technical brief January 2017
In this issue
News and crop production advice from Frontier
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Managing late sown winter wheat crops this season
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Managing late sown winter wheat crops this season Making a profit from spring cropping Managing forward rape in an improved market Visit valuable trials to get great green cover results Improving yields and protein with precision
Conditions last autumn allowed many growers to delay sowing winter wheat until late October and into early November. The benefits of this delay are well understood when it comes to grass weed control, but were even more relevant in 2016 with high dormancy and dry soils. Most of these later sown crops appear to have gone into good seedbeds, with residual herbicides applied in good time. After the Christmas break, most crops are at the 2 – 3 leaf stage through to early tillering and depending on the weather in the coming weeks, we should achieve 200 – 250 plants/m2 in the spring. When conditions start to improve, it will be time to turn our attention to the management of these crops. Crop production technical lead, Dr Paul Fogg, explains.
Yield potential A good starting point is to review crop potential. There is a clear yield penalty in most varieties from sowing later, but it is important to put this into context with the fact that establishment was delayed as part of the strategy to control black-grass, which on its own can result in a significant yield penalty: 100 heads/m2 equates to a 20% drop in yield.
Rooting Apart from depressed light levels during the critical grain filling period in 2016, rooting and especially deep rooting is thought to have a significant influence on final crop yields. The wet winter and spring of 2015/16 combined with the condition of some soils meant that roots remained close to the soil surface and crops were unable to access water held at depth within the soil profile later in the year. Recent work suggests that a root length density (RLD) of 1cm/cm3 of soil is critical and that many crops only reach this figure in the top 30cm, relative to crops in the 1970s-80s (Figure 1). So can we do anything to manipulate rooting? Clearly, longer term changes linked to soil health and physical status can be made, for example cultivation policy, placement of fertiliser at sowing and potentially cover crops. For crops in the ground now, consider early use of plant growth regulators to increase root plate spread and depth as well as tillering. Phosphites can also help trigger a response in the plant which can improve rooting, as can some fungicides.
Figure 1: Root length density (RLD) to 100cm soil depth for 17 winter wheat crops between 2004 and 2013. Published in White et al, Journal of Experimental Botany 66 (2015).
Early disease control With plant growth slow over winter, maintaining green leaf this spring will be fundamental in protecting yield potential. Yellow rust and septoria tritici can be found in crops and while no immediate action is required, early intervention may be needed in spring, particularly on more susceptible varieties. Looking at yellow rust in particular, only Costello, KWS Crispin and KWS Siskin have seedling resistance, with adult resistance generally not fully apparent until around flag leaf emergence. Also look for early manganese deficiency, particularly on unconsolidated seedbeds. In summary, review budgets based on crop potential. Look to build resilience into the crop through improved rooting and when it comes to early disease control, review your strategy based on relative risk. To achieve the best results for your business, talk to the experts.
“Rooting is thought to have a significant influence on final crop yields and it’s not too late to take action for this season’s crop.” Dr Paul Fogg
Crop production technical lead
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