The shortfall in winter sowings this season means spring barley will be the major crop of consideration in many situations. Provisional Defra forecast for spring barley sowings for 2020 are that the crop will rise by 28% compared to 2019, which is a huge rise, and many will be growing spring barley after a long break. We revisit the key agronomic requirements for establishing spring barley and for maintaining tiller counts for high final ear number:
1. Know your market/contract requirements
Specifications for differing malting barley markets will determine the agronomic inputs needed to achieve the required nitrogen percentage.
2. Choose the right variety
In many cases, variety choice is determined by the end-use/contract chosen. Newer, higher yielding varieties such as LG Diablo, offer a significant yield advantage over older historic varieties. They also offer very high yields in a feed barley situation.
3. Time of drilling
Generally, patience is required to wait for the right conditions for drilling. The window of opportunity should be taken then both the weather and soil conditions allow for good seedbeds with rising soil and air temperatures, to ensure rapid emergence and establishment with continued plant growth. Earlier drilling in the spring can boost yields and should be considered on lighter, more free-draining land that will dry and warm up quicker than heavier, wetter soil types. Drilling early will significantly increase disease risk, so it’s best to look at more disease resistant varieties for this situation.
4. Seed rate
Limagrain trials comparing variety seed rates over various seasons and regions, show that with the more vigorous, higher tillering varieties, the optimum seed rate is 350 seeds/m² when drilling in ideal conditions around mid-March. This figure can be adjusted up or down depending on weather, drilling date, seedbed quality, moisture availability and perhaps most importantly, the growers’ own experience on each site. A lower seed rate of 300-325 seeds/m² could suffice if drilling into an “onion bed” in March. Although, when forced to drill into April due to the weather or agronomic reasons such as black-grass control, pushing up to 400-450 seeds/m² may be more appropriate.
5. Maintain high tiller number
The AHDB Barley Growth Guide suggests that the final ear target population should be around 775 ears/m². Certainly in 2019, higher yields were achieved from above average, higher final tiller counts – backing up the theory that final ear counts approaching 800/m² achieve higher yields. One of the biggest factors for securing final tiller survival, is early nutrition. Spring barley has traditionally been a lower input crop, with growers reluctant to increase nitrogen application rates in spring malting barley crops, through fear of exceeding maltsters’ grain nitrogen limits.
Limagrain trials over several years, show a benefit with using higher nitrogen rates. A standard seedbed application of 120 kg/ha was compared with a split nitrogen application of 150 kg/ha, with half applied in the seedbed and half at tillering. This resulted in increased yield potential without exceeding grain nitrogen percentage.
Newer, higher yielding varieties respond to higher nitrogen inputs and due to the higher inherited yield, a dilution of the nitrogen grain content is achievable. Macronutrients such as phosphate, potash, magnesium and sulphur should be applied either in the seedbed or soon after drilling, to promote strong rooting and early plant growth.
Micronutrients including manganese, zinc, copper, iron and boron applied at the stem extension phase of growth into flowering, are also beneficial to ensure a healthy canopy and good ear fertility. Early PGR applications are recommended to promote additional rooting and strong uniform tillering. A minimum of two fungicide programmes should be considered to maintain plant health and final ear number.
For further information on market requirements: