Study of the use of maize and water spinach in a biotest for evaluation of soil fertility 

Chamnanwit Promkot

promkot@yahoo.com

Abstract 

Nine type of soils originated from different places in Cambodia were evaluated by using a biotest with either maize (Zea mays) or water spinach (Ipomoea aquatica) according to a  9x2 factorial arrangement  with four replica per treatment. The growth rate and biomass of plants were correlated with the pH, dry matter and organic matter content of the soil. 

The soils were uncultivated soil, soil under chicken cages, from either unfertilized or effluent fertilized cassava stands, from a eucalyptus plantation, from Kompong Cham province, from a rice field, and an uncultivated soil at the University Campus.  

There was significant interaction (P<0.05) soil x plant type on the criteria under study. There were significant differences (P< 0.05) when plant growth during 23 days was used as criteria of soil fertility. Soil characteristics as evaluated by a chemical approach were positively correlated to plant growth particularly in maize. Plant growth response was significantly different (P<0.05) when maize and water spinach parameters were compared. In both maize and water spinach a positive curvilinear response of biomass weight to level of organic matter of soils was found (R2 0.853 and 0.462 respectively). 

It is suggested that the use of a simple biotest in the evaluation of soil fertility is a practical and economical approach to on farm conditions in integrated farming systems. The maize biotest was better suitable evaluation of soil fertility by the biotest approach than water spinach.   

Key words: soil fertility, maize biotest, water spinach biotest, organic matter 

              

Water spinach grow in soil from chicken pen 23 days

Lay out of experimental unit

Maize grow in soil from 
chicken pen 23 days

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