Fertilizers / Pesticides

G. L. BRIDGER

Washington Research Center, W . R. Grace and Co., Clarksvil le, M d .

A, Ν ESTIMATE of the net domestic supply of primary plant nutrients for the United States and possessions for the year ended June 30, 1958, by the United States Department of Agriculture (Table I) shows that nitrogen supply increased slightly (4.9%), whereas phosphate and potash supplies decreased slightly (4.3 and 6.7%, respectively).

Table 1. Supply of Primary Plant Nutrients for United States and Pos­

sessions' N , P.Os , or K 2 O t

1000 Tons : 1956-57 1957-58 6

Nitrogen Supply from domestic

sources Ammonium nitrate 411 455 Ammonium sulfate 405 369 Urea 69 87 Ammonium phosphate 83 89 Ammonia (including

aqua) 684 755 Other solids 99 99 Other liquids 511 565

2262 2419 Imports 294 302 Exports 268 321 Net domestic supply 2288 2400

Phosphate Supply from domestic

sources Normal and enriched

superphosphate 1446 1313 Concentrated super­

phosphate 799 875 Ammonium phosphates 144 155 All other 149 150

2538 2493 Imports 54 62 Exports 256 320 Net domestic supply 2336 2235

Potash Supply from domest ic

sources Muriate 1982 1806 Sulfates 137 112 Manure salts 3 1 All other 20 20

2142 1939 Imports 179 195 Exports 315 263 Net domest ic supply 2006 1871

" C o m m o d i t y Stabilization Service, U. S. Department of Agriculture. * Est imated.

The consumption of fertilizers in the United States and possessions for the year ended June 30, 1958 (Table II) , was 22,358,000 tons, a 1.5% de­crease over the previous year. Con­sumption of nitrogen increased by 6.1%, while available P 2 0 6 decreased by 1.0%, and potash by 0.9%. Total consumption of primary plant nutrients of 6,465,000 tons repre­sented an increase of 1.4% over the previous year.

In 1957-58 the total consumption of fertilizer materials for direct application was 8,106,000 tons, which represented 36.2% of all fertilizers used compared with 35.3% for the preceding year. The propor­tion of nitrogen for direct applica­tion use was 62.5%, that of available P 2 0 6 21.5%, and that of K 2 0 12.8%.

Concentration of primary plant nutrients in all fertilizers was 30.2% as compared with 29.3% for the preceding year.

Nitrogen

U. S. capacity to produce fixed nitrogen continued to increase. On July 1, 1958, 54 anhydrous ammonia plants were reported to be in opera­tion and eight additional plants were

Table II. Consumption of and Primary Plant Nutrients

States and Possessioi Toi

1957-58»

Fertilizers in United

is"

IS 1956-57

Mixtures 14,252,000 14,702,807 Materials 8,106,000

Total 22,358,000 Primary plant nu­

trients Nitrogen 2,264,000 Available P2O5 2,280,000 K20 1,921,000

Total 6,465,000 " Agricultural Research Serv

Department of Agriculture. * Pr

8,006,204 22,709,011

2,135,287 2,303,991 1,938,263 6,377,541

ice, U. S. eliminary.

proposed or under construction. Total U. S. capacity for ammonia production is probably in excess of 5,000,000 tons per year. Further expansion is predicted ; one estimate is that there will be an 8 0 % expan­sion by 1975.

The proportion of nitrogen fer­tilizers applied directly continues to increase, 62.5% of all nitrogen being-applied in this manner in 1957-58. Use of direct application of anhydrous ammonia increased by 27.4%.

New nitrogen solutions for am-moniation in mixed fertilizer manu­facture continue to be offered. Some of the new solutions contain small percentages of urea as well as am­monium nitrate and ammonia, which permits the use of a higher propor­tion of fixed ammonia to free am­monia at practical salting out tem­peratures. A system of nitrogen solution nomenclature has been de­veloped and is being adopted by many nitrogen solution producers. For example, the designation 414 (19-66 6) means a solution contain­ing 41.4% total nitrogen, 19% ammonia, 66% ammonium nitrate, 6% urea, and 9% water (by differ­ence). This system, if widely adopted, should remove much of the confusion resulting from present solution designations, which differ from one manufacturer to another.

Phosphates

The proportion of available P2O6 produced as triple superphosphate continues to increase at the expense of normal superphosphate. In 1957—58 the supply of triple super-

6 0 A INDUSTRIAL AND ENGINEERING CHEMISTRY

I / E C A N N U A L R E V I E W 1 9 5 8 phosphate was 35% of all phos­phates, an increase from 3 1 % in the preceding year. Normal super­phosphate, on the other hand, de­creased to 53% from 57%. Al­though use of phosphoric acid in mixed fertilizer manufacture has con­tinued to increase, it still represents only about 1% of all phosphates.

On July 1, 1958, there were 15 major triple superphosphate plants in the United States. In addition, there are a number of other plants which could divert phosphoric acid to triple superphosphate manufacture if desired.

A new kind of superphosphate, called high analysis superphosphate, was developed by the Tennessee Valley Authority. This product, containing 54 to 56% available P2O6, has been made in pilot plant quantities by the reaction of super-phosphoric acid containing 74% P2O5 and phosphate rock. The new superphosphate is higher in analysis than triple superphosphate, primarily because its principal con­stituent is anhydrous monocalcium phosphate rather than monocalcium phosphate monohydrate. The new product is said to be satisfactory for ammoniation and mixed fertilizer manufacture.

Increasing attention is being given to the importance of using the proper source of phosphorus fertilizer for specific agronomic applications. There are ample agronomic data showing that the various sources of phosphorus do not necessarily give equivalent response for a given set of crop, soil, and climatic conditions. Factors such as water solubility, citrate solubility, fixation charac­teristics, resistance to leaching, and physical and chemical characteristics due to method of manufacture are important. For example, one recent field study showed that a phosphate fertilizer containing practically no water-soluble P2O6 gave response equivalent to another having com­plete water solubility, whereas still others of intermediate water solu­bility were distinctly inferior. The reasons for this and other similar results are not yet understood, but much work on such problems is un­der way.

Potash

Development of the Canadian potash deposits continues. The Potash Corp. of America expects to

be in production at its Saskatchewan facility late in 1958. International Minerals & Chemicals is developing its deposits in Saskatchewan but will not be in production for some time. A number of other companies have reserves in Canada and are con­sidering production. The Canadian deposit is said to be the largest in the world, and the quality of its ore as high or higher than that remaining at Carlsbad, Ν. Μ.

Some sources estimate that potash production capacity in North America will be doubled by 1970.

At present agricultural uses ac­count for about 94% of all potash produced.

Mixed Fertilizers

Dry blending of fertilizer materials continues to grow, particularly in the Midwest. Although raw materials for dry-blended fertilizers are more expensive than for wet-mixed fer­tilizers, capital and operating costs for blending plants are less than for wet-mixing plants. Bulk spreading is usually associated with dry blend­ing.

The trend to higher analysis mixed fertilizers continued, the major grades being 5-10-10, 4-12-12, 5-20-20, 4-16-16, 10-10-10, 3-12-12, 12-12-12, 3-9-9, 5-10-5, 6-12-12,

5-10-15, 4-10-7, 2-12-12, 0-20-20, and 6-8-8 in order of decreasing tonnage. These grades represent 64% of all mixed fertilizers used in the con­tinental United States. With the increasing concentration of the pri­mary plant nutrients more atten­tion is being given to the secondary and trace elements, as they are less plentiful in the higher analysis fertilizers. Statistics on total usage of secondary and trace elements are not available, but use is probably increasing substantially.

Recent developments in the field of growth regulators, such as gibber-ellic acid, may have a large in­fluence on fertilizer consumption. Gibbcrellic acid is coming into commercial use for a few crops and will probably be used for many more within a few years. This material increases rate of plant growth, but only when additional mineral nutrients are supplied. Any substantial use of gibberellic acid would therefore increase require­ments for mineral fertilizers.

Aerial spreading of fertilizers, which is very common in some other countries, particularly New Zealand, is finding use in some parts of this country. For such an application high analysis granular fertilizers are best suited.

An operator with a knowledge of fert i l izer analyses actually has a wide range of ratios a t his f ingert ips. Plant food applications can be exact ly ta i lored to farmers' soil test reports

VOL. 51, NO. 1 · JANUARY 1959 61 A