Zero till with a Moore Unidrill; note the independent discs and seed coulters (right) and press wheels on the rear (left) giving even depth of placement and good seed-soil contact. (Photo courtesy Agri-Linc.)
Direct drilling comes in two guises; drilling after a little cultivation (“min till” really), and what in the USA would be called “zero till”. Each has its own consequence in terms of weed control. Maybe I learned, years ago, most from a farms manager called Richard Noyce, he always had clean bottoms to his crops simply because, after harvest, he cultivated the surface several times to get weeds seeds to germinate, before putting the next crop in. The alternative of one pass to put the crop in does imply more work to do with selective herbicide – but that is probably going to happen anyway, so it is not an extra cost. Generally, in the hands of a sensitive husbandry man, zero till costs less and gives higher yields.
Good husbandry and using the right machinery is aiming at even depth of placement, good seed-soil contact, giving even emergence.
Bill Butterworth, Land Research Ltd, 20 August ‘18
In direst drilling, getting even depth of placement and good seed-soil contact is important.
Some will be old enough to remember the Bettinson 3D drill. Direct drilling went out of fashion in the early 1990’s but it is back and what a year in 2018 to start direct drilling! Drought is a killer in the seedbed and cultivations drive off water. So, this year will take a bit of managing and some luck, too. Harrow to get the weed seeds to chit. Shower of rain, please. Green up. Spay off with glyphosate. Direct drill. Showers of rain please. Roll if useful. Would that it were as easy as that. However, it is still much easier than trying to get a wider range of conventional cultivations through. Direct drilling is lower cost, faster and therefore there is a timeliness gain, conserves soil moisture, over-all does give a little better yields, certainly at lower cost.
A lot of this, this year. Yields down too. It is largely avoidable.
A sandy soil will hold about its own weight in water. A clay 2 or 3 times. A typical natural peat around 16 times!
A compost made from urban green waste will hold up to 10 times its own weight in water, maybe only 5 times if it is made from woody cuttings in winter (and it would have less N). However, compost made from urban green waste plus industrial wastes will (depending on the wastes used) hold 8 to 14 times its own weight in water and possibly a lot more NPK. Although the Environment Agency will restrict quantities, the truth is that the Fens, when Vermuyden drained them some 300 years ago, were up to 40 foot deep of almost pure compost. (Organic soils do not leak excessive N.) It is also true that high organic, well-composted soils, can halve cultivation energy inputs and reduce chemical spraying.
So, there really should be a national policy of maximizing urban waste recycling to urban farm land. Suggest get a copy of “Survival”, read it and send a copy to your MP.
“Recreational tillage” soothes the soul but it really does dramatically increase organic mater oxidation and loss. Forcing a tilth with a power harrow is the worst offender.
The problem with forcing a tilth with power harrows, or any other cultivation tools, is that organic matter is oxidised at a rate corresponding to power input. This was first shown by Sarah Wright working at the famous USDA research centre at Beltsville in the USA. It was reinforced by research I did for ICI Plant Protection back in the 70’s and early 80’s; then, a fair guide in most soils was that conventional, high-power-input cultivations would oxidise and lose around 35 % of the humus per annum but direct drilling would limit the losses to around 10%.
There are two results of this loss which are, amongst others, worthy of note in this context. Firstly, the more organic matter is lost, the greater the cultivation power needed next time around, leading to a declining soil structure, demanding progressively more power in a downward spiral. Secondly, N losses progressively rise in parallel. Further, as organic matter level falls, so does water-retaining capability. This, in turn, allows more soluble N to be leached out.
What Michal Gove needs to do it look at the energy we could save by recycling more to land, using science-based process to encourage it, rather than allowing regulation to progressively restrict it.
There is one fundamental rule in nature: Given enough dilution, given enough time, Nature will handle anything. The trick is to know how much dilution and how much time. To some extent, the two factors are interchangeable. Fortunately, humus (that complex mixture of hydrocarbons, carbo-hydrates and proteins with significant colloidal capacity) is a very effective chemical “buffer” which will smooth out release of toxins and nutrients. There is also a biological buffer in that the mycorrhizae can be selective and take what they need (and no more) from an otherwise too high a concentration of a toxin or nutrient in a feedstock (such as compost). These mechanisms add enormously to the safety of recycling to land.
Having said that, like all living mechanisms, don’t push it too far, knowing how far depends on reading the research, using common sense and not rushing the fence – build up slowly and learn to manage the stress in the system.
Also see “How to make on-farm composting work”, by Bill Butterworth, MX Publishing, London 1998,
As the previous post here showed, Organic N, then, is different. It just sits there in the store, alive with micro-organisms and giving some (but very low losses) to the soil atmosphere and groundwater. However, it is different in a staggeringly complex and important way. When conditions favour both plant and fungi, the mycorrhizae feed at one end of their hyphae on the organic matter and the other end of each hypha either crosses the root hair wall into the plant body, or wraps round the root hair (much like the placenta of a mammal). This is a closed conduit!Not only is this why natural ecosystems do not leak nutrients and pollute the ground water, they also feed the plant with complex molecules, already some way down the route for forming cellulose and amino acids – so accelerating growth. Even more staggering, these mycorrhizae can suck nutrients out of some plants (weeds?) and transfer then to others (crops?).
There is enough urban waste in the world to supply enough nutrients to feed the world – without manufacturing fertilisers. (But we do actually need both.)
See the next blog in this series for more on profitable, eco-mimic fertiliser mechanisms and also “Survival” by bill Butterworth, published on Amazon.
S Michael Gove’s staff look at the environment v. Farming, they might do woerse than to read this series of posts on N fertilisers.
When ammonium nitrate hits the soil moisture, it forms two “ions”. The ammonium carries a positive charge and is an “anion”. The nitrate carries a negative charge and is a “cation”. Sands have a very low ability to hold onto nutrients whether they be anions or cations.. Clays have some useful colloidal capacity which has some ability to hold onto anions (so it will hold some ammonium ion) but not much ability to hold cations (so it will hold very little nitrate).
“Humus” is a very complex and variable black tarry material made up of large, Carbon-based chain molecules (so in chemists’ language they are “organic Carbon” molecules) forming hydrocarbons, carbohydrates and proteins. The proteins carry one or more Nitrogen molecules. These molecules are insoluble in water. So this humus-N will not leach out in rain or irrigation. More than that, humus is very colloidal, so it will hold both ammonium and nitrate ions and reduce the leaching of synthetic N.
So, pushing up the organic matter in soils is a real economic and environmental plus.
See the next post on this blog for how organic N storage work sand promotes crop growth.