Cost advantages of the concentrated phosphate and potash materials over the lower analysis materials are apparent. Triple superphosphate, though far from a new material and costing more to make than ordinary superphosphate, is much more concentrated and therefore usually has an advantage in final cost.

The cost factor varies less among polynutrient fertilizers than among others but still is definitely weighted in favor of the newer and more concentrated products. For example, in comparing fertilizers of similar ratios, the 4-16-16 grade usually reaches the land cheaper than 3-12-12, and 10-20-20 is more economical than 5 10 10. Liquids are competitive with solids in some localities. Nitric phosphates and ammonium phosphates (especially diammonium phosphate) Show economic advantages in some areas.

Cost figures prove that the high-analysis fertilizers are to be preferred to the low-analysis products wherever the more concentrated materials meet agronomic requirements. One of the most beneficial effects of advanced fertilizer technology, as far as the farmer is concerned, is lower final cost. This indicates good prospects for the improved types of fertilizers.

Highly seasonal demand prevails for fertilizer products. Since deliveries reach the peaks during spring and fall plantings and drop to almost nothing the rest of the year, storage and transportation are big problems. Efforts to remedy this situation with lower prices during the off season thus far have met with only modest success. Nevertheless, the future seems to hold promise of progress in this direction. Many fertilizers produced today will hold up in bag storage for several weeks or months; some years ago fertilizers often deteriorated rapidly. If the farmer could be convinced that with reasonable care he can keep his fertilizer in storage on the farm for extended periods without deterioration in quality and if the price inducements were made attractive enough, the peak-season rush would be lightened.

NEW FERTILIZERS Will appear from several directions in response to specific needs. The trend toward higher analysis can be expected to bring the extra high grades.

Fertilizer grades such as 5-20-20, 10-20-20, and 14-14-14 are on the market. Still higher grades are realizable. Development work has begun on 17-17-17 and 26-26 0 fertilizers. They are combinations of ammonium phosphates and ammonium nitrate with or without potash, and are termed ammonium phosphate-nitrates. Various ratios can be produced from a variety of ingredients. This class of product is entirely soluble in water.

Other new fertilizers are on the horizon, especially one- and two-nutrient materials with built-in desirable characteristics that meet predetermined specifications.

The compounds used in fertilizers vary in water solubility. All the conventional compounds of potassium and of nitrogen, with the exception of natural organic materials, dissolve to about the same extent as table salt, whereas the natural organic nitrogen-bearing materials and some of the phosphates dissolve scarcely at all. This circumstance hampers adjustment of the nutrient reactivity of fertilizers to specific crop requirements. Adjustment is obtainable only by choosing compounds with either high or low solubilities, or mixtures of the two. There is a need for compounds that possess intermediate reactivities.

A urea-formaldehyde reaction product, termed urea-form and on the market under the names Urea-form, Uramite, Nitroform, and Borden's 38, represents a step in the direction of specially designed fertilizer compounds of nitrogen. This high-grade synthetic product is classed as water insoluble and was designed to supply the need for nonleachable nitrogen. It has quickly become competitive with natural organic products on the basis of nutrient cost. Urea-form should be regarded as a prototype of things to come. We envision a whole series of graduated reactivities, intermediate between the extremes now available.

Development work on potassium fertilizers of controlled solubility has started. Noteworthy is a study of the possibilities of fused potassium phosphates. Both potassium and phosphorus of these compounds are of intermediate solubility.

The metaphosphates, particularly the vitreous forms, are of similar type. Calcium metaphosphate, which has been produced as a fertilizer by the Tennessee Valley Authority for more than 15 years, is classed by conventional fertilizer criteria as a water-insoluble phosphate. Nevertheless, the quality of its insolubility differs from that of the common insoluble phosphates, because it can absorb water slowly and change to soluble mono-calcium phosphate. The pattern of behavior of this phosphate under soil environments has been placed under close study. The results of this research may point up the possibilities of this type of material in providing an intermediate phosphate reactivity.

Ammonium metaphosphate, analyzing about 17-73-0, is an experimental fertilizer with varying degrees of quick solubility in water. It is under study as a new material offering advantages of high concentration and possible improvements in other characteristics. As an ingredient for liquid fertilizers, it appears to give unusual opportunities for making more concentrated products.

Micronutrient materials for direct use and also for incorporation in mixtures containing major and secondary nutrients have been studied. Much of this work is concerned with adjustment of reactivity to soil environment for the improvement of nutrient utilization by crops. Thus chelating agents (organic complexing compounds) and glasses (frits) are used to control reactivity of micronutrients such as iron, copper, or boron.