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The Effect of Tillage System and Proceeding Crop on Phosphorus Response of Flax

Assess the interactive effects of tillage system, preceeding crop and P management on flax production.

IPNI-1999-CAN-MB11

Overview Related Interpretive Summary
18 Feb 2003

2002 Annual Interpretive Summary


The Effect of Tillage System and Preceding Crop on Phosphorus Response of Flax, 2002

Flax is a major oilseed crop grown on the western Canadian prairies, with the majority of the production exported into the industrial oil market. Phosphorus (P) fertilization of flax is a challenge, as the crop is very sensitive to seed-placed starter P. In the absence of specialized seeding equipment to place the fertilizer P in a side band, some farmers have resorted to increasing the P application in preceding crops, building soil residual P for use by the subsequent flax crop. Flax has been shown to have good association with arbuscular mycorrhizae (AM) fungi, increasing potential P uptake. The objective of this research is to evaluate the role of preceding crop, tillage system, and P fertilization of the preceding crop in optimizing flax yield and quality.

Cool early spring temperatures increased the frequency of P responses in southern Manitoba in 2002. Stand density of flax was higher when wheat rather than canola was the preceding crop and flax biomass yield at five weeks was 30 to 50% higher when the flax followed wheat rather than canola. Biomass yield was higher under reduced as compared to conventional tillage. Early season growth was increased by P fertilization of the flax on one of the two sites. Results from 2001 indicate that P nutrition of flax can be influenced by tillage system, preceding crop, residual P from fertilization of preceding crops, and side-banded P application. The AM association in flax at five weeks was higher when the flax was grown after the mycorrhizal crop (wheat) than after the non-mycorrhizal crop, in this case canola. Association between the flax and AM was also generally increased by using reduced tillage as compared to conventional tillage. Production of flax after canola appears to be a poor option, possibly because of the suppressed AM association with canola and the resulting reduction in soil P uptake. MB-11