Min-till elevates grass quality at Farming Connect demonstration site
3 March 2023
Using minimum tillage (min-till) techniques to rejuvenate tired pasture on a Welsh sheep and beef farm has elevated the feed quality of grass.
Edward and Ellis Griffith farm at Bodwi, near Pwllheli, and also rent a block of land at Criccieth to rotationally graze their Suffolk-cross ewes and Stabiliser suckler cows.
Although that block has not been cultivated for several decades, it is productive thanks to regular applications of lime and fertiliser.
But in recent years, grass yield and quality have been challenged by an incursion of moss.
As Farming Connect demonstration farmers, in June 2022 Edward and Ellis embarked on a project to rejuvenate the pasture with new grass varieties using min-till techniques including chain harrowing in combination with soil aeration.
Seed was introduced through direct drilling in three plots on 2.8 hectares (ha) where moss was particularly dominant.
One plot was aerated and chain harrowed, harrowing only was used on another and the third was a control plot with no intervention.
Samples were first taken to assess the nutrient status of the soil and the results were reasonable, except that, at index 1, the potassium (K) level was below optimal.
Soil was also visually assessed and this identified very few compaction issues.
The seed was drilled in June 2022 and the quality and quantity of the grass was then monitored throughout the growing season.
It proved to be a challenging growing season with exceptionally high and sustained temperatures and very limited rainfall.
The trial results showed that grass in the plot which had the dual intervention of aeration and harrowing recorded the highest digestibility (D) value, crude protein (CP) and metabolisable energy (ME) – at 62.9 D value, 21.4% CP and an ME of 9.9MJ/kg.
For the plot that was harrowed, the figures were 62.4 D value, 20.8% CP and an ME of 9.8MJ/kg.
The control plot scored the lowest on all three, at a D value of 61.7, 17.5% CP and an ME of 9.7MJ/kg.
Early samples showed that the potassium and chloride uptake was greater on the treated areas and, later in the season, the whole macronutrient profile was slightly higher on the treated areas, with an improved Cation Anion Balance (CAB) relative to the control area.
It was evidence that the reseed was doing its job, says Farming Connect Red Meat Technical Officer Non Williams, who oversaw the trial, as these trends suggest a grass sward in its younger stages of growth.
Samples taken later in the season showed crude protein, D-value and ME content to be higher in both min-till plots compared to the control.
Although these differences were small, they were consistent and once again indicate a younger sward, says Dr Williams.
The trial had demonstrated the value of min-till, she adds.
“Aeration and harrowing gave a marginally better result than harrowing alone, likely due to aeration scratching the soil surface and removing some thatch, however harrowing alone gave some benefit and is cheaper.’’
As a result, the sward in the min-till plots had a higher feed value, says Dr Williams.
Although the differences were not statistically significant, she said this was likely a result of the challenging growing season.
Grassland renewal with min-till or no-till establishment methods is increasing in popularity as farmers look to improve their soil management and organic matter content.
Dr Williams says rejuvenating older pastures by oversowing can be an effective approach for improving pasture productivity and quality without the financial and environmental burden of ploughing.
Top tips for getting fields ready for min-till or no-till
- Sample the soil - a recent test is crucial before getting started
- Always evaluate soil condition by digging holes to assess it visually
- Use the condition of the soil as an indicator of which level of intervention is most appropriate – that might simply be rest and recovery, or harrowing, aeration or subsoiling
- Don’t expect sward rejuvenation to give the same results as a full reseed but it will offer multiple benefits, including on cost and possibly not disturbing the soil if it is not needed
FARM FACTS
247ha farmed
1,170 Suffolk-cross ewes and 320 ewe lambs
January to March lambing
125 Stabiliser suckler cows
Calving in February and March