Effects of Tractor Weight and Field Soil Moistures During Tillage on Soil Properties and Barley Production Under the Soil Conditions of Al-Hassa Oasis, KSA

 The present study aims to evaluate the effects of the weight of the tractor and its attachments antecedent soil moisture content on soil characteristics and productivity of barley crop (Hareum vulgare L; Gusto variety). A field experiment was carried out for two consecutive seasons (2003/2004 and 2004/2005) at the Agricultural and Veterinary Training and Research Station of King Faisal University, Al-Hassa, KSA. The experimental field has a sandy soil texture with relatively high content of calcium carbonate, representing the most common soils characterizes in Al-Hassa Oasis. Two different sizes of tractors namely, New-Holland (large size) and Fiat (small size) were used to cultivate the field at three levels of soil moisture contents varying between the field capacity (M1) and wilting point (M3) with a third one in-between (M2) moisture content. These moisture levels were directly determined in the field before the start of the experiment. Some pertinent physical properties of the soil were determined including soil bulk density and cone penetration resistance. Plant measurements included yield characteristics (weights of whole plant, spikes, number of seeds per spike and total seed weight). Data was taken at locations not affected by the tractor’s passages. Results indicated that both tractor weight and the initial soil moisture content at cultivation had marked effects on soil characteristics and hence barley crop growth and production. The best values of yield was found when land was  prepared at a soil moisture content  between the field capacity and wilting point working with either of the two tractors  in the second season. However, the big tractor gave better results than the small one (4.81 and 4.17 ton/ha, respectively). This suggests that these two factors ought to be thoroughly considered when agricultural fields are being prepared, in order to avoid soil compaction and yield losses.