干旱区生态环境知识资源中心

The purpose of this study was to research the influence of four different tillage practices [T1: Conventional tillage (moldboard plow+disk harrow+combined harrows+precision seeder): T2: Reduced tillage-1 (cultivator+combined harrows+precision seeder): T3: Reduced tillage-II (rotary power harrow+precision seeder) and T4: No-till (no-till seeder)] on bulk density, total porosity, penetration resistance, field capacity, field water content and the infiltration rate of a loamy soil in a semi-arid region with a cool climate and an annual mean temperature of 5.6 degrees C. In particular, the effectiveness of the no-till practice was investigated. Since 1999, the experimental field has been tilled by the above-mentioned tillage practices and also applied a crop rotation (vetch-winter wheat-fallow) in dry conditions. We made assessments of selected soil properties according to the data during the sowing-germination period of winter wheat only in 2012 autumn. Therefore, the number of germinated seedlings of winter wheat was also evaluated. The data of this study carried out in three replications were statistically analyzed using the ANOVA and the regression technique.

The results indicated that the tillage treatments affected soil properties and wheat germination. The highest values in all examined parameters except for total porosity were obtained under the no-till practice for top soil layer of 30 cm. As was expected, the no-till treatment had the highest bulk density and provided the lowest total porosity. Generally, the plots tilled by conventional practice had the lowest values. Similar results were obtained for the top soil layer of 0-10 cm, which is seedbed. The penetration resistance measured to a depth of 30 cm in 5 cm increments increased as polynomial with increasing the soil depth in all treatments. The infiltration rate decreases as a function of elapsed time could be described by the Kostiakov equation. Also, significant linear relationships were obtained for penetration resistance-bulk density, field capacity-bulk density and field capacity-penetration resistance.

Although no-till treatment improved the hydraulic properties of soil, it had no positive effect on the soil physical properties. However, the linear relations with high correlation coefficients between penetration resistance and bulk density with field capacity at the no-till showed that soil physical and hydraulic properties revealed that they are connected to each other. According to the results of our study it could be concluded that the no-till practice increased winter wheat germination due to higher water content. (C) 2014 Elsevier B.V. All rights reserved.