In an attemDt to studv the nature of plant tolerance to soil acidity and related factors,'a series of investigations was conducted with sand cultures to determine the chemical composition of alfalfa as related to its response to various concentrations of manganese, aluminium and calcium' All clones studied were affected, but to a variable degree, by an excess of manganese and aluminium, They absorbed approximately the same amounts of these elements but considerable differences rvere noted in their rate of translocation from the roots to the aerial orsans. As a result, plants *'hich were the least affeeted hv manqanese and aluminium conrained smaller amounts of those trvo eleme-nts iniheir stems and leaves and larger amounts in their roots.Moreover, for a given content of manganese and aluminium in aerial organsi the degree of irrj-ury was approximatcl-y the same lor all clones. More tolal and witer-solubie ialcium'ii'as found in so-called tolerant than non-tolerant olants. Also. an increase in the calcium concentration of the nutrient culture uas effective'in reducine manqanese toxicity. These results suggest the theory that the rate of u"ptal

A study was made of: 1) the response of some pasture weeds of Eastern Canada when fertilizers were applied; 2) the productivity of pastures sprayed with 2,4-D, and 3) the over-all response when both fertilizer and 2,4-D were applied. Populations of orange, yellow and mouse-ear hawkweeds, ox-eye daisy, chicory, bugleweed, strawberry and wild carrot were decreased when nutrients were added but the numbers of dandelion, Canada thistle, tall buttercup, shore horsetail and yarrow were unchanged. Fertilizer not only improved the quantity but also the quality of the forage by reducing the weed content. Yield of total vegetation was not increased when weeds were controlled by 2,4-D but the forage consisted almost exclusively of desirable grasses. Best results from the standpoint of both yield and absence of weeds were obtained when fertilizer treatment was supplemented by applications of 2,4-D.

Two groups of alfalfa varieties and crosses were grown in nutrient solutions containing two levels of manganese: 0.5 and 25 parts per million. Significant differences between varieties in their ability to tolerate manganese toxicity were observed. Promising individuals from the variety trial were selected for strain building. Some resulting crosses were found to be highly tolerant to the toxic level of manganese. This character appears to be inherited.

A chlorosis of Ladino clover, which was attributed to a shortage of molybdenum on St. Onesime stony loam, did not appear unless sufficient superphosphate was applied. An excessive amount of superphosphate has rendered the chlorosis more acute. The situation could be corrected by applying to the soil either 1 pound of sodium molybdate or 100 pounds of ammonium nitrate or 2 tons of limestone. This tends to prove that the trouble was one of nitrogen deficiency induced by the lack of molybdenum. Greater yield increases could be obtained, however, with additions of nitrogen or limestone than of molybdenum. Therefore, the latter could not take the place of the former, at least not completely but, under the conditions of the experiment, the reverse seemed possible. Tissue content of molybdenum, nitrogen and phosphorus correlated with growth data.

Potatoes (Solanznn tuberosum L.) were glown on a soil with a pH of 4'5 and containing 12 ppm of exchangeable manganese, and in sand cultures where the manganese concentration ranfed from 02 to 10 ppm. Potassium was sgnplied in the forms of chloride, sulfate, carbonate, nitratc and hydroxide. On unlimed soils, the yields of tubers were in the following order: K,CO, > K-gtI

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