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Monday, April 23, 2018

Brown flour

Brown flour just ain't what is is cracked up to be.  Let me quote a paragraph or two from The Third Plate by Dan Barber (incidentally, highly recommended)

"The roller mill appeared in the late 1800's just in time to expand the divide between the wheat field and the table.  It was a technological breakthrough that revolutionized the wheat industry just as the cotton gin had done for the cotton industry a century earlier.  Until its widespread use, people used stone mills.  Stone mills like the one we use at Blue Hill work like molars, crushing the kernels between two large stones.  They are effective, but slow and tedious, and they do little to separate the kernel into its component parts, a key development in the drive to industrialize flour.
 Image result for image a water powered flour mill

A few years ago, Klaas's wife, Mary-Howell showed me a picture of a wheat kernel in cross section.  It looked like an ultrasound image of a six-or seven week old human gestational sac, which isnt a bad comparison; a wheat kernel is a seed, after all.  The grain's embryo or 'germ' is surrounded by the starchy endosperm, - the stuff of refined white flour - which stores food for the germ.  Surrounding the endosperm is the seed coat or bran, which protects the germ until moisture and heat levels indicate it's time to germinate. 
 Image result for image wheat kernel

Whereas stone mills had crushed the tiny germ, releasing oils that would turn the flour rancid within days, roller mills separated the germ and the bran from the endosperm.  This new ability to isolate the endosperm allowed for the production of self-stable white flour, able to be stored and transported long distances.  Overnight, flour became a commodity. 
 Related image

It's hard to fathom that merely removing a temperamental little germ could revolutionize a staple grain, but that's just what happened.  The settling of the Great Plains and the advent of roller-mill technology meant that white flour was suddenly cheaper and more readily available.  Small wheat farms, including those in the former grain belt of New York, couldn't compete. Gristmills dotting the landscape became the stuff of folklore.  The homogenization of the US wheat industry had begun

The whiter flour became, the greater the demand.  To be fair, that's been the history of wheat for thousands of years.  But for all its efficiency, steel couldn't match the old-school grindstone in two key respects.  In fully removing the germ - that vital, living element of wheat - and the bran, the roller mill not only killed wheat but also sacrificed nearly all of its nutrition.  While the bran and the germ represent less than 20% of a wheat kernel's total weight, together they comprise 80% of it's fiber and other nutrients.  And studies show that the nutritional benefits of whole grains can be gained only when all the edible parts of the grain - bran, germ and endosperm - are consumed together*.  But that's exactly what was lost in the new milling process.

*this probably relates to the fact that you need to consume all the amino acids in protein at the same time.  The digestive system takes up amino acids as balanced proteins.  If there is an excess of one amino acid, the excess is rejected. Presumably there are different amino acids in the various components of the wheat seed and only by consuming the whole seed do you get the full nutrition.

There was another cost as well, just as devastating. Stone-milled flour retained a golden hue from the crushed germ's oil and was fragrant with bits of nutty bran.  The roller mills might have finally achieved a truly white flour, but the dead chalky powder no longer tasted of wheat - or really of anything at all.  We didn't just kill wheat,  We killed the flavor.

The Chinese Dilema

You may have wondered why there are so many Chinese in the world today.  The answer is surprisingly simple.  Many many years ago some Chinese genius worked out that in order to have sustainable soils, you have to return every bit of organic material you can to the soil.  This includes animal waste, human waste and all the inedible parts of your crops.  You can also supplement this with material from the sea since you are sending huge amounts of nutrients down your rivers from the land.  It has worked a treat and despite  mongol hoards, palace revolutions and wars, the Chinese have grown and prospered.'

It helped that they had rich deep loes soils gratis of the continental glaciers that ground rock into fine powder to be carried and deposited by the wind but so did America and they have gone through meters of this 'god given' bounty in a few centuries.

In the mean time other empires have prospered and declined as they mined their soils and the area they occupied had to wait for the slow process of building new soils from the bottom up before significant numbers of people could once more occupy the areas where empires once existed.

Back to the Chinese, they are now coming into the 'modern world' and it doesn't auger well for them.  On the nutrient front, they now have flush toilets and will be sending massive amounts of nutrients to sewage plants to be detoxified, denitrified and what is left, sent down to the sea.

It doesn't have to be this way.  For instance, in Seattle, they now have a sewage plant that is turning their 'feed stock' into valuable fertilizer, the sale of which covers half their running costs.  If this becomes the norm instead of the exception, perhaps us westerners can also have a sustainable future.

The Chinese are sinning against sustainability in another way now.  In their rush to industrialize. they are polluting their air to an extreme extent. It is so bad that they are negatively affecting their agriculture.  Never mind. there is light on the horizon.  At the same time they are working as hard as they can to replace coal energy with wind and solar energy and petrol vehicles with electrics.  With their command economy, they will most likely succeed.

In the mean time the Chinese are buying up land all over the world to be able to feed their people.  If they adopt the western model of flushing nutrients down to the sea, they will have to buy up a lot more.

Monday, April 2, 2018

historical sea level

Time                         Level
 22000 years ago      Minus 120m
 15,000                                 -107
 10,000                                 -40
   9,000                                 -25
   8,000                                 -15
   7,000                                 -30cm


Sunday, April 1, 2018

Electrical demand balancing

Electricity generating companies are facing a couple of problems which can be solved by demand balancing but first, what is demand balancing.

At present, most generating companies monitor the use of electricity and as demand goes up, bring on more generators and as demand goes down, reduce the power output of generators and even shed them.  All generators have a certain range of output so as power demand increases, smaller variations in demand can be met by increasing the amount of power produced by a given generator but beyond a certain level, more generators must be brought on line Power companies have a dilemma in that they must have sufficient generating capacity to meet peak loads.  This is expensive.  To build new generation capacity when it will only be used occasionally is a nightmare to their accountants.

There are peak generation periods such as in the morning when everyone is getting ready to go to work or school and more so in the evening when everyone is home, the TV is running, mom is making dinner in the oven, it is winter and all the lights are on.  What the generating companies don't need is that at this peak load time you are also running the dish washer, cloths washer, cloths drier, water heater and so forth.  If these functions could be shifted to late at night when all the evening activity is over and the lights are out, then they could avoid having to build more 'plant' that will only be needed in peak hours.

This is where demand balancing comes on.  The power company has to find a way to induce us to use power whenever possible in trough hours so that we don't need this power in peak hours.  The inducement is simple.  The make power less expensive during trough demand.

They could simply make power less expensive for all uses as demand goes down but what is really the holy grail for them is to be able to switch on and off some of your electrical devices as needed to balance their base generation.

We need some hardware and soft ware to make this happen.  Here is an idea of how it will work.

You have special little units that you plug into your wall socket and then plug your device into the unit.  It 'talks' to your smart meter you have installed.  You can set the unit to come on at different prices for electricity and, of course, the power company, when they have a little excess power, will send a message down their lines that now power is at 24c, 23c, 22c and so forth as they need more demand to balance the base power they are producing.

You are unlikely to put one of these devices on your TV or stand up lamp.  If you do, the TV and/or the lamp will go off if the price for power goes above what you have selected. All these functions that are on demand.  ie that you can switch on and off as you want, you still pay the full power price of, let's say, 25c/kWh.  The only equipment you are likely to use these special plug in units for are your chothes and dish washer, any batteries you are charbing (such as your car or wall unit), your hot water cylinder and so forth.  On the front of the device will be a dial that you turn to the price you are willing to pay for the function in question.  But all devices are not equal.

With your car battery or hot water cylinder, the power can go off and on as the power company adjusts the price to use their base generation.  Your washing machine is something else.  Once the cycle starts, you want it to finish.  Otherwise you may have food baked on to your dishes or a wet mess in your clothes washer.  So we have another wee switch on the device which you can put in 'continue to the end' or intermitent.  Now we have one more problem.  For your dish washer, you will set the 'continue' function so once it starts it will finish.

A battery or water heater is something else again.  You may have set your car battery charging unit to, say 10c since past experience shows that you are likely to get some power at this price during the night but here we have a different problem. You want to be able to get to work in the morning.  so we need one more function in our wall plug device..

We have a timer on the device which you set so that full power comes on, say, an hour before you go to work.  If the battery is fully charged, it will not take any more power but if the battery is only partially charged, it will fill up your battery at the full cost.  Not to worry.  Even at the full day time rate, it costs about a third as much in fuel to drive a km than with fossil fuel.

Despite what you hear, power companies are more worried at present by the decrease in power demand.  People are putting in LED lights, factories are becoming more efficient and the power companies are seeing decreasing revenue.  The Electric car is a god send to them.  But they don't want to have to build generating plants that only work to take care of peak demand.  By shifting demand to off periods, they solve this problem and make existing generators much more revenue efficient.  For instance, when there is lot's of water, they can send more of the water through the generator rather than over the spill way.

This is also a great way to help solve the problem of intermitent generation of renewable energy.  Say that during the day, the generation of wind energy is unusually good.  They can lower the price for these special functions such as heating the water in your cylinder even during the day.  You get cheaper power, they sell the excess instead of wasting it and over all, less fossil fuel is used.  Win win all around.

Monday, January 29, 2018

Wasted Effort

We are wasting our effort, dissipating our effectiveness and ensuring failure.  I refer to our various disparate campaigns.  Save the flowers, save the bees, save the snails, save the trees.  We could go on and on with mitigating climate change, rewilding, stopping all sorts of pollution, getting control of trade agreements that shaft us, stopping subsidies to fossil fuel companies and on and on it goes.  There is one ring that controls them all.

Nowhere is that old adage "Who Pays the Piper Calls the Tune" more true.  We, the peasants,  think we are gaining some advantage by others paying for the election campaigns of our elected officials and then we wonder why the elected officials do the bidding of the vested interests.  What a great investment for them.

They pay pennies and get back dollars, pay millions and get back billions.  For big business this has to be one of the best investments they will ever make.  They support politicians, often on both sides, just to hedge their bets and the politicians make sure that the legislation is in favor of big business and ensure that they get tax breaks and subsidies.

This is costing us hugely in our day to day life and it is now clear that this system could bring down our civilization.  If even some of the milder scenarios from the scientists are correct with respect to the effects of climate change, we could be knocked back into the dark ages or even the stone age*

The fringe scientists suggest we could trigger a run away green house effect that would turn us into a new Venus.

If, for instance, some of the predicted tipping points are reached, climate could change faster than our very precariously balanced agriculture could cope with.  Even a single year of crop failure in the grain belts of the Northern Hemisphere would be disastrous.  Imagine a decade of such crop failure until we work out how to grow crops  under the new climate regime.

Or even more disastrous, it is a real possibility that our climate will flick flack back and forth between the existing and the new regime before it settles down.  This would be even more serious than a sudden change to a new climate.

We have seen, in the 1930's and again, even more so, in 2008 how interconnected the world  is.  Back many centuries ago, if Europe crashed, America didn't even know Europe existed.  Now one country going down economically brings all down.  How much more disastrous would it be if our food supply suddenly crashed.  America, Canada and Russia provide most of the grain to a wide range of third world countries.

The present refugee problem is just a tiny fore-taste of what would face us if climate change begins to get really serious.  Not to mention world wide famine.

So what is the bottom line.  If we want politicians to do what is best for us, the people, we must be the ones that pay for their election campaigns and the first order of business after this is achieved is to pass legislation that anyone who pays money to politicians gets mandatory jail time.  Campaign money must come from the exchequer.

And it doesn't have to cost the ridiculous amounts that it costs now.  Politicians can be given a legislated amount of money and a legislated time on national radio and television.  They would get a legislated amount of money for space on news papers .  Venues would be rented for them to hold town meetings where each candidate answers questions from each other, from the moderator and from the audience.  We should also set up a standard web site for each of them

On their individual, standardized web site, they can express themselves as they please but there will also be a section in which past promises are compared with their voting record and a section comparing their voting record with any other politician one is interested in.    Of course, they can use the Internet to their hearts content.  It costs nothing.

If we want to call the tune, we have to pay the piper.  We should stop all our campaigns for various causes and concentrate a huge ground swell on this one alone.  Then all our other aims will be so much easier to achieve.  We are so smart individually but so dumb in the collective.  How hard is it to understand.
Who Pays the Piper Calls the Tune

Saturday, January 20, 2018

Kao-pectin and the pharm industry

When I was a young fellow, some 60 years ago, there was a sovereign cure for the trots (diarrhea).  It was called Kao-pectin.  As the name suggests it was a suspension of fine clay in a solution of pectin.  It was mildly distasteful to swallow but, man, did it work.  After a few one table spoon doses taken about an hour apart, you could once more trust a fart.  I can only speculate how it works.

Clay is made of fine platelates and a small amount of clay has a huge surface area.  It apparently adsorbed the nasties in the GI* track and firmed up the contents so that peristalsis could move them down stream to be eliminated. 

Also, I only have a sample of one.  Myself.  The stuff was a miracle.  Can I buy it now in my local pharmacy. Not on your nelly.  At least in New Zealand, the UK or Canada, the pharmacies I have tried don't stock it.    Why not.  It is still produced in some other countries so it is available. 

I suspect that there is not enough profit in it.  After all, how much can you charge for a suspension of clay in a solution of Pectin.  When I was young, I watched the evolution of this product.

First the made the new improved Kao.  They added a bit of flavoring and some colour.  Judging by the colour, it was probably Tartrazine, not something you want in a medicine.  Whatever was added, the Pharm industry could now charge more.  It still worked so not too much harm done except perhaps for someone at the bottom of the earning ladder with sick kids.

Next they added some sort of medicine to it.  I seem to remember that it was an anti-biotic of some sort.  It wasn't needed.   The original formulation worked a treat but now they could charge even more.

Finally, the product was discontinued.  Still not enough profit??

There is no denying that we get valuable, effective cures for various conditions from the pharmacies but they have the morals of a cigarette salesman.  If their isn't enough profit or if it will detract us from buying a more expensive product, they ain't going to carry it.

I'd like to see some double blind testing done on simple Kao-pectin against other products to see just how effective it is and then, if it proves to be as good as I say it is, to publicize it widely.  Can't be done in a university.  They can't endanger their funding from the Pharm industry.  It would have to be an independent research outfit that isn't in thral to the pharm industry.  What we need is a government research branch for research that can't be funded by vested interests.

Mitigating the harm dairy causes to the environment

We are having a debate in New Zealand for and against irrigation.  It really boils down to a debate on our national dairy herd.  With irrigation, you can put cows on land that otherwise would not support them.  Our dairy herd can then increases and with it the pollution of our environment.

True, there are some concerns about the irrigation itself but the main concern is that it allows the increase in our national dairy herd and with it increased pollution.

To come out for or against irrigation  may be good for radio sound bites but as with most cases in the affairs of man, the devil is in the details.Clearly we need irrigation for our farmers to fill in the gaps left by nature. Even in the best areas, there are periods without rain.  A farmer needs reliable inputs to be able to run his business.

On the other hand, equally clearly, if we can not find ways of farming that preserve our environment then the crude sledge hammer method of reducing herds and restricting where they can graze must be taken.  The question is;

 Can we have dairy herds and not pollute.

The answer may be yes for some areas and no for others and will depend, to quite a large extent, on the details of how we farm.

The core of the problem is to be able to apply the waste output of the cows back on to the  land a) in a way, b) in a concentration and c) at the right time such that it constitutes a valuable fertilizer, is taken up by the pasture plants, and hence is not an environmental pollutant. If this can be done, dairying is no longer a source of pollution.

As a bonus and possibly the most important consideration, applying organic material such as the manure of cattle to our soils preserves the soil organisms on which we depend for fertile soils.

Throughout history, societies that trashed their soils, declined and disappeared.  One factor in trashing soils is not returning nutrients to the soil that are extracted. so far  as is possible, nutrients must be returned in an organic form that benefits the soil organisms.  Quite clearly, the urine, manure and spilt milk from a dairy herd constitutes a valuable resource for the enhancement of the soil.

That is not to say that chemical fertilizer should not be used but as you will see, much less of them can be used if farming methods are tweaked.

If farming remains a process of plow, add chemical nutrients, sow the seeds and irrigate then our soils will degrade, wash to the sea, pollution will be rampant and we will go the way of many previous societies that mined their soils  instead of farming them.

It takes a lot more 'smarts' to farm in a way that improves the soil, reduces  inputs, increased water infiltration,  and leaves you with a much better farm to pass on to your children or to sell at retirement than when you started.  What is not generally realized is that you can do this while improving your bottom line and your resilience to weather and  price fluctuations.

Let's look at some of the tools we have available.

Riparian Zones
Fencing off streams and encouraging the growth of trees, shrubs and grasses between the fence and the stream is a great help.  Not only does it stop the cows from entering the stream and urinating and defecating into it but the roots of the vegetation of the riparian zone take nutrients from the water table which is slowly flowing toward the stream.

However, it has been reported that 70% of the nutrients entering the streams comes from the very small feeder streams and ditches.  It is simply not possible to fence off every little feeder stream. We need some other measures in the pasture.

Composting Barns
Composting barns use deep layers of wood shavings or coarse saw dust as bedding and the cows are allowed (not forced)  to bed down there at night.  They also have free access to the barn to escape inclement weather.  The bedding is stirred mechanically every day, keeping it aerobic.  It has been found that cows prefer such an environment to bed down in, even choosing it ahead of a straw-lined byre.  The composting process produces heat which reduces the feed needed by  the cows and a rich compost eats up pathogens.  The compost captures all the nutrients from the waste of the cows including N and S which in an anaerobic system  go off as the gases NH3 and H2S.

The bedding can be applied to the fields at the correct concentration and correct time which most benefits the soil and the pasture plants and hence causes no pollution.  Some research needs to be done on what portion of the effluent of a cow is released while in such a barn compared to what proportion is released out on the pasture*.  Do they mainly urinate and defecate at night or in the day,,,, while they are grazing or when they are chewing their cud.  this would give an indication of how much of the nutrient stream can be captured by a composting barn.

*Great job for some long suffering masters student

Bio-Gas Generators.
At long last a farm in Southern New Zealand is using the waste produced in the milking shed* to generate bio-gas.  The biogas is use  to produce electricity. The waste heat from the motor which drives the generator is used to heat the water used in the milking shed.  This combination, utilizing the waste heat from the motor that powers the generator, makes for a very efficient system, energy wise.  The effluent from the biogas generator contains almost all the nutrients in the waste stream since mainly C and H have been taken off as biogas (and some of the S).   As with compost-bedding the effluent remaining after extracting the biogas, can be applied to the fields when and in what concentrations most benefits the pasture and hence least pollutes the environment. Excess electricity is sent to the grid for an added income stream and/or excess biogas can be used in the house and farm.

*More work for that long suffering student.

Managing the Pasture
We have now removed a portion of the waste stream with a)Riparian zones, b) compositing barns and c)biogas generators.  Let's see what we can do out on the pasture.  There is a fantastic book by David R Montgomery called Growing A Revolution; Bringing back our soils.  In it he describes visiting farmers all over the world who have independently come up with a way of farming.  The methods they use would be familiar to any farmer before the advent of cheap chemical fertilizers but each method is updated in light of modern knowledge. Farming this way results in an improved bottom line, slashed pollution to the environment, reduced farming costs, increased infiltration of rain, continually improving soils  and as a bonus sequesters significant amounts of carbon in the soils.

It has become to be known as Conservation Agriculture.

It also, due to the greatly increased organic content of the soil, results in the capture of much of the Nitrogen when a cow urinates. The urine is soaked up by the organic material giving the soil organisms time to scavenge the nitrogen.

Of course, it also results in the sequestration of considerable carbon in the soil.

Before we go off half cocked and reduce one of our most valuable industries, we must pay attention to the details.  Farming can not be allowed to degrade our environment but there are farming methods which address this problem.  What is great is that these methods can improve the bottom line of the farmer and his resilience to weather and fluctuating prices for his products while at the same time making him the darling of the greens.  The devil is in the detail.

Wednesday, January 17, 2018

Conservation agriculture

There is a 'new' sort of agriculture practiced by a handful of farmers in diverse locations around the world.  Conservation Agriculture is not a descriptor although the words describe to some extent what it is.  It is, rather, a name given to a suit of farming methods which taken together are called Conservation Agriculture.

This so called Conservation Agriculture involves a) not ploughing the soil, (and hence, direct drilling) b) rotating crops in a random fashion, with longer periods between growing the same crop, c) leaving all the unused parts (stems, leaves and, of course roots) of the past crop on the land as a mulch and d) the planting of cover crops between commercial crops.  It is not absolutely against using chemical fertilizers but results in great reduction or even  elimination of the use of such chemicals.  In addition it may involve grazing down the standing crop residue and/or cover crops, and thus converting them into dung and urine. If grazing is used, it is very intense, very infrequently.  It may also involve,  the incorporation of char into the soil.  To find more detail on the methods go to this site or to get a historical perspective on the fate of societies that didn't preserve their soils, to this site.  What I would like to explore in this blog is the logic behind the methods.

Let's take a corn plant as an example.  The seed grows into a plant and the plant uses water, carbon dioxide and various minerals to build it's roots, stems, leaves, and seeds (the corn we eat).  The energy to transform these simple, low energy substances into complex, high energy compounds comes from the sun and this captured energy is now in the form of chemical energy.  The resulting chemicals (largely cellulose along with many other  compounds in lesser amounts) can be burnt as a fuel but can also be 'burnt' by soil organisms just as we 'burn' the corn in our bodies for energy.  The soil organisms  incorporate some of this stover into the substance of their bodies, especially proteins and vitamins just as we do with the corn seeds.

Saprophytes (funguses) are specialist in using dead plant material for their sustenance.  Think of the fungus growing on dead wood in moist conditions.  But these are the fruiting bodies of the fungus.  Most of the fungus consists of thin filaments (mycelia) that extend through the media and collect nutrients.  Of particular importance in-so-far as we are talking about soil health for crop production is that the funguses not only use dead organic material for energy but can also mobilise minerals in the soil that are in insoluble, mineral form and make them available to plants.  Many of the funguses grow their mycellia inside or around root hairs and exchange the nutrients they have mobilized  for energy rich compounds that the plant provides. Anything to encourage the growth of these funguses and to avoid disrupting the mycellia that extend throughout the soil is good for the crop.  Therefore we put lots of organic material on the soil where the fungus can access it and we do not plough

 The obvious question is why don't we mix this material into the soil.  Firstly, this would involve ploughing and hence the disruption of the mycellia of the funguses but there is another reason.  If there is a large amount of reduced carbon (cellulose and other compounds) in the soil, the micro-organisms that produce cellulase* and hence can access this source of carbon and energy, will scavenge all the available soluable nutrients from the soil to build their bodies.  The funguses are not the only organisms that can utilise cellulose.  Many single cell soil organisms have the same ability.  If a considerable amount of cellulose is incorporated into the soil, there will be nothing available for the growth of the crop you have planted.  Put the organic material on the surface and it is gradually incorporated into the soil and nutrients are still available for the crop.  But the surface layer of mulch has other benefits.

* The enzyme that can break down cellulose.

The surface mulch shades the soil and keeps it from heating up so much.  The soil looses less water by evaporation, leaving more for the crop.  The mulch softens the blow of the rain and slows the flow across the ground and hence avoids sealing the surface of the soil and increases infiltration.  Again more water for the crop.

A word here about trophic levels.  As a first approximation, only ten percent of the material consumed is fixed into the next trophic level.  10 tons of algae will make one ton of krill and one ton of krill will make a tenth of a ton of whale.  Sounds good since the 90% excreted is mineralized. Some of it is in a form that can be taken up by plants, but here is the rub.  If there is lots of cellulose around, the micro-organisms which can break down cellulose will use the cellulose as energy and scavenge all the mineralised material, which has been released by other organisms, leaving none for the plants.  Of course as the quantity of remaining cellulose decreases, more and more of the mineralised nutrients will be available for the plants.

So, the next thing is why do we plant a cover crop when the main crop has been harvested.  First we capture more sun energy in the form of the chemical energy of the cover crop and hence produce more organic carbon for the soil organisms.  Secondly we scavenge any left over soluble nutrients from the soil and turn them into a slow release fertilizer (the bodies of the plants).  As this organic material breaks down it releases its nutrients into the soil over time.

If we include a deep and a shallow rooter, we scavenge nutrients throughout the depth of the soil as well as spreading roots through the soil which will not only disintegrate over time but will provide passages for water and air to penetrate the soil.

If we include a legume that is either inoculated with the appropriate rhyzobium bacteria or finds the correct bacteria in the ground, atmospheric nitrogen will be taken from the air and turned into a nitrogen compound that can be used by the next cash crop.  Since most of the nitrogen compounds produced will be incorporated into the leaves, stems and seeds of the legume, it is important that this material be left in the field to enrich the soil.

If we include a root crop such as a radish or turnip, as they later disintegrate, in addition to releasing their nutrients, they create tunnels for water to infiltrate.  They also often are deep rooted which will help to scavenge nutrients from lower levels.

It is important to cut down the cover crop or trample or roll it into the surface of the soil before it sets ripe seeds.  You don't want the plants of the cover crop to themselves become weeds.

If you decide to graze the cover crop, it is grazed very heavily for only a day or two.  This tramples some of the crop into the surface of the soil, ensures that all plants are utilized and not only the favorites, including weeds that you have not planted, and turns the cover crop into urine and manure.  This short sharp grazing leaves lots of time for the soil organisms to  sort out any surface damage and to incorporate the animal excretement into organic material.

When the cash crop is then planted by direct drilling, it has all the best of the soil structure and soil organisms to support it.