Description
Despite the importance of proteins, the cultivation of grain legumes, with excellent protein levels, has decreased considerably in the last few decades, particularly in Italy, in favour of cereal crops. The need to obtain alternative sources of protein, due to the effect of BSE and fear of the undefined effects of transgenic products including soya, the main source of protein for the animal feed industry, has renewed interest in leguminous plants.
Farming suggestion
FIELD PEA
Rotation
As the field pea is a nitrogen-fixing legume, of which the residues enrich the soil, it is an excellent starter crop for rotation. It has a similar cycle to winter cereals and so frees up land quickly. It is not advisable to sow after field ploughing, to avoid the risk of excess nitrogen and development of soil parasites. It may be used effectively in sequence with corn, increasing soil fertility levels.
Seedbed preparation Handle soil as little as possible, to avoid compaction. Avoid water stagnation, so ensure sufficient arable layer porosity. An even seedbed is important, for optimal harvesting, with potentially a lower product loss
Fertilising
Fertilising with nitrogen is not usually necessary because symbiotic bacteria ensure total coverage of requirements (see table 1). In particular cases (soils with little oxygen, a cold, wet start to spring, undersized crops), 30 – 40 units of surface nitrogen is recommended (at the height of the 10 - 12 cm seedlings). Crop residues leave on average 30 – 40 units of nitrogen in the soil. Phosphorous 100 – 110 units of phosphorous is sufficient in average conditions for a crop with a yield up to 6,000 kilos/ha of grain. Large volumes of potassium are not necessary; even if 200 or more units of K2O are released by the crop, used amounts are less significant, as most potassium is returned with crop residues. 100 - 120 units are recommended in soils with a sufficient mineral content, with a maximum of 160 units in impoverished soil. Organic fertilising - in soil impoverished by corn mono-crops and with a low mineral content, it is essential for achieving good yields, re-establishing an adequate microbial load in the soil and increasing the rate of organic matter.
Sowing time
Autumn, winter or spring, depending on the variety used
Depth
Special attention should be paid to sowing depth, to ensure proper, uniform germination particularly for autumn sowing, and to improve the selectivity of pre- and post-emergent herbicides. A depth of 3-4 cm is recommended in average mixed soil, or even down to 5 cm in loose soil.
Plant density
The best yield can be obtained with approximately 70-80 plants /m2 on harvesting
Packing down
Packing down in some cases is necessary to level out soil, bury stones and make harvesting easier. Excessive soil compaction and the formation of a surface crust should be avoided.
Weeding
Considering its slow growth, particularly in winter, the Pea is not very hardy against weeds. Treatment from the start of growth is therefore essential. Active ingredients currently registered for use on pea crops are: Aclonifen, Bentazon, Chlorthal-dimethil, Cycloxydim, Diclofop-methil, Diquat dibromide, fenoxaprop-ethyl, fluazifop-p-buthyl, Glyphosate, methabenzthiazuron, Pendimethalin, Prometrin propham, Qhizalofop-ethyl, Sethoxydim, Terbutrin, Trifluralin. (Veneto Region Handbook 1995)
Utilization
FIELD PEA
Composition The total content of nitrogenous substances in grams per kilo of dry matter may vary from 200 to 280. Composition of nitrogen substances: Pea nitrogen is highly digestible for ruminants (over 80%) and 75% is in a soluble form; balanced levels of essential amino-acids are important for non-ruminants.
Average composition of the Pea grain as raw matter.
Moisture content % 12
Nitrogenous substances % 23
Digestible proteins % 19
Raw fibre % 7
Fats % 2
Carbohydrates % 60
Lysine % 1.7
Methionine % 0.22
Cisterna % 0.33
Threonine % 0.84
Tryptophan % 0.18
Ca mg/100g 71
P mg/100g 346
Fe mg/100g 5
Na mg/100g 35
K mg/100g 1000
a) Pigs
As regards pig feed, the high energy value of the Pea, with 4000 kilocalories of digestible energy (DE) per kg/dry matter is close to corn and soya cake. For sucklings (10-25 Kg), Pea can be introduced, comprising up to 15% of the feed ration. When formulating rations, soya cake and cereals should be replaced based on the formula below, in order to balance lysine and DE: 1 Kg of soya cake + 1 Kg of cereal = 2 Kg of Pea
b) Poultry farming
In this case, the energy value of the Pea is slightly higher than that of soya cake (2800 kcal of metabolising energy / kilo of dry matter), and far lower than that of corn (3800 kcal of metabolising energy/kg of dry matter). Thus, to balance amino acids and metabolisable energy, soya cake is replaced after offsetting the energy value with animal fats and adding synthetic methionine.
c) Cattle
The energy concentration is high, similar for milk and meat production, and close to the value for soya cake. Use with dairy cattle does not pose any particular problems; Pea is well tolerated, and ingestion levels are not changed; milk production is comparable to that obtained with soya cake. Milk quality is normal. In the case of high yielders, Pea may not be used only as a corrective agent for feed which is not rich in nitrogen (corn silage) as it has a low nitrogen content. Pea can also entirely replace soya cake in feed for veal calves; animals find pea very palatable, without any change in their growth rate.
d) Rabbits
Rabbits tolerate protein crops well, up to a 30% content; this means soya cake can be entirely eliminated from their feed ration.
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