SEEDING RATE AND NITROGEN FERTILIZER LEVEL FOR BLACK BARLEY UNDER RAIN-FED CONDITIONS

Increasing grain production yield is crucial to achieving profitable production systems. The optimal seeding rate and nitrogen fertilization at the right dose are substantial production factors for a higher barley crop yield, especially in rainfed conditions. The experiment aimed to determine the optimal black barley seeding and nitrogen fertilizer rate under rainfed conditions in Kirkuk district, northern Iraq. The agronomic characteristics of black barley were evaluated at seeding rates (200, 300 and 400 seeds m-2) and different rates of nitrogen applications (0, 40 and 80 kg N ha-1). These seeding rates at 300 and 400 seeds m-2 significantly affect Spikes m-2, straw yield and biological yield compared to 200 seeds m-2. Most studied traits were affected significantly by nitrogen fertilizer, where 80 kg N ha-1 recorded the highest value in spike length, m-2, grains spike-1, grain yield, biological yield and harvest index compared to 40 kg N ha-1. Moreover, seeding rate x N fertilization had a significant influence on most of the studied traits, where 300 seeds m-2 × 80 kg N ha-1 significantly affected spike length, spikes m-2, grains spike-1, grain yield and harvest index, while straw yield and biological yield responded significantly to 400 seeds m-2 × 40 kg N ha-1. The most measured traits, especially grain yield, were impacted by nitrogen application rather than seeding rates. In this region, black barley should be sown with 300 seeds m-2 with an application of 80 kg N ha-1 to obtain better grain yields under rainfed conditions. Keywords: Hordeum distichum L.; plant density; urea fertilization; rain-fed agriculture. Taxa de semeadura e nível de fertilizante nitrogenado para cevada preta (Hordeum distichum L.) sob condições de sequeiro RESUMO: O aumento do rendimento da produção de grãos é crucial para a obtenção de sistemas de produção rentáveis. A taxa ótima de semeadura e a fertilização com nitrogênio na dose certa são fatores de produção substanciais para um maior rendimento da cultura da cevada, ...