Variations in Soil Physical Properties in a Cleared Forestland Continuously Cultivated for Seven Years in Eastern Nsukka, Nigeria

• Published in: Communications in Soil Science and Plant Analysis Vol. 41; no. 1-4; pp. 123 - 132
• Main Authors: Asadu, C.L.A, Obasi, S.C, Dixon, A.G.O
• Format: Journal Article
• Language: English
• Published: Philadelphia Taylor & Francis Group, LLC 15.01.2010; Taylor & Francis Ltd
• Subjects: agricultural soils; Bulk density; continuous cropping; crops; cultivation; forest soil; Forest soils; land use change; Nigeria; particle size; particle sizes; Physical properties; porosity; soil physical properties; soil pore system; Nigeria
• ISSN: 0010-3624; 1532-2416; 1532-4133
• DOI: 10.1080/00103620903426931

In this study, soil physical properties were evaluated in the top 40 cm of cleared forestland that had been subjected to continuous cultivation for 7 years to ascertain selected crop or crop combinations that influenced the soil physical properties the most. There was no significant effect of crop treatment on particle-size distributions over 6 years of cultivation. In year 7, clay values were significantly (p = 0.05) greater in plots grown with solely cassava (SC) and solely maize (SM) than in the plots grown with solely pigeon pea (SP). The soil depth effects over the 7 years were significant on the clay content. The mean values of bulk density, pore-size distribution, and hydraulic conductivity obtained from each plot fluctuated over the years. The bulk density values in 1998 ranged from 1.29 to 1.43 g cm3, but from 1999 to 2004, the range was from 1.12 to 1.40 g cm3. Thus, bulk density generally decreased when compared with their respective values in 1998. The greatest decrease of ≈ 22% was in 2000. More than 70% of the macroporosity values were significantly less than their respective values in 1998. The greatest decease of 72% was obtained from SM plots in 2001. All the microporosity were significantly more than the 1998 values. All the increases were >100% of the original values. These increases were reflected in the variations of total and saturated hydraulic conductivity (Ks) values. However, in 2004, Ks values decreased in the plots grown to C + P, SP, and SM. Generally, the C + M + P mixture appeared to be the most consistent in improving micro- and total porosities and Ks among the crop treatments.