Residual effects of fallows on selected soil hydraulic properties in a kaolinitic soil subjected to conventional tillage (CT) and no tillage (NT)

Abstract

Improved fallows have been used to reduce time required for soil fertility regeneration after cropping in low input agricultural systems. In semi-arid areas of Southern Africa, Acacia angustissima and Sesbania sesban are among some of the more widely used improved fallow species. However the residual effects of improved fallows on soil hydraulic properties during the cropping phase is not known. The aim of this study was to quantify the residual effects of fallows and tillage imposed at fallow termination on soil hydraulic properties (infiltration rates, hydraulic conductivity and soil porosity) during the cropping phase. Treatments evaluated were planted fallows of Acacia angustissima, Sesbania sesban and natural fallow (NF) and continuous maize as a control. Steady state infiltration rates were measured using a double ring infiltrometer and porosity was calculated as the difference between saturated infiltration rates and tension infiltration measurements on an initially saturated soil. Unsaturated hydraulic conductivity (K o ) and mean pore sizes of water conducting pores were measured using tension infiltrometer at tensions of 5 and 10 cm of water on an initially dry soil. While there was no significant difference in steady state infiltration rates from double ring infiltrometer measurements among the fallow treatments, these were significantly higher than the control. The steady state infiltration rates were 36, 67, 59 and 68 mm h -1 for continuous maize, A. angustissima, S. sesban and NF respectively. Tillage had no significant effect on steady state infiltration rate. Pore density at 5 cm tension was significantly higher in the three fallows than in maize and varied from 285-443 m -2 in fallows, while in continuous maize the pore density was less than 256 m -2 . At 10 cm tension pore density remained significantly higher in fallows and ranged from 4,521-8,911 m -2 compared to 2,689-3,938 m -2 in continuous maize. Unsaturated hydraulic conductivities at 5 cm tension were significantly higher in fallows than in continuous maize and were 0.9, 0.7, 0.8 cm and 0.5 cm h -1 for A. angustissima, S. sesban, NF and continuous maize, respectively. However there were no significant treatment differences at 10 cm tension. Fallows improved infiltration rates, G. Nyamadzawo

Infiltration and runoff losses under fallowing and conservation agriculture practices on contrasting soils, Zimbabwe

“…In improved fallows, legumes are planted on fallow land for 1 to 2 years to improve soil fertility. The other advantage of fallowing is that it also improves soil physical properties, such as infiltration rates, hydraulic conductivity, and soil porosity (Nyamadzawo et al, 2008a), besides reducing soil and nutrient losses through runoff (Nyamadzawo et al, 2003).…”

“…The integration of improved fallowing and conservation tillage can further improve the soil hydraulic properties (Alegre and Rao, 1996;Norwood, 1994), soil water-holding capacity (Nyamadzawo et al, 2008a) and improve organic carbon stocks in soils (Nyamadzawo et al, 2008b). Improved fallows can play an important role in mitigating climate change through carbon sequestration.…”

Fertiliser Trees for Sustainable Food Security in the Maize-Based Production Systems of East and Southern Africa

“…The improvement in soil structure under fertiliser trees was evident, as reflected by the results from time-to-runoff studies (Phiri et al, 2003). Rainfall simulation studies (Nyamadzawo et al, 2007) also indicated that sesbania and gliricidia mixed with Dolichos increased infiltration rates significantly compared with continuously fertilised maize plots.…”

“…2), soil penetration resistance (Fig. 3), and reduced runoff and soil losses (Nyamadzawo et al, 2007;Phiri et al, 2003). Treatments involving fertiliser trees (leucaena, gliricidia, sesbania) have consistently shown significantly higher infiltration rates than monoculture maize (Fig.…”

Changes in Physical Properties Especially, Three Phases, Bulk Density, Porosity and Correlations under No-tillage Clay Loam Soil with Ridge Cultivation of Rain Proof Plastic House

“…3(f) (Taylor et al, 1966;Kim et al, 2010). 그리고 대공극 은 토양침투와 직접적으로 관계가 있고 (Nyamadzawo et al, 2008;Wang et al, 1986) 경운에 의해서 토양특성이 바뀌기 때문에 (Elwell, 1992;Beare et al, 1994) …”