Effects of tillage induced soil physical and hydrological properties on the soil water balance and the growth of sorghum in the semi arid areas of Tanzania.
| dc.contributor.author | Chenjerayi, Guzha Alphonce | |
| dc.date.accessioned | 2026-03-26T12:04:41Z | |
| dc.date.available | 2026-03-26T12:04:41Z | |
| dc.date.issued | 1997 | |
| dc.description | Dissertation | |
| dc.description.abstract | Conservation of soil water is an important management objective for crop production objective is thus imperative. The integrated effects of tillage-induced soil physical and hydrologic properties on soil water balance on a sandy loam soil were evaluated. The field experiment consisted of five tillage treatments, namely tied ridging (TR), no till (NT), disc plough (DP), strip catchment tillage (SCT), and hand hoe (HH). Data measured in the field included soil moisture content, bulk density, surface roughness, infiltration, surface runoff and evaporation. Infiltration rates and depths were higher for the tilled soils than the untilled soils. The DP treatment had the highest cumulative infiltration. TR had low cumulative infiltration not significantly different from the NT treatment. SCT and HH treatments had almost similar values for cumulative infiltration but less than DP. The Kostiakov (1932) and Phillip (1957) infiltration models were fitted to the infiltration data and gave good fit. Depression storage determined using Mitchell and Jones (1976) depth-storage model was highest in the TR treatment. The higher the surface roughness the greater the depression storage volume. Regression analysis showed that random roughness decreased exponentially with increase in rainfall. Tillage increased total porosity and the DP plots in the semi arid tropics. Identification of the best tillage methods to achieve thishad the highest values. However total porosity decreased with cumulative rainfall in all treatments. Evaporation experiment results showed that a more open tillage-induced surface structure increased evaporation losses particularly during the first stages of evaporation. This resulted in higher cumulative losses for the DP and HH tilled soils than the other treatments. It therefore appeared that the acclaimed beneficial "soil mulch" effect was masked by the initial higher evaporation losses from the tilled soils under the atmospheric evaporative demands of the study area. Mean separation of the measured soil moisture showed significantly higher levels of soil moisture in the TR plots than the other treatments. Higher soil moisture contents were associated with treatments having higher depression storage. Field measured surface runoff after each rain storm also showed marked differences between the treatments. The tied ridged plots had the least runoff while the NT plots recorded very high runoff losses. Saturated conductivities estimated using van Genutchen model were highest in the DP soils and lowest in the NT soils. Analysis of the pF curves revealed that tillage reduced available water content and the NT had the highest total available water among all the treatments. | |
| dc.description.sponsorship | GTZ/SACCAR | |
| dc.identifier.uri | https://www.suaire.sua.ac.tz/handle/20.500.14820/7457 | |
| dc.language.iso | en | |
| dc.publisher | Sokoine University of Agriculture | |
| dc.subject | Hydrological properties | |
| dc.subject | Soil physical | |
| dc.subject | Soil water | |
| dc.subject | Water balance | |
| dc.subject | Sandy loam | |
| dc.subject | Sorghum | |
| dc.title | Effects of tillage induced soil physical and hydrological properties on the soil water balance and the growth of sorghum in the semi arid areas of Tanzania. | |
| dc.type | Thesis |