Growth of crop and weeds in growth chambers and outdoors

Abstract

The early growth of spring barley (Hordeum vulgare L.), Brassica rapa L. ssp. oleifera (DC.) Metzger, Stellaria media (L.) Vill. and Viola arvensis Murray in growth chambers and in shading cages outdoors at different irradiance levels was compared. Leaf area and shoot dry weight were lower outdoors than in growth chambers at similar irradiance and temperature. A simulation model with temperature and irradiance responses derived from growth-chamber experiments was used to test whether outdoor growth could be estimated properly. The correlations of the regressions between simulated and measured values of leaf area index (LAI) and shoot dry weight were high. However, with some exceptions, overestimations occurred, more for shoot dry weight than for LAI, and more for 100% daylight than for lower irradiance. The reasons for this are discussed.