RESPONSE OF REED CANARY GRASS GROWN ON TEN BRITISH COLUMBIA ORGANIC SOILS TO N, P, K AND LIME
Samples of 10 Organic soils, 1 with a humic surface layer and 9 with mesic surface layers, but representing a wide range of Humisol and Mesisol soil profiles, all of the euic reaction class, were collected for growth room fertilizer trials and subsampled for chemical analyses. Reed canary grass responded markedly to N, P and K applications on all soils, but to lime only on the humic surface layer which had the lowest extractable-Ca value. Soil-nutrient sufficiencies based on dry matter yields ranged between 6 and 44% for N, between 4 and 24% for P, and between 10 and 17% for K. Sufficiencies based on nutrient uptake ranged between 4 and 31% for N, between 1 and 13% for P, and between 3 and 21% for K. Correlations between N response measurements and degree of soil decomposition, as measured by bulk density, Na4P2O7-extractable organic matter, and water holding capacity, gave the highest significant [Formula: see text] values which averaged 0.86, 0.82 and −0.63, respectively. Linear regression equations show an increasing dependence of dry matter yield on soil bulk density with successive cuts for the treatment that received only P and K fertilizer. Bulk density would therefore be a good indicator for N requirement of Organic soils. Rubbed fibre (volume basis) was also negatively correlated with N response measurements (r = 0.77, [Formula: see text]) when the data for the humic surface layer were omitted and when all cuts were considered. Irreversibly dried granules in this layer adversely affected fibre determinations. Extractable P and K values were correlated positively, though not all were significant, with certain yield response measurements. Since reed canary grass grown on all soils responded to applications of P and K, the extractable P and K values were considered to be in the deficiency range and would serve as a basis for evaluating field situations.