Can a Wheat Combine Harvester Harvest Soybeans? Detailed Operating Instructions

Since last year the state began implementing the “rice-to-soybean” policy, and many farmer friends started growing soybeans, which made harvesting a troublesome matter again. So can a wheat harvester harvest soybeans? How do you use a wheat combine harvester to harvest soybeans? Can a wheat harvester harvest soybeans? This article provides a detailed introduction and explanation of methods for using a wheat combine harvester to harvest soybeans, such as reasonable adjustment to reduce losses and reasonable use to improve work quality.

First, a wheat harvester can indeed harvest soybeans, but some modification is required; of course, some machines do not even need modification, and you only need to pay attention to the method of use.

Reasonable adjustment to reduce losses

1. Control header losses.

In soybean harvesting, header losses generally account for more than 80% of total losses. Controlling header losses should start from 3 aspects: reducing missed cutting, dropped branches, and pod shattering.

(1) Reduce missed cutting. The current ridge spacing is generally 65-70 cm. Taking the 3060 model combine harvester as an example, the flexible soybean header has a cutting width of 2.75 m, and each pass cuts exactly 4 ridges, so the main cause of missed cutting lies in the stubble height. If the stubble is too low, pile-up in front of the header easily occurs; if the stubble is too high, "horse-ear stubble" and cutting of the bottom pods easily occur. The lowest pod-setting height of soybeans is generally 6-8 cm. Therefore, controlling the stubble within 4-6 cm will prevent "horse-ear stubble." However, pile-up sometimes occurs, and at this time the bottom drag plate of the header can be adjusted to reduce pile-up.

(2) Reduce losses from thrown and dropped branches. Thrown branches are mainly caused by improper reel speed (too low or too high), and this can be solved simply by paying attention to adjustment during operation. Dropped branches are mainly caused by uneven plant height or lodged plants; at this time, after the stems are cut, the soybean branches are not guided into the header, fall vertically or topple sideways, and after being cut a second time by the cutter fall under the header. The solution is to appropriately adjust the reel height or, when the feed amount allows, increase the machine speed.

(3) Reduce pod shattering losses. Reduce the impact and pulling of the cutter on the plants, ensure the cutter is sharp, and ensure the cutter clearance meets requirements; adjust the tension of the wobble box drive belt to prevent a drop in cutting speed caused by belt slippage, which affects cutting quality; reduce the striking and scraping of the reel against soybean stems and pods. In the early harvest period, soybean branches have a relatively high moisture content, so the reel speed can be appropriately higher; in the late period, soybean branches are dry and pod shattering easily occurs, so the reel speed should be lower. In addition, try not to let the reel teeth strike soybean branches directly; reel bats should be installed on the reel.

2. Reduce machine body losses.

(1) Control grain wrapping losses. Avoid harvesting crops that are too wet, when the grain moisture exceeds 19% (plants bend without breaking), because no matter how you increase the rotating speed, reduce the clearance, or increase the air volume, the problems of incomplete separation and soybean hulls wrapping grains cannot be solved. (2) Control incomplete threshing losses. Soybean threshing uses the impact, rubbing, and squeezing action of the rasp bars on the pods. The cylinder and concave mainly strike the front half of the soybean branches and mainly rub and squeeze the rear half. During this process, 60%-90% of the soybean grains are separated out through the concave grid, so the factors affecting threshing quality include the rotating speed of the threshing cylinder, the threshing clearance, the crop condition, and the feeding condition. Under normal circumstances, when harvesting soybeans, the rotating speed of the threshing cylinder can be selected as 715 r/min, the rotating speed of the separating cylinder can be selected as 608 r/min, the forward speed of the harvester is gear II, and the feed amount is controlled by stepless speed change. (3) Control entrainment losses. Adjust the fan air volume as large as possible, that is, increase the fan speed, and at the same time adjust the opening of the chaffer sieve to the maximum and raise the tail sieve angle. This can reduce soybean entrainment losses and improve grain cleanliness.

Reasonable use to improve work quality

1. Reduce the breakage rate.

Reducing the soybean breakage rate mainly starts from the following aspects.

(1) Harvest at the right time. Because soybeans go through multiple processes during harvest, including reeling, cutting, conveying, threshing, cleaning, and grain discharge, the grains are subjected to rubbing and impact in each process, and the grains must have sufficient strength and hardness not to break. When the grains are too wet, their hardness is low, their resistance to rubbing is poor, and they are easily flattened; when the grains are too dry, their toughness is poor, their strength is low, they are not resistant to impact, and they are easily broken by high-speed strikes. (2) Correctly select the threshing cylinder speed and clearance. In the early harvest period, the grain moisture is high and threshing is difficult, so the cylinder speed should be selected as 715 r/min, the inlet clearance as 20-28 cm, and the outlet clearance as 8-10 cm, with the left and right clearances kept consistent. In the early, middle, and late harvest periods, adjustments should be made according to the dryness and wetness of the stems. In the late harvest period, soybean branches are dry and easy to thresh and break, so the threshing cylinder speed should be selected as 500 r/min, the inlet clearance as 28-35 cm, and the outlet clearance as 10-16 cm. The selection of the threshing cylinder speed should follow the principle of complete threshing and no clogging, and the threshing clearance should be as large as possible on the premise of ensuring that no grains are entrained in the separated soybean stems. Such adjustments can both ensure complete threshing of the crop and reduce the breakage rate. (3) Correctly adjust the tightness of scraper chains such as the feed chain rake, grain elevator, and tailings elevator. If too loose, the chain and sprocket teeth easily crack the soybean grains. (4) Try to avoid clogging of conveying parts such as the threshing cylinder, rethresher, and grain and tailings augers to reduce soybean grain breakage.

2. Reduce soybean "muddy faces."

When harvesting soybeans, a very low stubble is required, and occasionally improper operation allows soil to enter the header, causing "muddy faces" on the soybeans. For this reason, several points should be noted during harvest.

(1) Harvest in a dry state. Because when the soil is moist, there is frost on the soybean branches, or the grain moisture is high, "muddy faces" are easily produced. (2) Install a soil retaining plate behind the cutter so that soil clods are difficult to bring into the header. (3) Clean soil from the header, concave, or sieve surface in a timely manner. (4) Add some small holes to the bottom flap of the grain elevator (the hole diameter must not exceed 4 mm) so that soil entering the machine body leaks out through the small holes.