Cluster sowing - fertilizer burying: The 'perfect couple' in rice cultivation

Superior results to other forms of seeding

Cluster sowing, also known as position sowing or seed transplanting, is a seeding solution that is receiving attention from farmers across the country, especially in the Mekong Delta region, due to its superior efficiency.

Cluster sown fields only use the minimum amount of seed (40–60 kg/ha), thereby helping to reduce the amount of fertilizers and pesticides used, emissions, environmental pollution, and falls, and at the same time, increase productivity, quality, and economic efficiency of rice production.

Moreover, if cluster sowing is combined with the solution of burying fertilizer at the same time as sowing, the advantages of cluster sowing will be more thoroughly exploited while adding the following advantages:

• Reduce fertilizer loss, especially nitrogenous fertilizer due to evaporation or drifting with the water flow if water overflows the field surface, and thereby also reduce environmental pollution.
• Stimulate rice roots to grow deeply, helping to limit rice fall, especially in the summer-autumn and autumn-winter crops, while increasing the drought tolerance of rice fields if they encounter drought or salinity at the end of the winter-spring crop.
• Fertilizer is buried close to the rice cluster, helping the rice cluster to access and get fertilizer easily, limiting the loss of fertilizer to surrounding weeds, thus helping to improve fertilizer use efficiency.
• Save labor costs due to a decrease in the frequency of fertilization.
• Especially, burying fertilizer at the same time as sowing will provide nutritional minerals to rice promptly, right from the first days after sowing, ensuring rice’s mineral needs and helping rice grow strongly, tiller early, tiller concentrated buds, thereby ensuring the number of buds and flowers per m2 for maximum yield.

With the above advantages, the solution of burying fertilizer can help reduce the amount of fertilizer by 20–30% compared to the process of fertilizer spreading on the field that has been done for a long time.

The above-mentioned advantages have been recorded by many experiments

Saigon Kim Hong has coordinated with fertilizer businesses and localities to deploy the cluster sowing-fertilizer burying model in some localities in the Mekong Delta from the 2021–2022 winter–spring crop to the 2023 summer–autumn crop. The model’s actual results have affirmed the superior advantages of cluster sowing-fertilizer burying solution. Specifically, as follows:

1. Model site at Vinh Thanh Trung - Chau Phu - An Giang in the 2021–2022 winter–spring crop

The model used Dau Trau growth-promoting fertilizer and Dau Trau grain-firming fertilizer from Binh Dien Fertilizer JSC (Dau Trau fertilizer), with the following results:

• On a base of fertilizer spreading of 300 kg of growth-promoting Dau Trau and 150 kg of grain-firming Dau Trau (81 N - 45 P2O5 - 47 K2O), the rice yield of the manual sowing model reached 5.15 tons/ha. Meanwhile, on the base of fertilizer burying, only 240 kg of growth-promoting Dau Trau and 150 kg of grain-firming Dau Trau (70 N - 39 P2O5 - 43 K2O) were used. Despite a 20% reduction in the amount of growth-promoting Dau Trau compared to the manual sowing model, the yield of the cluster sowing-fertilizer burying model reached 5.66 tons/ha (an increase of 0.51 tons/ha-10%) compared to the manual sowing-fertilizer spreading model.
• Accordingly, the cluster sowing-fertilizer burying model achieved a profit of VND 12,892,000/ha, VND 4,422,000/ha higher than the manual sowing-fertilizer spreading model, which only reached VND 8,470,000/ha (an increase of 52%).

2. Model site in 6 districts: Chau Phu, Chau Thanh, Cho Moi, Phu Tan, Thoai Son, and Tan Chau-An Giang in the 2023 summer-autumn crop.

The buried fertilizer used in the model is NPK fertilizer, produced and distributed by Binh Dien II Fertilizer Production and Trading JSC (2 Phong fertilizer). The fertilizer includes two preparations: (1) "green rice" preparation used as fertilizer to promote tillering with a recommended amount of 240–260 kg/ha; and (2) "firm grain" preparation used as fertilizer to stimulate young rice with a recommended amount of 80–120 kg/ha.

The model gives truly remarkable results, as follows:

• Due to buried fertilization, the model field proactively reduces the amount of "green rice" fertilizer by 20% compared to the spreading fertilization process. Accordingly, the model field’s amount of pure fertilizer (61 N - 37 P2O5 - 29 K2O) is much less than that of the control field (108 N - 55 P2O5 - 44 K2O), but rice still grows and develops well.
• Although the amount of fertilizer in the model field is only 80% of that in the control field, rice in the model field yielded highly: 6.82 tons/ha, 0.54 tons/ha (8.6%) higher than in the control field of 6.28 tons/ha.
• The total profit of the model field reached VND 25,546,056/ha, VND 6,423,792/ha (33.6%) higher than that of the control field, which only reached VND 19,122,264/ha.
• The model rice fields are sown thinly using the cluster sowing method. The rice fields receive full light on a balanced fertilizer base and are buried with fertilizer to help the rice roots grow deeply, so rice grows in a balanced manner with quite good limitations on the situation of falling compared to the control field.

3. Model site at Tri Ton - An Giang in the 2023 summer-autumn crop

The model used Dau Trau growth-promoting fertilizer and Dau Trau grain-firming fertilizer from Binh Dien Fertilizer JSC (Dau Trau fertilizer), with the following results:

• On a fertilizer base of 300 kg of growth-promoting Dau Trau and 100 kg of grain-firming Dau Trau (77 N – 40 P2O5 – 32 K2O), the rice yield of the manual sowing model reached 5.4 tons/ha and that of the cluster sowing-fertilizer burying model reached 5.83 tons/ha. Meanwhile, on a fertilizer base of 210 kg of growth-promoting Dau Trau and 100 kg of grain-firming Dau Trau (60 N - 29 P2O5 - 27 K2O), although the amount of fertilizer is reduced by 30% of growth-promoting Dau Trau compared to that of the models of manual sowing and cluster sowing with spreading fertilization, the yield of the cluster sowing-fertilizer burying model reached 6.33 tons/ha (an increase of 0.93 tons/ha, or 17.2%) compared to the manual sowing-fertilizer spreading model and 0.50 tons/ha (an increase of 8.6%) compared to the cluster sowing-fertilizer spreading model.
• Accordingly, the cluster sowing-fertilizer burying model achieved a profit of VND 30,640,000/ha, the cluster sowing-fertilizer spreading model achieved a profit of VND 25,175,000/ha, and the manual sowing-fertilizer spreading model achieved a profit of VND 21,841,000/ha. It means the profit of the cluster sowing-fertilizer burying model is VND 8,799,000/ha (40.2%) higher compared to the manual sowing model and even VND 5,465,000/ha (19%) higher than the cluster sowing-fertilizer spreading model.

The above actual results show that the cluster sowing model, especially cluster sowing combined with fertilizer burying, brought truly remarkable results.

Thereby, it can also be affirmed that cluster sowing has much more advantages than manual sowing. At the same time, if cluster sowing is combined with fertilizer burying at the same time as sowing, the above-mentioned advantages will be thoroughly exploited and bring superior results to other forms of seeding. Therefore, it can be said that cluster sowing combined with fertilizer burying is the "perfect couple" in rice cultivation.

Dr. Bui Ba Bong, former Deputy Minister of Agriculture and Rural Development:

"As for rice cultivation, the current limitation is the low rate of mechanization application in the sowing stage. Looking back a few years ago, at that time the transplanter was considered very good, but when implementing it, the cost was still high, and the stages of making seedlings and growing media encountered difficulty. Up to now, the solution of cluster sowing by machines is feasible, and if it can cover the fields in the next five years, it will be a huge development step."