Post-harvest preservation of agricultural products: Many challenges remain.

(Baonghean)The majority of farmers and production and business establishments harvest and process using manual methods, and the capacity for research and development of machinery for preservation, processing, and harvesting in our country is still limited... Therefore, the economic loss after harvest of agricultural products such as corn, peanuts, rice, vegetables, and beans is quite significant.

Mr. Tran Tuan, residing in Hamlet 5, Dinh Son Commune (Anh Son District), dries corn using traditional methods.

We visited Dinh Son commune, Anh Son district, in early April, during the peak of the winter corn harvest season on the Lam River floodplain. Ms. Nguyen Thi Ly from Hamlet 3, Dinh Son, who was harvesting corn, said: "This year's corn crop is good, averaging over 3 quintals per sao (approximately 300 kg per 1000 square meters), but the weather during the winter harvest was unpredictable, with alternating rain and sunshine. The corn couldn't be dried properly, so the kernels became damp and sprouted, forcing us to sell them at a low price." Ms. Ly calculated: "My family cultivated 3 sao and got 9 quintals of corn, but 1 quintal was ruined due to mold. The rest, not properly dried, could only be sold at 3,500 VND/kg, bringing in 2.8 million VND (the loss of 1 quintal of corn due to mold alone amounted to 350,000 VND)." Mr. Tran Tuan, from Hamlet 5, Dinh Son – a corn purchasing facility – said: “This winter, my facility purchased over 30 tons of corn from the farmers. Due to the gloomy weather these past few days, most farmers sold their fresh corn to us, at prices ranging from 3,500 to 3,800 VND/kg. We had to invest in hundreds of square meters of tarpaulin to spread out and dry the corn for 2-3 days before selling it to wholesalers in Hanoi and Hai Phong.” Mr. Tuan added: “The corn purchasing business is quite risky, because if it rains and gets cold for a long time, we can’t dry it and sometimes lose money.” I asked Tuan why he didn’t invest in a drying oven for the corn, and he explained: “Drying corn using electricity and coal, like some northern provinces do, is too expensive, so we have to utilize the drying process to make a profit.”

Along the alluvial plains of the Lam River, many households are facing a surplus of corn due to the weather. For example, Mr. Tran Van Kien's household in Thach Son harvested 2.5 tons of corn, but 200 kg of it became moldy, and he has only managed to sell 1.7 tons. Similarly, Ms. Vi Binh's household in Hamlet 5, Hoa Son commune, harvested 1.5 tons of corn but has only sold 1 ton.

Mr. Nguyen Van Hieu, Chairman of the People's Committee of Dinh Son commune, said: "The entire Dinh Son commune has over 200 hectares of corn. The most difficult challenge is the winter corn crop. Due to the weather, although the corn crop was good, achieving a yield of 6 tons/ha, the corn was affected by mold, resulting in economic losses. The commune advises farmers to regularly monitor the weather during the corn harvest to ensure that the harvested corn is not exposed to rain and waterlogging. The commune hopes that the district will have a post-harvest processing facility, such as building a large drying oven specifically for drying corn, so that farmers no longer have to worry when the harvest season arrives."

According to Mr. Nguyen Cong The, Head of the Agriculture Department of Anh Son District, Anh Son is the province's corn granary with over 3,000 hectares of corn. Post-harvest preservation faces many difficulties that have yet to be overcome. Farmers mainly sell fresh corn to purchasing facilities or dry it manually. Previously, some households invested in drying ovens, but due to the high cost, they have not used them.

Not only corn, but peanuts also face many difficulties after harvest. Dien Thinh peanuts (Dien Chau district) have long been considered top quality in the province; however, poor post-harvest preservation has led to the product not meeting export standards. Most traders buy them and export them through unofficial channels to China, often forcing down prices. Ms. Hoang Thi Thanh from Hamlet 9, Dien Thinh commune, Dien Chau district, shared: "We cultivate 4 sao (approximately 0.4 hectares) of peanuts, with an average yield of 1.8 quintals per sao. After harvesting, we usually store them to 'wait for better prices,' but because the storage conditions are not adequate, the peanuts often lose their color and become damp after only 1-2 months. Therefore, when we sell them, traders are often picky and force down the price."

Corn, peanuts, vegetables, and even oranges, the processing methods to enhance their value are still very limited. Thanks to the application of technical advancements in intensive farming, the average yield of orange orchards in Yen Khe, Con Cuong, and Minh Hop - Quy Hop is high. With a large orange production, post-harvest preservation is very important for orange growers, ensuring that the oranges stay fresh longer, fetch a good price, and are not harmful to consumers. In the 2013 orange harvest season in Yen Khe commune, the oranges ripened, and the difficult market conditions led to a massive fruit drop. Farmers lacked guidance on post-harvest preservation technology, causing significant economic losses. For example, Mr. Nguyen Hoa's family in Tan Huong village lost over 30 tons of Van Du oranges, and the entire commune, with 50 hectares of orange trees, suffered over 100 tons of fruit damage. Even in the specialized orange-growing area of ​​Xuan Thanh Agricultural Company Limited, a considerable amount of fruit was damaged during the ripening season. Nguyen Minh Ly from Minh Hop commune, Quy Hop district (belonging to Xuan Thanh Agricultural Company Limited) recounted: There were times when, due to not being able to sell the oranges in time, they spoiled. For example, in 2013, my family cultivated 3 hectares of oranges, but 500 kg spoiled, at an average price of 35,000 VND/kg.

Mr. Tuan Bay from Hamlet 2, Dien Thinh, Dien Chau, offered a good solution for preserving peanuts. Although peanuts are sun-dried, they can still become moldy if stored in bulk in warehouses. The best way to preserve peanuts is to store them in silos. Silos are cylindrical tubes with a conical bottom, 30-35 cm high, and a tight-fitting lid to keep peanuts cool or airtight. Silos are usually made of metal or enameled metal. They are widely used in India, primarily for storing rice and peanuts, reducing product spoilage and labor costs. In Dien Thinh, there are dozens of peanut purchasing businesses, but none have yet invested in silos due to the high cost. A silo that can hold 20 tons of peanuts costs between 150 and 200 million VND.

Regarding oranges, it is known that in the last two years, orange growers in Bac Cam district, Ha Giang province, have been using post-harvest technology by spraying Kivica on the trees and fruits. This slows down ripening and causes uneven ripening on the same tree or in the same orchard, extending the harvest time by more than a month compared to normal oranges. Spraying Kivica can be effectively applied to early-ripening orange varieties like Van Du in Yen Khe - Con Cuong. In addition, farmers in Ha Giang also preserve oranges using semi-permeable technology, applying BOQ-15 by evenly coating the oranges before storing them in warehouses. This technology has the advantage of being non-toxic, and the oranges can be used immediately after preservation. Mr. Vi Van Dau, Chairman of the People's Committee of Yen Khe commune, Con Cuong district, believes that if oranges can be preserved after harvest, it will not only prevent losses for orange growers but also alleviate the worry of a bumper harvest leading to low prices.

It can be said that post-harvest preservation of agricultural products is one of the most important stages in the production process, both preserving products from spoilage and enhancing their value, creating a stable supply when sold to the market. Therefore, farmers urgently need investment from relevant sectors in post-harvest science and technology research, as well as support in terms of both finance and knowledge to meet the requirements for preserving and improving the quality of agricultural products.

Van Truong