Neil Kinsey on drought management
Fertility for growing under dry conditions
Notes from a conference presentation.
“Upon this handful of soil our survival depends”-- Sanskrit text,1500 BC
Neil Kinsey is well known for his expertise on soil management over 45 years of consultancy work, having trained under William Albrecht http://kinseyag.com His only business is advice, so he does not have any potential conflict of interest.
The presentation was based on Albrecht’s philosophy of the link between the health of soil, plant, animal and human. The soil management principles involved are to ensure the availability of sufficient plant nutrients, microbe nutrients, air and water and to know what the soil needs in the way of minerals and other inputs. The presentation focused on production under dry conditions but it covered the principles of Albrecht soil management.
The basis of Albrecht is that Calcium (Ca), Magnesium (Mg), Potassium (K) and Sodium (Na) must be sorted. Ca and Sulphur (S) are the most poorly understood and managed. Nitrogen (N) analysis needs to include both nitrate and ammonia.
Total Exchange Capacity (TEC) is important but it can’t be changed, as it is largely dependent on the clay fraction.
Only sulphur changes during year, due to microbial action. There is not much change in other elements, except N.
Calcium and Magnesium
Great emphasis is put on calcium and magnesium, particularly ensuring that the percentage of each as a component of total cations is correct.
Ca increases flocculation, increases pore space and improves soil structure; Mg and Na do the opposite and make the soil tighter. There is an ideal cation proportion of 68-70% Ca and 10-12% Mg, which needs to be achieved by the use of Ca, Mg and S. Ca and Mg substitute for each other 1:1, so if Ca is too high this can be rectified by adding sulphur, fixing to Ca and increasing the relative level of Mg. Where Ca is low lime or other calcium minerals may be used, possibly even on calcareous soils.
Limitations under dry conditions
Ensuring adequate potassium (K) is the priority for dry conditions. Need at least 2% of the cations as K and preferably 5-7%.
Zinc is the next limiting nutrient in dry conditions; deficiency can be rectified with zinc sulphate applied at 5 - 33kgs/ha. (Do not use zinc oxysulphate, or oxides of anything.)
Low Ca reduces root growth and aggravates drought.
Sulphur promotes root growth, but leaches very readily.
High Mg will tend to hold water.
Don’t burn residues
The effects of too much water
Seasonal waterlogging will result in
Shallow roots and poor drought tolerance
Temporary P deficiency due to the death of mycorrhiza, which may take 8 weeks to recover.
Potassium is also needed for winter hardiness and to ensure strong wood.
Where K is needed potassium sulphate should be used for all tree crops as it negatively affects soil micro-organisms, and for sweetness, particularly in walnuts.
Manganese (Mn) and copper (Cu) are also needed for tree strength.
For frost protection foliar application of magnesium sulphate, manganese sulphate and nitrogen may be needed, applied 3 days before frost if possible.
If Boron (Bo) is below 1.5ppm then apply 1.4 kg/ha SoluBor
Anyone interested in Albrecht analysis and soil management recommendations should go to the Worldwide Agriculture Conference, Missouri 25 – 27 July 2018 https://www.wwag.co.nz