MANURES 



Vegetable 



MANURES AND FERTILISERS 



Leguminous 

 Crops. 



Advantages and 

 Eequirements. 



Q reen crops or as, green manure was appreciated for centuries before their exact action 



Manuring. was understood: The chief crops of this nature are Cajanus (see pp. 197-8), 



Cicer (see p. 298), Crotalaria (p. 433), Dolicnos (p. 504), Indigofera (pp. 672, 679), 

 Phaseolus (pp. 225, 879), and Vigna (see p. 1107). It is significant that all these, and 

 a good few others that might be mentioned, belong, like clover, to the special 

 sub-order of leguminous plants that have been shown to possess in the 

 strongest degree the power of producing on their roots, warts that harbour 

 bacterial organisms that have the power of fixing the free nitrogen of the 

 air and thus enriching the soil. Unless, therefore, leguminous crops have 

 been grown so extensively as to render some other plant a desirable rotation, 

 it is preferable in green manuring to select a leguminous crop for that purpose. 

 In that way the advantages of green soiling as well as the supply of nitrogen to 

 the soil may be secured. A green manure should, in fact, be a plant that de- 

 velops rapidly ; should give the largest volume of green vegetation ; should 

 be as deep-rooting as possible, thus opening up the soil to a fair depth ; should 

 be sufficiently hardy as to nourish under what might be called unfavourable 

 conditions ; should occupy the soil and the atmosphere at a season when the 

 crop it is designed to assist is either not on the soil or not growing vigorously 

 at the time ; should return more to the land than it has removed ; should 

 serve to retain manurial constituents that might otherwise be washed out ; 

 and lastly, should easily rot when hoed into the ground. [Cf. Gilbert, Fixation 

 of Free Nitrogen, Lect. deliv. at Cirencester, July 1890 ; Lawes and Gilbert, 

 Sources Nitrogen of Legum. Crops, 1892 ; Warrington, Six Lect. on Rothamsted 

 Exper. Stat., etc., U.S. Dept. Agri. Bull., 1892, No. 8 ; Frankland, The Chem. 

 and Bacteriology of Ferment. Indust., in Journ. Soc. Arts, 1893 ; Agri. Ledg., 1893, 

 No. 20, 141-3 ; 1894, No. 7, 189-200 ; 1897, No. 8, 173-5 ; Nitrogen and Forest 

 Crops, in Ind. For., 1897, xxiii., 439-52 ; Green Manuring, in Journ. Board of 

 Agri., 1897, 1-10 ; Fixation of Atmospheric Nitrogen of Legum. PL, West Ind. 

 Bull., 1900, i., 396-401 ; Mollison, Textbook Ind. Agri., 1901, i., 105-7 ; Allen, 

 Legum. PI. for Green Manuring, U.S. Dept. Agri. Farmer's Butt., 1894, No. 16 ; 

 Watt and Mann, Pests and Blights, etc., 1903, 134-47 ; Nitrogenous and Nematode 

 PL, Circ. Agri. Journ. Roy. Bot. Gard. Ceylon, 1904, No. 18, 273-7 ; Wright, 

 Soil Bacteria in Relation to Agri., in Trop. Agrist., 1905, xxiv., 116-9 ; Green Man- 

 ures, Circ. Agri. Journ. Roy. Bot. Gard. Ceylon, 1905, iii., 181-98 ; Woods, In- 

 oculation of Soil with Nitrogen Fixing Bacteria, in U.S. Dept. Agri. Bureau. PL 

 Indust. Bull., 1905, No. 72.] 



Jumming. Burning or Rabing and Jamming. Burning of weeds in heaps collected 



all over the fields is less commonly seen in India than in Europe. Aboriginal 

 tribes are fond of cutting down the trees and brushwood and firing these on the 

 surface of the soil a process of both clearing new land and manuring it with 

 vegetable ash. This is known as jumming. A civilised modification of this 

 is pursued in Western (and to some extent also in Southern) India. Seecl- 

 Rabing. beds or even whole fields are manured by what is called rdb. This consists in 



burning the surface soil by means of layers of dried manure, leaves, branches 

 and weeds. After the burning has ceased, the soil and ashes are ploughed in, 

 and thus mixed together. The reader will find much useful information re- 

 garding the production of rdb soil in Mollison (Textbook Ind. Agri., i., 83-5). 

 Silt. Top-dressing of Soil by silt from canals and streams or by the soil from 



dried-up tanks, bhils, etc., is a subject that has attracted much attention re- 

 cently. To the tea-planter a dressing of " peat bhil soil " has been proved in 

 some cases profitable, but it is feared soil of comparatively little value has, in 

 many cases, been used in top-dressings, with the result that the cost has far 

 Peat-soil, exceeded the value. Much, therefore, depends on the quality of the bhil soil 



available. What may be called peaty soil is formed by the decay of many genera- 

 tions of rank-growing plants, especially if the decomposition has been accom- 

 plished under water. Soil of that nature is most valuable, and has with great 

 advantage been used in many tea estates. [Cf. Pests and Blights, I.e. 122-30.] 

 For many other crops silt deposits have been highly commended. For ex- 

 ample, of this nature may be mentioned the special cultivation of ground-nuts 

 in South India, manured with tank-soil (see p. 79). [Cf. with Leather, Agri. 

 Ledg., 1897, No. 8, 172-3 ; Silt of Rivers as Manure, in Journ. Board Aqri., 

 1897, iv., 351.] 



D.E.P., Oil-seed Cake The Indian cultivators fully recognise the value of oil- 



v., 463-79. seed cake or the refuse of such, both in feeding cattle and as manures of 

 Oil-cake. great value. The edible sorts of oil-cake, such as Linseed (see p. 731), Rape and 



770 



