December. 1930
INDUSTRIAL A N D ENGINEERING CHEMISTRY
1405
Free-Ammonia Injury with Concentrated Fertilizers'" L. G. Willis and W. H. Rankin X O R T XCAROLIXA STATECOLLEGE,R ~ L E I G H N., C
Effect of Cottonseed Meal Cottonseed meal, used as a fertilizer representative STUDY of a peculiar on Cotton Seedlings of the organic ammoniates that are readily ammoniinjurious effect on cotfied, may cause serious root injury to seedling plants For the pot work Sorfolk ton seedlings folloiving on light, sandy soils. The injury is related to a high sand was used in 1 gallon the use of concentrated ferconcentration of free ammonia in contact with the glazed pots with cottonseed tilizer on a light sandy soil roots and control is effected by neutralizing this ammeal added at rates equiva(1) showed that tlie injury monia with gypsum or by allowing the fertilizer to relent to 16 and 32 pounds of was most severe when diammain in the soil until the ammonia has been dissipated nitrogen per acre. Gypsum monium phosphate was used by diffusion or volatilization. Nitrification in the preswas used at rates of 110 and as a source of phosphoric acid, ence of the free ammonia seems not to be effective as a 220 pounds per acre. and the principal injurious preventative of injury. Rates of application and factor appeared to be the free In concentrated fertilizers some calcium salt should mixtures of soil, cottonseed ammonia produced by the be used if ingredients decomposable into free ammonia meal, and gypsum were calhydrolysis of this phosphate. are used, or if the fertilizer is to be practically free of culated on the basis of all The inclusion of a neutral calcium no such sources of free ammonia should be the fertilizer being p l a c e d calcium salt in the fertilizer included in the formula. in furrows 6 inches wide, served to control the injury spaced 4 feet apart, and verg effectively. Although there was some evidence -of physiological antagonism be- with the fertilizer mixed with 1 inch of soil in the iottom of tween the calcium and ammonium ions, the most impor- the furrow. tant function of the calcium salt seemed to be the conFor the pots 4.81 or 9.63 grams of cottonseed meal (6.02 version of the free ammonia, in the presence of the carbon per cent nitrogen) and 2 or 4 grams of gypsum were mixed dioxide of the soil, into the nun-injurious neutral ammonium with 756 grams of soil, making a layer 1 inch in depth which salt with the precipitation of calcium carbonate. It was was placed 11/* inches below the surface. Fifteen delinted concluded that any material that would furnish free ammonia cottonseed were planted 1 inch deep in duplicate pots of in appreciable quantities to the soil in contact with plant each treatment immediately after preparing the pots and roots would be likely to cause injury unless converted to a thereafter at 4-day intervals for 16 days. non-toxic form as by reaction with a soluble calcium salt. Injury was recorded when the tap root of the seedlings I n addition to the diammonium phosphate the only sources was destroyed at the plane of contact with the fertilized of free ammonia having any practical significance are the layer. high-grade organic materials, from which the ammonia is The results are given in Table I. produced in the process of microbiological decomposition. Table I-Injury t o C o t t o n Seedlings by Cottonseed Meal a s These compounds have been used safely for years in mixed Influenced by T i m e of Application a n d Admixture of G v o s u m fertilizers, but always with superphosphate carrying an C O T r O N SEEDLIXGSa IXTERVAL RATE RATE abundant supply of calcium salts. The possible value of BEFORE SITRUGEX GyPsUhf Total Number ye: cent the calcium content of superphosphate for rendering organic PLAXTIXG PER ACRE PBn ACRE number injured injury ammoniates safe for use seems not to have attracted much attention heretofore, but now the current interest in conDays Lbs. Lbs. 70 0 16 0 14 5 12.5 86 centrated fertilizers from which neutral salts of calcium are 110 15 0 0 largely eliminated makes the subject one meriting some atten220 14 5 1 7 32 0 15 15 100 tion. 110 14 14 100 220 15 15 100 I n its present aspects concentrated fertilizers serve prin0 15 12 80 4 16 cipally as vehicles for the products of the synthetic nitrogen 110 14.5 0 0 220 1 4 . 5 2 14 industry, and there is little immediate prospect of the in32 0 15 15 100 110 14.5 14 97 clusion of any of the older types of organic nitrogen in con120 14 14 100 centrated goods. There is, however, a persistent demand 15 1.5 10 8 16 0 110 15 0 5 3 for organic ammoniates in mixed fertilizers, and this work is 220 15 0 0 32 0 15 15 100 of interest as it shows one of the limitations imposed on the 110 15 1.5 10 use of these materials in calcium-free mixtures. 220 13 5 3 22 12 16 0 1 4 . 5 0 0 This effect of organic sources of ammonia was studied 110 14.5 0 0 220 using cottonseed meal as a representative of the class and 15 0.5 3 32 0 15 14.5 97 with c. P. calcium sulfate (gypsum) as the calcium salt. Pot 110 15 0.5 3 220 14.5 0 0 culture tests with cotton seedlings were used to establish 0 15 0 0 16 16 the relation between fertilization and injury, and the cause 110 15 0 0 220 14 0 0 of injury was studied by the analysis of ammonifying cultures 13.5 0 0 32 0 110 14 0 0 of the cottonseed meal-soil-gypsum mixtures. 220 14 ,5 0 0
A
I Received September 22, 1930 Presented b y L. G. Willis before t h e Division of Fertilizer Chemistry a t t h e 80th Meeting of t h e American Chemical Society, Cincinnati, Ohio, September 8 t o 12, 1930. Published with t h e approval of t h e Director of the N o r t h Carolina Agricultural Experiment Station as paper No 43 of the Journal Series.
*
a
Average of duplicate pots.
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It appears from these results that cotton cannot be planted without risk of root injury over a fertilizer containing 16
INDUSTRIAL AND ENGINEERING CHEMISTRY
1406
NfirR4TE
FREEANWOMA
Vol. 22, No. 12
is some question as to the absolute accuracy of this method of determining OKOOEN free ammonia, as the extraction with sodium chloride involves the exchange 70-70 of bases which might result in an inexact value for free ammonia. However, the 60- 60 results given in Figures 1and 2, &owing values comparable to the treatments, a p -SO pear to be a reliable representation of the ratios of free to fixed ammonia and -e nitrates. These results show that ammonia is freely and rapidly produced in all cul-&7 tures, but that in the presence of gypsum the greater part of this is combined, pre-20 sumably as the sulfate. Without gypsum approximately one-half of the total -10 nitrogen is in the free state. As the period of incubation increased it a p 0 peared that ammonia was freely lost,from Figure 1-Ammonification of Cottonseed Meal. 16 Pounds Nitrogen per Acre the cultures without gypsum. Although there was no appreciable amount of nipounds of nitrogen per acre in the form of cottonseed meal trate nitrogen at any time, the cultures with the lower rate of until after a lapse of 8 days unless the fertilizer contains a mixture of cottonseed meal had a slightly greater concentracalcium salt, in which case planting can be done immediately tion of nitrate in those treatments having the lowest content without damage from the cottonseed meal. of free ammonia. It is not improbable that the failure of With 32 pounds of nitrogen per acre the protective effect these cultures to show active nitrification was due to the inof gypsum was not evident until the third planting a t 8 days hibitory effect of the free ammonia. If this is so, it follows after fertilization, and without gypsum the injury was severe that the loss of free ammonia by volatilization or by diffusion until 16 days had elapsed. and absorption by the soil are the only important natural The simplest apparent explanation of the injury from the means of avoidance of this type of injury. cottonseed meal is that it results from the formation of a toxic Neither the amounts of total and free ammonia in the culconcentration of free ammonia by microorganisms and that tures nor the degree of control of seedling injury were a p the beneficial effect of gypsum results from the conversion preciably different with the two amounts of gypsum chosen, of this, in the presence of carbon dioxide, to the harmless the inference being that some lesser amount than the miniammonium sulfate. The favorable influence of the lapse mum used would have been fully as effective. At the lighter of time may come from the loss of ammonia by volatilization rate of application the gypsum was furnished in about the or the conversion to the non-injurious nitrate by nitrifica- same quantity as would be supplied by 800 pounds of an tion. 8-4-4 fertilizer having the phosphoric acid derived from superphosphate, so it appears that some concentration of the present mixtures can be undertaken even when organic Ammonification ammoniates are included. These possibilities, which could not have been tested diDiscussion rectly in the pot cultures, were studied in a series of ammoniThe purpose of this work was not to determine the optimum fication cultures which consisted of 200-gram lots of the same soil as used in the pots, with cottonseed meal and gypsum ratios of calcium salt to free ammonia concentration, but to in the same proportions as in the 1-inch layer of fertilized soil. The cultures were maintained at 10 per cent moisture Man NlrRoern content. Analyses were made of duplicates of - 70 the several treatments immediately after 73t preparation of the cultures and there-60 after at 4-day intervals. The analyses 6Cgiven are the contents of the cultures - 50 above those found in the first deter- 20mination which showed very low concentrations of soluble nitrogen. - 90 46The ammoniacal and nitrate nitrogen was extracted from the culture with - 30 JOnormal sodium chloride and total ammonia was determined by the distillaTO -20 tion of an aliquot with magnesium oxide. Nitrate nitrogen was determined in the - /u /Oresidue by Devarda’s method. Free ammonia was estimated by the titration -I7 0of another aliquot with standard acid /6 D ?rcF usingmethyl red as an indicator. There Figure 2-Ammonification of Cottonseed Meal. 32 Pounds Nitrogen per Acre fiXfOAA/rMON/A
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INDUSTRIAL AND ENGINEERING CHEMISTRY
December, 1930
1407
A
B
C
..
Gypsum Added Without G v ~ r u m Figure 3 4 o t t o n s e e d Meal I n j u r y to Cotton Seedlings (16 Pounds Nitrogen per Arne) A-Planted immediately: B-planted after 4 dags; C q l a n t e d after S days
test the hypothesis that toxic concentrations of free ammonia might he evolved from decomposing organic ammoniates and that a calcium salt would control the injury. In its practical aspects it appear8 that high-grade organic ammoniates can safely be used to constitute a part of the nitrogen in mixtures with superphosphate where this does not involve a greater concentration of such nitrogen than would he found in applications equivalent to 16 pounds per acre in furrows 4 feet apart. On highly absorptive soils the injury might never occur, whereas on light, sandy mils it might reach serious proportions 8 8 a result of the injndicious use of the organic materials.
I n concentrated mixtures free of calcium salts this type of injury can be avoided by the use of nitrogenous materials that do not produce free ammonia by hydrolysis or by hiological decomposition, hut the practice occasionally followed in the cotton-raising sections of mixing locally produced cottonseed meal with the commercial complete fertiliw would he decidedly inadvisable if calcium-free fertilizers become generally used. Literature Cited (1)
wiltis and Piland, Soil
Scirnce. io pres$,
Monazite Markets and Prices The demand for monazite sand in the United Statps is limited t o the incandescent gas mantle and the pyrophoric-alloy industries, according t o the United States Bureau of Mines. Requirements far the manufacture of gas mantles have declined rapidly in recent years, while those for the manufacture of “flints” or sparking metal have increased considerably because of the more extensive use of automatic cigar lighters, gas lighters, miners’ lamps, etc. Despite the attempted monopoly of the manufacture of thorium nitrate by German and Austrian firms, France and the United States for some time previous t o the outbreak of the World War had been manufacturing this product chiefly from Brazilian and American monazite. As a result of the war and the serious shortage of thorium nitrate caused by the stoppage of ship-
ments from Germany, other countries took up the manufacture of this product. The price of monazite sand has fluctuated considerably since the war, in most cases reflecting the declining use of this mineral. During the war the price of monazite sand delivered to New York, exclusive of the duty of $80 a ton, varied from $25 t o $40 per unit (1 per cent per short ton) of thoria or from $150 to $240 per ton. Immediately after the wer the price was quoted (November, 1919) at $27 per unit, or about $162 per ton of the 6 per cent (thoria) sand, plus duty. Before the end of 1925 the price had dropped to $120 per ton. After increasing slightly during the Iatter part of 1928 t o $130 per ton. the price dropped in 1929 t o $60 B ton, the lowest figure so far recorded.
