Why is moisture so important?
At a time when circumstance isn’t the gamekeepers friend – we all know that feed costs, energy costs, the cost of poults are considerably higher – getting something like moisture retention right is a must. It is something that we can, partially, control, and nobody can begin charging us more for!
We all know the basics of why moisture is so vital – nothing can grow without water. But retaining good levels of moisture in your soil is arguably more important than in years gone by, and we have to look at weather patterns over the last few years to understand why.
Over the last four or five years, the weather in the UK has followed a noticeable, repeated pattern. That is, cold and wet weather, followed by a sudden dry, hot drought, and not really anything in between.
The issue we’ve seen here is that the drought is sudden and prolonged, which means the majority of the moisture is removed. And, when there is a drought, crops need moisture lower down in the sub-soil. So, if land isn’t cultivated properly, this moisture becomes even harder to find for the searching roots.
Furthermore, a lot of the game and conservation cover crops that are now popular are originally from exotic climates. Because of this, crops such as maize, sorghum, millet and quinoa need warmth and moisture to get away, otherwise they become easy pickings for flea beetle, slugs, pigeons and deer. This also goes for slow growing brassicas such as Kale, which is notoriously slow growing. As ever, timing is key, and once a crop starts putting down roots, it is essential that moisture is present in the soil.
Don’t top too soon!
Something that happens far too often come the end of the shooting season is topping too early. Understandably, we are all keen to get out and top cover crops, giving us plenty of time or an early start for the following years crops. But this can be, and often is, detrimental to the process – and detrimental to retaining that all important moisture.
For example, if the ground is wet – as it so often is at the end of February – getting the topper out will only serve to further compact the soil, not allowing moisture to move freely through the column, which is what we want. The only conditions that can be conducive for early topping are if there has been a deep freeze or a prolonged dry spell, as this firms up the ground and sub-soil and prevents the compaction issues.
For those in the AB9 Winter Bird Food stewardship scheme, topping cannot legally take place until after the 15th February. And, even after this date, if there is still a food source, then there is a moral quandary on when to top.
With the amount of rain we have had across the UK, it’s safe to say soil will be saturated in most areas, so let it dry out. Patience is a virtue!
What Needs to be Done?
So, once a decision has been made on when to top, how can we continue to hold moisture in the topsoil and sub-soil? Well, much like topping, cultivation can be undertaken too early. In an ideal world, it is advised to dig down in the middle of the plot – around eight inches – with a spade, to see what the soil looks like.
Much like with topping too early, trying to cultivate saturated soil will result in damage to the soil structure. As a rule, the deeper one is cultivating, the longer one should wait to begin. This is a fine balance and a bit of a double edged sword. Some moisture needs to be gone to allow cultivation, but if too much moisture escapes, the incoming crops will struggle.
The next thing to consider, and there are age-old debates on this, is cultivation technique. The most important advice here, is to plough rotationally – every one in three, or even every one in five years, depending on the conditions and the availability of machinery.
Once the conditions allow it, I like to top, and then after two-three weeks, check the soil isn’t too saturated and go in with a set of discs to break up the hard crust on top – this then allows moisture to come up through the moisture column. Then, use the discs, wings and roller on the Sumo Trio (if it is still wet and depth, use the machine with the wings up and then in a few weeks, once dried out, go back with wings down to break up compaction at sub-soil depth). If the conditions are looking like staying dry, Cambridge roll the plot. This will help seal moisture in and help retain moisture for a drought situation.
Even when min tilling, it is a good idea to add some organic matter to the soil. Last year, I ploughed in farmyard manure, and this year I’m planning to muck it and minimum tillage. This should mean that I have organic matter at both plough and min till depths.
A final thing to remember is weed control. If a plot has been minimum tilled for 3-5 years, using glyphosate for a stale seed bed, weed burdens will still build up. This is when ploughing can help. Not only will ploughing break up the compaction, it will also bury things like Black Grass and kill the seed – leading to weed control through cultivation.
Finding A Balance
As I’ve discussed previously, the need to balance moisture retention and soil compaction is difficult and a fine balance is required. Moisture at depth is essential for periods and drought, which we have seen regularly around Spring over the last four or five years.
One problem with game cover is that it is often not treated as well as cash or other conservation crops. Too often it is topped and cultivated early, using machinery that it too big, on ground that nothing else is grown on. So, game cover often has a lot going against it. Making the right decisions in terms of topping and cultivation (as well has having some luck with the weather) can go a long way to helping crops get away and grow successfully.