No till farming of winter wheat and direct seeding into existing stubble are becoming increasingly popular practices around Montana, especially as producers consider the added workload required to convert CRP land to tillable ground for next spring. The key to success with a reduced tillage system is good management beginning with residue management and carrying all the way through to planting the crop, controlling weeds, and making plans for harvest and the management of residue for the next crop. Besides residue management, grain growers need to make special considerations for seeding date, seeding rate, row spacing, seeding depth. Drill penetration and seeding depth are, of course, very important. Unless the seed is placed in good contact with moist soil, it will not germinate. One remedy to the problem of cutting through residue is to increase the weight on the drill by use of rock boxes or other added weights. Another option is to set the planting depth about 1 inch deeper than normal, through small grain seed should never be planted deeper than 3 to 4 inches in moist soil. Still another method of improving drill penetration is to place a double disk furrow opener or modified sweep ahead of the planter shoe or hoe.
Straw on the soil surface often affects seedling emergence. Young seedlings have difficulty emerging through dense straw or the chaff row. Consequently, the density or population of the stand is often reduced in no tillage and reduced tillage systems below that where clean fallow has been used. Much of the problem of reduced stand density can be overcome by increasing the seeding rate 10 to 20 percent above that normally used.
Effective control of weeds and diseases is essential to successful no tillage and reduced tillage farming. Probably the most effective and economical means of disease control is crop rotation and selection of disease resistant varieties. If small grain diseases were evident at significant levels in a field this year, a non host crop should be planted next year. Most likely the disease will occur in greater proportion next year if the same crop is grown, regardless of the tillage system used.
Weeds can be effectively and economically controlled with the proper timing and rate of application of herbicides. Perennial weeds, including quack grass, Canadian thistle and milkweed, are persistent and will often require repeated herbicide applications. Best times to apply herbicides are in the fall after the fall terminating weeds have emerged. Annual weeds are also a common problem and must be effectively controlled with selective herbicides, applied either pre or postemergence.
"The use of narrow row spacing should consistently increase wheat yields, primarily because productive tiller numbers are increased without depressing the other yield components". This statement, by Canadian agronomists Frederick and Marshall, reinforces everything the Europeans have known and practiced for a long time, narrower row spacings generally produce higher yields than wide row spacings at the same seeding rate. In other words, if you normally seed 60 pounds per acre on 11 inch spacing, you will generally get a greater yield if you seed the same 60 pounds per acre on 7 inch spacing.
The research that has been conducted on the effects of row spacing on cereal crop yields has resulted in several consistencies being reported in the literature. Generally, under irrigation, when adequate water is available throughout the growing season, narrower row spacings produce greater grain yields than wider spacings. Conversely, test weight usually increases as row width is reduced.
Frederick and Marshall compared 7 and 9 inch row spacings and reported that by decreasing row spacing from 9 inches to 7 inches, grain yield was increased by 8.2 percent. In a second study, they compared row spacings of 6, 9, and 12 inches in seeding rates of 30, 60, and 90 pounds per acre. Yields ranged from approximately 43 bushels per acre at 12 inches row spacing to 52 bushels per acre at 6 inch row spacing.
Many producers are likely to comment that they don't have the flexibility to go to narrow row spacing without purchasing new drills. However, that is not true. While working on a wheat seed generation and production project in eastern Europe, I was repeatedly impressed with the extent to which "cross‑seeding" with disk drills was used. And, closer to home, during a field tour near Toston, Montana, I observed at least three fields in which the producer had cross‑seeded with convention disk drills. He reported that he could consistently count on a 10 to 20% yield increase as a result of the cross seeding. Where he previously would seed 70 pounds per acre in a single operation, he now cross seeds at 35 pounds per acre, i.e., the same amount of seed per acre, but at right angle passes.
The following table helps illustrate this concept, reported by Findlay, et. al., from Canada.
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Effect of row spacing and cross-row spacing on grain yield of barley. |
|
|
4" cross rows |
61.4 bu/acre |
|
4" equidistant |
60.5 bu/acre |
|
7" cross rows |
62.0 bu/acre |
|
7" equidistant |
58.6 bu/acre |
|
9" equidistant |
57.7 bu/acre |
|
12" equidistant |
55.2 bu/acre |
They reported that high yielding cultivars demonstrated a greater yield response to narrowing the row spacing than did lower yielding cultivars and the number of spikes per unit area could be increased and the number of kernels per spike decreased with narrower row spacings.
So.... as the fall planting preparation time draws closer, consider the potential benefits of conservation tillage, no till, or reduced tillage. And, if some changes are possible which are "management" but don't require a great deal of capital input, give them serious consideration . . . . rotations, variety selection, residue management, row spacings.
Categories: Seeding Rate, Tillage
Date: 1995-1996