Strip tillage is increasingly being used for wide row crops such as sugar beet, maize and oilseed rape in a number of geographical regions of the world including North America, New Zealand and Europe. Strip tillage has been shown to offer many benefits both economically (reduced fuel inputs and decreased labour costs due to fewer field operations; Overstreet, 2009) and environmentally (by reducing soil and wind erosion through crop residue retention). Data suggests that this can more than halve the fuel usage associated with crop establishment (cf plough based systems), lower broad leaf weed burdens (through reduced soil disturbance between rows) and also reduce labour costs and the number of field operations. In addition studies in the United States, Canada and the UK (BBRO project 07/25) have demonstrated strip tillage increases work rates with fewer field operations and, in some circumstances, can offer improved margins compared to plough tillage.
It is envisaged that the outcomes of this research would improve the current understanding for the potential use of strip tillage in sugar beet production in the UK. Outputs from this project would enable growers to make more informed decisions by developing a decision support tool by means of a flow diagram detailing under which conditions strip tillage is most likely to be effective. From the information gathered as part of the literature review would identify any outstanding research and knowledge transfer requirements that would enable growers to utilise strip tillage techniques effectively in the UK.
Outcomes / Key Message For Growers And Industry
The use of strip tillage techniques in sugar beet production would potentially allow a number of benefits including reduced cultivation costs (from work rate efficiencies and a reduction in fuel used). Other benefits to the environment include increased biodiversity through the retention of over-wintered stubbles and the reduced soil erosion risk both from wind and water.
Before strip tillage cultivations are chosen for sugar beet it is important to consider if the fields have been extensively wheeled from harvesting or straw collection operations or suffer soil compaction caused below the depth of cultivation (>20cm). Further consideration should be made to particular fields that suffer from a high pressure of grass weeds that are difficult to control in sugar beet. In these situations it is unlikely that these fields will be suited to strip tillage.
To ensure that strip tillage is successfully employed a number of considerations are required including the use of GPS (RTK) guidance, the timeliness of operations and the depth of soil disturbance. These all have an impact on the quality and uniformity of the strips created. The timing of strip tillage operations depend upon soil type; on light soil types a single strip tillage operation is sufficient, however, on medium and heavy soil types (18-45% clay content) it is best to complete strip tillage cultivations at two timings; once in the autumn when the soil is relatively dry and again in the spring to 'freshen up' the strip prior to drilling. In either circumstance drilling is best completed as a separate operation to ensure consistent and uniform seed placement.
From studies in the UK and across Europe yield performance using strip tillage indicates that strip tillage yields tend to be more variable compared to the standard approach particularly on medium and heavy soils. The sensitivity of strip tillage to soil conditions is considered to be one of the critical factors.
Whilst yields tend to be slightly lower than standard cultivation approaches there are a number of significant benefits that strip tillage may provide. Reductions in costs are possible through increased speed of working and this should improve the timeliness of such operations. Less soil disturbance generally reduces the emergence of broad leaved weeds. There is some evidence to suggest that strip tillage may reduce the pressure on weed beet emergence within the crop due less soil disturbance although further research to quantify this would seem prudent.
Further benefits of integrating strip tillage with the use of cover crops or fertiliser placement would seem to be of significant interest. Cover crops could enable improved soil physical characteristics; capture nitrogen over winter and allow opportunities to increase the biological activity within the soil that could enhance nutrient availability to the sugar beet crop. Currently there is little information available on the specific species of cover crop most suited to the autumn I winter period prior to sugar beet that does not affect the spring cultivation or drilling operations. Also there is little available data at present to quantify the yield results in sugar beet following a cover crop. The potential to improve fertiliser use efficiency through targeting placement within row could allow for potential saving in fertiliser costs thus making the economics of using strip tillage more credible.