Water Acidification

농사를 지을 때 산도를 조정하는 방법엔 크게 두가지가 있다.
토양을 상대로 직접 시도하는 것과 관수를 통해 접근하는 것이 그것이다.
아래 인용문에는 황산을 이용한 방법이 나오고 있다.
그러나 황산은 결정적인 문제를 가지고 있다.

예전부터 황산은 황과 함께 줄곧 쓰여왔으나 최근에 나는 치명적인 문제가 있음을 발견했다.  
질산 역시 원예업자들이 흔히 사용하곤 하지만 재배하는
작물에 따라서는 적당치 않은 수가 있다.

제3의 방법은 없는가?
궁즉통이라고 나는 이 방법을 찾아냈다.
명년 봄에 포장에서 시험을 하고 그 결과를 정리할 예정이다.

Water Acidification

Alkaline irrigation water can be neutralized or

acidified for the maintenance of pH when growing

blueberries in acidic soil materials or growing media

(peat, potting mixes, etc.). This is done by mixing acid

(usually sulfuric acid) directly with water in appropriate

amounts, or by oxidizing (burning) elemental sulfur in

the presence of water to form sulfuric acid which is then

mixed with the irrigation water (known as the sulfur

burner process). Homeowner-scale sulfur burners are not

available, so the process is generally restricted to

commercial production.

Handling concentrated acid solutions is a difficult

and potentially hazardous procedure and should only be

undertaken with the utmost care and according to the

safety precautions outlined by the manufacturer of the

acid product. Always use rubber gloves and eye

protection when handling acid. When mixing acid and

water, ALWAYS add acid to water, NEVER add water

to acid as this can be a violent, volatile reaction!

Typical water sources in Utah contain from 60 to

1200 mg/L (or ppm) dissolved carbonate and

bicarbonate which buffers pH between 7 and 8.

Neutralizing the alkalinity of the water and reducing the

pH to about 5 (optimal for blueberries) requires from

160 to 3,175 pounds of sulfuric acid per acre foot of

water. This is about 16 to 355 gallons of fertilzer-grade

(62%) sulfuric acid (or 10 to 220 gallons of concentrated

(98%) sulfuric acid) per acre foot of water treated. For

the home garden, this would be equivalent to 0.5 to 8

teaspoons of fertilizer grade sulfuric acid per 100 gallons

of water. The water will need to be treated each time the

blueberry plants are irrigated. The amount added is

critical, as too much acid will lower the pH below 4.0

and can damage the blueberry plants. It should also be

noted that for secondary irrigation water sources, the

carbonate and bicarbonate content varies over the course

of the season. Therefore, the amount of acid required to

treat your irrigation water will vary somewhat from

spring to fall. For best results, you may need to invest in

a test kit or pH meter to measure water pH, then monitor

your treated irrigation water and periodically adjust the

amount of acid added.

(ⓒ http://usu.edu/, http://extension.usu.edu/files/publications/publication/Horticulture_Furit_2009-01pr.pdf )