Crop Rotation and Irrigation Influence on Wheat Yield and the Correlations Climate-Yield in the Crişurilor Plain Conditions

Abstract

The paper is based on the researches carried out during 2003-2008 in a long term trial placed in 1990 on the preluvosoil from Oradea. Climate indicator “de Martonne aridity index” (IdM) was used for quantification the correlation between climate and wheat yield in unirrigated and irrigated conditions and new class called “arid” was purposed for climate index characterization. Maintaining the soil water reserve on 0-50 cm depth between easily available water content and field capacity using the irrigation determined the increase of the IdM values for period IV – VI with 79% in 2003, 73% in 2004, 36% in 2005,16% in 2006, 162% in 2007 and with 131% in 2008; using the irrigation and the improvement of the microclimate conditions determined to obtain the yield gains, very significant every year and every crop rotation studied; both in unirrigated conditions and in irrigated conditions, the smallest yields wheat were obtained in monocrop and the biggest in the wheat – maize – soybean crop rotation; in the all three crop rotation, the direct links statistically assured were registered between the values of the De Martonne aridity index and yields in unirrigated and irrigated wheat. These correlations sustain the need of the irrigation in wheat from Crisurilor Plain; correlation between De Martonne aridity index is stronger (R2 = 0.7361xx) in the wheat – maize – soybean crop rotation in comparison with wheat – maize crop rotation (R2 = 0.6215x) and with wheat monocrop (R2 = 0.6105x). As consequence, crop rotation of wheat-maize-soybean is recomanded because the climate and microclimate conditions are better use.