The nodules on the roots of leguminous plants are induced by the presence of a minute organism now known to do no injury to the plant.
The western dry areas have the old-world leguminous Astragalus and Prosopis (Mesquit), but are especially characterized by the northward extension of the new-world tropical Cactaceae, Mgmmillaria, Cereus and Opuntia, by succulent Amar llideae such as A gave (of which the so-called American aloe is a type), and by arborescent Liliaceae (Yucca).
The results show that, unlike leguminous crops such as beans or clover, wheat may be successfully grown for many years in succession on ordinary arable land, provided suitable manures be applied and the land be kept clean.
It was in the year 1886 that Hellriegel and Wilfarth first published in Germany the results of investigations in which they demonstrated that, through the agency of micro-organisms dwelling in nodular outgrowths on the roots of ordinary leguminous plants, the latter are enabled to assimilate the free nitrogen of the air.
To the former belong the ordinary leguminous crops - the clovers, beans, peas, vetches or tares, sainfoin, lucerne, for example - which obtain their nitrogen from the air, and are independent of the application of nitrogenous manures, whilst in their roots they accumulate a store of nitrogen which will ultimately become available for future crops of other kinds.
The cereal crops (wheat, barley, oats, rye, maize); the cruciferous crops (turnips, cabbage, kale, rape, mustard); the solanaceous crops (potatoes); the chenopodiaceous crops (mangels, sugar-beets), and other non-leguminous crops have, so far as is known, no such power, and are therefore more or less benefited by the direct application of nitrogenous manures.
The field experiments on leguminous plants at Rothamsted have shown that land which is, so to speak, exhausted so far as the growth of one leguminous crop is concerned, may still grow very luxuriant crops of another plant of the same natural order, but of different habits of growth, and especially of different character and range of roots.
It seems certain that success in any system involving a more extended growth of leguminous crops in rotations must be dependent on a considerable variation in the description grown.
Other essential conditions of success will commonly include the liberal application of potash and phosphatic manures, and sometimes chalking or liming for the leguminous crop. As to how long the leguminous crop should occupy the land, the extent to which it should be consumed on the land, or the manure from its consumption be returned, and under what conditions the whole or part of it should be ploughed in - these are points which must be decided as they arise in practice.
It seems obvious that the lighter and poorer soils would benefit more than the heavier or richer soils by the extended growth of leguminous crops.
But it gave some impetus to the practice of green manuring with leguminous crops, which are equally capable with such a crop as mustard of enriching the soil in humus, whilst in addition they bring into the soil from the atmosphere a quantity of nitrogen available for the use of subsequent crops of any kind.
In Canada and the United States this rational employment of a leguminous crop for ploughing in green is largely resorted to for the amelioration of worn-out wheat lands and other soils, the condition of which has been lowered to an unremunerative level by the repeated growth year after year of a cereal crop. The well-known paper of Lawes, Gilbert and Pugh (1861), " On the Sources of the Nitrogen of Vegetation,.
Plants of the gramineous, the leguminous and of other families were operated upon.
This has taken the form of inoculating the soil with the particular organism required by the particular kind of leguminous crop. To this end the endeavour has been made to produce preparations which shall contain in portable form the organisms required by the several plants, and though, as yet, it can hardly be claimed that they have been generally successful, the work done justifies hopes that the problem will eventually be solved in a practical direction.
The farmer therefore arranges his cropping in such a way that roots, or leguminous crops, succeed the cereal crops.
Although many different rotations of crops are practised, they may for the most part be considered as little more than local adaptations of the system of alternating root-crops and leguminous crops with cereal crops, as exemplified in the old four-course rotation - roots, barley, clover, wheat.
They are effected chiefly by some alteration in the description of the root-crop, and perhaps by the introduction of the potato crop; by growing a different cereal, or it may be more than one cereal consecutively; by the growth of some other leguminous crop than clover, since " clover-sickness " may result if that crop is grown at too short intervals, or the intermixture of grass seeds with the clover, and perhaps by the extension by one or more years of the period allotted to this member of the rotation.
Whatever the specific rotation, there may in practice be deviations from the plan of retaining on the farm the whole of the root-crops, the straw of the grain crops and the leguminous fodder crops (clover, vetches, sainfoin, &c.) for the production of meat or milk, and, coincidently, for that of manure to be returned to the land.
The remainder, that in the straw, as well as that in the roots and the leguminous crops, is supposed to be retained on the farm, excepting the small amount exported in meat and milk.
But much less potash than phosphoric acid is exported in the cereal grains, much more being retained in the straw, whilst the other products of the rotation - the root and leguminous crops - which are also supposed to be retained on the farm, contain very much more potash than the cereals, and comparatively little of it is exported in meat and milk.
Of lime, very little is taken up by the cereal crops, and by the root-crops much less than of potash; more by the leguminous than by the other crops, and, by the clover especially, sometimes much more than by all the other crops of the rotation put together.
The root-crops, indeed, may contain two or more times as much nitrogen as either of the cereals, and the leguminous crops, especially the clover, much more than the root-crops.
The greater part of the nitrogen of the cereals is, however, sold off the farm; but perhaps not more than to or 15% of that of either the root-crop or the clover (or other forage leguminous crop) is sold off in animal increase or in milk.
The still more highly nitrogenous leguminous crops, although not characteristically benefited by nitrogenous manures, nevertheless contribute much more nitrogen to the total produce of the rotation than any of the other crops comprised in it.
It is the leguminous fodder crops-especially clover, which has a much more extended period of growth, and much wider range of collection within the soil and subsoil, than any of the other crops of the rotation-that yield in their produce the largest amount of nitrogen per acre.
There are still, however, in the coast belt woods of leguminous evergreens bearing bright-coloured flowers.
Olibanum of Java), corrupted in the parlance of Europe into benjamin and benzoin; camphor, produced by Cinnamomum Camphora, the "camphor laurel" of China and Japan, and by Dryobalanops aromatica, a native of the Indian Archipelago, and widely used as incense throughout the East, particularly in China; elemi, the resin of an unknown tree of the Philippine Islands, the elemi of old writers being the resin of Boswellia Frereana; gumdragon or dragon's blood, obtained from Calamus Draco, one of the ratan palms of the Indian Archipelago, Dracaena Draco, a liliaceous plant of the Canary Island, and Pterocarpus Draco, a leguminous tree of the island of Socotra; rose-malloes, a corruption of the Javanese rasamala, or liquid storax, the resinous exudation of Liquidambar Altingia, a native of the Indian Archipelago (an American Liquidambar also produces a rose-malloes-like exudation); star anise, the starlike fruit of the Illicum anisatum of Yunan and south-western China, burnt as incense in the temples of Japan; sweet flag, the root of Acorus Calamus, the bath of the Hindus, much used for incense in India.
Leguminous crops take some of the nitrogen which they require from the air, but most plants obtain it from the nitrates present in the soil.
Certain bacteria of the nitrogenfixing class enter into association with the roots of green plants, the best-known examples being those which are met with in the nodules upon the roots of clover, peas, beans, sainfoin and other plants belonging to the leguminous order.
When wheat, barley, turnips and similar plants are grown, the soil upon which they are cultivated becomes depleted of its nitrogen; yet after a crop of clover or other leguminous plants the soil is found to be richer in nitrogen than it was before the crop was grown.
Upon the roots of leguminous plants characteristic swollen nodules or tubercles are present.
After the decay of the roots some of the unchanged bacteria are left in the soil, where they remain ready to infect a new leguminous crop.
The method of using them most frequently adopted consists in applying them to the seeds of leguminous plants before sowing, the seed being dipped for a time in a liquid containing the bacteria.
The plants most frequently used are white mustard, rape, buckwheat, spurry, rye, and several kinds of leguminous plants, especially vetches, lupins and serradella.
By far the most satisfactory crops as green manures are those of the leguminous class, since they add to the land considerable amounts of the valuable fertilizing constituent, nitrogen, which is obtained from the atmosphere.
He estimated that by using leguminous crops in this manner for the purpose of obtaining cheap nitrogen he reduced the cost of production of wheat more than 50%.
Besides the grasses there are leguminous plants valuable for pasture - Astragalus, Vicia (wild vetch), Lathyrus (wild pea) of which there are many species.
Urid, mashkalai), also known as green gram, is perhaps the most esteemed of the leguminous plants of India, where the meal of its seed enters into the composition of the more delicate cakes and dishes.
CALABAR BEAN, the seed of a leguminous plant, Physostigma venenosum, a native of tropical Africa.
Although thus highly poisonous, the bean has nothing in external aspect, taste or smell to distinguish it from any harmless leguminous seed, and very disastrous effects have resulted from its being incautiously left in the way of children.
- A strong-growing leguminous plant, 2 to 5 ft.
In Leguminous plants (the pea tribe) the pinnae are frequently modified to form tendrils, as in Lathyrus Aphaca, in which the stipules perform the function of true leaves.
Of the few leguminous plants which are in any degree suitable for water-meadows, Lotus corniculatus major, Trifolium hybridum, and T.
Without this occasional drying of the soil the finer grasses and the leguminous plants will infallibly be lost; while a scum of confervae and other algae will collect upon the surface and choke the higher forms of vegetation.
Meal derived from leguminous seeds makes the flesh firm and improves the quality.
In the low brushwood scattered over portions of the dreary plains of the Kandahar table-lands, we find leguminous thorny plants of the papilionaceous sub-order, such as camel-thorn (Hedysarum Alhagi), Astragalus in several varieties, spiny rest-harrow (Ononis spinosa), the fibrous roots of which often serve as a tooth-brush; plants of the sub-order Mimosae, as the sensitive mimosa; a plant of the rue family, called by the natives lipdtd; the common wormwood; also certain orchids, and several species of Salsola.
In common language the term Acacia is often applied to species of the genus Robinia which belongs also to the Leguminous family, but is placed in a different section.
By far the most useful crops are leguminous green manures, especially alfalfa, which grows four to seven cuttings in a year and as a soil flocculator and nitrogen-storer has proved of the greatest value.
Hence leguminous plants are essential in all rotation of crops.
But if a little water in which arable soil had been shaken up was added to the sand, then the leguminous plants flourished in the absence of nitrates and showed an increase in nitrogenous material.