September 24, 2021 / 0 Comment / in Australia, China, International Consulting, Japan, Lawns Parks and Reserves, New Zealand, Soil Nutrient testing, Soil testing Organics / by Bryan McLeod

Importance of monitoring the nutritional status of your soil, with a good soil analysis If you don’t test it, you can’t guess it Soil Acidification or Cation depletion. That is decreased pH, as a result of decreased soil cations being Ca, Mg, K and Na What decreases pH?  the Hydrogen(H) does. That is the H in pH, the pH can be classed as Phase of Hydrogen. It doesn't mean percentage of Calcium.  So how does this happen. Acids result from both soil and plant processes, both natural and accelerated by agriculture.

1. Product removal (hay, crop, animal).

Dung and legume product removal is the most important Agricultural plants redistribute acidity in the soil profile

2. Nitrate leaching (N03). Worst when growing legumes, using N

fertilisers and when there are good seasonal breaks, ie soils store N during dry spells, heavy rains then leach surplus

3. Increased soil organic matter

All plants as they grow start to acidify/degrade a soil, this is a natural process, happens in all forms of agriculture, conventional, organic and regenerative farming operations, and even in the home garden, this is the reason why we need to constantly monitor and correct our soils limiting factors to help maintain its nutritional status. If we want to maintain a biologically active soil we need to maintain, for the biology, a good healthy home environment, create and maintain a good home for them to live in, sure over time they may create their own home but we can help by building the basics for them How one may ask do plants degrade the soil? Fact is, it’s a natural process, plants take in C02 and H2O, they use the C as building blocks, expel O2 for our benefit, then H is used by a plants root system to exchange for cations, (positively charged elements Ca, Mg, K and Na plus positively charged trace elements), so as they exchange H, the percentage of these exchangeable cations decrease and are replaced by the exchangeable H, with the increased exchangeable H, the soil pH decreases (PH is a measurement of a soils H status, more H the lower the pH, less H = a higher pH). M The more H that is exchanged equals increased acidity, so over time a soils biological activity and productivity can decrease. Understanding that the ideal pH for optimum biological activity is 6.0 to 6.5 based on a good Ca, Mg, K and Na ratio So increased vegetation, decreases a soils pH, its a natural result, can also be natural due to climate variations, this can be seen around the world, with high rainfall areas showing naturally low pH soils due to increased vegetation/trees/natural forests growing in those areas eg many parts of NZ, Tasmania and areas of Victoria, whereas drier areas often show a higher pH level, although there are some exceptions eg WA Monitoring by all, with regular soil tests will ensure that one can maintain a highly productive soil, simply by identifying your soils limiting factors, whether it be Ca, Mg or K to maintain a good pH LIME REQUIRED TO BALANCE THE ACIDIFYING EFFECTS OF FARM PRODUCTS This chart, prepared by the Sth Australian Primary Industries, shows the amount of lime required to maintain a soils nutrient status based on Ca removal. You can see how the rate per tn of product varies, 1tn lucerne removes twice that of meadow hay, reason being that lucerne tissue contains approx twice the Ca as that in grass crops plus the nitrogen from the lucerne root nodules also increases the removal soil Ca. C02 emissions from our soil As we increase a soil’s biological activity, we increase that soils C02 emissions, this is a natural process, aerobic organisms live on O2 and expel C02, so as our soil becomes healthier, we see increased levels of C02 being naturally expelled to support healthy plant growth. To measure a soil’s biological activity, we used to use a CO2 metre, which was placed on the soils surface, the higher the reading the more active a soil. This applied to all types of agriculture, just think, its O2 in C02 out Hard compacted soils lack air space, lack available O2 so have naturally low biology levels. Looking at high Mg soils of which there are many in Australia and around the world, they are compacted soils, naturally lacking O2 as a result they contain very low levels of desirable biology, and they also produce a sulphide gas, which is a greenhouse gas, and also producing an alcohol solution, both of these reactions acts as a soil sterilant effectively killing or suppressing desirable biology. With these soils I have found the application of lime to be the most effective treatment although many will recommend gypsum, which can also be effective, personally I stay with lime. Personally, there is no alternative but to support regenerative farming. To do this I have been using the Albrecht model for the past 40 years,  we all need to be aware of the natural functions/processes taking place, minute by minute, sec by sec in our soils and do everything to help them achieve their goals. Bryan L McLeod