Nursery production fields are not all planted in exactly the same way. The grower usually considers a number of factors that determine how each field will be laid out:

1. Eliminating opportunities for erosion.

2. Using the land as efficiently as possible.

3. Grouping together plants with similar requirements for cultivation but, possibly, different harvesting schedules.

4. Making cultivation and harvest as easy as possible.

5. Knowing the length of time the crops will be in the field and the size they will attain.

6. Knowing whether the field will be harvested all at one time or over a period of several seasons.

The simplest layout for a nursery is a single species planted in side-by-side rows on level land (Figure 21-1). Erosion is minimal, and

figure 21-1. An example of a single species field planting in rows that are evenly spaced. Arrows indicate the two directions possible for cultivation. The broken diagonal lines indicate a possible harvest pattern that allows additional growing room for the plants that remain. (Delmar/Cengage Learning)

cultivation equipment can pass easily down the rows and across per­pendicular to the rows between the plants. Harvesting is just as simple when this layout is used, making it ideal for bare-rooting trees and shrubs. Partial or selective harvesting can also be accomplished by digging plants in a diagonal pattern across the field. The open space remaining allows further growth by the plants that remain.

Side-by-side rows can also be used on rolling land, with the rows oriented to follow the contours of the slope and thereby minimize ero­sion. Cross-cultivation is seldom possible on slopes because of the soil erosion it would encourage. Also, total harvesting is not wise; some plants should always be left to hold the soil until replacement plants can become established.

Another variation of row planting is the staggered or offset layout (Figure 21-2). Plants in alternate rows are not set directly opposite those in adjacent rows but in a staggered pattern similar to the fives on dice. Cross­cultivation is not possible with this arrangement. Harvesting is by rows, not diagonally. Every other row can be harvested the first year and either all remaining rows or every other remaining row harvested in the second year. All plants would be cleared by the end of the third year. As rows are cleared, the soil can be conditioned and planted again, or a cover crop seeded to hold the soil. (Cover crops are discussed later in the chapter.)

When space is at a premium, narrower aisles can be left between alternate rows (Figure 2І-3). This permits large equipment to be moved into the field while only slightly increasing the difficulty of cultivating and harvesting.

Mixing species within a single production field adds some compli­cations but is not uncommon. First, the species must have the same soil and moisture requirements. Second, if shading or winter protec-

rows that are offset. Arrows indicate the single direction of cultivation possible. The broken lines indicate a first-year harvest pattern, leaving remaining plants to grow another season or two. (Delmar/Cengage Learning)

tion is required, it must benefit all the plants. Finally, if the plants are of different sizes or on differing harvest schedules, cross-cultivation may be impossible. Species are often mixed between rows to combine fast-growing and slow-growing species, the first for quick sale and cash turnover, the latter for future sale (Figure 21-4).

figure 21-3. To conserve space, alternate rows of a nursery planting can be placed closer together. Arrows indicate the directions of cultivation. The broken lines show first-year harvest pattern. (Delmar/ Cengage Learning)

figure 21-4. Mixing fast-growing and slow-growing species in alternating rows allows the fast-growing species to be harvested while giving the slower ones more time and space to develop. Arrows indicate the single direction of cultivation. (Delmar/Cengage Learning)