Crop rotations are a vital part of direct seeding systems. Rotations maximize the benefits of moisture conservation and reduce the impacts of diseases, weeds and insect pests.
Direct seeding is a relatively new approach to crop production and it uses some new terms. Not everyone uses these terms in the same way. The following definitions are those used in this Direct Seeding series.
Row spacing is the distance from the centre of one seed tube outlet to the centre of the next outlet . Row spacing is related to nutrient placement, weed competition and sunlight. Seeding rate is primarily related to weed competition and available moisture. As a result, row spacing usually changes and seeding rates sometimes change with the move to direct seeding.
Soil temperature can serve as a useful guide for timing spring seeding operations. Once the seed is planted, it is important that germination proceed uniformly and without delay. If the soil is too cool, germination is delayed, which results in seed damage and uneven or inadequate seeding emergence. It may even be necessary to reseed. On the other hand, if the soil is unusually warm in the spring, it may be better to seed earlier than normal. In either case the soil temperature at seeding depth can be a practical guide.
The 1,000 kernel (1,000 K) weight is a measure of seed size. It is the weight in grams of 1,000 seeds. Seed size and the 1,000 K weight can vary from one crop to another, between varieties of the same crop and even from year to year or from field to field of the same variety. Because of this variation in seed size, the number of seeds and, consequently, the number of plants in a pound or a bushel of seed is also highly variable. By using the 1,000 K weight, a producer can account for seed size variations when calculating seeding rates, calibrating seed drills and estimating shattering and combine losses.