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Cutting height is one of the most important adjustments on a silage header. It affects silage quality, soil contamination, fuel efficiency, and crop regrowth. Proper silage header cutting height settings balance yield and feed value. Setting the header too low picks up soil and ash, which reduces digestibility. Setting it too high leaves valuable feed in the field. This article explains how to determine the optimal cutting height for different crops, how to adjust your header, and how these principles relate to other headers—such as when you need how to adjust a sunflower header (covered separately). Shijiazhuang Tianren Agricultural Machinery Equipment Co., Ltd. provides wear parts and adjustment components for silage headers.
For disc headers (corn, sorghum):
Locate the header lift cylinders (manual or hydraulic).
On most headers, gauge wheels or skid shoes control minimum height. Adjust the gauge wheel brackets.
Use the harvester’s header height control system (if equipped) to maintain a set height automatically.
For manual adjustment: lower the header until the discs are at desired height above ground. Lock the hydraulic or mechanical stops.
For pickup headers (grass):
Adjust the front roller or skid shoes.
The cutting height is determined by the position of the cutter bar relative to the skids.
Typical setting: cutter bar 6–8 cm above ground for grass.
Measurement tip: Use a tape measure on level ground. Lower the header, stop the engine, and measure from the tip of the disc knife (or cutter bar) to the soil surface. Repeat in three locations.
Soil contamination and ash content: Every centimeter of cutting height reduction below 15 cm increases ash content by approximately 0.5–1.0% dry matter. Silage with over 8% ash (on a dry matter basis) indicates significant soil pickup. High-ash silage reduces intake by dairy cows.
Effect on starch content in corn: The lower stalk has high fiber and low starch. Raising cut height from 10 cm to 20 cm removes the fibrous butt and increases the proportion of grain in the harvested mass. Starch content can rise by 2–5 percentage points.
Harvest speed interaction: A lower cut height (5 cm) forces the header to handle more material per meter, reducing ground speed by 10–15% for the same power. Raising the cut height to 20 cm allows faster travel.
Choose a representative area of the field.
Set the header to your starting height (e.g., 15 cm for corn).
Harvest 20–30 meters at normal speed.
Stop and check stubble height in three spots. Use a ruler to measure from ground to the top of the cut stalk.
Check the silage sample for soil particles (look for gray or black specks) and length of cut.
Adjust the header height or gauge wheels by 2–3 cm and repeat step 3–5.
Lock the setting when you are satisfied.
Q1: Can I set the same silage header cutting height settings for all fields?
A: No. Adjust based on soil type, crop maturity, and regrowth requirements. Sandy soils tolerate lower cuts better than clay soils because less soil sticks to the cutter.
Q2: How do I know if my cutting height is too low?
A: Look for these signs: excessive dust during harvest, gray ash on the silage surface after fermentation, and worn skid shoes or knives after short use. A laboratory ash test over 7% DM confirms the problem.
Q3: What is the relationship between cutting height and kernel processing?
A: Lower cut height does not directly affect kernel processing, but it adds more stalk fiber, which can dilute the effect of a kernel processor. For best results, combine a moderate cutting height (15–18 cm) with a properly set kernel processor.
Q4: How do I adjust cutting height on a header without gauge wheels?
A: Use the harvester’s hydraulic header height control. You must manually monitor and maintain height by watching the stubble. This requires a skilled operator and is less consistent than gauge wheels.
Q5: Does Shijiazhuang Tianren Agricultural Machinery Equipment Co., Ltd. offer components to help maintain consistent cutting height?
A: Yes. The company supplies skid shoes, gauge wheel arms, and wear plates that, when kept in good condition, help maintain accurate silage header cutting height settings. Worn skid shoes cause the header to cut lower on one side.
Q6: Can the same principles apply when learning how to adjust a sunflower header?
A: Partially. For sunflowers, cutting height is measured from the head, not the ground. The goal is different (remove only the head). However, the method of using gauge wheels and checking stubble length is similar.
Some modern forage harvesters offer automatic header height control using ultrasonic or laser sensors. These sensors measure the distance to the ground or crop. They maintain a preset cutting height even on rolling terrain. If your machine has this feature, calibrate it on level ground first. The calibration procedure usually involves lowering the header to a known height (e.g., 15 cm) and teaching the sensor that position. Without calibration, automatic systems may drift and cut too low or high.
Proper silage header cutting height settings improve silage quality, reduce soil contamination, and lower fuel use. For corn silage, a height of 15–25 cm is recommended. For grass, 6–10 cm. Always adjust based on field conditions and crop type. Combine correct settings with a well-maintained header and sharp knives. Shijiazhuang Tianren Agricultural Machinery Equipment Co., Ltd. provides the replacement parts needed to keep your header operating at the desired height. For information on other headers, see our guide on how to adjust a sunflower header.