Download - New Zealand Society of Soil Science

Abstract
Increasing atmospheric CO 2 concentrations are expected to affect ecosystems processes, and while a
New Zealand study reported a response in soil biological activity after 4 years of CO 2 enrichment,
apparently reflecting increased populations of Longidorus elongatus, similar findings have not been
reported from other sites. Soil microfauna in 0–10 cm soil under a sheep-grazed pasture on a sand was
assessed quarterly in FACE rings that were either at ambient CO 2 or had been exposed to 475 μl l -1
CO 2 for some 9 years. Although the area had been subject to a severe drought and microfaunal
populations were lower than previously found, the effects of elevated CO 2 on microfaunal populations
were broadly similar to those at 4 years. Average populations of the root-feeding Longidorus
elongatus increased from 67,000 to 233,000 m -2 (3.48×) compared with a 4.26× increase after 4 years,
microbial-feeding nematodes increased slightly, while predacious nematodes showed a 2.0× increase.
A pot experiment showed an additive effect of elevated CO 2 and L. elongatus abundance in reducing
specific root length. That similar effects have been found 4 and 9 years after CO 2 enrichment
commenced suggests they are real, and emphasises the difference to other sites around the world
where much lower responses to elevated CO 2 have been found. This, in part, reflects the unique
combination of soil, plant and soil biological conditions at each site and confirms the strong effect of
soil type and vegetation on soil biological processes. Just as the effects of global climate change on a
given region are idiosyncratic, so it seems are the effects of elevated CO 2 on soil and ecosystem
processes. In part, this reflects our limited understanding of below-ground processes.
Biology and Fertility of Soils 45,799-808, 2009
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Interpretation of pre-AD 472 Roman soils from physicochemical and
mineralogical properties of buried tephric paleosols at Somma
Vesuviana ruin, southwest Italy
Yudzuru Inoue A , Jamsranjav Baasansuren B , Makiko Watanabe C , Hiroyuki Kamei D , and David J. Lowe E
A
Center of Advanced Instrumental Analysis, Kyushu University, 6-1 Kasuga- kouen,
Kasuga, Fukuoka 816-8580, Japan. B Center for Global Environmental Research, National Institute for
Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan. C Graduate School of Urban
Environmental Sciences, Tokyo Metropolitan University,1-1, Minami-Osawa, Hachioji, Tokyo 192-0397,
Japan. D Graduate School of Information Science and Engineering, Tokyo Institute of Technology, 2-12-1
Ookayama, Meguro-ku, Tokyo, 152-8552, Japan. E Department of Earth and Ocean Sciences, University of
Waikato, Private Bag 3105 Hamilton, New Zealand 3240
Abstract
This study aimed to interpret soil fertility around Somma Vesuviana in ancient Rome from
investigation of buried paleosols developed beneath thick pumice deposits of the AD 472 Pollena
eruption of Mt. Vesuvius. Two buried pedons derived mainly from phonolitic tephra deposits of the
AD 79 Pompeii eruption, and ancient construction waste, were excavated and sampled at the Somma
Vesuviana villa ruins on the northern flanks of Mt. Vesuvius, Italy. For comparison, a buried paleosol
on equivalent Pompeii tephra deposits in a nearby forest, and a modern soil on AD 1631 tephra
deposits (compositionally similar to Pompeii eruptives) in an adjacent orchard, were similarly
analyzed for physical, chemical, and mineralogical properties, including phosphorus fractions and
primary mineral compositions. The two buried pedons in the ruin had abundant available P and K and
contained moderate amounts of exchangeable cations. Leucite was the dominant primary mineral and,
with alkali feldspars, is probably the major source of K in the buried horizons. A high content of
―authigenic P (Ca-bound P)‖ characterized all the pedons. We concluded that the buried Somma
Vesuviana paleosols had a relatively high ability to supply nutrients and that they were fertile prior to
the AD 472 eruption, although manuring to increase nitrogen was probably needed to maintain high
productivity. Their physical properties such as water retention were probably enhanced by small but
significant amounts of short-range order clays.
Source: Geoderma (2009) 152, 243-251.
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