Effect of cattle manure application on the gaseous regime of a sandy soil
2005
Hossain, M.S. | Barrington, S.F. | Barthakur, N.N.
Organic amendments are essential to the sustainability of soils, as they help maintain the soil's physical and chemical properties. But, when applied in large dosage amounts, these amendments can drastically change the soil gas composition and have detrimental effects on plant roots and the microbial population. For 208 h, the present study monitored the O2 deficit and loads of CO2 and NH3 in 750 mm deep sand columns, after applying cattle manure at rates equivalent to 0, 20, 40 and 80 tons/ha, within a layer at a depth of 150 mm to 250 mm. Also, a first order model using a manure biological oxygen demand (BOD) reaction rate coefficient k1 and a soil re-aeration rate k2 were used to model the O2 deficit occurring over time in the soil columns. The results indicated that all three gases demonstrated a peak O2 deficit, and loads of CO2 and NH3 after 16 h of manure application and in proportion with the rate of manure application. These peaks dropped quickly during the next 24 h, followed by a steady state up to 168 h and then a gradual loss of gas deficit and loads thereafter. This indicated that the manure/soil layer, at a depth of 150 mm to 250 mm, started to loose its permeability, 24 h after applying the manure. The first order model adequately simulated the soil column O2 deficit and loads of CO2 and NH3, as long as the value of the re-aeration rate k2 drops exponentially with time, as of 24 h. More research work is required to be able to predict the manure/soil gas permeability and its effect on the soil's gaseous regime.
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