Studies on Establishment of Italian Ryegrass-Rhodes Grass Pasture by Sod-sowing Method : 2. An Evaluation of Sod-sowing of Rhodes Grass to Italian Ryegrass Field

1. The authors reported in previous paper that introducing method of Italian ryegrass to Rhodes pasture by sod-sowing was promising because of its high yield than that of customary method and its labor saving merit. With similar objectives and technic, field tests were conducted to introduce Rhodes grass by sod-sowing to Italian ryegrass field on volcanic ash soil from 1964 to 1965. In the tests, various sowing periods and sowing systems of Rhodes grass on one hand, and various cutting heights of and amounts of top dressing to Italian ryegrass on the other were taken. Customary plots of plowing under existing Italian ryegrass and sod-sowing of introducing Rhodes grass were taken for comparison. 2. Total dry matter yield of Italian ryegrass was 10-60kg/a higher in non-plowed plot than plowed plot. 3. Total dry matter yield of Rhodes grass was higher in customary plot than any of sod-sown plots, and higher in May sod-sown plot than April and June sod-sown plots. In the plot where regrowth of Italian ryegrass was suppressed by lower fertilization at the time of Rhodes grass sowing, the latter showed better early growth and gave higher yield. In plots where Rhodes grass was broad cast and where it was sown in row, there was no yield difference between them. 4. Sum total of yearly dry matter yields of existing Italian ryegrass and introduced Rhodes grass was 240-260kg/a in May sod-sown plot, and 220-240kg/a in April and June sown Plots. In any of sowing periods, there was not much difference of yield between sod-sown plot and customary plot. 5. It was shown that sod-sown plot gave less forage supply interruption than customary plot throughout a year.