Interaction of nutrient-loaded black spruce seedlings with neighbouring vegetation in greenhouse environments

Abstract

The interaction of newly planted, nutrient-loaded black spruce (Piceamariana (Mill.) B.S.P.) seedlings with naturally occurring vegetation was investigated for one growing season under greenhouse conditions using bioassays retrieved from a boreal mixedwood site. Nutrient-loaded seedlings were similar in height and biomass to conventionally fertilized seedlings at planting, but contained 43, 76, and 33% more tissue N, P, and K content due to higher nursery fertilization, which induced luxury consumption. Nutrient-loaded seedlings outperformed conventionally fertilized seedlings in respective height and biomass growth by 35 and 28% in herbicide-treated plots, and by 44 and 37% in untreated plots, resulting in a 27% reduction in neighbouring vegetation biomass by the end of the season. The loading treatments stimulated nutrient uptake after planting, although the depletion of preplant nutrient reserves was greater. A significant negative correlation was observed between tree and weed biomass accumulation. Slope differences indicated that loaded trees were less sensitive to neighbouring vegetation than conventionally fertilized trees. The enhanced competitive ability of loaded seedlings against naturally occurring vegetation was probably due to the translocation of more nutrients to actively growing parts from reserves built up during the nursery preconditioning phase.

Modeling nitrogen and phosphorus interactions in intensively managed nursery soil-plant systems

“…4) (Table 4). At the end of the 3-yr rotation, on au"iug", the largest trees (16.9 g seedlinSt) were produced iV up"pfy-g N"at 1.19 and P at 1.08 Mg ha-l rotation-r, which-was ilso the biological optimum (with the greatest N x P interaction) projected by greenhouse (Malik and Timmer 1995). However, the optimum N rate, applied with any p rate, failed to improve P fertiiizer recovery on a meaningful scale (Table 4). Actual P recovery in all treatments was very low, a problem noticed by other investigators (Barber 1979, Stevenson 1986) and is a topic, therefore, deserving further investigation.…”

Managing Competition for Nutrients in Agro-Ecosystems

“…Management practices can also influence competition intensity as was demonstrated with herbicide application and nutrient loading (Malik and Timmer 1995;. On the basis of these results, various possible impacts of weed management practices on the competitive interactions of crops and weeds, for example, herbicide application, may reduce weed competition in favor of the crop because of weed elimination.…”

“…The slope indicates no interactions when it is not significantly different from zero (0); indicates beneficial or facilitative effects of the vegetation if it is positive (+); and indicates competitive effects of the vegetation if it is negative (-). Malik and Timmer (1995; have shown the effectiveness of this approach in describing relationships between growth of interacting black spruce (Picea mariana) seedlings and neighboring vegetation over a two-year period, which clearly demonstrated a significant negative relationship between seedling biomass and neighboring vegetation with seedling performance suffering at the expense of weed growth (Malik and Timmer 1996). Thus, reduction in weed biomass due to herbicide application resulted in reduced weed competition and a corresponding increase in biomass or nutrient content of the target crop.…”

“…Vector competition analysis is modeled on regression analysis to evaluate competition effects (Goldberg and Werner 1983;Malik and Timmer 1995), and vector diagnosis is often used to assess plant nutrient status by identifying nutritional effects of nutrient dilution, deficiency, sufficiency and excess uptake (Haase and Rose 1995;Imo and Timmer 1997). The effect of non-crop weedy vegetation (V) on the target crop (T) is evaluated using the linear relationship {(…”

Biomass allocation and nitrogen distribution of Pinus wallichiana Jackson seedlings under different nitrogen fertigation levels

“…Nutrient loaded seedling performed better than conventionally produced seedlings when out planted especially in nutrient poor sites (Malik and Timmer, 1995;Xu and Timmer, 1999). Planting nutrient loaded seedlings is a more effective method of stimulating growth than post transplanting fertilizer application (Xu and Timmer, 1999).…”