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Show "Fertile Rock" Not Recommended For Use On Irrigated Soils Fertile Pvock" on the basis of chemical analysis is a good grade , of agriiult'ifal lin.o and does no. ,arrv any of Hie "hl,U 100,1 eleinenls (nitrogen, phosphoi as. ! ;,d potassiiiml usually conadered viien purchasing commercial ler-tilizer. ler-tilizer. according to the University of Idaho agricultural exper'.r.enl I station, in response lo many m quiries concerning the aluo ol Fertile Rock" as a fertilizer lor the soils of Ihe irrigated areas of southern Idaho. The analysis shows Ihe follow ing I ingredients and per cent of e,;vh: Calcium carbonate SU.5ti Magnesium carbonate 2.10 lion and aluminum l ''t' Calcium-bicarbonate l.''u Insoluble material -SO This analysis show s I here is o er 90 per cent of -calcium carbonate magnesium carbonate, and calcium-bicarbonate, calcium-bicarbonate, materials which uv the main ingredients of agricultural agricultur-al lime. In a field fertilizer test at the Aberdeen branch experiment station sta-tion during (he 1040 growing season, sea-son, "Fertile Rock" was applied to potatoes with a fertilizer attachment attach-ment on the potato1 planter, at the rate of 2H0 pounds per acre to both tinmantired and manured land. No increase in yield over the unlvoated plat was obtained in either case. Irrigated soils, m most cases, tire alkaline in reaction, already containing con-taining an excess of lime. These soils show a lime content ranging from no free lime to more than 100 tons per acre, furrow slice, which is the soil . f. ' " ; : ves , ep per acre. The r .-.-.' .rate is around 35 to 40 tons. Tests have shown 'hat as (he lime content of the surface sur-face soil increases, the availability of the soil phosphorus decreases until a point is soon reached where it is necessary to apply some type of phosphate fertilizer high in water wa-ter soluble phosphate in order to produce a normal yield. Experiments have shown that chlorosis (a type of yellowing in plants) is caused indirectly by high lime content in the soil. The liuu .akes the iron into a form that the plants cannot use lo main-lain main-lain their green color. In general, the irrigation water used in southern Idaho contains the equivalent of from 100 to over "Oo pounds of lime per acre foot of water applied. Thus, irrigation water vil supply all (ile ijnle nec cssary for plant growth even if the soil were low or deficient in lime. As a result of data collected if is not the recommendation of (he experiment station that this material ma-terial be used as a fertilizer or a soil amendment for irrigated soils |