Aggregate-associated soil organic carbon and total nitrogen following amendment of puddled and sawah-managed rice soils in southeastern Nigeria

作者：Igwe Charles A^*; Nwite John C; Agharanya Kingsley U; Watanabe Yoshinori; Obalum Sunday E; Okebalama Chinyere B; Wakatsuki Toshiyuki

来源：Archives for Agronomy and Soil Science, 2013, 59(6): 859-874.

DOI：10.1080/03650340.2012.684877

• aggregate-associated carbon
• mean-weight diameter
• soil aggregates
• soil organic carbon
• thixotropic age hardening

Puddling during sawah rice cultivation destabilizes the soil structure. The re-formation of soil water-stable aggregates (WSA) following puddling and amendments, and their associated organic carbon (SOC) and total N were studied at Akaeze and Ikwo in south-eastern Nigeria. The amendments, which were randomized in triplicate, include control, NPK fertilizer, poultry dropping, rice husk powder and rice husk ashes (RHA). Soil samples from 0 to 15 cm depth were taken from the field after 2years of cultivation. Most of the SOC were found in the very fine aggregates. There was no consistent trend in the treatment effects. However, the NPK-amended soils showed the lowest values of WSA>2 mm in both locations, whereas the poultry dropping-amended soils showed the least and the highest mean-weight diameter (MWD) values at Akaeze and Ikwo, respectively. The SOC of the whole soil in Akaeze correlated positively with MWD (r=0.92*). Irrespective of location, SOC in soils and WSA>2.00 mm correlated positively with MWD (r=0.56*; 0.65*, respectively) while SOC in WSA 0.50-0.25 mm accounted for low MWD values. More carbon was sequestered at Akaeze than at Ikwo, with the RHA-amended soils being the highest at both locations.

• 出版日期2013-6-1