Plant Analysis for Mineral Deficiencies in Permaculture

Permaculture Designers Manual

 

CHAPTER 8 – WATER IN PERMACULTURE

Section 8.14 –

Plant Analysis for Mineral Deficiencies in Permaculture

Some Remedies

Figure 8.8 (after Clark and Smith, “leaf Analysis of Persimmons“, Crowing Today, New Zealand Feb.’86, pp. 15-17) illustrates the seasonal levels of important plant nutrients (as 90% dry matter) and micro-nutrients (as micrograms/gm) in leaf.

The figures illustrate several things:

I. SEASONAL CHANGE IN LEVELS: Thus, the potential for early intervention in adjusting levels (before it is too late to save the crop).

2.VERY DIFFERENT BEHAVIOUR OF NUTRIENTS:

Type 1: Zinc, Iron, Copper: high in new spring growth, falling over summer, and finally (as leaves are lost to the tree) becoming more concentrated in the last leaves, as uptake by roots concentrates these elements in the last leaves.

Type 2: Boron, Manganese, Calcium: increase throughout the whole season of growth. Not “mobile” once in the plant.

Type 3: Nitrogen, Phosphorus. Sulphur: rapid early uptake, then a gradual decline over the season.

Type 4: Potassium: remains steady over the year, then declines as wood storage and root reserves build up.

As persimmons are not atypical plants, these findings have implications for pre-emptive adjustment (e.g. by  foliar sprays), and selective mulch (e.g. the season at which leaves are taken for compost).

 

MINERAL FERTILISERS OR SOlL AMENDMENTS

The present testing method used on specific soil types is to sow down mixed legume {clover), Brossico, and grass crop (or any important crop that may be grown)

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This sowing is then divided into TRIAL PLOTS which are treated at varying levels, and with soil or foliar spray amendments, to test plant health and response, based on a soil test for pH and mineral availability, or on a leaf analysis such as given in Table 8.7.

For the home gardener, or keen observer, a deliberate wander through the system, and a good key to mineral deficiencies may be all that is needed to spot specific problems.

Problems are in any case rare in well-drained garden beds using composts and organic moulds, and where one-species cropping is not constantly practiced.

On a broader scale, as in prairie or forest re­establishment and erosion control, land reclamation, or plantation, every practical farmer and forester uses TEST STRIPS of light to heavy soil treatments (from soil loosening to fertilizer, micronutrient, and grazing, cutting, or culling trials).

When such field trials (as side-by-side strips) are run, it is wise to include typical areas of soil and drainage, and to avoid areas under trees, on the sites of old stockyards or hay-stacks, intense fire scars, watering points, and gateways and roads (all of which have minor but special features and need a separate assessment from the  open field situation).

I have often noted, for instance, the colonization of chicory, thistles, and tough and deep-rooted weeds on the inhospitable areas of old roads and trafficked areas; this sort of data is of use for some cases, but does not need to suggest that we compact a whole field in order to grow chicory, rather that chicory is a useful pioneer of compacted soils.

Plant response on the test strips, which can be as little as 1% of the total acreage, may quickly indicate how modest and innovative soil treatment, minute amounts of micronutrients, or the liming of grazing or browsing can be managed to give good effects at least cost.

There is no assurance as certain as the actual, assessed plant response. To see two small plots of pines, coconuts, or cabbages side by side, the one healthy, vigorous, and productive, and the other (lacking a key nutrient or on compacted soils) stunted, sickly, and unproductive, is a definite guide to future treatments.

The same sort of trials are applied to plant mixtures or polycultures, pest controls, and the benefits or otherwise of mulch for a specific soil or crop.

Assessment can be casual (in clear-cut cases), or analytic and careful where only slight differences appear.

Such test strips are best securely marked by stout pegs for long-term visits, as effects of some treatments persist, or become evident, over several seasons.

Not until trials are assessed is it wise to widen the area treated, although in commonsense it may always be wise to add humus or manures to non-peaty soils, or dolomite to add sands.

In alkaline and heavy day soils, trace elements may become insoluble, and these are best added as foliar sprays to mulch or green crop, or to trees.

 

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