Hybrid Rye Growing Guide

Whole Crop Silage Rye for Biogas

Why Hybrid Rye?

Hybrid rye is a high value substrate for all year round use in the biogas plant. It helps to balance the high productivity of energy beet or maize substrates, providing an alternative nutrient source for the bacteria in the digester and stabilising gas output.

Retention time in the AD plant is similar to that of maize, at 60 – 90 days, and biogas yields of around 200 cu/m3 are also on par with maize silage.

Hybrid rye is relatively straightforward to grow and suits a wide range of soils across the UK, providing high DM yields and some major agronomic benefits, alongside an ability to spread the workload on farm.

Trials and farm experience show that a realistic fresh yield of 35 – 40 t/ha is typically achieved in the UK. Highest yields will be where good establishment and tillering is achieved and the season and soil type allows for strong grain fill and ripening before harvest.

Rye is not a break crop and will carry take-all, but there is no effect of the disease on yield and rye it probably best positioned as a second cereal in the rotation.

Experience has now shown that hybrid rye can help to reduce the black-grass population through competition alone and will further reduce the population when harvesting the rye before the black-grass has matured. Use of rye will also help delay the maturity of the black-grass by approximately 1 week and the weed is poorly developed under a vigorous rye canopy.


Unlike wheat or barley, rye is a cross pollinating species which means that it can be more susceptible to poor flowering and pollinating leading to lower grain yields and in some cases high incidence of ergot. Breeders have tried to overcome this problem by using an additional variety as a pollinator with the variety purchased.

KWS has now found a complete solution to this by introducing a gene into all their hybrids that increases the formation of pollen massively, ensuring good quality flowering and pollination of grain sites. As a result, grain yields are more consistent from season to season helping ensure some of the highest total biomass yields and high quality crops with a good grain yield.

The POLLENPLUS technology is present in all KWS hybrid rye varieties which means when you buy a unit of KWS Hybrid Rye, you will receive 100% of that variety - there is no need for the addition of a synchronous pollinator type.

Seasonal Agronomic Guide:

Hybrid Rye is a moderate input crop, with input costs significantly lower than those required for winter wheat, and producing a rewarding yield where crops are well managed.

Hybrid Rye establishes and grows very quickly, particularly in the early spring, so growers should be ready to apply all inputs in good time to ensure they are applied at correct growth stages. This is especially important for timing of plant growth regulators.


Hybrid Rye has a well-developed root system that extracts nutrients and water from greater soil depths than most cereals. This minimises N-loss during the winter and can also help minimise soil erosion acting both as a cover crop and cash crop.

Drill Timing


Seed Rate m2


Mid to late Sept








Seed rates should be based on time of drilling, along with seed bed, soil and moisture conditions; the above seed rates are a guide only.

Seed is sold in unit packs with 1 unit containing 1 million viable seeds. So, sowing 2 units per hectare will provide 200 seeds/m2.


Hybrid rye has a very high yield potential with subsequent high nutrient removals. Fertiliser inputs need to reflect this and it is important to correct any potential major nutrient deficits before drilling.




Growth stage 25

60 – 80 kg

Growth stage 31

30 – 40 kg

Growth stage 37

30 – 40 kg


120 – 160 kg

110 kg max

130 kg max

Weed Control:

The early vigour and competitive nature of hybrid rye means that most crops will require just 1 -2 autumn herbicide applications to control the weed population. Conventional practice is to apply a pre-emergence herbicide followed by a peri- or post-emergence application if further control is needed. Where fields are heavily infested with blackgrass a strong residual based programme is likely to be necessary. For all pesticides please check label recommendations for winter rye.

Disease Control:

The main leaf disease that affects hybrid rye is brown rust. This is mainly present in those areas where rye is traditionally grown around East Anglia, Nottinghamshire and Dorset, though not exclusively so. Brown rust tends to be less problematic in the northern areas of the UK but growers should remain vigilant.

Brown rust can be controlled with a robust 2 – 3 spray fungicide programme with applications timed in the spring. In a high pressure season such as 2014, 3 sprays are more likely to be required, the final one being made after ear emergence. It is important, as with rust diseases on other species, to maintain protection rather than rely on eradicating the disease once it is established. Again, check product labels for specific recommendations.

Plant Growth Regulators:

Traditionally, rye has been regarded as a crop that is prone to lodging. With advances made in hybrid breeding we have now brought varieties to market that are shorter but also with stiffer and thicker straw that is hollow and provide even greater straw strength. This has meant a more stable plant with greater potential. Hybrid rye will still need a robust PGR programme and we would recommend that growers and their advisors take a conservative approach to PGR’s in their first year of growing the crop and adjust their application rates and quantities with future crops.


Harvest Timing:

Correct harvest timing for wholecrop silage is important to ensure optimal yield, quality and ensiling conditions. Crops should be between 35 – 40% DM, otherwise known as the ‘cheesy dough’ stage. This allows for maximum grain fill which is a large contributor to yield and quality. It is at this stage that ensiling compaction is most efficient and anaerobic conditions most easily achieved during fermentation.

Approaching harvest, the dry matter of the crop will increase by around 1% per day allowing for a narrow harvest window. It is important to have the harvesting capacity available for your acreage so that you can achieve close to optimum maturity across the crop. In practice this will mean commencing harvest with a DM% that is slightly below optimum, say 32 – 33% and finishing harvest with DM% 37 – 38%. Harvesting too late (>40% DM) will lead to compaction problems in the clamp and greater ensiling losses, as well as lower digestibility in the AD plant.

Stage of maturity

Harvest Time

Dry Matter (%)

Biogas Yield (m) / Tonne (Fresh)

Ear tip

Mid May

< 20%

< 100


Mid June

20 – 25 %

130 – 160

Grain at ‘soft dough’ stage

Late June

35 - 40%


Harvest Management:

Direct foraging is preferred as it will cause less soil contamination. Chopping and swathing, leaving the crop to wilt can lead to a fast increase in DM% of 1% per hour and drying out of the crop. A short chop of 6 – 10mm is desirable to increase the surface area of the rye and help maximise the speed of digestion.