The leguminous crops in the crop rotation is a group of crops in the crop rotation that includes such crops as peas, cicer, lentils, lathyrus, vetch, pelushka for seeds, lupine and others. They are of great value as a predecessor because of their ability to accumulate nitrogen in the soil. They are inferior to perennial grasses such as clover and alfalfa in the amount of accumulated nitrogen, but even this amount is enough for many crops on low fertility podzolic soils.
Main article: Leguminous crops
The importance of crop rotation for leguminous crops
There are a number of traditional reasons for the need for crop rotation when cultivating peas or beans. Weed control can be improved by using spring crops, and residual nitrogen improves soil fertility for the following crop. Large-seeded legumes fit well in crop rotations with cereals and can be grown with the same machinery and stored on existing equipment. Vegetable crops are more demanding in terms of machinery, labor and harvesting equipment, but their value as a catch crop and general soil improver remains the same.
The occurrence of soil-borne pests and diseases depends largely on the proximity of pea, bean, or other host crops. Nematode pests may infest peas or horse beans and be soil-borne or, in the case of stem and bulb nematodes, may be introduced into the field through infested seeds. Fungal pathogens that cause downy mildew and fungi involved in the soil root infection complex, such as Fusarium solani f. sp. pisi, Didymella pinodella (syn. Phoma medicaginis var. pinodella) and Aphanomyces euteiches, are likely to increase their intensity with long-term cultivation.
Both peas and beans may be in the same crop rotation, and since there are commonalities between the pest or pathogen and the legume host crop, peas and beans should be classified as the same crop for rotation purposes. The longer the period of absence of host crops that can be provided in a rotation, the less likely it is that pathogen and pest populations will accumulate in the soil.
Currently, in the UK and Europe, the minimum period between large-seeded legume crops is 4 years, during which neither peas nor beans are grown. In practice in the UK, experience has shown that a longer break is useful in reducing the risk of losses from a complex of root diseases.
Some legumes are early spring crops that grow quickly and are harvested early from the fields. Thanks to the early closing of rows and dense covering of the soil surface, legume crops reduce the weediness of fields, being strong competitors, preserve moisture and soil structure, activate microbial processes in the rhizosphere, contributing to the translation of hardly soluble forms of phosphorus in available to plants.
Diseases and pests characteristic of legume crops do not affect crops of cereals and other subsequent crops.
Predecessors of leguminous crops
The best predecessors for legumes are corn and winter wheat. At the state farm “Petrovsky” in the Lipetsk region, the yield of peas after corn was 4.65 t/ha, while after buckwheat, barley and beets for seed – 4.06 t/ha.
Sugar beets, potatoes and millet are good predecessors for peas. For cicer and lathyrus Sudan grass is not inferior as a predecessor to corn, while for spring cereals and winter wheat it is a bad predecessor.
Potatoes, spring and winter cereals are good precursors of leguminous crops in the Non-Black Soil Zone.
In general, leguminous crops in the crop rotation can be well placed on any predecessors, except for repeated and permanent crops, in which their yield decreases sharply, and the susceptibility to specialized diseases and pests increases.
Leguminous crops as predecessors
Due to the short growing season and early harvesting followed by tillage, leguminous crops can be considered good predecessors of winter wheat and winter rye. According to observations, for many regions of Russia, leguminous crops are not inferior to bare and seeded fallow in their influence on the yield of subsequent crops and soil fertility. For example, according to the All-Russian Institute of Legumes and Cereals, the yield of winter wheat in the Orel region for black fallow was 3.35 t/ha, for vetch – 3.40 t/ha, for pea – 3.51 t/ha, for clover fallow – 3.49 t/ha. Under the same conditions, winter rye yield for peas was 3.62 t/ha and for vetch – 3.58 t/ha.
When moving to areas with increasing continentality of climate, peas as a precursor is inferior to bare fallow. According to the NPO “Niva Tatarstan”, the yield of winter rye on black fallow was 3.21 t/ha of grain, and on pea – only 2.67 t/ha. However, the total productivity of the crop rotation section with peas due to the additional yield was higher by 1.1 t/ha, or 13%, compared with the section with bare fallow. Similar data are given by NPO “Don”: the yield of winter wheat after peas decreased by 26.6% compared with bare fallow, but even in this case, the productivity due to the additional yield of peas was approximately equal.
Leguminous predecessors influence the quality of rye and wheat grains by increasing the protein content.
The leguminous crops in the crop rotation are good precursors for long-fibre flax, oats, barley, millet, buckwheat, most row crops – sugar beets, potatoes, corn, sunflowers, tobacco, hemp, vegetable crops. Sowing these crops after leguminous crops allows obtaining the same yields as after winter wheat following the best predecessors.
Sources
Farming. Textbook for universities / G.I. Bazdyrev, V.G. Loshakov, A.I. Puponin et al. – Moscow: Publishing House “Kolos”, 2000. – 551 с.
Fundamentals of agricultural production technology. Farming and crop production. Edited by V.S. Niklyaev. – Moscow: Bylina, 2000. – 555 с.
Peas and beans. Crop production science in horticulture / Antony J. Biddle. 2017. UK.