Flyash as a soil conditioner and fertilizer

Abstract

Field experiments were conducted in villages around the National Capital Power Project, Ghaziabad, Uttar Pradesh and IARI Farm, New Delhi to evaluate the effects of flyash incorporation on soil properties and the growth and yield of wheat ( Triticum aestivum L.), mustard ( Brassica juncea L.), rice ( Oryza sativa L.) and maize (Zea mays L.). Flyash application levels (up to 50 t/ha) were decided on the basis of an ash/dust fall range of 5–12 t/ha/y in villages adjoining the thermal power station. The grain yield of maize increased in flyash-treated plots with the addition of ash up to a maximum addition of 10 t/ha. Dusting crop canopies with ash decreased the yield in proportion to the amount applied. The yield of wheat increased up to an addition of ash of 20 t/ha, and declined thereafter, but was still higher than the yield when no flyash was added. Paddy yield when 10 t/ha of ash was added was similar to that with no flyash, whereas mustard showed improvements in seed yield with flyash addition at 10 t/ha level. Flyash-treated plots had a marginally higher uptake of Zn, Cu, Fe, Mn and Cd. Flyash addition to soil resulted in lower bulk density, although the differences compared with non-treated plots were not significant. The addition of flyash also reduced the hydraulic conductivity and improved moisture retention at field capacity and wilting point, but no changes in available water were observed. These changes in soil properties might have been due to modifications in macro- and micro-pore size distribution and which may also have contributed to the increased crop yields in light- and medium-textured soils. However, the effects of ash addition on soil health and crop productivity need to be established with long-term studies.