Leek growth and productivity in response to light interception and nitrogen nutrition

Abstract

The aim of this project was to investigate the effect of nitrogen supply and light interception on productivity and growth,of leek (Allium porrum L.). A field experiment, with leek hybrid Alita (Royal Sluis, The Netherlands), was carried out with different levels of nitrogen fertilization. Nitrogen was applied as urea at a rate of 250 kg N/ha at different times: a) the whole amount applied just before transplanting (250+0), or twenty days after transplanting plants (0+250). and b) in split application (125+125), where half of the total amount was applied just before transplanting and the other half twenty days after transplanting plants. Plant analysis was based on the determination of the following crop growth, productivity and light interception parameters: dry matter production (W), leaf area index (LAI), light interception (1), cumulative light interception (CI), light use efficiency (LUE) and relative growth rate (RGR). Crop nitrogen crop status was determined as total nitrogen and critical nitrogen concentration in dry matter (Nt; Ne), nitrogen demand (ND) and nitrogen uptake (Nu). Results showed that N fertilizer increasing effect on all investigated parameters, but the effect was dependent on the applied dose of fertilizer. The biggest effect was measured with 125+125 kg N/ha splitted dose. Based on the obtained results and the relationships between light interception, dry weight and LAI, a model of growth and productivity of leek in field conditions was constructed. The main advantage of this model is that it allows monitoring of leek growth and productivity, N status and nitrogen demand during ontogeny using simple and nondestructive measurements.