Abstract: A controlled slow release potassium divalent metal phosphate composition for agriculture and an effective method of preparing the composition. The cold water insolubilities of each of the contained nutrients are between 35 and 98 percent. The potassium exhibits an Activity Index between 20 and 85. The release of all contained nutrients is substantially complete in one growing season without damage to plant foliage or roots. Divalent metals effectively forming the new composition include magnesium, manganese, zinc, iron, cobalt, and copper. The effective method of preparing the new composition requires the exothermic coreaction of concentrated potassium hydroxide, divalent metal oxide powder, and concentrated phosphoric acid, with a molecular ratio of 1 potassium/1 divalent metal/1 phosphate with the total water content of the initial reaction mixture between 20 and 50 percent, at a maximum temperature between 85.degree. and 150.degree. C.

Abstract: A vitreous product which can be used in agriculture is disclosed. With the exception of nitrogen, this vitreous product contains all the major and minor mineral elements which are essential for the nutrition of plants.The vitreous products can contain the following constituents, taken in the following proportions by weight:______________________________________ SiO.sub.2 25 to 65% Fe.sub.2 O.sub.3 1 to 15% P.sub.2 O.sub.5 1 to 15% B.sub.2 O.sub.3 0.01 to 2% K.sub.2 O 5 to 35% MnO 0.01 to 3% CaO 11 to 35% ZnO 0.01 to 3% MgO 1 to 10% CuO 0.01 to 2% SO.sub.3 0.01 to 1% MoO.sub.3 0.01 to 3% Na.sub.2 O 0 to 2% Al.sub.2 O.sub.3 0 to 25%.

Abstract: A composition of matter for use as a vitreous fertilizer comprising a soluble vitreous constituent comprising the following ingredients: 35 to 55 moles %, P.sub.2 O.sub.5 ; less than 10 moles %, K.sub.2 O; and the balance to 100 moles %, CaO and/or MgO. The balance of the composition, if any, is constituted by optional additions of nutrient proportions of one or more micro-nutrients in plant assimilable form, and/or optional additions of one or more plant-inert filler materials. Such compositions have favorable nutrient release rates. The invention also encompasses compositions of matter adapted for use as a plant fertilizer which comprises soluble vitreous plant nutrient release material in expanded or cellular form, and to methods of plant cultivation using such compositions.

Abstract: Langbeinite (2MgSO.sub.4,K.sub.2 SO.sub.4) is reacted with diammonium phosphate (NH.sub.4).sub.2 HPO.sub.4 to yield a dry farm field fertilizer of grade 21-12-7+1.22 Mg.The chemical process is also adjusted for a dry farm field "double cropping" fertilizer.The cost of the basic liquid fertilizer containing Magnesium has been likewise reduced.These fertilizers contain magnesium in the presence of phosphorus.The micronutrients, Zn, Cu, Fe, Mn and B may be added in rates proportional to the deficiency shown by soil tests.