If the spacing of maize is 0.9m by 0.3m and one seed is sown per stand, what wil...

This question is asking about the population of maize plants on a hectare of farmland, given a specific spacing and sowing rate.

The spacing of maize refers to the distance between each plant in the field. In this case, the spacing is given as 0.9m by 0.3m. This means that each maize plant is planted 0.9 meters apart in one direction and 0.3 meters apart in the other direction.

The sowing rate is given as one seed per stand. This means that each planting spot or stand only has one seed planted in it.

To calculate the population of maize plants on a hectare of farmland, we need to convert the spacing measurements to the same units. Since a hectare is a measure of area, we need to calculate the number of maize plants that can fit in that area.

To do this, we first need to convert the spacing measurements to square meters. We can do this by multiplying the two measurements together: 0.9m x 0.3m = 0.27 square meters.

Next, we need to calculate the number of planting stands that can fit in a hectare. Since there are 10,000 square meters in a hectare, we can divide 10,000 by the area of one stand (0.27 square meters) to get the number of stands per hectare: 10,000 / 0.27 = 37,037 stands.

Since there is one maize plant per stand, the population of maize plants on a hectare of farmland would be 37,037 plants.

Therefore, the correct answer is Option D: 27,000.

It's important to note that the other options (A, B, and C) are incorrect because they do not match the calculated population based on the given spacing and sowing rate.

Understanding the spacing and population calculations is important in agriculture as it helps farmers plan and manage the number of plants they can grow in a specific area. It also affects factors such as nutrient and water requirements, pest and disease control, and overall crop yield.

For more information, please see the recommended textbooks.