The objective of this approach is to target both the ‘source’ and ‘sink’ of the plant. The source is the parts of the plant where light is intercepted and converted into sugars e.g. the flag leaf. The larger the source (e.g. leaf size, shoot number) the more light can be intercepted. The sink is the storage of these sugars; during grain fill 20-50% of final grain weight is re-mobilised from reserves stored in the stem and leaves.
This indicates the importance of the ensuring the sink is not limited pre grain fill to achieve yield potential. Crop momentum (feeding the crop little and often) ensures the plant can exploit good conditions (e.g. cool and bright) when they occur, to build a sufficient sink size to create yield later in the season. Plants often have to cope with adverse or constraining environmental conditions (stress), and the effect of sub-optimal conditions (e.g. drought or nutrient shortage) at one stage will tend to reduce the sink at the next stage and hence the rate of photosynthesis at the next stage, so crop momentum will be lost.
Professor Roger Sylvester-Bradly explains, “The basic physiological theory is that final performance will benefit if crops avoid any set-backs due to inadequate storage capacity for assimilate (nutrients and sugars). So the idea is to keep asking yourself: ‘What storage have I got to grow in each phase of development (tillering – stem extension – ear development & floret production – floret survival – flowering – grain expansion – grain filling & canopy survival) for there to be adequate storage in the next phase of growth?’”
ADAS has provided farmers with an á la carte menu of husbandry options aimed at promoting crop momentum by alleviating stresses (biotic and abiotic), and promoting momentum. Treatment options include the use of biostimulants and foliar sprays (particularly micro-nutrients and phosphites) on a little and often basis. Farmers in the group are encouraged to monitor crops frequently, respond to adverse growth conditions and make full use of tissue analysis and (if available) grain nutrient benchmarking results from previous YEN competition reports.
This is the largest and and most widely dispersed of the YEN FIGs, with 11 farmers using a wide range of strategies to develop the ‘momentum’ of their wheat crops. ADAS has been particularly pleased to help one Scottish participant, Peter Chapman, to link up with an orthophosphate supplier whom he persuaded to drive all the way from Holland to northern Scotland with a new product for use on his trial area. A special mention must also go to Norfolk farmer, Chris Eglington, for his innovative use of superimposed treatments and variable rate N. This should provide much useful information and will test the ADAS Agronomics team’s new statistical procedures to the limit!
Members of the Crop Momentum FIG are scattered across the UK (farm locations may be seen on the map). Participants are looking forward to discussing their results at the YEN Awards Conference on 19th November 2019.
For more information on the Crop Momentum FIG contact Damian Hatley