Effect of Fertilizers and Fly Ash Addition on Suction–Water Content Relationship of a Sandy Soil: Fid-Bau Portal

Effect of Fertilizers and Fly Ash Addition on Suction–Water Content Relationship of a Sandy Soil

Malaya, C. / Sreedeep, S.

Abstract Past studies indicate different factors influencing the suction–water content relationship (SWR) of soil especially in the low range of suction. Tensiometer measures low soil suction directly with its range generally less than 100 kPa. It is extensively used in agriculture for optimizing the use of water by determining the initiation and duration of irrigation. The basis of irrigation scheduling is the monitoring of soil water potential (suction) at which the plant roots can draw moisture with ease. An appropriate irrigation scheduling protocol will depend upon the precise soil water potential measured using tensiometer. It is not clear from the literature on the effect of additives like fertilizers and fly ash on the soil SWR measured using a tensiometer. Tensiometer cup is a ceramic (clay) that has a possibility of acting as semi-permeable membrane. This can lead to osmosis when the soil contains additives. Therefore, it is important to understand whether the tensiometer measurements are affected by the presence of additives in the soils. This study evaluated the tensiometer measurements in locally available non-plastic sandy soil mixed with fertilizer or fly ash by using two different suction measurement procedures. The study indicated that the additives in the form of solid inclusions would alter the water retention measurement using tensiometer. The liquid inclusions were not capable of developing semipermeable membrane effect in the ceramic tip of the tensiometer and hence the water retention of soil remains unaltered.