Aluminium species in soil solution and their effects on Rhizobium inoculation and root growth of field beans (phaseolus vulgaris L.) cv "rosecoco"
Nutrient solution experiments were conducted in l a greenhouse to determine the effect of aluminium and i pH on root growth and Rh i 20b i urn inoculation of field beans (Phaseo1 us vulgaris L. > cv "Roseco.o". Nutrient solution pH’s were adjusted to simulate the pH’s of the three soils to be used to perform similar experiments, viz., Gituamba, Kitale and Kabete soils. Experiments were conducted in the greenhouse using the above named soiis sampled at O-lb and 15-30 cm depths. Gituamba soils had the lowest pH and lowest aluminium content and Kabete had the highest pH and content aluminium content. Kitale was intermediate in thes roper tie . Aluminium content in the s i Is was determined colorimetrica11y using the aluminium methoed after leaching the soil with IN KC1 solution. The nutrient solution experiments were performed using Leonard jars. Some inoculated and non- inoculated pregerminated seeds were planted in the jars; after 14 days, the shoots were harvested and dried. The roots were removed and the nodules were counted; taproot length and the root dry matter weights determined. A high negative correlation was found between taproot length and aluminium content