What effect will seeding directly into standing stubble have on a number of crops? How will that compare to cultivating prior to seeding those same crops? These are some of the questions posed by Dr. Brian McConkey of the Semi-arid Prairie Agriculture Research Centre (SPARC) at Swift Current prior to setting up the High Disturbance vs. Low Disturbance Seeding Trials at the East Central Research Foundation (ECRF) farm near Canora. A wide variety of crops were selected for this study. "I wanted to use a variety of crops with different seed sizes to determine how the different seed sizes responded to the 2 tillage methods", said Dr. McConkey. In the spring of 1998, half the plots were cultivated while the stubble on the other half was left standing. The crops, including mustard, corriander, fenugreek, lentil, field bean and peas were then seeded using a Seed Hawk drill. This drill has a 2-knife system that puts the fertilizer down the first knife with the second knife placing the seed above and to the side of the fertilizer trench.
When the results were tabulated that fall, it was shown that there was very little difference in plant populations between the two seeding systems. The difference in yield, however, was very striking. Dr. McConkey said, "On average, the low disturbance system had a 17% increase in yield over the high disturbance system. The two crops with the largest yield differences were barley and lentil. The barley seeded in the low disturbance system yielded 12 bushels more than that seeded under high disturbance. Lentils seeded under low disturbance yielded 400 lbs. more than the high disturbance lentils."
In 1999, the project took on a little different look, becoming the Rotational Benefits Study. The study is also being conducted at Swift Current and Redvers. The objective of this project was to determine how different cereal crops respond to various rates of nitrogen on different stubble. The crops seeded were Canada Extra Strong wheat, barley and Hard Red Spring wheat across the stubbles in the High vs. Low Disturbance trials. The cereals were seeded with the Seed Hawk and a blend of fertilizers was applied at seeding with the nitrogen rate varying from 35 lbs. actual N to 65 lbs. actual N. Dr. McConkey said two interesting points have been determined to date. "One finding so far is that cereals do not appear to like corriander stubble. Another interesting point is that wheat was most responsive to N fertilizer when grown on pea stubble. This is despite the fact that wheat on pea stubble had higher yields at low fertilizer N application than on other broadleaf stubbles".
The question yet to be answered is how do different cereals respond to different broadleaf crop stubbles. Dr. McConkey indicated that once this question has been answered, it would help to determine how much money should be spent on fertilizer.
For more information on these projects, contact Dr. Brian McConkey at 778-7281. His email address is mcconkeyb@em.agr.ca
Brian will also be speaking at the SSCA Annual Conference Feb. 9 & 10, 2000 in Regina. His topic is "Carbon Sequestration and Direct Seeding."