Chloride by Variety Interactions in Spring Wheat
Chloride is known to suppress several wheat diseases or increase the ability of wheat to withstand infection. Wheat response to chloride fertilizer has been variable, because response depends upon many factors, including soil chloride levels, pH, plant tissue levels, and variety.
IPNI-1996-USA-ND9
15 Mar 2001
Methodology
- Two large field trials are planned for 1996 and again in 1997. One of the two trails each year will be in eastern North Dakota, within 50 miles of Fargo, and one of two trials each year will be in western North Dakota, around Dickinson. The wheat will be planted on small grain or soybean ground in eastern North Dakota and on summer fallow in western North Dakota. Soil tests will be taken the prior fall, to assure chloride levels less than 20 lb/A in the top 2 feet of soil, and hopefully less than 10 lb/A.
These trails will have 30 treatments, 15 varieties x two rates of chloride. The methods used to select the varieties will be discussed below. The chloride rates will be 0 and 70 lb Cl/A, broadcast and incorporated into the ground just before planting. Phosphorus, as 0-45-0 will be drilled with the seed to assure vigorous early growth, and adequate nitrogen, as urea, will be broadcast and incorporated into the soil before planting. Soil nitrate + fertilizer N will total at least 120 lb/A. Nitrogen will be applied as urea broadcast and incorporated before planting.
At the time of this writing, the varieties selected for testing are being finalized and seed obtained. Proposed varieties are listed at the end of this proposal. Variety selection followed the following general philosophy. Thirteen hard red spring wheat varieties will be tested. Two of the 13 varieties will be 'historic' varieties, of known Cl responsiveness. "Present" varieties are those varieties that are widely grown at present, including two Canadian varieties. "Future" varieties are those that have been just released, or are scheduled for soon release. In addition the two most popular durum wheat varieties will be included, for a total of fifteen varieties x two chloride rates. Similar studies are also being conducted by Dr. Cindy Grant of Agriculture Canada, Brandon, MB.
A second Cl-rate study will be performed along side of the Cl x variety study, with one variety x 5 Cl rates (0, 10, 20, 40, 60 lb Cl/A). The variety will be a popular variety grown in North Dakota, either Grandin or Pioneer 2375.
In-season measurements will include a leaf tissue Cl analyses at around the "boot" stage of growth. A measure of maturity effects of chloride, either by Haun rating around flag leaf emergence or by careful heading emergence measurements will be made, to see if crop yield responsiveness to Cl is also related to crop maturity responsiveness.
The presence and development of foliar diseases will be monitored weekly. If foliar diseases develop (tan spot, Septoria, spot blotch) to measurable levels on the flag leaf, a leaf disease severity rating will be made. Also, it is now known that Cl deficiency causes a physiological leaf spot on wheat (Engel, et al. 1996). Lesions will be inspected to determine if they are physiological or pathological in nature. Fusarium head blight (scab) severity will be monitored and a severity rating taken if the disease develops to significant levels. Common root rot may be significant, particularly at the Dickinson site.
Grain will be harvested with a plot combine. As kernel weight is the major yield component increased by chloride fertilization, thousand kernel counts will be made. If scab is moderate to severe, heads will be collected at maturity for measurement of scab-affected "tombstone" kernels.
This is a two year project, with minor revisions (changes in varieties selected, etc.) allowed upon agreement between the principal researchers and the FAR.