Impact of time of sowing, temperature and irrigation on faba bean (Vicia faba) productivity in northern NSW

Abstract

Faba bean is a significant rotation crop in northern NSW and is susceptible to drought while the reproductive structures are sensitive to high temperatures. For high yield, early sowing allows accumulation of a large biomass and avoidance of terminal stress. Trials at Breeza and Narrabri in North West New South Wales examined the influence of sowing date on yield components, maturity, pod distribution and biomass production and at Breeza the influence of irrigation was also examined. Tagged plants were used to study pod development in relationship to temperature regimes. Sowing in early May produced the highest yield and seed weight at both sites. At Breeza the latest sowing date produced greater yield than the earliest and this was associated with very high final biomass at the earliest sowing date. At Narrabri the earliest sowing date yielded similar to the latest indicating that early sowing was less detrimental to yield at Narrabri. Poor yield in late sown material is likely due to terminal stress and is more likely in less favourable locations and seasons. Poor yield in early sown material is likely due to production of excessive biomass in favourable seasons and locations. Irrigation had no impact on yield but reduced harvest index and seed weight. Lower seed weight overall was observed at the Breeza site possibly as a result of intraplant competition. The quickest maturing genotype, gave the highest yield and seed weight at both sites. Dry matter production was greater with early sowing, higher moisture and warmer temperatures. In contrast to other studies, a weak relationship between biomass and yield was observed. Production of pods was maximized with average daily temperatures in the range of 12.5 – 13.5 °C, daily maximum in the range 23.5 – 25.5 °C and daily minimum in the range of 3 – 4 °C.