TITLE:
Yield and Uptake of Phosphorus by Wheat and Canola Grown after Two Years of Forage Legume and Annual Crops
AUTHORS:
Rehemuti Miheguli, Jeff J. Schoenau, Paul G. Jefferson
KEYWORDS:
Yield, Phosphorus Uptake, Wheat, Canola, Forage Legume, Crop Rotations
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.9 No.9,
August
10,
2018
ABSTRACT: Annual legumes have been
shown to enhance the growth and phosphorus (P) uptake by following rotational
crops. However, there is lack of information on the effect of perennial forage
legumes included in rotation for a short duration on yield and P uptake of crops
like wheat (Triticum aestivum L.) and canola (Brassica napus L.) grown after the forage
legume. A field study was conducted in four soil zones of Saskatchewan, Canada
to assess: 1) the effect of two
years of forage legume versus annual cereal, oilseed and grain legume on yield
and P uptake of wheat and canola grown in the two subsequent years and 2) the effect of the
complete four-year rotation on soil P dynamics and P balance. Four different
crop sequences (alfalfa-alfalfa, red clover-red clover, barley-pea and
barley-flax) employed over the first two years of crop rotation were compared
as treatments followed by wheat and canola. Wheat grain yield was improved 32% - 60% by alfalfa (Medicago sativa L.) and red clover (Trifolium pretense L.) rotations at three of the four sites (P = 0.008,
P = 0.001, P - 43% by red clover and
alfalfa rotation at two sites (P = 0.013, P = 0.033). In the following year, positive
yield benefits (55% - 64%) of having two
years of alfalfa and red clover were observed at three sites. Four years of
continuous cropping with a limited addition of fertilizer P resulted in a
negative soil P balance and significant depletion of soil P fertility at all
locations.