Low Input Weed Management in Field Peas

Abstract

Two trials were conducted on a Templeton silt loam soil at Lincoln University, New Zealand (43 ° 38' S, 172 o 28' E.) in 2007/08. The aim was to compare the competitive ability of different pea canopy architectures as influenced by genotype, population, sowing date and their interaction as a means of low input weed control strategy. The first experiment had three sowing dates, two pea genotypes and two herbicide treatments. Experiment 2 treatments were a factorial combination of four pea populations and three sown artificial weed populations. A significant sowing date x pea genotype interaction showed that in the August sowing genotype had no effect on seed yield. However, in September sown plots Pro 7035 yielded 559 g m^-2, which was 40% more than Midichi, and in the October sowing, the difference was 87% more. Herbicide-sprayed peas produced 19% more seed (508 g m^-2) than the unsprayed plants. When no weeds were sown, the highest pea total dry matter (TDM) of 1,129 g m^-2 occurred at 200 plants m^-2. This was more than twice (513 g m^-2) the yield of the lowest population (50 plants m^-2). There was distinct variation in the weed spectrum over time. Coronopus didymus, Stellaria media and Lolium spp were present in relatively large numbers throughout the season. Some weeds only occurred late in the season meaning they could be successfully controlled by early sowing. It could be concluded that it is possible to obtain high pea yields by using the right sowing date and appropriate seed rate as a means of low input weed management strategy.