urban irrigation landscape

SOIL MOISTURE IN URBAN LANDSCAPE

If a plant looks green & healthy, certain factors keep a plant healthy. You might have read a lot of stuff on this topic. But when it comes to maintaining greenery, more or less- we use the Referral Standards as if you are in Dubai, then take water evapotranspiration as 12 mm/m2/day and then multiply by area and derive a water quantity and whole the calculation, so-called hydraulic design revolves around it.

Soil moisture is an important state variable in the earth’s water movement or dynamics system. Soil moisture depends much on the soil type, organic matter in the soil & climatic conditions. So you can precisely customize the irrigation watering schedule as needed. The attached picture shows the touch feel and soil meter reading to help you understand the concept. This concept will help decide the watering quantity. As soil approaches field capacity, it becomes much more plastic and moldable and will leave a slight muddy impression on your hand when squeezed. Above field capacity, the soil will start to look shiny, with free water coating the soil, and your hand will become muddy. As the soil nears total saturation, samples will become fluid.

Soil Type: Sandy- clay

Actual feel– Passing through fingers

Tensiometer-9.6% means 9.6 gm water available in 100 gm volume of water.

Impression– Needs to be rinsed.

Soil Type: Sandy- clay

Actual feel– Sticky Moist Feel 

Tensiometer-17.5% means 17.5 gm water available in 100 gm volume of water.

Impression– There is no need for irrigation for two days with a climatic temperature of 35 degrees.

Soil Moisture Content

Soil moisture is the water present in the space between the soil particles. It influences the soil’s physical, chemical, and biological characteristics. Soil moisture is the percentage of moisture (on a weight basis) in a soil sample at any given time. It shows the general moisture content of the soil. Soil moisture helps to understand the water movement and aeration of the soil.

Allowable Depletion:

In general, the allowable depletion for most weather station-equipped irrigation controllers is 35%, but it can be adjusted to 15 – 70%.

The attached picture shows the calculated ET, and irrigation scheduling can be done based on precipitation rates.

Conclusion:
This is based on our previous project experience.

The available moisture content for Sandy Soil
FC: 7-8%, WP: 3%

The available moisture content for Clay Soil
FC: 16-17%, WP: 8%