An ecological study of barley growing under three contrasting regimens of farm management

Abstract

Using barley (Hordeum vulgare L.) as a phytometer, comparisons were made of the three systems of farm management (Organic, Mixed and Stockless), maintained as a long-term experiment by the Soil Research Association (Pye Research Centre) at Haughley in Suffolk. Special attention being paid to the geochemicals of the crops/soil system. Significant differences were indicated between both 'total' and 'available' geochemicals of the three soil systems. The differences of available geochemicals are undoubtedly related to the differing long-term management, especially the continuous and predominant use of organic manures and mulches on both the Organic and Mixed systems. The unexpected differences in total geochemicals (significantly more Ca, Mg and K in the Organic soils) is tentatively explained on the basis of deterioration of soil structural characteristics in the Stockless system, leading to interruption of the supply of geochemicals by capillary water. The data collected allowed crude geochemical budgets for the farm systems to be attempted and the work was, therefore, supplemented by the lysimeter studies. The indications for this work are that the geochemicals in the Organic soil are more readily 'available' to leaching than those of the Stockless soil. Phytometry, using both the old "Rika' barley variety used in the long-term experiment, and the new varieties 'Julia' and 'Sultan', did not, in the main, back up the above findings. This was especially true of the field experiments when environmental factors other than geochemical supply, probably govern the performance of the barley. However, in the majority of cases where significant differences were shown, the Organic system always shows better performance of the plant or greater flux of geochemicals into the plants than the Stockless system. No indication of a developed dependence of the barley on the three farm systems was obtained. Nitrogen fixation by soil microorganisms appear to be unimportant on the Haughley systems.