
%0 Journal Article
%A Parfitt, R. L. 
%A Salt, G. J. 
%A Saggar, S. 
%T Effect of leaching and clay content on carbon and nitrogen mineralisation in maize and pasture soils
%J Soil Research
%D 2001/04/24
%V 39
%N 3
%P 535-542
%K aerobic incubation, allophane, C mineralisation, New Zealand soils.
%R https://doi.org/10.1071/SR00044
%U https://www.publish.csiro.au/paper/SR00044 
%X We conducted a 7-week laboratory incubation experiment to evaluate the effect of leaching on net C and N mineralisation in soils. The soils were collected from adjacent fields of long-term pasture and maize, where each field contained an Inceptisol and an Andisol. The concentration of clay mineral was 200 g/kg halloysite in the Inceptisol and 120 g/kg allophane in the Andisol. Half the samples were leached weekly with 0.002 M CaCl2 at a suction of 20 kPa to remove soluble products, and half were not leached. Carbon mineralisation was determined from CO2-C evolved each week. Net N mineralisation was measured for the leached samples from the NH4-N and NO3-N in the CaCl2 extracts, and for the batch of non-leached samples by extraction in 0.5 M K2SO4. Carbon and net N mineralisation were greater in the soils under pasture than in soils under maize. The proportion of total C mineralised as CO2-C, and of total N mineralised as NH4-N and NO3-N, followed the order Inceptisol-pasture &#62; Inceptisol-maize &#62; Andisol-pasture &#62; Andisol-maize, suggesting that allophane and Al ions reduced net mineralisation. Dissolved organic carbon (DOC) produced during incubation, as a proportion of total C, was greatest for the Inceptisol-maize sample and least for the Andisol-pasture sample. Non-leaching resulted in the accumulation of acids and solutes, and decreased C mineralisation for the Inceptisol samples. 
