The canopy structure of the naked and husked forms of spring barley under different conditions of crop protection

Cezary Kwiatkowski

Marian Wesołowski

Abstract

A field experiment with spring barley was conducted in 2002–2003 in Czesławice (Lublin Agricultural University). The experiment was localized on loess soil classified as the second evaluation class. The soil was characterized by light acid reaction and high content of available forms of phosphorus, potassium and magnesium. Two forms of barley naked (Rastik variety) and husked (Rataj variety) were tested. Extensive protection of the canopy consisted of seed dressing and mechanical weed removal (harrowing). In the intensive variant herbicides, fungicides, insecticides and growth regulators were additionally applied. Mineral fertilization on all treatments was identical: an N – 40, P – 50, K – 60 kg ha^-1. The forecrop prior to the spring barley was the potato on manure (30 t ha^-1). The sowing rate for both forms of barley was identical and equalled 300 grains per one square metre (140 kg ha^-1). The research objective was the analysis of the differences in the structure of spring barley canopy under conditions of differentiated crop protection. The productivity of individual ears of spring barley was in close relation with their distribution within the canopy. The shortening of the shoot length by 10 cm led to a radical and systematic decrease in the weight and number of grains per ear. The grain yield per one spike from the shortest stems (< 50 cm) was only 20% of the yield obtained from the longest (>80 cm) shoots. The canopy of the naked barley was characterized by a reduced percentage of short shoots and increased percentage of both long and the longest shoots in relation to the husked form. Extensive protection of spring barley caused wide differentiation of the canopy, while intensive protection decreased this differentiation. The highest grain yield of spring barley was obtained from sowings of the naked form with intensive protection.