With an area of high pressure to the north of the Netherlands, a period of stable and mostly dry weather has started. With wind from northerly and easterly directions, there is little chance of great volatility. That means a lot of sun, and now that the days are long, there are also many hours of evaporation. After all the rain, locally in the form of cloudbursts, the drought will become a bottleneck sooner than was thought a few weeks ago.
"It will be different on every plot," says Niek van Andel, meteorologist at AgroExact. "Emerging crops with barely developed roots depend on moisture in the top layer. A few days with sun and the top 10 centimeters have already dried out, especially on sandy soils.
The most treacherous are the crops that are already in full growth, without the root system being fully developed. The crops themselves naturally use a lot of water to grow and in addition, a lot of water evaporates from the soil itself. Because the plant can only tap into the relatively shallow stock, the moisture in this soil layer may have run out within about five days. On sunny days, a crop then easily evaporates 5 millimeters per day, even at temperatures below 20 degrees. And of course, evaporation will only increase if the sun shines longer and the temperature rises further."
"However, it remains to be seen how this will develop in practice." The precise moment of sowing or planting, the quality of the soil, the soil type and the local weather are all important in this calculation, explains Van Andel. "That's why, as a meteorologist, I never manage to give good irrigation advice based on precipitation and evaporation alone, precisely because so many factors are important."
Exactly the reason why we at AgroExact decided to use tensiometers to measure the amount of suction pressure in the soil. These sensors measure how hard a plant has to 'pull' the soil to get water. At a certain point, this will be at the expense of growth, and of course you want to prevent that. This is often earlier than people think, and also differs from plot to plot. We provide notifications if irrigation is necessary to prevent the crop from running out of moisture within a day or two. It is then often possible to maintain growth with a limited amount of water, until the roots have developed in such a way that moisture can also be absorbed from deeper layers. It is better to irrigate a little less earlier. Then you don't lag behind the facts and that demonstrably makes a difference in the total amount of irrigation." Want to know more? Check it out on the AgroExact website