480 



HORTICULTURE 



April 3, 1915 



NITROGEN TRAPS FOR THE FARM. 



• illhcrt K, HnlU-v. rrofcimor of Uooloiry, 

 I'nlviTiiliy of SiiutliiTii Oillfornln. 



NitriiteM urc exin'uslvo, iiiid u cry 

 goes up from llu- KiirdciiH uf llu- At- 

 lantic to tJie orclmrds of the I'lu-lflc 

 for more nllrutes; cheaper iiitrateH. If 

 pohslble. but cheap or not, we must 

 have (hem. 



Our Uovernment has men out seurch- 

 liiK Uie deserts of the West for possi- 

 ble su|iplies, and manufacturers of 

 fertilizers are racking their brains for 

 means of obtaining clieaper supplies. 



It is a matter of nalloiial importance, 

 for well tilled, produclivi- farms make 

 for prosperity and a decrease in tlie 

 productiveness of the soil is inevitably 

 followed by a correspondinK ebb in 

 the tide of prosperity. 



It Is time that everyone realized the 

 fact that there are millions of tons of 

 nitrogen resting on every acre of laud, 

 and that it can be trapped and used. 

 All that is necessary is to use some 

 explosives to open up the soil so that 

 the air can penetrate it deeply, and 

 then set out a few million little traps 

 attached to some plant roots and trap 

 all the nitrogen you want into the soil. 

 Nitrogen. 

 This element is a colorless, odorless, 

 tasteless, inert gas that refuses to join 

 with anything else under ordinary con- 

 ditions, and is seemingly neither harm- 

 ful nor beneficial; yet it is really the 

 Proteus of the elements, the harlequin 

 of the laboratory. In one form it may 

 be neutral, in another a helpful friend, 

 or it may be a powerful, dangerous 

 enemy. Breathed in as part of the air 

 it is not noticed. Inhaled in ammonia 

 its pungency is appreciated. Used as 

 nitric acid its vigor is realized. Fired 

 as nitroglycerine its disruptive quali- 

 ties are respected. Its use in medi- 

 cine fills a large space in the indexes. 

 It is useful in all the arts and sciences, 

 but in none is it of greater value to 

 mankind than in agriculture, for in 

 some form or other it is an essential 

 constituent of animals and plants, ani- 

 mals getting their supply from plants. 

 The atmosphere consists essenliallv 

 of a mixture — not a combination — of 

 oxygen and nitrogen in the proportion 

 of 79 volumes of nitrogen to 21 vol- 

 umes of oxygen, or by weight, of 77 

 per cent, of nitrogen to 23 per cent, of 

 oxygen. In the air it is inert, neither 

 burning nor sunporting combustion, 

 hut serving the useful purpose of dilut- 

 ing the oxvgen. 



An Inexhaustible Supply. 

 The atmosphere gives us a great 

 reservoir to draw from, an inexhausti- 

 ble supply, for all that is drawn from 

 it. in time, returns to it in the cycles of 

 plant and animal life. It has been 

 estimated that if the population of the 

 earth was 1000 million it would take 

 3800 years for their respiration to use 

 up 1 per cent, of the oxygen of the air 

 if none was returned to the air in the 

 meantime: and there is about four 

 times as much nitrogen to draw from 

 as there is oxygen. This nitrogen in 

 the air is pressing down upon the soil 

 demanding entrance, the atmospheric 

 pressure being nearly 1.5 pounds to the 

 square inch, or more than a ton to the 

 square foot. 



Ordinary sources of nitrogen are 

 found in nitrate of soda— Chile salt- 

 peter — which contains 15 to 16 per 

 cent.: dried blood containing 12 to 14 

 per cent.: sulphate of ammonia 20: 



and cotton-seed meal 7 per cent, of 



nitrogen. Some of the oilier sourcos 

 are hoof meal, dry ground llsh, guano, 

 meat meal, linseed im-al and castor 

 pomace. It Is also obtained cominer' 

 dally from the air. Stable manure 

 contains ordinarily only about one-half 

 of 1 per <-ent.: while legunes Inocul- 

 ated with the nitrogen-producing bac- 

 teria yield 8 per lent. or more. 



The use of chemicals is not an un- 

 mixed blessing, for there are certain 

 objectionable features that must not 

 be overlooked. Nitrate of soda leaches 

 out rapidly and cannot he applied very 

 long l>efore the date when the plants 

 need it most, and its application at 

 such a time may he dlfllcull. expensive 

 and at least very Inconvenient. It it at 

 best only a temi'orary expedient and 

 does not add nitrogen to the soil for 

 succeeding crops. An excess of chemi- 

 cal nitrates may prove Injurious. i)ro- 

 ducing an excessive leaf and branch 

 growth at the expense of the fruit. 

 Continued use of tlie Chile saltpeter, 

 as the plant uses only the nitrogen, 

 may in some soils cause an accumula- 

 tion of the soda, creating an alkali con- 

 dition. 



Nitrogen Traps. 

 While most crops exhaust the ni- 

 trogen in the soil, it has been known 

 ever since the days of Rhome that the 

 pod-bearing beans, i>eas, lupines and 

 other legumes actually increase It, 

 leaving supplies of it in the soil ready 

 for the next crop. Now it is known 

 that the nodules or wart-like growths 

 on the roots of the legumes are nitro- 

 gen traps. They are the tenement 

 houses inhabited by myriads of certain 

 bacteria that are specialists in chemis- 

 ry. They devote their lives to tiTking 

 nitrogen out of the soil atmosphere, 

 out of the air. and of storing it in their 

 nodular laboratories in a form that the 

 host plant can use. 



Nitrogen Bacteria. 



Bacteria are the smallest living or- 

 ganisms known. Thousands of them 

 could rest comfortably together on the 

 head of a pin, and a single nodule. 

 One tiny nitrogen trai) is big enough 

 to contain more inhabitants than there 

 are in one of our largest cities. They 

 occupy tlie border line between the 

 animal and vegetable kingdom. The 

 names of the individual numbers of 

 the tribes is legion. Many are useful 

 some are neutral or harmless, and 

 some are belligerent and dangerous. 

 They multiply by cell division with 

 wonderful rapidity and also form rest- 

 ing spores which serve to tide the spe- 

 cies over a period of drought, famine 

 or unsuitable temperature, and to pre- 

 serve alive in a hostile environment 

 enough individuals to provide against 

 extinction. In this stage tliey may be 

 dormant for years. These nitrogen 

 bacteria go into partnership with the 

 host plant, the legume supplying sugar 

 and the salts upon which the bacteria 

 live, and the Ijacteria pay for their 

 board and lodgings by supplying the 

 plants witli the nitrogen they need. 



.Vitrification is one of the most in- 

 teresting phases of soil life, for when 

 any animal or vegetable matter dies 

 and decomposes there is a seething 

 caldron of chemical changes set in ac- 

 tion from which finally emerge sim- 

 ple bodies like carbon dioxide and am- 

 monia. The ammonia is oxidized into 

 nitrites by one form of bacteria, and 

 another form oxidizes these still far- 



ther Into soluble nitrates, In which 

 form the plants i-an use It, 



The vast Importance of these home- 

 made nitrogen traps will be better ap- 

 preciated if we n-nicniber that wliile 

 nitrogen is absoliiti'ly cHHentlal, yet It 

 Is not a imrt of the minerals compos- 

 ing the soil, that It is the most expen- 

 sive to supply in chemical form and Is 

 the most dlfilcult to retain In the soil 

 if in the form of soluble chemicals. 

 With these simple traps the growing 

 crop is suiiplled with all the nitrates It 

 needs and large quantities are left In 

 the decaying roots for following crops. 



The different species of nitrogen 

 bacteria are strikingly different In size 

 and shape, and each legume has Its 

 own pet bacteria with which It works 

 In heartiest co-operation and grows to 

 best advantage. About thirty varie- 

 ties are now cultivated and bred. 

 Beans should he Inoculated with bean 

 bacteria, alfalfa must have alfalfa bac- 

 teria and vetch Its own kind. 



If the correct bacteria are not al- 

 ready in the soil. It becomes necessary 

 to add tliem. This may he done In the 

 form of commercial cultures added to 

 the seed or soil, or by adding soli from 

 a field that is known to have them In 

 large amounts, to the soil and harrow- 

 ing it immediately. Other things being 

 equal, the better the inoculation, the 

 better the crop, the richer the land 

 in nitrates, and the broader the smile 

 of the man who shatters his soil to 

 sufficient depths and sets the traps. 



Benefits. 



Nitrates are used by the plants in 

 forming a variety of compounds, most- 

 ly of the nature of proteids, like the 

 gluten of wheat and legumen of peas. 

 These proteids are the great muscle- 

 building foods of animal life. The use 

 of these nitrogen traps often increases 

 the proteid contents of a crop 25 per 

 cent. The distribution of nitrogen 

 through a plant is shown by an analysis 

 of a peach, the pulp, containing .08 per 

 cent, of nitrogen, the stones .27 per 

 cent., the leaves .9, and the new wood 

 .43 per cent. Nitrogen promotes the 

 growth of leaves and stem, and deep- 

 ens the color of the leaves; while a 

 lack of this food often shows itself in 

 paleness of leaf, lack of gloss, scanty 

 foliage, and an apparent lack of vigor. 

 Inoculated plants give quicker growth, 

 earlier maturity and an increased food 

 value: enrich the soil for future crops, 

 and call for less labor and expense. 

 Legume roots go deep and bring up 

 potash and phosphorus from the 

 depths below. By inoculating the 

 seed of the soil the baby roots are sup- 

 plied from the first and do not have 

 to search for nitrogen, while the tops 

 have to wait until the supplies begin 

 to arrive. Legumes not inoculated are 

 great soil robbers, and alfalfa exhausts 

 instead of improving the ground. 



Explosives Necessary. 



The iirocess is one of oxidation, and 

 air must penetrate the soil and go 

 down deep into the subsoil. The 

 ground must be cracked and the parti- 

 cles loosened or separated, and the 

 subsoil should not be mixed with the 

 top soil. The ground should be well 

 drained, without destroying the capil- 

 larity. Only explosives will do this 

 work deep enough so that the roots 

 of the legumes will go down 4. 

 6 or more feet, leaving nitrogen in the 

 ground, forming liumus from the decay 



