Characterization of soil temperature, water content, and maize root distribution in two tillage systems

Abstract

Previous research has shown that soil temperature and soil water regimes are influenced by tillage practices. Root growth is affected by both soil temperature and water content; therefore, root distribution can be significantly different among various tillage systems. The objectives of this field study were to characterize the distribution of maize ( Zea mays L.) roots in the top 30 cm of the profile of a Chalmers silty clay loam soil (Typic Haplaquoll) under a ridge till-plant system and a conventional tillage system and to determine if any significant differences exist among soil temperature and water regimes in these two tillage systems and if these differences were related to maize root distribution. Measurements were taken over a 3 year period on three replicates of a long-term tillage experiment. Soil cores (2.1 cm diameter) were taken after approximately 5, 7, and 10 weeks of growth to determine root length density with depth and distance from the row. Soil temperature was measured with thermocouples at depths of 2.5, 10, and 30 cm in the row and midrow. Soil water content was determined gravimetrically on samples taken two to three times per week from the row and midrow. Root length density (RLD) was higher in the row and midrow in the ridge till treatments; whereas in the conventional treatments, RLD was highest in the row and decreased with distance from the row. Mean 24 h temperatures in the row of ridge till treatments paralleled those in the row of conventional treatments. Midrow temperatures tended to be lower in ridge till than in conventional treatments, especially during the 3 week period after planting. Water content in the row of both tillage treatments was similar from planting to midsilk in both years. Water content in the midrow of ridge till was greater than that of conventional treatments throughout the sampling period. No significant correlations between RLD and soil temperature or water content were found; however, significant differences in soil temperature, water content, and RLD between the two tillage treatments suggest that some relationship does exist.