Background
Pea is a good choice for Prairie growers because it is an earlier maturing pulse crop that performs well under cooler temperatures, which is characteristic of this region. Like most other pulses, pea fixes its nitrogen through nodulation and subsequent biological fixation. As such, pea is well-adapted to the prairie growing environment.
However, information on nutrient uptake and biomass accumulation for pulse crops grown in the Prairies is limited. Due to the high correlation between efficient nutrient use and overall crop yield, growers and agronomists seek regionally-specific data on nutrient use, removal and yield in pea.
Research by Malhi et al. (2007) addressed these concerns by studying nutrient uptake and seasonal biomass accumulation patterns in pea. Xie et al. (2018) evaluated pea crop yield and grain nutrient content compared to other Prairie-grown pulse crops.
Methods
The Malhi et al. research group seeded two varieties each of pea and lentil at the Agriculture and Agri-Food Canada (AAFC) Research Farm in Melfort, Saskatchewan, in 1998 and 1999 (one variety per crop per year). The 1999 growing season saw a significant hail event that substantially damaged and reduced crop yields in this study.
The experiment was arranged in a randomized complete block design (RCBD) with four replicates per site. The site consisted of Black Chernozem soil with a pH of 6.0 and 8.2% soil organic matter. The soil texture was silty clay loam.
Fertilizer was band applied to all plots before seeding at a rate of 26 kg N, 17 kg P, 17 kg K, and 20 kg S per hectare. Both crop species were inoculated per grower recommendations and seeded using 23cm (~9”) row spacing. Pea and lentil were seeded at rates of 226 kg/ha (~201 lbs/ac) and 112 kg/ha (~100 lbs/ac) respectively in 1998, and 164kg/ha (~146 lbs/ac) and 112 kg/ha respectively in 1999.
Crop growth estimates were made, and biomass samples were collected seven or eight times throughout the growing season, starting at two weeks post-emergence. Samples were processed and analyzed for total N, P, K, and S in the lab (Thomas et al., 1967).
Xie et al. (2018) compared straw and grain yields and N and P contents of pea, lentil, and soybean grown at four sites across Saskatchewan: Rosthern, Saskatoon, Yorkton, and Scott.
Nutrient Uptake, Biomass Accumulation & Yield
In Melfort, pea took up primary nutrients at a higher rate than lentil (figs. 1, 2, 3) (Malhi et al., 2007). Indeed, maximum accumulation rates and amounts for biomass and nutrient uptake were more significant in pea than in lentil.
Maximum nutrient uptake rates occurred between 28 and 49 days after emergence (DAE) at branching to the early bud-forming stage (fig 4). The flowering to seed fill stage reached Maximum nutrient amounts between 66 and 85 DAE. Maximum biomass was achieved by the early seed-filling stage, or between 75 and 82 DAE.
Xie et al. (2018) found that pea grown at four sites across Saskatchewan was nearly on par with lentil in terms of N and P content in the end grain but did not measure the rate of accumulation throughout the season.
The harvest index (HI), a measure of a crop grain yield relative to overall aboveground biomass, was more significant in pea in both years (fig 5) (Malhi et al., 2007). Pea produces greater yields than other pulse crops, including lentil and soybean (fig. 6) (Xie et al., 2018). In general, these data imply that pea efficiently translates nutrients to grain when those nutrients are available in a timely manner.
Fig. 6: Grain yield of pea, lentil, and soybean grown at four sites in Saskatchewan in 2014 and 2015.
Table 1: Estimated nutrient removal rates by a field pea crop, based on a 50 bu/ac yield (Manitoba Pulse & Soybean Growers).
| Nutrient | Removal (lbs/ac) |
| Nitrogen (N) | 117 |
| Phosphorus (P2O5) | 34.5 |
| Potassium (K2O) | 35.5 |
| Sulfur (S) | 6.5 |
Summary
Pea is well-adapted to the prairie growing environment and has proven to be a pulse crop of choice. It accumulates nutrients at its highest rates between branching and early budding and reaches its peak nutrient amounts between flowering and seed-filling stages (Malhi et al., 2007). Pea typically produces high yields relative to other pulse crops, especially in comparison to lentil (Xie et al., 2018).
Successful, high-yielding pea production relies on continuous adequate nutrient supply, especially in early growth stages when nutrient demand is highest (Malhi et al., 2007). In later growth stages, those nutrients are translocated within the plant and become essential for high yields. As such, meeting those nutrient demands early in the growing season is the key to setting the crop up to achieve its yield potential at harvest time.
References
- Malhi, S. S., Johnston, A. M., Schoenau, J. J., Wang, Z. H. and Vera, C. L.. 2007. Seasonal Biomass Accumulation and Nutrient Uptake of Pea and Lentil on a Black Chernozem Soil in Saskatchewan. Journal of Plant Nutrition. 30(5): 721 – 737.
- Manitoba Pulse & Soybean Growers. N.d.. Field Pea Production: Crop Nutrition. https://manitobapulse.ca/production/field-pea-production/crop-nutrition/
- Thomas, R., Sheard, R.W., and Moyer, I.P.. 1967. Comparison of conventional and automated procedures for nitrogen, phosphorus, and potassium analysis of plant material using a single digest. Agronomy Journal. 59: 240–243
- Xie, J., Schoenau, J. and Warkentin, T.D.. 2018. Yield and uptake of nitrogen and phosphorus in soybean, pea, and lentil and effects on soil nutrient supply and crop yield in the succeeding year in Saskatchewan, Canada. Canadian Journal of Plant Science. 98(1): 5-16.
