Automatic length of cut (AutoLoc™) improves bunk density


  1. HarvestLab™ — dry matter and ingredients on the go
  2. Manual control (operator)
  3. AutoLoc — automatic control
  4. Infinitely variable length of cut (IVLOC™) — length of control changes on the go
AutoLoc, first introduced by John Deere, brings added value to the HarvestLab sensor and John Deere self-propelled forage harvester (SPFH). AutoLoc works in conjunction with the HarvestLab sensor and IVLOC transmission to automatically adjust the length of cut, based on crop-dry matter levels, to improve bunk density and reduce long particles in dry corn. Nutritionists, herdsmen, and SPFH operators will all benefit from this innovation.

John Deere is leading the industry in providing real-time information that matters most to forage production. Quality forage comes from properly packed silage, which is directly related to the dry matter content and length of cut of the crop.
Length-of-cut changes are made automatically in the field based on dry matter readings and predetermined settings determined by operator requirements. No in-field calibration is required to load the length-of-cut (LOC) requirements; the operator simply uses the GreenStar™ display to program the desired LOC settings at different dry matter levels.
When dry matter levels of crop in the field change, the IVLOC drive automatically responds to either increase or decrease the feedroll speed, which in turn changes the LOC. If dry matter levels of the crop are outside of the desired range, the IVLOC transmission adjusts and limits the LOC, based on the maximum and minimum LOC settings, as determined by the operator.

Why AutoLoc is a must to ensure silage quality and overall profitability

It impacts the silage compaction in the bunker to ensure the quality of feed being stored is of the best quality possible.

Silage density and AutoLoc

Good silage starts with high bunk density to preserve the crop value. This is the main objective for both dairy/beef producers and also for biogas plants. Many factors are involved in achieving high bunk density, including type of crop, dry matter levels, length of cut, and bunk filling speed.
Some of these factors cannot be easily changed while harvesting. AutoLoc adds an improved sense of control to the harvesting and silage storage operation. Now, operators do not need to compromise when choosing the proper length of cut based on dry matter. AutoLoc takes care of this chore automatically.
Oftentimes, producers are so focused on getting the job done that important tasks and details are overlooked during the harvesting operation. Knowing the growing period for corn silage covers five months growing in the field and only a few days harvesting for 10 to 12 months of feeding, the process of the silage harvest and storage should be managed as well as possible.
The impact of the silage quality, which can be harvested and stored in just a few days, can have a huge impact on income throughout the entire year. The silage cost is a major part of the expenses in the dairy/beef and biogas plant businesses. Poor forage quality can cost tens of thousands of dollars per year in increased feed costs resulting in the producer having to invest in additional silage to reach the desired feed ration.
Spoilage/reheating and seeping losses are the biggest problems in silage bunks. These problems often happen due to insufficient compaction and an incorrect LOC. In order to achieve the right amount of silage compaction and keep as much air out of the silage as possible, the LOC has to be adjusted according to the dry matter levels of the crop - the wetter the material, the bigger the particle size.
While varying lengths of cut can dramatically help to achieve high density levels, the length of cut of the material must be consistent in order to maintain normal rumination, chewing, and saliva production in the rumen. If the particles are too small, the food does not fit anymore with the process of the cow rumen and the compaction becomes difficult due to the instability of the material.
For this reason, John Deere created AutoLoc, which automatically adjusts the length of cut to the dry matter value, while staying within the preset LOC range.
Having some limited LOC variations in a bunk silo should not affect the effective fiber in the ration on a daily basis. Using AutoLoc in conjunction with upright or bag silos can vary the effective fiber fed to animals on a daily basis.

Looking at the studies done by Honig and Rohr in 1985, as can be seen in the following table, it is possible to get high-density levels of dryer crop when the crop is chopped at a shorter LOC.

Length of cut

mm (in.)

Bunk density, kg/m3 (lb/ft3)

27 percent dry matter 36 percent dry matter

4 mm (0.16 in.)

205 kg/m3 (12.8 lb/ft3)

179.7 kg/m3 (11.2 lb/ft3)

7 mm (0.28 in.)

192.2 kg/m3 (12.0 lb/ft3)

174.6 kg/m3 (10.9 lb/ft3)

14 mm (0.55 in.)

173 kg/m3 (10.8 lb/ft3)

157 kg/m3 (9.8 lb/ft3)

AutoLoc screen

AutoLoc screen

AutoLoc chart

AutoLoc chart

AutoLoc solves the dry matter and LOC puzzle

On-the-go, accurate LOC adjustment is unique in the market. John Deere AutoLoc is linked to the HarvestLab sensor, which measures the dry matter and ingredient content on the go with more than 4000 measurements per second, using the most accurate technology in the market — near-infrared technology.

According to the accurate dry matter readings, AutoLoc is able to adjust the proper LOC automatically in steps as small as 1 mm (0.04 in.). This process is faster and more accurate than any operator could do manually because of all the other important operating functions being performed. This can increase overall efficiency dramatically.
With AutoLoc, the SPFH operator simply sets the minimum, optimum, and maximum dry matter levels and the corresponding lengths of cut. AutoLoc then creates a linear curve between the minimum and the optimum and between the optimum and the maximum. LOCs are then determined based on those lines.
For example, if the optimum LOC were set to 15 mm (0.59 in.) at 68 percent dry matter and 8 mm (0.31 in.) at 50 percent dry matter, and the actual dry matter of the crop was 63 percent, AutoLoc would change the length of cut to be 13 mm (0.51 in.) based on the linear curve it created.
Forage harvester performance and AutoLoc

The following equipment is required for AutoLoc functionality:
  • GS 2 or 3 system
  • HarvestLab sensor
  • 9000 Series Self-Propelled Forage Harvester
Last Updated : 26-Sep-2018