Abstract: A method serving the purpose of spraying a crop with a plant protective liquid. The liquid is sent out in the shape of a number of clouds (10) of atomized liquid in the direction of the crop (11) via a number of liquid nozzles (9) placed on a sprayer boom (8) which, at the same time, is driven across the crop (11). The nozzles (9) are adjusted to put each atomized liquid cloud (10) into whirling movement. The whirls (10) created thereby are stiff and stable against drifting. The liquid whirls (10) can be supported by a curtain of air whirls (14). By means of the method and the sprayer boom according to the invention, a crop can be sprayed efficiently with a minimum use of crop spray.

Abstract: Method and device for separating a fine-grained solid material into a fines fraction and a coarse fraction at a cut point size of below 50 .mu.m, preferably below approx. 10 .mu.m. The fine-grained solid is dispersed in a liquid capable of forming drops and this dispersion is forced into a defined sink flow with a superimposed rotational flow that is generated independently from the jink flow. The relationship between the two rates, namely the sink flow rate and the rotational flow rate, is dictated by the cut point size. The device includes a deflector wheel which has a direction of flow from the outside to the inside, and vanes are fitted in the wheel parallel to its rotational axis to form flow channels, whereby the feed dispersion is charged to the deflector wheel at its outer periphery.

Abstract: The present invention relates to a controlled release fertilizer having water-soluble fertilizers as nucleus and limited-soluble plant nutrient compounds as coating layers, characterized in that more than two coating layers of limited-soluble compounds are formed around the nucleus, and that the release rates of the fertilizer can be controlled by regulating the solubilities of the limited-soluble compounds. The invention also relates to a process for preparing the controlled release fertilizer.