The best mowing time depends on the growth stage of grasses and legumes. For quality forage, mowing should balance protein and energy content, dry matter yield and regrowth. For grasses, SIP recommends a cutting height of 6–9 cm to support regrowth and reduce soil contamination.
Proper spring management of grasslands enables faster grass growth and earlier mowing. The most important factor affecting the nutritional value of forage is the stage of plant development at the time of mowing. The cutting height is also important for high-quality turf and rapid plant regrowth
Plant growth stage at the time of mowing
The plant growth stage at the time of mowing has a significant impact on the retention and digestibility of nutrients in the forage. The highest proportion of proteins, sugars, minerals, and other nutrients is found in the leaves of grasses and clovers. As plants mature, the ratio of leaves to stems changes or decreases. At the same time, the proportion of fiber and lignin in the stems increases, thereby reducing the forage’s nutritional value.
The earlier the mowing, the younger the plants, and the higher the protein content; however, the total dry matter yield is lower. While total protein decreases as the plant grows, total energy continues to increase for a while and then begins to decline. The ratio suitable for good milk production and favorable economic results is found in the beginning of grass headling and in the budding stage of clover and alfalfa. By mowing plants at the right stage of growth, the ratio of protein to energy in the plants ensures excellent nutritional value of the forage, and we also achieve the desired dry matter yield.
Although mowing later will increase the amount of grass yield, the forage’s nutritional value drops significantly after the headling and budding phase. The increased fiber and lignin content in the plants negatively affects forage digestibility and animal appetite. As plants age, the content of carotenoids also decreases; among these, β-carotene plays an important role, as it is a precursor to vitamin A and is strongly linked to cattle reproduction.
Optimally set cutting height for grasses
In multiple cuttings and permanent grassland, the cutting height is of primary importance for the recovery of the turf and the quality of the next cut. The optimum cutting height for grasses is between 6 and 9 cm. That preserves the green part of the plant which is needed for nutrient assimilation. Cutting lower results in regeneration of the plant through the roots. This prolongs the time it takes for the sward to fill in. Due to the slower growth of grasses, this can lead to excessive weed growth and, in the summer heat, exposure to desiccation.
Cutting too low introduces soil, sand or stones into the forage, thus reducing its quality. Higher cuttings allow air to circulate under the cut plants, allowing them to dry more evenly. And also prevents soil and sand contamination of the forage. For grasses that are intended to be cut only once, the height of the cut may be slightly lower. But this risks excessive soil contamination of the forage and poorer wilting of the forage in unpredictable spring conditions.
Optimally set cutting height for legumes
The cutting height must be higher for legumes, specifically between 8 and 10 cm. the reason is the way legumes branch out and regenerate, which is quite different from that of grasses. A characteristic feature of legumes, and especially alfalfa, is that the crown or head of the root system is located a few centimeters above ground level. New shoots emerging from the crown have not yet developed sufficient leaf area. So they draw nutrients from the roots; additionally, they depend on the assimilates produced by the leaves on older shoots.
If we mow too low and remove the older shoots, the development of new shoots is also slowed down, so the ground is not covered quickly enough. If mowing is done too early, the new shoots are not yet sufficiently developed. If mowing is done too late, the problem is that the new shoots already extend above the cutting height. That means that we thin them out and impair the plant’s hardiness and regrowth. For alfalfa, it is therefore recommended that no fewer than 35 days elapse between two consecutive harvests and that new shoots in the growing area measure at least 2 cm.
With the correct mowing height, a clean cut, and timely fertilization, we can achieve the desired number of cuts per season under favorable weather conditions. Proper mowing is also important for the quality of the harvested forage, and above all for the optimal regrowth of the turf.
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Keywords: sip, agriculture, agricultural machinery, agricultural machines, agricultural equipment, grassland harvesting, making hay, meadow, mowing, disc mowers, tedder, rake, pick-up rake…
Author: SIP Lab – Grassland Harvesting Specialist. References.
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FAQ: Frequently asked questions about grassland mowing
The best time to mow grassland depends on the growth stage of the plants and the desired forage quality. For high-quality forage, mowing should take place when grasses and legumes provide the best balance between protein, energy, fibre content, and dry matter yield. Cutting too late can increase fibre and lignin content, which may reduce digestibility and feed value.
For most grasslands, the recommended cutting height is between 6 and 9 cm. This helps protect the plant base, supports faster regrowth. And also reduces the risk of soil, sand, and stone contamination in the forage.
Cutting grass too low can damage the plant, slow down regrowth, and increase the amount of soil and impurities entering the forage. A very low cutting height can also increase ash content. This lowers forage quality and can negatively affect animal intake and performance.
Correct cutting height helps produce cleaner forage and supports healthy regrowth after mowing. If the mower is set too low, more soil and stones may enter the crop. If the crop is cut too high, part of the yield may be left in the field. The goal is to find the right balance between forage yield, cleanliness, and regrowth.
FAQ: Frequently asked questions about grassland mowing and SIP machines
Good ground adaptation allows the mower to follow the terrain evenly and maintain a consistent cutting height. This helps prevent scalping, reduces soil contamination, and improves forage quality, especially on uneven or sloping grassland.
Forage contamination can be reduced by setting the correct cutting height, adjusting the mower suspension, and ensuring that the mower follows the ground smoothly. Properly adjusted mowing equipment helps keep soil, sand, and stones out of the forage.
For mountain farms and sloping terrain, a lightweight mower with good ground adaptation and stable operation is recommended. SIP DISC ALP mowers are designed for mowing on slopes and demanding terrain. There low weight, stability, and clean cutting are very important.
Large farms and contractors usually need high-capacity mowing solutions with wider working widths and strong performance. SIP DISC ROBUST and SIP DISC HD mowers are designed for demanding users who need productivity, durability and efficient mowing across large areas.
Mowing is the first step in the forage harvesting process and has a strong influence on drying. A clean and even cut, correct swath formation, and suitable conditioning can help speed up wilting. And also support the production of high-quality forage.
Before the mowing season, it is important to check blades, blade holders, skids, suspension, hydraulic hoses, PTO shafts, safety guards, and lubrication points. Proper machine preparation improves mowing quality, reduces downtime, and supports safer operation in the field.
Key Takeaways
- Optimal mowing time depends on plant growth stage, balancing nutritional value and dry matter yield.
- Cutting height for grasses should be 6-9 cm, while for legumes it should be 8-10 cm to support regrowth and minimize soil contamination.
- Mowing too late increases fiber and lignin content, reducing forage digestibility and quality.
- Younger plants yield higher protein but lower total dry matter; thus, timing and cutting height are crucial for forage quality.
- Correct mowing techniques, including proper cutting height and machine settings, enhance forage quality and regrowth efficiency.
