Impact of tillage and organic materials management on the physico-chemical properties of a ferric acrisol in the semi-deciduous forest zone of Ghana

Organic materials are important resources for the improvement of soil physical and chemical properties. This study was carried out to examine the impact of tillage and organic materials management on some soil physical and chemical properties and maize grain yield in the semi-deciduous forest zone of Ghana. The experiment was conducted in three seasons (2013 major and minor, and 2014 major seasons) at the experimental field of Crops Research Institute, Kumasi. The experiment was laid in split-plot in Randomized Complete Block Design with four replications. Hoe tillage and no-tillage were assigned to the main plot whilst the subplot comprised cowpea residue, cattle manure, control (no organic residue applied), maize residues and elephant grass. The test crop was maize (variety Obatanpa). Some of the parameters measured include bulk density, porosity, volumetric water content, aggregate stability, hydraulic conductivity, infiltration and infiltration parameters, soil nutrient characteristics, leaf area index and grain yield. Bulk density decreased in 2013 minor season but increased in the 2014 major season for all the treatments. Values recorded in 2013 minor season ranged from 1.34 Mg m-3 to 1.51 Mg m-3. Porosity also ranged from 49.28 - 42.98 % in the second season (2013 minor season). The cattle manure treated plots produced the highest volumetric water content of 20.25 % and the control gave the lowest value of 16.20 % at the end of the last growing season (2014 major season). The highest aggregate stability (74.91 %) was recorded on cattle manure plots whilst the control gave the lowest value (71.11 %). No-till with cowpea residues interacted to produce significantly (P < 0.05) higher hydraulic conductivity than other treatment combinations. The infiltration amount, sorptivity and steady state infiltrability were higher in cowpea residue plots under both tillage treatments. There were positive relationships between organic carbon and sorptivity and steady state infiltrability but the relationships were poor. Soil organic carbon decreased at the end of the last season for all the treatments but the reduction was more rapid in the control plots. The cattle manure gave the highest value of 1.74 % whilst the control produced the lowest value of 0.97 %. The cattle manure and the cowpea residue produced significantly (P < 0.05) higher soil total nitrogen than the control. The cowpea residue plots produced the highest value of 0.14 % whilst the control gave the lowest value of 0.10 %. No-tillage with cattle manure and cowpea residue interactions produced significantly (P < 0.05) higher soil total nitrogen content than the other treatment interactions at the end of the last season. There was a marginal reduction in available phosphorus content at the end of the last season. The cowpea residue produced significantly (P < 0.05) the highest grain yield in the second and third seasons. At the end of the last season (2014 major season), the highest grain yield of 3.28 Mg ha-1 was recorded for cowpea residue plots whilst the lowest value of 2.50 Mg ha-1 was recorded for the control plots. Cattle manure and cowpea residues were identified to be good source of organic material for the improvement of soil physical properties (infiltration and hydraulic conductivity) and crop yield. Proper management of organic materials can help reduce the loss of soil organic carbon and soil nutrients which will lead to sustainable maize yield in the study area.

Source: KNUST