The short term effect of tillage on soil physicochemical properties in Bayelsa State, Nigeria

Abstract

The objective of the research was to determine the effect of different tillage methods on some soil physicochemical properties in Niger Delta University Teaching and Research Farms. The land was divided into plots measuring 5 x 5 m with three replicates per treatment. Five tillage treatments considered were: No Till, hoeing, digging, hoeing + digging once, and hoeing + digging twice. Two samples were collected per plot at 0-15 cm and 15-30 cm depth. A total number of thirty (30) samples were collected from the field. The research was laid out using the Randomized Complete Block Design. Results showed that the tillage methods had no significant effect on the soil's chemical properties but influenced the physical. Mean pH across all plots ranged from 4.42–4.49 indicating strongly acidic state, electrical conductivity ranged 65.67-82 dS m-1 indicating no salinity stress, detrimental to crops; organic carbon and organic matter were moderate with a range of 18.52-21.55 g kg-1 and 37.03-43.10 g kg-1 respectively. Total nitrogen was at its moderate range of 7.88-12.17 g kg-1. Exchangeable acidity was low with a range of 1.52-1.71 cmol kg-1. The tillage methods influenced soil bulk density and porosity; the highest bulk density was recorded in the NT zone (1.18 g cm-3) which decreased steadily with an increase in tillage intensity. With the hoe+digging (twice) recording the lowest value of 0.94 g cm-3. Similarly, the highest porosity value was found in the tillage method with the lowest bulk density value (0.94 g cm-3: 64.7%), while the lowest was observed in the tillage method with the highest bulk density value (1.18 g cm-3: 55.7%). pH had positive correlation (P<0.05) with electrical conductivity (r=0.62), organic carbon (r=0.94), organic matter (r=0.90), and negative correlation with exchangeable acidity (r=-0.52). Organic carbon had strong positive correlation with organic matter (r=0.99), effective cation exchange capacity (r=0.69), clay (r=0.50), and total nitrogen (r=0.61). Silt (r=0.74) and clay (r=0.70) showed positive relationship with bulk density, while bulk density (r= -0.99) showed strong negative correlation with porosity. It is therefore recommended that crude tillage methods be used for sustainable and conservative agriculture.