Water and nitrogen stress effects on canopy development and biomass allocation in fodder beet (Beta vulgaris L.)

Abstract

ABSTRACT The effects of water stress on fodder beet (Beta vulgaris L.) production in the field are confounded by the influences of variable inter- and intra-season rainfall. In this study, a rain shelter experiment investigated the effect of water and nitrogen (N) stress on dry matter (DM) production, DM allocation and N partitioning in fodder beet (‘Rivage’). Two water-management treatments, irrigated (replacement of the profile water lost weekly) and unirrigated (limited water applied only during fertigation), and three fertiliser N treatments (0, 50 and 300 kg N ha−1 (hereafter, 0N, 50N, 300N)) were evaluated during the 2016–2017 season. Under irrigation, the yield was greater (P = .02) for the 50N than 0N treatments (29.4 and 24.9 t DM ha−1, respectively). Yield did not differ (P = .42) between irrigated 50N and 300N (30.6 t DM ha−1) treatments, indicating surplus N application to the latter. Water and N stress restricted leaf growth, lowered N uptake and reduced yield by 48%–51%. Surplus N in irrigated 300N treatments resulted in increased N uptake and leaf proportion but reduced the storage root proportion. These results demonstrate the plasticity of fodder beet biomass and N allocation in adapting to the availability of water and N.