Spring barley (Hordeum vulgare L.) Responses to Soil Injected Liquid Ammonium Nutrition under Different Growth Temperatures

Abstract

Controlled chamber experiments were performed at Braunschweig, Germany to examine the potential effects of global warming on spring barley (Hordeum vulgare L.) shoot and root biomass accumulation, yield forming structures (tillers) and attainable grain yield through the adoption of a novel fertilization technique that injects liquid ammonium nutrition into soil for crop uptake. Three growth temperature regimes; low (Temperate), medium (Intermediate) and high (Tropical) were set to mimic different climatic conditions experienced globally. Each temperature regime comprised of three nitrogen fertilization treatments of which conventional nitrate application and non-fertilized control were compared to soil injected liquid ammonium nutrition herein referred to as Controlled Uptake Long Term Ammonium Nutrition (CULTAN). Each of the three nitrogen treatments was replicated twice in each of the three temperature regimes. The experiment was repeated in two seasons during which chamber randomization was performed eliminate chamber effects. Nitrogen fertilized barley attained superior grain yields under low temperature regime (LTR) as compared to high temperature regimes (HTR). Similarly, low temperature regimes supported higher shoot and root biomasses, more tillers and ear bearing tillers than the other two temperature regimes. Grain yields were correlated to ear bearing tillers and grain numbers. Low temperature regime supported more grains that weighed less per grain in comparison to warmer temperatures which compensated for less grain numbers by heavy grains. This is the first time interaction effects between soil injected liquid ammonium nutrition (CULTAN fertilization) and temperature regimes have been reported in a cereal crop production model. The results demonstrate that growth temperatures and nitrogen nutrition forms jointly can cause a suite of responses on barley growth and yield formation with potential for exploitation in enhancement of food security.