(97) BENTONITE AND LEACHING REQUIREMENTS EFFECTS IN IMPROVING SANDY SOIL PROPERTIES AND COWPEA (Vigna spp.) YIELD AND GROWTH

Abstract

The laboratory Experiment was conducted in Falluja city (20 km east of Ramadi) in the autumn season 2006 to study the effects of Bentonite and leaching requirements on some of the soil and plant properties. Sandy loam soil has been selected and classified under (Typic torrifluvent) subgroup; the soil was treated with four levels of Bentonite (B0, B1, B2, B3) as 0% (control), 2%, 4%, and 6%. The soil was planted with cowpea (Vigna spp.) “Rahawiyah” cultivar and was irrigated after 50% exhaustion of field capacity moisture content. Four levels of leaching requirements were applied (W0, W1, W2, W3) as 0% (control), 5%, 10%, and 15%. The results indicated high significant effect for each of Bentonite and leaching requirements separately in decreasing soil EC and pH but the interaction between the two treatments was significant in the same parameters. The two treatments had significantly high effect in decreasing hydraulic conductivity and increasing modulus of rupture for the same soil. The effects of Bentonite and leaching requirements were highly significant in increasing plant height and vegetal dry weight.