New Crops News, Spring 1992, vol. 2 no. 1
We learned much during the past growing season from field observations and research plots. For example, excessive rates of nitrogen applied in the fall as either commercial fertilizer or animal manures will result in significant winter injury and kill. Three fields were abandoned in the spring of 1991 as a result of late summer applications of high rates of animal manure. Similar damage was observed in fields where the fall applications of commercial nitrogen fertilize was doubled.
During 1990-91, evaluation of nitrogen rates, date of planting, and variety were conducted at three locations in Indiana: the Northeast Purdue Agricultural Center near Columbia City, the Throckmorton Purdue Agricultural Center south of Lafayette, and the Southwest Purdue Agricultural Center near Vincennes. Northeast PAC and Southwest PAC sites were located on course textured soils and were negatively impacted by the dry conditions in late May and June. The Throckmorton site, with heavier soils, gave near normal results.
If canola production is to succeed in Indiana, it is essential to determine the ideal period in which to plant the crop. Four varieties of canola were planted on three different dates at each of the three locations. All plots planted after October 1 resulted in winter kill approaching 100%. The early September planting date gave the highest yield at two of the locations (NEPAC September 4 and TPAC September 6) and the mid September date at SWPAC (September 25). In the future, a late August planting date needs to be incorporated into the study.
Nitrogen fertilizer is the single most expensive input to canola production. To define the appropriate rate of nitrogen for canola production a study was conducted at the three locations as above with four varieties and six spring N rates (0, 30, 60, 90, 120, and 150 lbs/acre). One-half of the plots received 30 lb of the total N in the fall with the balance supplied in the spring. All four varieties responded similarly.
The response was statistically and economically significant up to the 120 pound rate. The droughty conditions in late May and June placed abnormal stress on the canola, resulting in lower yields than expected. It is essential that this study continue for a period of three to five years to adequately define the appropriate rate at which nitrogen should be applied to canola under Indiana conditions. The application of 30 pounds of nitrogen to canola in the fall resulted in a significant yield increase at two of the three sites but no increase at the third site. Plans are underway to expand the nitrogen study next year to include at least two sources of nitrogen, with one of the sources also providing a source of sulfur.
Despite the negative impact of the drought in late May and June, many of the growers were pleased with their experiences in 1990-91. The fall 1991 plantings of canola are not accurately known, but it is estimated that area will be in excess of 7,000 acres. The 1991 fall and early winter weather conditions have significantly damaged winter wheat, and similar damage can be expected to occur to the canola crop. The extent of the damage, if any, will not be known until the canola breaks dormancy in March of 1992.