Field Pea Growth and Nutrient Uptake: Response to Tillage Systems and Nitrogen Fertilizer Applications

Abstract

A two-year [1999, 2001] study of field pea (Pisum sativum L.) in rotation with small grain was conducted on a Fargo clay soil [fine, smetitic, frigid, Typic Epiaquert] to determine the influence of tillage system [fall PLOW, fall CHISEL PLOW, fall DISK, and NOTILL] and spring applied nitrogen fertilizer rates [0, 45, 90, and 135 kg ha−1] on dry matter production at three growth stages, and nitrogen–phosphorus–potassium [NPK] concentration and uptake. Plants were sampled at first flower [code 203] after 870 GDD and maximum dry matter production [code 208] after 1364 GDD. Seed was harvested for yield [code 303] after 1692 GDD. Dry matter production at flower stage 203 averaged 2400 kg ha−1 the first year and 1960 kg ha−1 the second year with the PLOW system producing the lowest dry matter in both years. Applications of nitrogen fertilizer at the high rate increased dry matter from 500 to 700 kg ha−1. Dry matter at stage 208 in 2001 ranged from 4260 kg ha−1 without fertilizer nitrogen applied, to 6360 kg ha−1 with 135 kg ha−1 of nitrogen fertilizer applied. In contrast to the earlier stage, the PLOW system produced the greatest total dry matter production at stage 208. Minimum pea seed yield, stage 303, averaged 2740 and 2410 kg ha−1 without any nitrogen fertilizer applied in 1999 and 2001. Maximum seed yields at harvest [3530 kg ha−1 in 1999 and 3140 kg ha−1 in 2001] were obtained only when 135 kg ha−1 nitrogen fertilizer was applied. Average seed yields were not always significantly different between tillage systems, but the CHISEL PLOW and DISK were consistently higher than PLOW or NOTILL at all nitrogen fertilizer rates. This research provided estimates of the amount of NPK nutrients required to maximize field pea production under various tillage systems and nitrogen fertilizer rates at various growth stages. When averaged across years, nitrogen fertilizer rates, and tillage systems, concentrations of N, P, and K were measured at 3.0, 0.30, and 2.6% at stage 203, with 2.4, 0.23, and 1.5% at stage 208 and finally the seed [stage 303] at 3.4, 0.38 and 1.2%. The pea plant required 0.031 kg N, 0.0032 kg P, and 0.027 kg K for each kilogram of plant dry matter produced by flowering stage 203. By stage 208 when the pea plant has reached maximum dry matter production, the nutrient requirement was 0.023 kg N, 0.0025 kg P, and 0.0162 kg K to produce 1 kg of plant material. By harvest, stage 303, the nutrients removed by the seed were 0.034 kg N, 0.0041 kg P, and 0.0115 kg K for each kilogram of seed produced. This study indicated that adequate nitrogen (derived from the soil, through N fixation or applied as fertilizer) was equally if not more important than tillage system and this management practice must be included in the overall plan for maxim field pea production in the Northern Great Plains.