The main objective of this paper is to assess the spatial variability of arbuscular mycorrhizal (AM) spore numbers in following two contrasting soil uses. Adjacent plots, one irrigated farmland and the other dry farmland, were marked on a transect (300 m long), with 10-m spacing. | Turk J Biol 29 (2005) 149-153 © TÜB‹TAK The Effect of Agricultural Practices on the Spatial Variability of Arbuscular Mycorrhiza Spores Ali Akbar Safari SINEGANI, Ali Akbar MAHBOOBI, Farzad NAZARIZADEH Faculty of Agriculture, Bu-Ali Sina University, Hamadan - IRAN Received: Abstract: The main objective of this paper is to assess the spatial variability of arbuscular mycorrhizal (AM) spore numbers in following two contrasting soil uses. Adjacent plots, one irrigated farmland and the other dry farmland, were marked on a transect (300 m long), with 10-m spacing. Soil samples were collected at 0–30 and 30–60 cm depth and were then analyzed for AM spore numbers and some other soil properties. The analytical results were submitted to different kinds of analysis: classical statistical and geostatistical analysis which showed that coefficient of variations (CV’s) and standard deviations for spore numbers in both farmlands were considerably low. Variations of spore numbers in irrigated farmland was lower than those in dry farmland. The soils of irrigated farmland was found to be much more homogeneous than the adjacent dry farmland soil. The results showed that in both farmland, CV’s of spores numbers in topsoil horizon were lower than those of subsoil horizon. The pattern of spatial variability of this soil property was found to be different for the two lands. Spore numbers of AM fungi in topsoil and subsoil of irrigated farmland exhibited spatial dependence at the sampled scale and their experimental semivariograms were adjusted to a spherical and linear model respectively. However these data for dry farmland did not exhibit spatial dependence. Key Words: Spatial variability, AM spore numbers, irrigated and dry farmlands Introduction Spatial variability in soils occurs naturally from pedogenetic factors. In addition, much variability can occur as a result of land use and management. As a consequence, soils can exhibit marked spatial variability at the macro-
