, it includes commercially available organic fertilizers, and the large number of on-site organic fertilizers is not yet calculated as followed by Organic Fertilizer market.
The advantages of inorganic and organic fertilizers are very different in agricultural productivity and environmental effect. While inorganic fertilizers are quick-acting, highly specialized, helping plants grow (improve plants growth) and develop at a high rate, with higher yields as compared with organic fertilizers that have a multi-dimensional, multi-functional effect and slower release. In addition to providing balanced, macro, secondary and micro nutrients which inorganic fertilizers do not have in sufficient quantities, organic composts also add organic matter and beneficial microorganisms to the soil. As a result, soil fertility is improved, as well as enhancing the efficiency of inorganic fertilizer in Vietnam. In addition, the toxicity of iron and aluminum is also reduced. On sloping land, light texture (sandy soil, gray soil), organic fertilizers can reduce leaching, soil erosion and nutrient loss. In the dry season, organic fertilizers also enhance drought tolerance of crops increasing moisture holding capacity of the soils, so increasing the amount of water available (Figure 1).
In addition, recent studies show that organic matter increases the ability of carbon to accumulate in the soil, reducing greenhouse gas emissions. When using organic fertilizer, the rate of C absorption into the soil can reach 8,221 kg CO2/ha/year. Thus, with a total world agricultural land area of 4.88 billion hectares (FAO, 2010), if applying 8.2 tons of organic fertilizer/ha we will be able to absorb 40 Gt CO2, equal to 80% of the total global emissions (49 Gt).
However, the use of organic fertilizer also has potential risks of environmental pollution such as heavy metal accumulation or eutrophication of water resources. Many people still think that only inorganic nitrogen fertilizer is the source of nitrate residue in agricultural products. In fact, nitrate can be generated from soil organic matter, farmyard manure, agricultural by-products. In Runnels, Texas (USA), it was found in groundwater up to 3,000 mg NO3/L (the WHO standard is 50 mg NO3/L) which is mainly caused by decomposing organic matter after waste disposal. Studies of PPI with isotope 15N also found that most NO3 was leached out not directly from mineral fertilizer, but from organic matter (Bumb and Baanante, 1996). Research results of Rothamsted (Reference) also have the same conclusion: sources of NO3 leached mostly from organic matter and plant residues. Protein from these sources in the digestion cycles more likely to accumulate longer than in organic fertilizer. Therefore, the application of organic fertilizer, agricultural residue sin conditions of high temperature and heavy rainfall will also be a great source of NO3.
INORGANIC-ORGANIC BALANCE IS THE BASIC OF SUSTAINABLE AGRICULTURAL DEVELOPMENT
The goal of agricultural production is to provide products to make products readily available to the market and in sufficient and best quality.
Many research results have proved that in most types of soil, inorganic fertilizers have a very similar with organic fertilizer. Applying 10 tons/ha of organic fertilizer increases the efficiency of using nitrogen of 30~40%, phosphorus of 20~25% and replacing 30~40% of potassium. The only one practice is the right balance between inorganic and organic both in terms of proportion and dosage for each crop per soil type (Bo et al., 2003;Doberman and Fairhurst, 2000;Helen, 2019).
Development of new generation inorganic fertilizer
Currently, Vietnam is mainly using single inorganic fertilizers or NPK in a blended form. The efficiency of the use is very low (on average, only 45~50% for nitrogen, 35~40% for phosphate, including both residual potency and 55~60% for potassium). Thus, in general about 50% of the inorganic fertilizer used are lost. This not only brings economic losses but also pollutes the environment and increases greenhouse gas emissions.
The current trend of the world is the use of slow release fertilizer (SRF), controlled release fertilizer (CRF) and stabilized fertilizer (SF). General characteristics and typical product types of SRF, CRF and SF fertilizers are presented in Table 9.
Table 10 shows that, among the new generation fertilizer groups, the SF accounted for the highest proportion (68.1% in 2016 and 68.8% in 2018) and also focused on the group which inhibits urea and nitrate metabolism.
The SF fertilizer distribution is shown in Table 11. It shows that North America and North Asia use the majority of these fertilizers, accounting for 5.45 million tons and 2.33 million tons, respectively. The common active ingredients used are N-(n-butyl) thiophosphorictriamide (NBPT) and Dicyandiamide (DCD), of which NBPT is a urea metabolism inhibitor and DCD inhibits nitrate metabolism.
At present, the use of Hydroquinone (HQ) is ineffective due to the high cost because of the need to mix at least 1% of urea, so only East Asian countries use it. NBPT is the most commonly used active ingredient on all continents, due to its lower cost than other active ingredients. However, NBPT is very sensitive to temperature, humidity and pH when pH is 4, NBPT only exists for 12 hours, so it is very difficult to ensure stability and almost impossible to use for conventional NPK fertilizer.
In order to solve the problem of NBPT, fertilizer companies have introduced N-PROTECT inoculant containing 18~50% of NBPT but supplemented with bio-solvent, so the stability time can be up to 1 year. In order to limit the existence of DCD (using a high ratio of mixed gas), NH4- PROTECT can be used on the basis of improving DCD from powder to a solution containing 30% of DCD. The combination of DCD and NBPT or N PROTECT with NH4-PROTECT is also effective. It is also possible to use Avail and similar preparations to improve the efficiency of phosphorus use.
Thus, in addition to improving the nutritional content in fertilizers to reduce transportation costs and quantity of fertilizer, producing specialized fertilizers suitable for each crop, each growth period, each soil type, especially the use of slow-release fertilizers, controlled fertilizers and especially stable fertilizers may increase the use efficiency by 15~20% and reduce the use of traditional fertilizers by 30~35%, improving both farmers' income and contributing to reducing environmental pollution and reducing greenhouse gas emissions.
Developing high quality organic fertilizer
Currently, we are using different sources of information to assume that Vietnam uses about 1.2 million tons of organic fertilizer annually. Moreover, Vietnam's organic fertilizers come from 5 main sources: i) Organic fertilizers industrially produced including bio-organic, microbialorganic and organo-mineral; ii) Manure composted by farmers or farms; iii) Night soils and urine; iv) Green manure; and v) Green manure, crops residues and agricultural by-products and they are not fully estimated. However, the volume of organic fertilizers of all kinds used for crops had declined with a severe imbalance compared to inorganic fertilizers due to the raw materials for organic fertilizer production like livestock manure are being wasted.
According to a survey of the Low Carbon Agriculture Support Project (LCASP) in 10 provinces in 2013 (Table 12), up to 62.1% of livestock wastes were released into the environment and only 10% were used for composting. This is mainly related to the technology of pig raising, using too much water. Partly because people are not aware of the role of compost as well as livestock management wherein animal waste is lost. Similarly, an average of 49% of rice crop residue, straw is burned, up to 75% in some provinces, and only an average of 8.8% used for composting (Table 13). This is the reason why the amount of organic fertilizer for agricultural production is decreasing.
Thus, with the waste of crop and livestock by-products nowadays, we lose millions of tons of nutrients every year (Table 14).
Considering the optimal ratio of nutrients from the organic source which is 30% to balance with about 4 million tons of nutrients (from 9 million tons of inorganic fertilizer) in use, we need about 2 million tons of nutrients from organic sources of all kinds, equivalent to 50~60 million tons of traditional farmyard manure.
In terms of potential, Vietnam can produce the abovementioned amount of organic fertilizer to have an average of 4 tons of organic fertilizer/ha of cultivated land with high quality raw materials like 60~65 million tons of livestock and poultry manure containing about 800,000 tons of nutrients, 50~55 million tons of crop residues (containing about 1 million tons of nutrients). That is not to mention a large amount of unused night soils about 3.5-4.0 million tons. Therefore, we propose some solutions to increase the production of organic fertilizer for the target of 50 million tons/year as follows:
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i) Institutionalize the use of available organic resources, considering cattle, piggery and poultry manure as natural resources instead of releasing into the environment.
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ii) Adopt policies to support and encourage enterprises to produce organic fertilizers. According to the statistics, there are currently 137 enterprises specializing in organic fertilizer production and 88 enterprises producing both organic and inorganic fertilizers with a total registered capacity of nearly 3.2 million tons of organic fertilizer. Although, there is a majority of enterprises producing organic fertilizer based on low nutritional quality like peat. If we support 50 companies with a capacity of 200 thousand tons/year, we will have 10 million tons of processed organic fertilizer, meeting 20% of the country's organic fertilizer demand, and for the remainder, crop and livestock enterprises will produce for onsite needs. However, the government needs to support enterprises with microbial strains to decompose organic material efficiently; together with support capacity building.
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iii) Adjust the structure of animal husbandry, increase the proportion of cattle, and reduce the percentage of pigs to help restructure land use more efficiently to grow fodder crops especially in mountainous and midland, and also more efficient exploitation of crop residues, including biomass of forage and silage. Currently, the proportion of pork in Vietnam's meat structure is very high, accounting for about 72% of total meat production of all kinds, while red meat such as cattle, goat and sheep is only 8.35%. In addition, epidemic disease of a large scale such as avian influenza on poultry, African swine fever, not affect cattle at large scale.
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iv) Currently, in raising pigs, most farmers use too much water for farm cleaning, pig bathing and cooling with the amount of 30~50 liters of water/pig/day. This is an imported technology that reduces labor costs but creates a burden for waste treatment because solid waste collection is very difficult. Therefore, it is essential to develop and expand the application of water-saving technology in pig production. The research results of the LCASP project show that many models of water-saving pig raising technology are very effective, reducing the average from 30~35 to 5~6 L/head/day of water. This model allows the thorough collection of solid waste for manure production, and not discharging liquid waste into the environment.
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v) With liquid livestock wastes, there should be reasonable regulations so that farmers can apply directly to crops after appropriate treatment steps. In the immediate future, when appraising a project to develop farm animal husbandry, commitments should be made to use the entire source of organic fertilizer with solid and liquid types to fertilize its own farm or associate with a crop farm.
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vi) At present, we have over 500 thousand biogas plants of all kinds, mainly small scale (<10 m3). However, with the current operation model, it has not met the goal of both treating livestock waste and providing biogas for daily use. Many small biogas plants are over loaded, untreated waste, unused biogas, discharged into the environment. Therefore, the government needs to adjust the objectives of the biogas program, with the need to use biogas as the target, otherwise, it is necessary to have other solutions to collect wastes for organic fertilizer production.
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vii) Development of technologies to maximize recycling crop residues both during harvest and processing. In particular, crop residues especially straw and rice husks that are rich in potassium can reduce the amount of potassium fertilizer applied by 25~30%, which we annually import 100% about 1.04 million tons in 2018. Incorporation of by-products of the previous crop for the next ones is also important.
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viii) Perhaps, it is time to invest in technology to treat night soils that are rich in plant nutrients. It is necessary to gradually eliminate the “diluting” technology of this waste, by using dry treatment technology.
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ix) Diversification of green manure sources is an effective and radical solution, especially on sloping land, sandy soil and gray degraded soils. In perennial crop farms, intercropping green manure or legume crops should be strengthened. In food production areas, rotation with legumes crops can both generate products as well as contribute to soil improvement.
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x) Encourage the production of organic-mineral fertilizers to improve the nutritional content of fertilizers, to reduce transportation costs.
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xi) Vietnam has a large sea area, which is suitable for seaweed development, so we should soon have a strategy for developing seaweed culture in providing product for human needs and supplying raw materials for organic fertilizer production.
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xii) Strengthen the organization system and human resources to effectively monitor the quality of organic fertilizers from production conditions and technologies, origin and quality of raw materials and product standards to ensure fair and progressive businesses are protected. Organic fertilizers use materials and technologies that are diverse and quality is difficult to stabilize. In addition, it is also necessary to raise people's awareness about environmental pollution in animal husbandry, cultivation as well as the role of organic fertilizer in agricultural production so that they voluntarily collect, produce and use it.
CONCLUSION
Fertilizers have a very important role in agricultural production. For thousands of years, our ancestors summarized that: First, water; second, fertilizer. Recently, the IT billionaire & philanthropist, Bill Gates, also had a very enthusiastic statement: “I am somewhat obsessed with fertilizer. That means I am interested in its role, not how it is used. Every two of the five people on this earth live on the increased crop yields of fertilizer. Fertilizers fuel the green revolution, boost productivity to bring hundreds of millions of people out of poverty. These days, I spend a lot of time creating new technologies to improve people's lives like fertilizers have been and are doing. Also, 40% of the world's population is alive today because in 1909, the German chemist, Fritz Haber invented a method to synthesize ammonia”. Agrium agriculture group also said: “Without fertilizer, we need to increase at least 50% of arable land, equivalent to about 25% of the global forest area to have enough food for 10 billion people”. By 2050, the Food and Agriculture Organization of the United Nations (FAO) believes that food production globally will need to increase by 60% and 77% in developing countries while land area cannot increase.
To ensure food and nutritional security, Vietnam needs to access agriculture in a smart way, namely: i) Market intelligence, ii) Intelligence with specific natural and climatic conditions to best exploit the advantages and iii) Be smart with the investment capacity and technological level, including being smart with the nutrients supplied to plants. Therefore, in the field of fertilizers, the role of any fertilizer should not be to strong and dominant, but balanced. The purpose of agricultural production is to create safe products that meet the diversity of market demands. From this perspective, the balance between nutrition resources suitable for the soil, climate, crops and markets will play a decisive role. For developing countries like AFACI members, organic agriculture is and will be a important share of agricultural production, especially for premium market. However, non-organic agriculture will still play an important role in ensuring national food security.
적 요
비료는 작물 재배 및 생산성 증대를 위해 필수 농업자재이 다. 식량안보 및 영양결핍 해소를 위해 베트남에서는 스마트 한 방법으로 농업의 혁신을 가속화하고 있다. 작물 생산의 주 된 목적은 시장 요구에 맞는 안전한 농산물을 재배하는 것으 로 본 논문에서는 작물 생산 측면에서의 베트남의 화학비료 및 유기비료에 대한 현황 등을 소개하였다.
1960년대부터 최근까지 베트남의 비료 역사와 작물 재배에 있어 화학비료와 유기비료의 현황 등을 소개하였다. 베트남에 서 대부분의 작물 재배에 있어 화학비료와 유기비료를 7:3의 비율로 사용하는 것을 권장하였다. 그러나, 무엇보다 토양, 기 후, 작물 및 시장의 요구에 맞게 양분 균형을 이루어지게 활 용하는 것이 중요하다고 제안하였다. 또한, 완효성 비료 등 차 세대 글로벌 시장의 비료 산업에 대한 전망도 제안하였다.
