Various planting patterns or planting arrangements can be applied in orchard establishments. In row-planted fruit trees, the common types are the square, rectangular or hedgerow, quincunx or diamond, and triangular or hexagonal. These planting arrangements are based on the geometric shape that the closest hills form when connected by an imaginary line. These are also applied in other perennial crops like coconut, oil palm, and rubber.
In square planting, one plant or a group of plants in a common hill occupies the corners of a square which has 4 sides of equal lengths. A 10 m x 10 m spacing in square planting will result in a crop area having 10 rows and 10 cross-rows that are both 10 meters apart and perpendicular to each other. Diagonally, the plants also form rows that are about 7.1 meters apart.
The rectangular arrangement is similar to a square pattern except that a rectangle has two sets of opposite sides having different lengths. A rectangular planting with 10 m x 12 m will mean that two adjacent rows will be 12 meters apart and plants within each row will be spaced 10 m apart; perpendicular to these rows are cross-rows that are spaced 10 m with plants that are 12 m apart. When the plant-to-plant distance within the row is 1/3 to 1/2 of the distance between rows, the planting pattern is usually called hedgerow.
The quincunx or diamond pattern of arranging row-planted crops is a modified form of the square pattern. It consists of a square that is formed by 4 closest plants with an additional plant at the center of these 4 plants. The 4 plants that form a square are the main crops while the hill at the center is intended for another crop or variety and is called a filler crop. By connecting with imaginary lines 4 closest hills that include 2 main hills and 2 filler hills, the shape that is formed is a diamond.
With 10 m x 10 m quincunx planting, the distance from maincrop to maincrop will be 10 meters while the distance from maincrop to filler crop will be 8.66 meters. Viewed from the outside peripheries, the crop area will have rows and cross-rows that are 5 meters apart with alternating main crop and filler crop.
In orchards that employ square planting, there is a possibility that with time the canopies of adjacent trees will overlap. As a result, light penetration will be hampered. As with mango, the final resort is thinning, the removal of excess plants, in order to widen the distances of the remaining plants. This also applies to rectangular planting and is done by removing alternate rows and cross-rows.
By cutting alternate rows and cross-rows that are spaced 10 meters, the resulting new planting pattern will be 20 m x 20 m in square. However, the total removal of alternate rows and cross-rows can be delayed by converting the planting arrangement from 10 m x 10 m square to 20 m x 20 m quincunx. This is done by removing alternate slanting lines of trees. As a result, the new closest plant-to-plant (filler to the main hill) distance will be about 14.1 meters while both the row-to-row and cross-row to cross-row distances become 10 meters. Ultimately, the filler hills will be removed resulting in a square planting pattern with 20 m x 20 m spacing.
The triangular or hexagonal pattern of planting arrangement is based on an equilateral triangle, a triangle with three equal sides, that is formed by connecting the 3 closest planets with an imaginary line. Six of these triangles that are connected to a common center hill will also form a perimeter that is hexagonal in shape. With 10-meter plant-to-plant spacing, there will be rows that are 5 meters apart and, perpendicular to these rows, cross-rows that are 8.66 meters apart. But within each row, adjacent plants are spaced 17.32 meters and within each cross-row adjacent plants will be 10 meters apart. To maximize light exposure, the rows having the widest plant-to-plant spacing (17.32 m) are oriented in an east-west direction.
Comparison of Plant Population Densities
Of these planting patterns, triangular planting finds little application because of the difficulty in constructing and executing a layout plan. Putting the plan on paper requires familiarity with mathematical concepts, particularly the Pythagorean theorem. Also, calculated distances between cross-rows are always in exacting (in decimal). In 10 m x 10 m square planting, rows and cross-rows are both 10 m apart; in 10 m x 12 m rectangular planting, 10 m and 12 m apart. But in 10 m x 10 m triangular planting, rows and cross-rows are 5 m and 8.66 m apart, respectively; and in 12 m x 12 m spacing, 6 m, and 10.4 m apart.
Formulas differ in the calculation of plant population densities depending on the planting pattern. In both square and rectangular planting, the applicable formula is the same as that for the hill method of direct seeding which is:
PD = [A /(d1 x d2)] x NPh
where PD = population density, A = farm area (sq m), d1 = distance between rows (m), d2 = distance between hills within the row (m), and NPh = number of plants per hill.
Applying this formula, a 1-hectare orchard (10,000 sq. m) in which individual crops are arranged in 10 m x 10 m square planting has a plant population density of 100 plants while rectangular planting of 10 m x 12 m spacing will yield a calculated population of 83.33 plants. The decimal indicates that the perfect planting density needs to be ascertained by constructing first a planting layout plan on paper.
For the triangular planting pattern, the planting density is about 15 percent more than that in the square or rectangular planting so that the same formula applies, multiplied by 1.15. With 10 m x 10 m triangular planting, the calculated plant population in one hectare will be 115.
For the quincunx planting pattern, the number of maincrop hills is calculated using the same formula for square planting. Thus in quincunx planting at 10 m x 10 m spacing, the maincrop population is 100 per hectare, just like in square planting. For the filler crops that occupy the center of every square, the plant population density is calculated by multiplying the number of rows in square planting less 1 row (10-1= 9) by the number of cross-rows less 1 row (10-1=9) or 9 x 9 = 81. Combining the main crop and the filler crop, the total plant population will be 181, with the filler crops accounting for 81 hills or 81% of the main crop population.