The pH of Leaf Water Extracts and Amount of Acid required lowering the pH of Leaf Water Extracts to 5.0
Mr. Njagi E. Silas, Prof. Jane I. Murungi, Dr. R.N. Wanjau

Abstract
Expansion of agricultural activities has led to farms being cultivation throughout the years which, has led to reduction in soil fertility. Use of commercial inorganic fertilizers in these farms tends to be ultimate solution in maintaining high yield. Too much use of inorganic fertilizers has led to low soil pH. Low soil pH reduces availability of essential nutrients to plants, results in formation of toxic chemicals in the soil and leads to low rate of decomposition of organic matter which is required to increase buffering capacity of the soil and also release nutrients. Soil acidity is reduced by liming which, is an expensive exercise and does not add fertility to the soil. There was need to look for alternative to liming materials which would at the same time be adding essential nutrients to the soil. This study was aimed at identifying potential plants whose leaves may be used to raise soil pH. The pH trends of leaf water extracts and the volume of 0.05M sulphuric acid required to reduce pH of the water extracts to 5.0 was determined. The pH of leaf water extract ranged from 3.85 to 8.08 for the 90 days it was monitored. The volume of acid required to reduce pH to 5.0 ranged from 0.1 to 20.7 ml. It was found that leaves of cassia, sunflower, Markhamia lutea, Croton macrostachyus, meru oak, Cordia africana, peacock flower and mexican sunflower produces extracts of high pH and these extracts accommodate large amount of acid before their pH goes below 5.0. These plants should therefore be planted in farms so that their leaves will spread in farms, be used to make manure or make leaf water extracts to be applied in farms.

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