Question

given a daily et rate of 0.15 cm/day. how often would you need to water the top 30 cm of the soil, represented by the water retention curve below, to maintain adequate plant growth? group of answer choices every 12 days every 30 days every 15 days every 6 days

Answer 1

to ensure the plants do not reach a stress level, you would need to water every 15 days. So, the correct answer with the provided data is "every 15 days". Therefore, option C is correct

To determine how often to water the top 30 cm of soil based on a daily evapotranspiration (ET) rate of 0.15 cm/day, we need to consider the following:

- Field capacity is at the point (-33 kPa, 0.4 or 40% volumetric water content).

- Permanent wilting point is at the point (-1500 kPa, 0.25 or 25% volumetric water content).

The available water capacity (AWC) in the top 30 cm of soil can now be calculated as the difference in volumetric water content between field capacity and permanent wilting point, multiplied by the depth of the soil:

This means that there are 4.5 cm of water available to plants in the top 30 cm of soil before it reaches the permanent wilting point.

Given a daily ET rate of 0.15 cm/day, the number of days until the soil reaches the permanent wilting point would be:

However, as mentioned previously, it's best practice to water before the soil water content reaches the permanent wilting point to maintain plant health. Therefore, if we water when about half of the AWC is used, the irrigation interval would be:

Based on this information, and to ensure the plants do not reach a stress level, you would need to water every 15 days. So, the correct answer with the provided data is "every 15 days".

the complete Question is given below:

Given a daily ET rate of 0.15 cm/day. How often would you need to water the top 30 cm of the soil, represented by the water retention curve below, to maintain adequate plant growth?

every 30 days

every 12 days

every 15 days

every 6 days.

Answer 2

to ensure the plants do not reach a stress level, you would need to water every 15 days. So, the correct answer with the provided data is "every 15 days". Therefore, option C is correct

To determine how often to water the top 30 cm of soil based on a daily evapotranspiration (ET) rate of 0.15 cm/day, we need to consider the following:

- Field capacity is at the point (-33 kPa, 0.4 or 40% volumetric water content).

- Permanent wilting point is at the point (-1500 kPa, 0.25 or 25% volumetric water content).

The available water capacity (AWC) in the top 30 cm of soil can now be calculated as the difference in volumetric water content between field capacity and permanent wilting point, multiplied by the depth of the soil:

`\[ AWC = (\text{θv at field capacity} - \text{θv at permanent wilting point}) * \text{depth of soil} \]`

`\[ AWC = (0.4 - 0.25) * 30 \text{ cm} \]`

`\[ AWC = 0.15 * 30 \text{ cm} \]`

`\[ AWC = 4.5 \text{ cm} \]`

This means that there are 4.5 cm of water available to plants in the top 30 cm of soil before it reaches the permanent wilting point.

Given a daily ET rate of 0.15 cm/day, the number of days until the soil reaches the permanent wilting point would be:

`\[ \text{Days until irrigation needed} = \frac{AWC}{\text{ET rate}} \]`

`\[ \text{Days until irrigation needed} = \frac{4.5 \text{ cm}}{0.15 \text{ cm/day}} \]`

`\[ \text{Days until irrigation needed} = 30 \text{ days} \]`

However, as mentioned previously, it's best practice to water before the soil water content reaches the permanent wilting point to maintain plant health. Therefore, if we water when about half of the AWC is used, the irrigation interval would be:

`\[ \text{Irrigation interval} = \frac{4.5 \text{ cm} / 2}{0.15 \text{ cm/day}} \]`

`\[ \text{Irrigation interval} = \frac{2.25 \text{ cm}}{0.15 \text{ cm/day}} \]`

`\[ \text{Irrigation interval} = 15 \text{ days} \]`

Based on this information, and to ensure the plants do not reach a stress level, you would need to water every 15 days. So, the correct answer with the provided data is "every 15 days".

the complete Question is given below:

Given a daily ET rate of 0.15 cm/day. How often would you need to water the top 30 cm of the soil, represented by the water retention curve below, to maintain adequate plant growth?

every 30 days

every 12 days

every 15 days

every 6 days.