[Farm Machinery Spotlighted at KIEMSTA] Kubota Multipurpose Combine ZRH1200 Reduces Soybean Breakage with Flail-Type Threshing

As more farms plant soybeans instead of rice in paddy fields, requirements for harvesting equipment are also changing. Soybeans bear pods starting close to the ground, so they must be cut as low as possible, and if the kernels break during threshing, farmers lose out on procurement grades. If there are many broken soybeans, they must go through a sorting facility again before delivery. Farms that grow barley along with soybeans also need to consider whether one machine can harvest both crops. At the “2026 Korea International Exhibition of Machinery, Equipment, Science and Technology for Agriculture (KIEMSTA),” held at EXCO in Daegu from the 4th to the 7th, Korea Kubota showcased the “ZRH1200” multipurpose combine as its flagship product. It was launched domestically in March last year and was exhibited at KIEMSTA for the first time.
 

The “Miracle Bar” threshes by striking…reducing soybean damage and resisting clogging

The biggest feature of the ZRH1200 is its threshing method called the “Miracle Bar.” Existing head-feeding combines (for rice harvesting) have triangular cone-shaped protrusions, or threshing teeth, on the threshing drum and strip grains off, while the ZRH1200 has long rods on the threshing drum that strike the soybean stems like a flail.

Min Hong-gi, head of Korea Kubota’s agricultural machinery procurement team, who says he grows soybeans himself, said, “When soybeans are dry, they pop open with just a light strike, so there is no need to forcibly tear them off,” adding, “Kernels that undergo a lot of stress during threshing crack immediately later during the drying process to adjust moisture.” Unlike rice, whose grains are firmly attached to the ears and must be stripped off to fall, soybeans need a different threshing method because their pods burst open with a light strike when dry, he explained.

Because it is constructed with rods, there is empty space inside the threshing drum. Existing threshing drums filled with steel plates and threshing teeth clog up when a large amount of crop enters at once, but the ZRH1200 has space for crops to escape, reducing the load. The threshing drum is a large-diameter unit measuring 620 mm in diameter and 2,210 mm in length.

The way clogs are handled has also changed. Previously, the operator had to get down, lift the feed section, pull out the stuck crop by hand, or rotate it manually with a rod. The ZRH1200, however, is equipped with a reverse-rotation gear, so pressing a button from the operator’s seat ejects the stuck crop and then work can continue. Team leader Min said, “Because soybeans hang low, unmanaged weeds can get caught, and if the crop condition is very good and too much enters at once, it can also clog,” adding, “What matters is not the clogging itself but how quickly you recover when it clogs.”
 

2.6 m working width and 2.3-ton grain tank…10,000 pyeong in 8 hours

The engine produces 118 horsepower, and the working width is 2.6 m, allowing up to three soybean rows to be harvested at once. Skilled operators can work up to four rows. The grain tank capacity is about 2.3 tons by design, but considering machine load, it is generally filled to around 2 tons in actual use. It is also equipped with a function that automatically levels the cutting section and the body, as well as 550 mm wide and 2,160 mm long crawlers to reduce sinking even in wet paddy fields.

Regarding work speed, team leader Min said, “Based on my own experience operating it, it can handle about 10,000 pyeong (approximately 33,058 square meters) in an eight-hour day,” adding, “Compared with small models from 10 years ago, it is more than twice as fast in terms of area.”

It is also equipped with functions that assist the operator. “Auto Accel” keeps engine rpm at maximum during straight-line work and automatically lowers it when turning to reduce fuel waste. “One-touch lodging control,” used when harvesting lodged soybeans, slowly rotates the front reel with a single button to lift the crop while taking it in.

Team leader Min explained, “You can think of the reel (rotating rake) as a person’s hand. If it turns too fast, the crop bounces upward, and if it turns too slowly, it fails to feed and spills,” adding, “With older models, the operator had to judge and operate everything manually, but this function partially assists with areas beginners are not good at.”
 

A variety of crops can also be harvested by simply changing kits

As a multipurpose combine, it can harvest multiple crops by changing kits. The barley kit is installed as standard, and the soybean kit is provided as well. The barley kit has a closed bottom steel plate to prevent kernels from leaking downward, while the soybean kit has holes to shake out soil brought in during the low-cutting process. Crops can be switched by changing only a few parts, such as pulleys, and the settings.

For crops with small kernels, such as red beans, mung beans, buckwheat, and sprouting soybeans, the sieve (screen) kit can be replaced. The soil-shaking sieve in the soybean kit has holes of about 5 mm, so small kernels like red beans fall out together with the soil. For these crops, it must be replaced with a 2.5 mm sieve. However, it cannot be used to harvest rice. 

Team leader Min said, “Among nearby farms, there are some that have shifted from rice farming to soybeans, and those who grow soybeans and barley together use this machine.” In terms of work speed alone, a head-feeding combine for rice harvesting may be ahead, but for farms that do not have a head-feeding combine, this machine is sufficient, he explained.