Modelling Soil Compaction Effects on Maize Growth and Yield in a Sandy Loam Soil

Abstract

A mathematical model has been developed for the prediction of soil compaction effects on the growth and yield of maize crop in a sandy loam soil in tropical climates. The field work was done at the teaching and research farm of Rivers State University, Port Harcourt, Nigeria. A plot of land measuring 18 m x 4 m was divided into five sub-plots of equal dimensions and labelled as: plot 1 – un-compacted and untilled; plot 2 – un-compacted but tilled; and plots 3, 4 and 5 - tilled and compacted to varying degrees of tractor passes, viz 2, 4 and 6 tractor passes respectively. A Massey Ferguson (MF) 90 model disc plough was used for the tillage and an MF 260 model tractor used for the soil compaction treatments. Irrigation, weed and pest control were done equally on all plots when necessary. The maize crops were planted in the month of October and grew to maturity fourteen weeks thereafter. Field measurements gave values of soil bulk densities and moisture contents as 1.20, 1.17, 1.23, 1.28 and 1.35 g/cm³ and 5.17, 6.02, 4.89, 4.43 and 3.39% respectively for plots 1-5. The height and yield of the maize crop at the fourteenth week for the plots 1-5 are respectively 0.941, 1.380, 0.872, 1.146 and 1.402 m and 1192, 2859,1195, 1311 and 2320 kg/ha. The model was development based on the response of the maize crop growth and yield to the different levels of compaction treatment, using dimensional analysis. The field results showed that at p<0.05, there is a statistically significant effect between soil compaction and growth and yield of maize in a tropical sandy loam soil and the model predictions correlated experimental data up to about 99.5%.