Effects of compost, mycorrhiza, manure and fertilizer on some physical properties of a Chromoxerert soil

Addition of organic materials of various origins to soil has been one of the most common rehabilitation practices to improve soil physical properties. Mycorrhiza has been known to play a significant role in forming stable soil aggregates. In this study. a 5-year field experiment was conducted to explore the role of mycorrhizal inoculation and organic fertilizers on the alteration of physical properties of a semi-arid Mediterranean soil (Entic Chromoxerert, Arik clay-loam soil). From 1995 to 1999. wheat (Triticum aestivum L.), pepper (Capsicum annumn L.), maize (Zea mays L.) and wheat were sequentially planted with one of five fertilizers: (1) control, (2) inorganic (160-26-83 kg N-P-K ha(-1)), (3) compost at 25 t ha(-1), (4) farm manure at 25 t ha(-1) and (5) mycorrhiza-inoculated compost at 10 t ha(-1). Soil physical properties were significantly affected by organic fertilizers. For soil depths of 0-15 and 15-30 cm, mean weight diameter (MWD) was highest under the manure treatment while total porosity and saturated hydraulic conductivity were highest under the compost treatment. For a soil depth of 0-15 cm, the compost and manure-treated plots significantly decreased soil bulk density and increased soil organic matter concentration compared with other treatments. Compost and manure treatments increased available water content (AWC) of soils by 86 and 56%, respectively. The effect of inorganic fertilizer treatment on most soil physical properties was insignificant (P > 0.05) compared with the control. Mycorrhizal inoculation + compost was more effective in improving soil physical properties than the inorganic treatment. Organic fertilizer sources were shown to have major positive effects on soil physical properties. (C) 2004 Elsevier B.V. All rights reserved.