Effects of Long Run Rotary Tilling on Soil Structure and Maize (Zea mays L) Root Growth

An experiment was conducted to examine the influence of soil aggregate size on maize root growth and development. The loamy soil samples resulted from different number of passes of rotary tilling experimental runs under the controlled soil bin were selected. The soil texture chosen in this study was sandy loam. The soil samples were obtained after the interval of 10 passes of rotary tilling (10, 20, 30, 40, 50, 60 passes) at moisture content of 10.28 % (w.b). Soil samples collected were kept for the pot experiment. The roots were analysed at 8DAE, 16DAE, and 24DAE for their early growth. Duncan’s multiple range tests for the effect of soil aggregate size on root growth showed the decrease in root growth in soil aggregates finer than 1.5 mm. The decline in root length considerable after 30 passes of rotary tilling (40 passes:74.32cm, 50passes:63.77cm, 60passes:46.63cm).The declined root growth in soil aggregates finer than 1.5mm was attributed to continuous rotary tilling deteriorated the soil structure and hindered the root growth. The soil structure starts degrading with excessive application of rotavator and which in turn develops compacted soil layers in 20-30cm sub soil depth.