Wilting point
Wilting point is the minimum soil moisture required by a plant not to wilt. At this point, any decrease in soil moisture will result in wilting. When a plant wilts, its leaves dry out, droop, and wither. Although we generally discuss wilting due to lack of water, there are also other causes of wilt to consider. Wilting is important to monitor as a plant will die if it passes the wilting point. OnFarm uses field capacity and permanent wilting point in our PAW models. We often receive questions regarding both these values, what they are, and how they’re used. Field Capacity is the amount of water that the soil can hold. We determine an approximation of your unique field capacity based on a soil profile using the soil types at the different soil depths. This gives us a general idea of how much water can be held within the soil. From the depth and soil type, we are also able to calculate an approximation of your permanent wilting point. Many growers provide us with their actual permanent wilting point and field capacity when setting up their soil profiles. Soil surveys are more accurate than our approximations as these include soil types that are mixed in their calculations. Permanent wilting point is the minimum soil moisture required by a plant not to wilt, specifically at the root level. We use these values to assist in monitoring water to ensure your plants have adequate water, while also helping you save as much as possible by not over-watering.
As mentioned and the most well-known cause of wilting in plants, is a lack of water. This coupled with high temperatures or extreme sunlight can really do damage to a crop. A dry environment will pull moisture out of the plant and insufficient water will prevent nutrients from reaching the ends of the plant. Plants will generally recover when temperatures decline such as during the night. Effective irrigation scheduling will keep plants hydrated and prevent crop loss. Over-watering is another cause of wilt and it is often forgotten about. When soil is completely saturated with water, it creates an environment that is deficient of oxygen.
Knowing your soil type is key to determining how much water can be retained in the soil and helps prevent over-watering. For example, in a clay soil, more water will be retained and you’ll need to be more cognizant of irrigating precisely to ensure that you do not over-water.
At OnFarm, we’re tackling these two big water issues and the most common causes of wilt, over-watering and under-watering. We give farmers the tools to schedule irrigation with precision. We’re helping growers to monitor the Plant Available Water (PAW) through our PAW model. This model provides growers with insight on when to irrigate and how much water is required. For extra help with irrigation, you can also set-up a control tool through OnFarm, which allows you to directly control your irrigation switches, turning them on and off through the app.