Optimizing Seeding Rates for Chickpeas and Lentils in the Pacific Northwest.

Chickpeas and lentils are important commodity and rotation crops in Pacific Northwest cereal based production systems. However, newer and widely grown varieties need to be seeded at optimal rates to maximize yield and economic returns. Two chickpea and two lentil varieties were seeded at six rates in trials near Pullman and Walla Walla for chickpea and Pullman and Farmington for lentil in 2013. Yield and seed size were the primary factors considered to determine optimal seeding rates. Yield of Avondale lentils did not significantly change across seeding rates. However, seeding rate did result in significant yield differences for Morena lentils. Considering yield and economic production factors, the optimal seeding rate for Morena was 108 seeds m^-2. 100 seed weight was not different for Morena lentils across seeding rates, but for Avondale, lower seeding rates (65, 75, 86 seeds m^-2) produced higher seed weights than the higher seeding rates (97, 108, 118 seeds m^-2).  Seeding rate had a significant effect on the yield of Sierra chickpeas, and after considering production costs the optimal seeding rate was 65 seeds m^-2. For Billybeans, only the lowest seeding rate was significantly lower yielding than all other seeding rates. As a result, the optimal rate was 43 seeds m^-2. Decreased seed size has been shown to be an indicator of plant stress in legumes, and is an important consideration when choosing seeding rates for large-kabuli chickpeas like Sierras. Seeding rate did not significantly affect 100 seed weights of Billybeans, and while differences were found for 100 seed weights of Sierras, there was no clear relationship to seeding rate.  Producers should be empowered to reach the full economic potential of their crops by planting each variety at optimal densities.