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The ability of sawdusts, peats, and bark to withstand decomposition when used as soil substitutes in greenhouse culture was determined for differing particle sizes, nutrient additions, and admixtures with soil by means of incubation in the laboratory over a 36‐month period. Particle size was not an important factor but the presence of soil greatly increased the rate of decomposition of bark, sawdusts, and sphagnum peats, which shows the necessity of avoiding contamination of these media by soil. The additions of a nutrient solution containing fairly low levels of N, P, and K increased the rate of decomposition greatly in red alder (Alnus rubra Bong.) sawdust, moderately in Douglas‐fir (Pseudotsuga menziesii (Mirb.) Franco) sawdust, but by only a small amount in Douglas‐fir bark, and decreased the rate of decomposition in the peats. The combination of soil and nutrient solution was particularly detrimental to alder and Douglas‐fir sawdusts but had less effect on Douglasfir bark. The addition of sand to Douglas‐fir and alder sawdusts did not increase their decomposition rates either with or without nutrient solution and its inclusion in a growing medium may be useful in facilitating the establishment of new transplants.

Synopsis Greatest yield response occurred in the month of application while the residual effect in the second month was small. Dividing the N among more frequent applications gave greater uniformity of yield but no increase. Frequency of N applications had no effect on the N content of the forage or the percentage clover. An increase in the N application rate increased the N content of the forage in spite of a reduction in the clover content.

Fertilizer trials which included ten treatments (N, P, K, Mg, B, Zn, and two limestone rates as soil amendments, a control plus an untreated pollenizer cultivar) were conducted on two commercial filbert (Corylus avellana L.) orchards in the coastal area of British Columbia. One of the sites had Daviana as the main cultivar and Duchilly as the pollenizer (Daviana trial), and the other had Duchilly as the main and Daviana as the pollenizer cultivar (Duchilly trial). The Daviana trial was conducted in 1974 and 1975, and the Duchilly trial from 1974 to 1976. There were no significant treatment effects on yield in either trial. There were limited treatment effects on leaf N, P, Ca and Mg concentrations which were assumed to have occurred because of adequate to abundant supplies of these nutrients in the soil. Leaf K concentration was increased by K application in the Duchilly trial and leaf Zn concentration was increased by Zn application in the Daviana trial. Both B and Mn in the leaves were affected by treatments in both trials. Leaf B concentration was increased readily by soil B application. Leaf Mn concentration was increased by N treatment and to a lesser extent by K treatment. Good positive correlations between soil extraction values and leaf concentrations for P, K and Mn suggest the former as a promising diagnostic method for fertilizer recommendations. This, however, was not true for Ca and Mg.