Plants Groan In Our Care
The following are the conclusions reached after talking to very knowledgeable agronomists, reading books written by clever though not necessarily mainstream people, research via the internet and observations during personal experiences in putting sound soil management theories into practice. Innumerable books, lectures, courses etc are available to advise how to obtain maximum crop yields but this is about shedding a little light on how to get the very best quality produce.
To begin, one of the great oddities of the planet is that plants left entirely to their own devices will produce very little in the way of what we term 'a bountiful harvest'. It matters not whether the plants are in their original natural habitat, if the soil is fertile, average or nearly wasteland. The competition between plant species for dominance in an area usually means that none of them will be. The exceptions only occur where man has imported a species from one continent to another, then it flourishes because the limiting factors of its normal eco system didn’t come with it. Apart from that perhaps the Genesis passage that says "man was put into the garden of Eden to dress it and keep it" rings true after all. For only when a farmer tends his orchard by keeping the grass down, keeping other plants from growing near the trunk of the tree, cutting off the deadwood, pruning to allow sunlight to permeate the entire tree not just the outside and to feed the tree as necessary, then a bountiful harvest becomes possible.
So, as we have 'progressed' in agriculture, in an effort to feed the ever increasing masses who like to stay put in cities, we have evolved worse and worse practices till finally we realise we are facing our own destruction unless we work with nature instead of trying to batter her into submission so we can milk her dry.
In early times our soils were fertile, especially river deltas and rainfall was reliable. However, reaping a good harvest year in year out was at the cost of soil fertility. The bright idea of irrigating to try and get a maximum yield from every crop hastened the depletion.
Of all the species on the planet we pride ourselves on being the most intelligent and that may well be true, it certainly is when judged against our standards. However we are the only species able and willing to totally desecrate our own environment and by that standard we are among the least intelligent. By any yardstick, we are undoubtedly and absolutely the biggest meddlers in natural processes that there ever was and it seems the more we learn, the worse we get.
By the time the 20th century came along we moved into the era where we knew about minerals, that they were present in the soil and that plants needed them to grow. We also learned how to apply them to the soil by the bagful and marvelled at how clever we were when after we applied nitrogen, the plant leaves turned green and growth increased two and threefold. We didn't put two and two together at the time but this was usually followed by an invasion of pests, either bacterial, fungal or insect, sometimes all three. Never mind, the same company who sold us the fertilizer will also sell us poisonous sprays to take care of those problems.
Late in the 20th century it starts to become apparent that these poisons stay on the produce, build up in the soil and accumulate in our bodies which in turn triggers an inordinate amount of ill health. Thus the organic produce system was born, vowing never to use poisonous sprays nor to use chemical fertilizers as they too were contributing to our not being well.
The seeking of optimum quality raises questions about the way our fruit and veggies are grown in this 21st century and why the quality of today’s produce is abysmal compared to that of 50 years ago. First we have conventional produce, that’s what fills the supermarket shelves. It is grown for maximum volume and minimum price. Quality, other than appearance, is not a consideration. True quality produce does find its way to the shelves sometimes but it is a rare occasion, 80% of the time the quality is so poor it isn't even fit for composting so it's not worth discussing it further.
Organic produce, this industry is caught between a rock and a hard place. It's catch cry is that its certified produce is chemical and pesticide free and by and large that much is true. The demand for organic produce is growing at a phenomenal rate throughout the world and there aren't enough new organic farmers coming on line each year to keep pace. The industry needs to encourage new producers not discourage them so while the non-chemical aspect is justifiably rigid, the standards are nowhere near as high as they should be in the area of quality.
It is so strange that while consumer demand grows for less poisons and less chemicals, hydroponic farming managed to find a niche in the market but probably as an adjunct to conventional produce. Consumers of such produce either don't know, don't care and/or seek to buy the cheapest possible food. After all, hydroponics is about growing plants not in soil, but actually in chemicals.
The practice of irrigation is a bit of a conundrum. Yes, it allows crops to be grown in areas otherwise too dry to support plant growth but eventually, and it may take decades, salt from the irrigation water will make the soil uninhabitable to plants. Not only that but the day eventually comes when suddenly, there is no water for irrigation. This has spelled the end of more than a few past civilisations, being irrigation dependent is not sustainable agriculture. The rights and wrongs in this situation would fill a book on its own and won't be pursued here. The thrust of this article is aimed at tropical, subtropical and temperate climate zones.
Irrigating in areas of low to medium rainfall is thought to be essential particularly when maximum yields are sought and in commercial circumstances, that's all the time. Remember, this about growing top quality produce so irrigating is out of the question. An instrument has recently been invented that measures taste. One of the earliest things discovered with it, was that produce from irrigated plants had a taste reading only 60% of the reading from non-irrigated plants !! Why is this so?
If we take a fruit tree growing without irrigation in the times when rainfall is adequate the tree will grow leaves aplenty
(A) because it has plenty of moisture to support the new growth and
(B) because it needs to draw up the water from around its root system to prevent it from drowning and transpire the excess moisture out through its leaves as water vapour into the air.
The minerals potassium and sodium play a part in this water management. Potassium allows the plant to absorb moisture, sodium regulates how much moisture it should hold. In the wet times, the tree will shed its sodium back to the soil which allows the heavy flow of transpiration to take place.
Along comes a dry time. The tree now doesn't have unlimited water at its fingertips, ah, root tips, so the leaf growth is curtailed and root growth is enhanced for the purpose of gaining a larger area from which to harvest moisture. Sodium is now drawn from the soil back into the plant effectively reducing transpiration and allowing the plant to retain its moisture. The drier it gets, the more sodium is drawn up and the better the plant retains its moisture in what is now a low humidity, very evaporative atmosphere.
Then along comes another wet week. The tree now has this enhanced root system and can really put its resources into vigorous above ground growth. Sodium heads south once again until the next dry spell.
Look now at what happens with irrigation under similar climatic conditions. It rains, irrigation not needed, same deal as above, lots of leaf growth, sodium sent to ground. It stops raining and starts to get dry. On goes the irrigation, plant keeps growing top, roots just sit tight, there's no need to go out and search for moisture. After a month or two of this the root system is out of balance with the relatively oversized top. During a dry spell, a very short time after the sprinklers are turned off the plant starts to wilt. Suddenly the plant is without sodium or an adequate root system and its leaves are exposed to the dry highly evaporative atmosphere - no wonder its severely stressed and wilting. Panic stations - turn the irrigation back on!!! The plants are now irrigation dependant, if they don't get it there is a high probability they will die.
But there's more, another disastrous effect of irrigation is that over time it severely depletes the soils percentage of organic carbon. Many apparently fertile soils have carbon levels of 1.5%, even down to 0.5%. Again, it would take a whole book to explain the importance and benefits of having good levels of organic carbon in the 4% to 6% range, not the least of which is the 10 to 20 fold increase in the soils water holding capacity.
Back to the taste race, most old time non irrigating farmers will have noticed that at harvest time for citrus it is usually dry and the fruit tastes sweet and full flavoured. Suddenly it rains all day, the following day fruit from the tree is no longer sweet, not nice at all. A week or so of dry weather and the fruit returns to being sweet and tasty. This is the mineral sodium at work again. A spin off from its water regulating qualities is that it has a huge influence on the taste department. That’s just one facet of why non irrigated produce tastes almost twice as good as irrigated.
Then there is the practice of ‘fertigation’. This means that soluble minerals/chemicals are metered into the irrigation water for the purpose of providing plants with water and nutrients at the same time. In most instances all the plants perceived needs, from seedling to crop harvest, are provided in this way. It is only a small step away from hydroponics. It is though, one way that allows micronutrients, Boron for example at the rate of 3 Kg per Hectare, to be spread evenly over a large area. Were irrigation not practiced, the micronutrients can still be water mixed and applied from a spray tank.
The latest technology in plant nourishment is ‘folia feeding’. This is the practice of applying water with nutrients onto the plants leaves, usually by misting or spraying at 2 or 3 week intervals. This means the plants are fed nutrients through their leaves rather than through their root system. It is a bit like an intravenous drip applied to someone in a hospital ward - its great in an emergency but you wouldn't want to live like that. Imaging being always connected to your bottle on a pole with wheels - at least you wouldn't have to stop work for lunch.
Spectacular results are being obtained in plant health and crop yields from folia feeding. I tend to wonder if this can be compared to taking drugs in sport - is the plant being induced to yield greater than its design intended. Its success is hinged on the farmer being able to pick what nutrient the plant needs at the time of feeding as its needs do vary according to time in its life cycle, the weather and the season.
Just take note here, that plants are very smart, much smarter than we give them credit for. Providing we ensure their soil has a full compliment of minerals and microbes, they will effortlessly manage their circumstances rain, hail or shine. Picture this, you are shopping for the family groceries and when you get to the supermarket the doors are closed but the takeaway window will sell you a food package that will last you a week. What are the chances you wouldn't normally buy what's in there, did they take into account what you already have at home in the pantry and will you be coerced into eating something you didn't really feel like or need?
The best thing to do for plants is ensure that:-
A every possible mineral is in the soil in the right proportions. This will involve one application of 10 tonnes of rock dust per acre and regular soil tests to guide the application of the major minerals.
B the organic carbon is over 4% going on 6%. This may require the application of copious quantities of cow manure, chook manure and/or compost.
C no poisonous sprays are applied at all. This will allow all the beneficial microbes to flourish, promoting growth and allow the plant to chemically structure itself to be unpalatable to what we consider pests.
D don't irrigate. The writer has 5 acres of bananas, not irrigated, has just survived the worst ever drought, produced bananas through out and didn't lose a plant. Bunch sizes were up to 40% smaller but in economic terms this was an incredibly better outcome than irrigating. In ecology terms, energy usage to produce a crop was decimated, greenhouse gas emissions probably went into negative territory as throughout the drought this soils organic carbon content actually increased.
The above paragraph for most farmers no doubt drops like the proverbial bombshell. To irrigate or not to irrigate, that is the monumental question. Looking back though all of mankind’s history it is found that ALL of the successful modern (for the era) civilisations were dependant on irrigation and when the water ran out EVERY ONE OF THEM failed, their people either starved to death or dispersed to the countryside. Essentially, irrigation allows us as a species, to proliferate out beyond what our ecosystem can support. The better we are at irrigating, the more we proliferate, the longer we can stave off the inevitable and the more horrendous the crunch will be when it comes – and it has to come.
The key to all this is carbon, the buzzword element in 2007’s hot debate about climate change. Increasing the carbon content of the soil (instead of increasing it in the air) if done on a large enough scale, will actually increase rainfall. As rainfall increases, the soils are enabled to contain a greater percentage of carbon thus further increasing rainfall. Where it rains almost every other day, the carbon content of soil can easily be 10%, in 700 mm per year rainfall areas (not irrigated) 4% to 5% is probably as high as it is able to go.
Regular irrigation has the reverse effect. The carbon is leached from the soil, less soil carbon means less rainfall and irrigation really is dependent on rainfall to fill dams, rivers and underground aquifers. The soils in these areas have a carbon content of 1.5% if they are lucky, down to 0.5% where they have a long history of heavy cropping. Apart from the rainfall aspect, the ramifications of low soil carbon on nutrition and health is nothing short of disastrous, again, covering such details is already in books.
The big question is “How do we tell if the produce is top quality?” It should be by taste but after thirty years of substandard agriculture and a continued diet of poor produce we have forgotten what quality tastes like. All is not lost, there is now an instrument that puts a number against the juice of any item of fruit or vegetable. This number is called the BRIX number which primarily represents the percentage of sugar content of the sample. It works by squeezing juice from the sample, passing light through it via a prism and reading the level on a scale. This light is refracted by the prism and the amount it gets ‘bent’ is related to the sugar content of the juice.
Refractometers for reading the Brix percentages are now commercially available for A$160. They also indicate if adequate calcium/phosporous is present in the sample or not.
Of course there is more than just sugar in the juice, it also contains minerals, enzymes and amino acids etc, etc but the sugars comprise the lion’s share of the total. In order to get a high Brix reading not only do the sugars have to be there but so do the minerals which means the plant that grew the sample would have to be grown in well managed soil with a full compliment of minerals in the right proportions.
There is more to taste than just sugars, for example the presence of the mineral sodium plays a large role in how good something tastes and yet it won’t be a major component of the fruit’s juice or have much influence on Brix readings even when at high levels. Therefore the situation can arise where the fruit tastes relatively good but the Brix reading is low. However, the bottom line is that produce with a high Brix reading will be top quality produce, always taste great and always be nutritionally good for us.
Not every species of plant is capable of producing fruit with high readings, asparagus is one of the lowest with readings from 2 - 8% while sweet corn, grapes, pawpaw, oranges and pineapple can yield readings of 20% plus. The book, “Mainline Farming for Century 21” has a comparison chart that outlines the Brix readings for many varieties of produce and gives readings for poor, average, good and excellent in each species. In reality, produce from plants grown in well managed soil will have Brix readings that exceed ‘excellent’. Such will be hard to find. Most commercially grown produce will rate poor, average or good and should be consigned to the compost heap. Supermarkets strike contracts with growers where the emphasis is on quantity and price. Neither party is interested in sugar content or quality (other than visual), produce grown to a price and picked long before maturity will definitely be abysmally short on quality.
Here is a table showing readings of fruit during year 2007 from various sources compared to the ‘excellent’ standard with actual taste comments.