The influence of plant population, nitrogen and irrigation on yield and yield components of linseed

A field trial was carried out on a Wakanui silt loam from December 2003 to April 2004 at Lincoln University, Canterbury to determine the influence of irrigation level (nil and full), nitrogen (N) (0 and 150 kg/ha N) and a range of plant populations (238, 389, 583 and 769 plants/m(2)) on yield and yield components of linseed (Linum usitatissimum (L.) Griesb.). The design was a split plot with irrigation as main plots and factorial combinations of N and plant population as sub-plots. Linseed seed, straw and total dry matter (TDM) yield responded well to irrigation. Total dry matter production increased with irrigation from 509 g/m(2) to 763 g/m(2). The main effects of plant population on seed and straw yield were also significant. However, N and plant density did not influence TDM production. The fibre yield/plant in irrigated plots was three times more than in rainfed plants. Without irrigation, fibre yield/plant did not respond to N. In irrigated plots, plants given 150 kg N/ha produced nearly twice as much fibre (0.8 g/plant) than plants which received no N (0.5 g/plant). Plant population influenced production of primary branches more in irrigated plants than in unirrigated plants. Seed yield components except for the thousand seed weight (TSW), responded favourably to irrigation. Addition of N had no effect on yield components except for seed yield/plant. Increasing the plant population reduced capsule production/plant. Under dryland conditions plant population had little effect on capsule number/plant and seed yield. However, there was a large effect in plants from irrigated plots.