
%0 Journal Article
%A Parfitt, R. L. 
%A Parshotam, A. 
%A Salt, G. J. 
%T Carbon turnover in two soils with contrasting mineralogy under long-term maize and pasture
%J Soil Research
%D 2002/02/06
%V 40
%N 1
%P 127-136
%K clover, grass, New Zealand soils.
%R https://doi.org/10.1071/SR00105
%U https://www.publish.csiro.au/paper/SR00105 
%X Total organic carbon (C) and natural 13C abundance were measured in adjacent allophanic soils (Andisols) and non-allophanic soils (Inceptisols) under maize (Zea mays L.) and ryegrass pasture (Lolium perenne L.) to assess the C turnover rate in soils of contrasting mineralogy and specific surface area. The allophanic soil contained more total C than the non-allophanic soil (139 v. 101 t C&sol;ha in the upper 0&#8211;35 cm) but neither soil showed a significant difference in C content between pasture and maize, provided maize residue was retained and incorporated. The gross annual inputs under maize and pasture were both estimated to be about 9 t C&sol;ha, consistent with the similar soil total C contents. Since the soil total C content did not appear to change with time, the gross C mineralisation was about 9 t C&sol;ha each year. The proportion of old pasture C remaining in the soil after maize cropping for 25 years was about 78&percnt; in the allophanic soils and about 69&percnt; in the non-allophanic soils, reflecting the influence of both Al and allophane, with its high specific surface area, on the retention of old C. The maize C retained in 25 years was similar in both the allophanic soil and the non-allophanic soil (29 t&sol;ha). Therefore, the higher total C content of the allophanic soil would appear to arise from stabilisation of old pasture and forest C by Al and allophane. clover, grass, New Zealand soils. 
