Inter-Row Cultivation for Weed Control in Organic Field Pea (Pisum sativum L.) and Lentil (Lens culinaris L.)

Abstract

The yield potential in pulse crops is limited by their uncompetitive nature in the presence of weeds. Inter-row cultivation, commonly used in wide-row crops has previously demonstrated weed control potential in cereal crops. No research has been conducted on crop tolerance to inter-row cultivation under weed-free conditions, and studies are limited on the efficacy of inter-row cultivation in other narrow-row field crops. It was hypothesized that inter-row cultivation would manage weeds with minimal crop damage at early stages of crop growth. Two objectives were developed; the first, to determine the tolerance of field pea (Pisum sativum L.) and lentil (Lens culinaris L.) to inter-row cultivation and the second, to determine the ability of inter-row cultivation to manage weeds. To determine this, two replicated field experiments were conducted in Saskatchewan, Canada. The first experiment, conducted over four site-years in 2014 and 2015 examined the tolerance of field pea and lentil to cultivation at different growth stages under weed-free conditions. Single cultivation treatments began at the 3.5 node stage, continuing weekly for six weeks. Multiple cultivation treatments and an uncultivated control were included. The second experiment, conducted at two locations on organic land in 2015 examined the ability of inter-row cultivation to manage natural weed populations. Treatments were similar to the first experiment, including a weed-free control. In the crop tolerance experiment the mean of four site-years demonstrated a 15% yield decline (P<0.05) in lentil when cultivation was delayed from the 3.5 node stage to 16 nodes and 31% in field pea when cultivation was delayed to 17 nodes. In the organic study, weed biomass declined 30% when cultivation was delayed to the sixth week. No reduction in weed biomass occurred in lentil. Inter-row cultivation did not increase yield (P>0.05) in either crop. This limited response may be attributed to below-average rainfall in 2015 and substantial weed presence in the intra-row spaces. Future research should examine supplementing inter-row cultivation with mechanical weed control in the intra-row spaces. In conclusion, while field pea and lentil exhibited tolerance to inter-row cultivation at early crop growth stages, no yield increase was observed.