By Donna Fleury
Higher seeding rates increase yields, improve crop competition and reduce weed biomass.
Western Canada leads lentil production globally, with over 94 per cent grown in Saskatchewan. Red lentils are the most commonly consumed lentil worldwide, and dominate most of the global trade. Over the past few years, research has focused on improving lentil productivity in Saskatchewan, including studies on seeding rates, inoculants, other inputs and economics.
“In 2016, we conducted a one-year study at two sites at Scott and Swift Current to determine whether the findings from previous research on seeding rates and inoculants for lentils would be similar in our area,” explains Jessica Weber, research manager for the Western Applied Research Corporation (WARC) in Scott, Sask. “Our project objectives were to determine which combination of agronomic practices produce the greatest yield and to determine which inputs provide the greatest economic return.”
In the project, treatments included a comparison of the current recommended seeding rate of 130 seeds per square metre (seeds/m2) with higher rates of 190 and 260 seeds/m2 for both small and large red lentils, which are the same seeding rates compared in recent research by Steve Shirtliffe at the University of Saskatchewan. Treatments also compared liquid and granular inoculants, building on research done by Yantai Gan at Agriculture and Agri-Food Canada in Swift Current. Fungicides treatments included a comparison of no application to a single application. Information on plant densities, disease ratings and yield were collected at both sites.
“At the end of the one-year study, our results did line up quite nicely with previous findings,” Weber says. “Our results showed that with small seeded red lentils, a higher seeding rate of 190 seeds/m2 resulted in the highest yields. However, for large-seeded red lentils, there was no benefit to increasing the seeding rate and the current recommendation of 130 seeds/m2 is still the best rate. Higher seeding rates for small seeded red lentils also resulted in a denser canopy and may require a bit more reliance on fungicides depending on disease pressure.”
Granular inoculants resulted in higher yields with more nodulation compared to the liquid inoculants. Weber adds however, that a large difference between inoculant formulations may not always be detected. Although granular inoculants result in excellent nodule formation, a response may be muted depending on specific crop rotations and previous nodulation habits. For example, if there is a strong rotational background of pulses in a field, then there might not be as big of a benefit of granular over peat or liquid inoculants because there might not be as big of a benefit of granular over peat or liquid inoculants as there may already be a build up of the natural rhizobium within the soil. If budget allows and growers are comfortable using them, then granular inoculants are the way to go, but they are more expensive than liquid or peat options.
In 2017, researchers launched a larger three-year small red lentil input study to determine which combination of the common agronomic practices produce the greatest lentil yield, and which integrated production system is the most economically feasible. The study was conducted at five locations in Saskatchewan: Western Applied Research Corporation at Scott, Indian Head Agriculture Research Foundation at Indian Head, Irrigation Crop Diversification Centre at Outlook, Wheatland Conservation Area at Swift Current, and East Central Research Foundation at Yorkton (2017)/University of Saskatchewan, Saskatoon (2018). Treatments included comparison of three seeding rates (130, 190 and 260 seeds/m2), three fungicide treatments (no application, single application, two applications) and two herbicide management practices (pre-seed burn-off vs. pre-seed residual) in each location. The crop response data collected included crop and weed density, crop and weed biomass, disease ratings, days to flowering, days to maturity, seed yield, thousand kernel weights, and test weight.
“We have some preliminary results from the first year of the study, and are waiting to complete the analysis from the 2018 trials,” Weber explains. “The study will continue for one more year in 2019, with final results available after that. Overall, the preliminary results showed that best practice for seeding small red lentils includes higher seeding rates of at least 190 seeds/m2, which also resulted in optimal yields. Higher seeding rates improve crop competitive ability and canopy closure. Early results also showed that overall the pre-seed residual herbicide application was beneficial as it provided long-term weed control, reduced weed biomass and resulted in a slight yield increase.”
Increasing seeding rates also resulted in a denser canopy, increasing disease pressure as compared to lower seeding rates. However, with drier conditions over the first two years of the trials, disease pressure was very low across all sites. Dual fungicide applications tended to have the least amount of disease pressure compared to single applications and unsprayed lentils. However, in years where moisture is not a limiting factor and under high disease pressure conditions, management strategies including fungicide applications are expected to return the highest profit.
“Our preliminary economic analysis shows that a seeding rate of 190 seeds/m2 provided a yield advantage and proved to be the most economically feasible overall,” Weber says.
“Higher seeding rates also improved crop competitiveness, reduced weed biomass and improved canopy closure. An integrated approach using higher seeding rates of 190 seeds/m2, pre-seed residual herbicide and a fungicide application under higher disease pressure is so far proving to be the most economically feasible. Once we have completed the last year of the study in 2019, final results and a more complete economic analysis will be made available.”