Guide: The cultivation of fodder peas and its advantages in nitrogen fixation
The fodder pea (Pisum sativum ssp. arvense), also known as field pea, belongs to the grain legumes. It is used in pig, cattle and poultry feed and is characterised by its high protein and starch content. Together with the faba bean, the fodder pea is a regional source of protein for livestock feed, the area under cultivation of which has increased enormously in Germany in recent years.
Globally, crop production is dominated by cereals, with only 11% of arable land used to grow legumes. However, legumes play an important role in agriculture. Cultivated as a preceding crop, they can have a considerable influence on the yields of the following crop. They can interrupt chains of infection, inhibit weed growth, improve soil fertility and are known above all for their nitrogen fixation. In the case of peas, this can be up to 180 kg/ha of nitrogen.
Recommendations for growing fodder peas
When growing peas, there are a few things for farms to consider. In addition to grain yield and crude protein content, standability and thus harvestability are of great importance when selecting varieties. The sowing density is around 80 seeds/m², although it can be varied depending on the soil type, the seed used and in the case of single-seed sowing.
The fodder pea places some demands on the soil. Among other things, it prefers a neutral pH value of 7. It grows in a range of soil types, from light sandy to medium-heavy clay soils. Waterlogging or compacted areas in the soil structure inhibit root growth, therefore appropriate soil tillage must be ensured. The sowing depth is up to 8 cm on lighter soils and up to 6 cm on medium-heavy soils. Peas are sown from mid-March to the end of April in a relatively dry seedbed with good soil tilth. A cultivation break of five to six years should be adhered to.
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How do fodder peas fix nitrogen?
Legumes, such as peas, form a biological bond with nitrogen-fixing nodule bacteria, which enables them to bind atmospheric nitrogen (N2). The bacteria, also known as rhizobia, form a symbiotic relationship with the roots of the legume and form small nodules in which they convert nitrogen from the environment into ammonia that can be utilised by the plant. In return, the plant provides the nodule bacteria with assimilates such as sugar from the photosynthesis process. Fertilisation with mineral nitrogen is therefore not normally necessary when growing peas.
What are the advantages of this N-fixation?
Efforts are being made worldwide to reduce the use of mineral nitrogen fertilisers. If fertiliser is not used in accordance with requirements, some of the nitrogen applied cannot be used by the plant but is lost to the environment in the form of leaching or atmospheric nitrogen.
In comparison, legumes are a sustainable source of nitrogen due to their symbiosis with nitrogen-fixing nodule bacteria. The use of mineral nitrogen fertilisers could be reduced by expanding the area under legumes and using them effectively in crop rotation. The input costs of the subsequent crop would also be reduced, as the residual nitrogen that remains in the soil after harvesting legumes would be available for the following crop.
Positive effects of legumes in crop rotation
Studies on the yields of subsequent legume crops have shown how useful nitrogen-fixing crops can be. A study that tested the crop rotation effect of peas on winter wheat, among other crops, also showed positive yield effects in the subsequent crop. On average over the four trial years, the yield of winter wheat after pea cultivation was 68 dt/ha, which is over 25 per cent higher compared to the previous crop oats (average wheat yield over the trial years: 42 dt/ha) (Maidl et al. 1996). Of course, there are a number of factors that influence this, such as site conditions, the crop and variety. Researchers have also found that the yield effect of legumes is significantly lower in soils that were previously fertilised with nitrogen.
Peas for animal consumption
Fodder peas are mainly used in cattle, pig and poultry feed and offer a local and GMO-free alternative to imported soya from South America, for example. By blending peas and other legumes, such as faba beans and lupins, as well as other protein components such as oilseed rape, it is possible to reduce the use of soya or, in some cases, replace it altogether.
Peas are characterised by a high crude protein content of approx. 23% and a starch content of 41%. Other important properties in animal nutrition are the amino acid composition and the content of antinutritive substances. Peas are rich in lysine but low in methionine, which makes a combination with rapeseed meal a good way of achieving optimum amino acid levels in a ration. In addition to breeding suitable varieties, the reduction of antinutritive substances is achieved by fermentation (ensiling) or heat treatment (toasting), which can increase the digestibility of peas.
Creating ideal conditions for stable yields with LEGUGUARD
With the LEGUGUARD seed treatment, the initial stage of the vegetation period can be optimally utilised thanks to reliable germination and a 6% increase in vigour. By specifically promoting the nodule bacteria, the N-fixing capacity can be increased, enabling high protein yields to be achieved. Increased root mass (+ 20%) and an enlarged root surface ensure more efficient development and utilisation of resources such as water and immobile nutrients. LEGUGUARD therefore creates the best conditions for guaranteed yield stability (+ 5% additional yield).
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Find out more about the mode of action and yield results.
Average values based on 10 plot trials in the period 2020 - 2022, compared to the check without LEGUGUARD, depending on seed, soil and environmental factors. As of: 04/2023
Source: F. X. Maidl; F. X. Haunz; A. Panse; G. Fischbeck (1996). Transfer of Grain Legume Nitrogen within a Crop Rotation Containing Winter Wheat and Winter Barley., 176(1), 47–57. doi:10.1111/j.1439-037x.1996.tb00445.x