Forage Response to N, P, and S Fertilization on Clearcut Lodgepole Pine Sites

Abstract

The response of selected plant species to a single application of factorial combinations of nitrogen (N), phosphorus(P), and sulfur (S) on 2 lodgepole pine (Pinus contorlo Dougi.) clenrcut-logged sites In British Columbia was evaluated over 3 years. Increasing N rates typically resulted in higher forage standing crop on both sites, in all years, but standing crop at Fly Creek was nearly double that at Beaverdam Lake. On both sites, forage yields peaked at 400 kg N/ha in 1982 and carry-over of the fertilizer effect lasted for 3 years although yields declined annually. Addition of P to N applications enhanced (P<O.O5) total standing crop, other grass standing crop, and pinegrass (Gdmagrostis rubescens Buckl.) standing crop at Beaverdam Lake and grass standing crop at Fly Creek, but bad no effect (mO.05) on other species and groups. Sulfur, added to N applications, enhanced total yields compared to control on both clearcuts although at Fly Creek this response nearly doubled that produced at Beaverdam Lake. Nitrogen fertilization increased (P<O.O5) pinegrass crude protein (CP) content, particularly in the first year after fertilization. Acid detergent fiber (ADF) generally increased in response to increasing N levels in 1982, but declined compared to control in 1983 and 1984. Elevated forage CP levels, litter N concentrations, and soil N levels in 1984 indicated that the carry-over response on these forest sites resulted directly from N remaining in the soil or again becoming available for plant growth.

An overview of the forage resource and beef production on Crown land in British Columbia

“…Indeed, Wikeem et al (1993) found that increasing N rates from 100 to 400kg N ha-' at 100-kg increments increased forage yields to more thar. 400% of control on two lodgepole pine sites in the south Cariboo.…”

Influence of repeated fertilization and cattle grazing on forest ecosystems: Abundance and diversity of forest-floor small mammals

“…Stand thinning reduces shade and delays canopy closure, and hence may increase forage yields and prolong the silvopasture potential (Hall, 1988;Lindgren et al, 2006). In addition, the quality and quantity of forage produced within forest rangeland may be enhanced by fertilization (Freyman and van Ryswyk, 1969;Wikeem et al, 1993b;Lindgren and Sullivan, 2012). From a forest ecosystem perspective, positive biomass responses of understory vegetation have been reported for stand thinning (Crouch, 1986;Sullivan et al, 2001;Lindgren et al, 2006) and fertilization ( VanderSchaaf et al, 2000;Turkington et al, 2001).…”

“…To enhance forage production for cattle, both study areas were aerially seeded (in the first year after forest harvesting) with an agronomic grass-legume mix including species such as timothy (Phleum pratense), orchardgrass (Dactylis glomerata), smooth brome (Bromus inermis), intermediate wheatgrass (Agropyron intermedium), and alsike clover (Trifolium hybridum) (Quinton, 1984;Wikeem et al, 1993b). Such seeding has been a common range improvement practice throughout the interior of BC since the 1960s (Wikeem et al, 1993a).…”

Response of forage yield and quality to thinning and fertilization of young forests: implications for silvopasture management

“…In general, forage productivity peaks soon after any disturbance that removes tree cover (e.g., wildfire, harvesting) and predictably decreases as the tree layer regains dominance and shades out the understory forage. In most temperate and boreal coniferous forests, natural succession limits the post-disturbance period when the forage resource is capable of sustaining grazing cattle to approximately 10 to 20 years (Basile and Jensen 1971;Wikeem et al 1993b). A quality forage needs to have minimum crude protein levels of at least 12% to maintain active growth of calves and 8.3% for lactating cows (McLean et al 1969).…”