Controlled traffic to increase productivity of irrigated row crops in the semi-arid tropics

Abstract

The tropical environment generally allows 2 crops/year to be grown. Controlled traffic has been suggested as a means of improving soil conditions, which may also lead to increased crop yield. A field trial at Millaroo Research Station, North Queensland, on a cracking clay (Entic Chromustert) studied the effect of controlled traffic (in conjunction with direct drilling and tillage) and conventional ridging on soil properties and crop yield. Maize (Zea mays L. cv. Hybrid 50) was grown as the winter crop and soybean [Glycine max (L.) Merr. cv. Canapolis] as the summer crop. With few exceptions, there was no significant difference between any pair of treatments in sowing line water content, bulk density, aggregate size distribution, seedling emergence, mean time of seedling emergence, and final yield. Differences that did occur between crop cycles were due to climatic variation. Cone index measurements indicated no lateral spread of compaction from the traffic lanes in the controlled traffic system to the soil in the plant growth area. Under the ridged area, however, it appeared that a plough pan began to develop just below the depth of tillage. Although no marked benefit in soil properties or plant yield resulted from controlled traffic, it was possible to grow 2 crops/year for the duration of the experiment. In one season, only the controlled traffic treatments could be planted, due to unsuitable conditions for seedbed preparation. Double cropping under conventional cultivation systems is unreliable, due to the limited opportunity for seedbed preparation at the beginning of the wet season and the large number (up to 8) of operations required to prepare a seedbed. Controlled traffic, restricting soil compaction to the traffic lanes, is a system that helps to maintain a zone more favourable for plant growth, as indicated by the cone index measurements.

Agronomic consequences of tractor wheel compaction on a clay soil

“…Such situations can arise when the underlying impediments to root growth have not been removed prior to imposing controlled traffic and the soil is slow to self repair, or they might reflect growing seasons where an adequate water supply results in either a reduced level of soil strength during crop development and/or a limited crop reliance on subsoil water for growth (Kirkegaard et al, 1992;Braunack et al, 1995;Radford et al, 2000).…”

“…Ellington, 1986;Radford et al, 2001;Hamza and Anderson, 2003;Sadras et al, 2005) and irrigated crops (e.g. McGarry and Chan, 1984;McGarry, 1990;Braunack et al, 1995) across a wide range of soil types and environments. From a management point of view, it is useful to identify the processes responsible for changes in soil physical properties so that farming systems and practices can be adopted to either ameliorate, avoid or minimise soil compaction problems and reduce the subsequent risk of poor agronomic performance.…”

Soil compaction due to forest harvest operations

“…Researchers have showed that the risk of compaction is likely to occur in soils with high moisture content, under tracks of heavy vehicles with high loads Raper, 2005). A solution for this problem would be a controlled traffic (Horn et al, 2004) to maintain the more favorable area for plant growth by restricting soil compaction to traffic lanes (Braunack et al, 1995).…”

High clay contents, dense soils, and spatial variability are the principal subsoil constraints to cropping the higher rainfall land in south-eastern Australia

“…Improved infiltration and access to stored soil water also increases the timeliness of operations and enterprise flexibility (Braunack et al 1995;McPhee et al 1995a). The implementation of controlled traffic is an essential partner to soil loosening if ongoing compaction is to be reduced (McPhee et al 1995a(McPhee et al , 1995b(McPhee et al , 1995c.…”

“…Controlled traffic farming (Bailey 1997) minimises compaction through the use of designated vehicle pathways and is highly suited to row-cropping activities (Halderson et al 1993;Braunack et al 1995;McPhee et al 1995a). It has gained momentum in Australia with the advent of precision agriculture technology and is an important component of raised beds (Peries et al 2004).…”