Seedling emergence and growth of winter barley as affected by sowing date and sowing depth: a dissertation submitted in partial fulfilment of the requirements for the degree of Bachelor of Agricultural Science with Honours in the University of Canterbury

Abstract

Establishment and growth of winter barley, c.v. "Illia", was compared at five sowing dates (22 April, 2, 14 and 30 May and 20 June) and two nominal sowing depths (20 mm and 50 mm) at Lincoln, Canterbury. Seedling emergence rate, total emergence and canopy development (number of leaves on the main stern, number of tillers and dry matter accumulation) were measured. A high level of total emergence (83-93%) resulted from all treatment combinations. Early May sowings provided rapid establishment and the highest total emergence. Seedling emergence rate and total emergence declined as sowing date was delayed. Soil temperatures in the seed zone were monitored. The minimum temperature for emergence was estimated at 2.4°c from the relationship of emergence rate and soil temperature. Actual sowing depth of 19-50 mm did not markedly affect seedling establishment and growth. The highest level of canopy development was found in the 22 April sowing and was related to the greatest accumulation of day degrees.

Seedling establishment from five sowing depths (30,60, 90, 120 and 150 mm) was evaluated in a controlled environment experiment. Increasing sowing depth from 30 - 120 mm delayed the duration from sowing to initial emergence by 10 days and reduced final emergence (92% and 5% at 30 mm and 120 mm respectively). No seedlings emerged at 150 mm. The low establishment was caused by the seedlings failing to reach the soil surface, rather than seeds not germinating at depth.

The effect of temperature (1, 2, 3, 5, 15 and 20°c) on seed germination was determined in a controlled environment experiment. Optimum and minimum temperatures for germination were 15°C and -0.6° C respectively. Germination rate and total germination declined as temperature was reduced.

Soil temperature and sowing depth controlled rate of seedling emergence and establishment while seedling growth was related to the accumulation of day degrees.