Application of acidic electrolyzed water and alkaline electrolyzed water in agriculture

What is Soil pH?

Technically, it is the measurement of the hydrogen ion concentration.  Basically, pH is a measure of how acidic or alkaline your soil is. The pH scale ranges 1 to 14. If your soil has a pH value of less than 7, then you have acidic soil. On the other hand, if your soil has a pH value of greater than 7, then you have alkaline soil. A pH value of 7 is neutral, meaning you have neither acidic nor alkaline soil. 

pH Scale

Below is a scale we made to illustrate the soil acidity spectrum. Soil pH ranges from 0 to 14, with 7 being perfectly neutral soil.

What are the effects of soil pH on plant growth?

The pH value of the soil affects the fertility of the soil. Soil with inappropriate pH value will reduce the effective components of the soil. The most direct manifestation of this is the impact on the utilization rate of fertilizer.

A soil’s pH is directly connected to its concentration of major nutrients, as well as its composition of microelements available for uptake by plants. When soil pH is extremely high or low, the plants growing in it may suffer from nutrient deficiencies or toxicities.

PH levels affect the microbial processes that allow organic matter to decompose and deliver nutrients to the soil. In general, a neutral pH provides the best conditions for microbial action that makes nitrogen, sulfur and phosphorus available in the soil.

The pH of soil or, more precisely, the pH of the soil solution, is very important because it impacts nutrient availability. Soil carries nutrients such as Nitrogen (N), Potassium (K) and Phosphorus (P) that plants need in specific amounts to grow, thrive and fight off diseases.

If the pH of the soil is increased above 5.5, Nitrogen (in the form of nitrate) is made available to plants. Phosphorus, on the other hand, is available to plants when soil pH is between 6.0 and 7.0.

Certain bacteria help plants obtain N by converting atmospheric Nitrogen into a form of N that plants can use. These bacteria live in root nodules of legumes (like alfalfa and soybeans) and  function best when the pH of the plant in which they live is growing in soil within an acceptable pH range.

Effects of Soil Acidity

Low pH caused by soil acidity increases the solubility of zinc, manganese, iron and aluminum, which can lead to rapid accumulation and toxicity. As well, the high levels of aluminum and iron in acid soil cause tie-up, reducing phosphorus availability; molybdenum becomes less available to plants, which affects nitrogen and phosphorus uptake and utilization, restricts root growth and reduces nodulation in pulse crops; microbial activity, the decomposition of organic matter and mineralization are negatively affected; and, under acid conditions, calcium, magnesium, and potassium deficiencies become more pronounced.

That is, a small amount of aluminum in the soil solution in excess of what is normal causes the roots of most plants to either deteriorate or stop growing. As a result, the plants are unable to absorb water and nutrients normally and will appear stunted and exhibit nutrient deficiency symptoms, especially those for phosphorus. The final effect is either complete crop failure or significant yield loss. Often the field will appear to be under greater stress from pests, such as weeds, because of the poor condition of the crop and its inability to compete.

Toxic levels of manganese interfere with the normal growth processes of the above ground plant parts.This usually results in stunted, discolored growth and poor yields.

Alkalinity Effects on Soils

Alkali or alkaline soils have been defined as soils with high pH-value, which is caused by excessive (usually more than 15% of the exchange sites) amount of exchangeable sodium ions or/and soluble salts capable of alkaline hydrolysis. The most injurious alkaline sodium compounds in the soils and irrigation waters are Na2CO3 (sodium carbonate) or NaHCO3 (sodium bicarbonate).

Consequences of Soil Alkalinity

Generally speaking, alkaline soil contains a high calcium carbonate content, which prevents plants from absorbing most of the other essential nutrients. Even if adequate nutrients are present in the soil, plants cannot benefit from them. 

Experimental method of watering with electrolysis water 

Relevant researchers have studied the effects of acidic electrolysis water or alkaline electrolysis water on the pH value of cultivated soil. The study aims to explore the effectiveness and stability of electrolysis water in regulating the pH value of cultivated soil and explore the feasibility and feasible plans of actual application.

1. Single irrigation with electrolysis water: First, measure the pH value of the cultivated soil before treatment; then irrigate the cultivated soil with acidic electrolysis water and alkaline electrolysis water (0.5 L for each test point), immediately measure the pH value of the cultivated soil after treatment, and observe the change of the pH value of the cultivated soil after treatment. Each treatment was repeated 3 times, and the area of each plot was 40 m2; 1~2 times a day were measured to observe the stability of the pH value of the cultivated soil, and the irrigation with pure water was used as the control; the detection time was before treatment, 10 min after treatment and 1, 2, 3, 4, 5, 6 d.

2. Multiple irrigation with  electrolysis water: This experiment detected the pH value of the cultivated soil after continuous multiple irrigation with acidic  electrolysis water. A total of 2 treatments were set up, namely multiple irrigation with acidic electrolysis water and multiple irrigation with pure water (control), and the detection time was before treatment, 10 min after treatment and 1, 2, 3, 4, 5, 6 d after treatment, respectively. Each treatment was repeated 3 times, and the area of the plot was 40 m2.

Experimental conclusions on the application of electrolysis water in agriculture

① Watering with acidic electrolysis water and alkaline electrolysis water can effectively adjust the pH value of the cultivated soil, but the effect of alkaline electrolysis water is more stable than that of acidic electrolysis water. Under the condition of single watering with alkaline electrolysis water, the effect of improving the pH value of the cultivated soil can be maintained for a long time; under the condition of single watering with acidic electrolysis water, the pH value of the cultivated soil will return to the level before treatment in a short time. Therefore, it is not practical to use single watering with acidic electrolysis water to adjust the pH value of the cultivated soil.

② The acidification of the cultivated soil has important practical significance in the field production process. The method of using strong (medium-strong) acid fast adjustment and weak acid maintenance has good operability in the field production process and can achieve certain effects.