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Title: Intercropping of oat and field pea in Alaska: an alternative approach to quality forage production and weed control

item Begna, Sultan
item Fielding, Dennis
item TSEGAYE, T - Alabama A & M University
item VAN VELDHUISEN, R - University Of Alaska
item ANGADI, S - New Mexico State University
item SMITH, D - McGill University - Canada

Submitted to: Acta Agriculturae Scandinavica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/28/2010
Publication Date: 3/9/2011
Citation: Begna, S.H., Fielding, D.J., Tsegaye, T., Van Veldhuisen, R., Angadi, S., Smith, D.L. 2011. Intercropping of oat and field pea in Alaska: an alternative approach to quality forage production and weed control. Acta Agriculturae Scandinavica. Section B-Soil and Plant Science. pp 1-10.

Interpretive Summary: Mixed planting of legumes with non-legumes (intercropping) is an ancient method of improving yield and quality of forages, but there has been little research exploring these methods in high-latitude agricultural systems. The objective of this study was to evaluate yield, forage quality, and weed control of oats and field peas when grown separately or together. In general, dry matter yield was similar between sole-cropped and intercropped methods, but forage quality, measured as percentage fiber, was improved by intercropping. Weed dry matter was generally lower with intercropping. Furthermore, the most common weed, lamb's quarters, had crude protein content higher than oats or peas and similar fiber content. Therefore, if the forage is harvested before the lamb's quarters produces seed, the weeds, if in moderate amounts, will make a positive contribution to the quality of the forage produced, and intercropping will facilitate weed control.

Technical Abstract: Intercropping of legumes with non-legumes is an ancient crop production method used to improve quality and dry matter (DM) yields of forage and grain, and to control weeds. However, there is little information regarding intercropping at high latitudes. The objectives of this field study were to evaluate performance of (1) sole cropped oat (Avena sativa L.) (cultivars Toral and Calibre) and pea (Pisum sativum L.) (cultivars Carneval and Orb) and their intercrop combinations, and (2) inter- and sole-crop responses to weeds. The different cropping systems were studied with different weed treatments (weed-free all season long, weed-free until flowering, and left weedy all season long). In general, intercrops of oat and pea produced DM (forage) and grain yields similar to sole oat crops and higher than sole pea crops although the difference was not statistically significant. Furthermore, forage quality was improved by intercropping. Most of the variables measured were unaffected by weed treatments, however, weed DM was generally lower in sole oat and oat-pea intercropping than sole pea cropping systems. More than 80% of the weed DM was from common lambsquarter (Chenopodium album L.). The protein content of this weed was higher than oat and pea, and fiber was equivalent to the sole cropped oat. Thus, including weeds as part of the forage is possible. However, if crops are grown for grain, weeds are likely to produce large numbers of seeds that would enter the seed bank. Thus pea-oat intercrops show potential as an alternative and sustainable approach for optimum yield and high quality forage and weed control under Alaskan subarctic conditions.