Wet winters and dry summers


2023 was undoubtedly a year of weather extremes. Until September we had a precipitation deficit of 120 millimetres, and then we ended the year with a precipitation record of more than 1,100 millimetres. It was the year of a super El Niño, and the fall of 2023 was extremely wet.

This also caused problems in the nursery stock industry, including issues with planting and delivering crops. Additionally, it may be that losses become more visible, especially during the planting of Taxus and Fagus, which will only become apparent in the summer months. And although nursery stock growers are accustomed to the whims of nature, the extremes seem to be increasing, and it is important to adapt to them. This can be done, for example, with one of these four methods.

Method 1: level-controlled drainage

In level-controlled drainage, excess water is pumped to ditches, lowering the water level on the land. In November, we saw the impact of this at Boomkwekerij Maarten van Overbeek BV. After heavy rains, the planting could still proceed. Level-controlled drainage can also be effectively used for irrigating fields. During dry spells, water supply (from wells or surface water) can be used to raise the water level in the field. Capillary action makes moisture more accessible to plants. Not all soils are suitable for level-controlled drainage, and it may not be possible to implement everywhere due to zoning restrictions. However, where possible, it is strongly advised to implement this.

Method 2: increase humus content

Soils with high humus content have better buffering capacity, beneficial in both drought and excessive rainfall. Increasing humus content for better buffering is a long-term commitment. Different options for increasing humus content include:

• Supply of animal manure, preferably solid animal manure

• Supply of compost

• Green manure

• A combination of the solutions mentioned above

Although the use of green manure, solid animal manure, and compost is fairly well-established in nursery stock cultivation compared to other industries, more attention can still be given to these practices. At some companies, such as Liwardi Quality Hedging BV, green manure is used for a number of years. The first year in full cultivation, and the year after that another cultivation, to make sure that the soil is ready in time for planting in August or September. The incorporation of the green manure takes place in the top layer, without deep ploughing. This allows for rapid growth and optimal utilisation of minerals. The increase in humus ultimately provides a better buffering capacity. The use of green manure can also contribute to the restoration of soils that have been frequently traversed in wet conditions during the autumn.

Method 3: common sense

While this is a broad term, it includes:

• Assessing field conditions and adjusting crops accordingly. For example, consider the situation

with potatoes and other crops on the riverbanks this year.

• Promptly responding to water boards to discharge excess water.

• Timely drainage of water, ensuring culverts are open, ditches are cleaned, and trenches are dug during heavy rainfall. Don’t wait for the water to naturally disappear.

• Using the right irrigation at the right time. Don’t turn on the rain hose during dry, windy weather in the heat of the day.

Method 4: drip irrigation

This solution is not related to excessive rainfall, but addresses moisture supply during dry weather. Drip irrigation delivers water close to the plant when needed, with less evaporation compared to a rain hose. It’s essential to consider water delivery per kg of product or product dimensions rather than the total amount of water used. Ultimately, less water is spent per product yield, benefiting both quality and quantity.

Fortunately, the nursery stock cultivation industry is progressive in these matters. Can we prevent all problems of drought and excessive rainfall? Not entirely, but every measure taken, whether simple or comprehensive, reduces losses. Using biostimulants requires expert advice

We also discussed this theme with Handelsonderneming C.J. Klep BV from Etten-Leur, a participant in the 2024 edition of trade fair GrootGroenPlus. Corné Klep, owner of this company dealing with agriculture, safety, technology, work wear, and research, said the following: “Dry summers and wet winters are extra challenging for plants, soil, and growers. How do we keep the plant growing, the soil in shape, and manage all the work with the vagaries of the climate? Our specific biostimulants such as Nov@ and Folicist are a solution for this.” According to Corné Klep, consistent use of biostimulants results in super-healthy plants that can continue growing despite stress. They also improve the air and water balance, soil structure, and mineral-supplying capacity. Additionally, they enhance the plant’s efficient moisture and nutrient absorption, providing more peace of mind for the grower.

Corné continues: “The use of biostimulants, among other things, requires expert advice. Dosage and timing are crucial. We continually conduct research into this and have extensive experience with it. The use of sensors can be valuable. For instance, our SOSensor helps provide insight into the moisture condition of substrate and/or soil in relation to water applications. This allows for better coordination of the timing of watering and the use of resources, influencing both plants and soil and promoting more efficientwater use.”

 Getting the most out of every drop

“With an average of 850 mm of rainfall per year, there is no shortage of freshwater for the agricultural industry. However, to use it during dry summers, we must be able to cleverly store a surplus,” says Arie-Jan Broere of Broere Irrigation. This specialist in irrigation and irrigation is an advocate for drip irrigation, which yields much more from every drop of water and can save 10 to 35 per cent of water compared to reel irrigation. Broere foresees that drip irrigation will be widelyapplied in the future: “You not only use water efficiently in dry periods, but there is also a significantly greater yield and better crop quality. It prevents stress in planting, and disease pressure is lessbecause the leaves stay dry.” By providing water in a  controlled manner, as opposed to a large amount at once with a hose reel, there will be less soil compaction, benefiting the root system. It is also possible to fertilize through the drip irrigation system.

Combination with solar

For remote fields without electricity, Broere Irrigation has developed a Mobile Solar Irrigation System. In combination with drip irrigation, this is a perfect stand-alone solution. As much less electricity is needed with drip irrigation, this system can irrigate a plot of 1 to 10 hectares, depending on the crop. This can be done directly using sunlight and combined with a battery. The system can be controlled via a mobile phone. 