Evaluation of the potential of zeolite as a soil conditioner for two Zambian soils – Makungwe, Mirriam.
Evaluation of the potential of zeolite as a soil conditioner for two Zambian soils – Makungwe, Mirriam.
Degree: 2015, University of Zambia
Highly weathered soils are characterised by poor nutrient and water-holding capacities, thereby limiting soil productivity. This study was conducted to investigate the potential for improving soil productivity by amending soils with zeolite to enhance moisture and cation retention capacities. Two experiments were carried out: i) In the first experiment, an ALISOL and an ACRISOL were each amended with zeolite to increase the cation exchange capacity (CEC) by 0, 25, 50, 75, 100 and 125 per cent. The mixtures were placed in pots and allowed to reach equilibrium for a period of six weeks, after which soil moisture retention and CEC were determined. ii) In the second experiment, the agronomic performance of zeolite was evaluated on the same soils used in the first experiment. A factorial experiment was carried out in the greenhouse with five levels of urea (0, 1, 2, 3, 4 g per plant) as the main plot, and zeolite to increase CEC by 0, 25, 50, 75 and 100 per cent as the sub-plot. Maize was used as the test crop and was harvested at the end of eight weeks, when dry matter yield was determined. Significant (p<0.05) increases in moisture retention and CEC were observed. For every gram of zeolite added to a kilogram of soil, plant-available water increased by 0.12 per cent for ACRISOL and by a non-significant 0.02 per cent for ALISOL. Soil CEC increased by 0.10 cmol/kg and 0.11 cmol/kg for ALISOL and ACRISOL respectively. A combination of urea at 2 g/pot and zeolite at 100 per cent of CEC increased maize dry matter yield by 75 per cent in ALISOL and 57 per cent in ACRISOL. When the zeolite application rate exceeded 16.21 g/kg of soil (36.58% in ALISOL and 60.27% in ACRISOL), maize dry matter yield declined. This was found to correlate with a decline in maize tolerance to increasing sodium (Na) concentrations. This study has shown that, within a limited range, the addition of zeolite IV to soils can help increase soil productivity by enhancing soil moisture retention and cation exchange capacity.
Subjects/Keywords: Soil Conditioner; Zeolite; Moisture Retention; Nutrient Retention
source: oatd.org