Factors effecting the establishment of spring-sown Phalaris tuberosa

Abstract

When Phalaris tuberosa L. is sown in spring on short fallow, regenerating plants from the previous sward and invading annuals may compete with and restrict the phalaris. On light textured soils of low fertility at Ginninderra, A.C.T., fallows were prepared by either mouldboard or chisel ploughing with or without rolling after sowing. The effect on yields and density of sown phalaris, of clover oversown in the following autumn, and of competing species was measured. After twelve months the treatments had the following effects : On the unrolled seedbeds yield of Phalaris was 140 per cent higher after mouldboard ploughing than after chisel ploughing ; the yield of competing species was 16 per cent after mouldboard ploughing, and 59 per cent after chisel ploughing. Total yield was higher (+ 18 per cent) on the chisel ploughed seedbed. Rolling decreased yield of Phalaris by 10 per cent after mouldboard ploughing, but increased yield by 76 per cent after chisel ploughing. After three years the yields of Phalaris were still higher and those of competing species lower on the mouldboard ploughed seedbeds. Total yields were the same on both types of seedbed.