Dr. Steve Oosthuyse (Marketing Development Director, SQM) and his SQM Chinese colleagues visited the apple farm recently developed in the Shaanxi Fruit Industrial Group CO, at the end of June 2015 LTD (Figure 1). The objective of the trip was to obtain professional information for the design of fertigation programs for the producers of apple orchards. Currently, the total area of the high-density orchards is 1.334 hectares, all of which has drip irrigation and is oriented to fertigation.

This implies that the absorption of nutrients from the roots is only required after flowering has been completed, to support the growth of new buds and the development of the fruit. Fertilization efficiency is strongly related to the irrigation practices and the absorption of nutrients needed by the trees. Leaching and nutrient loss is prevented through the application of water and nutrients according to the program readings of the irrigation equipment, using tensiometers. By applying nutrients in accordance with the trees’ dynamics of demand in the irrigation program, one can expect a considerable efficiency increase in the use of fertilizers in contrast to a fixed irrigation system. The efficient use of nutrients can be increased even more with Ultrasol® K (potassium nitrate) instead of potassium chloride or potassium sulfate as a source of potassium in the fertigation mix. It was clearly demonstrated by Dr. Oosthuyse in 2014, that replacing potassium chloride (KCl) or potassium sulfate (K2SO4) with K Plus (potassium nitrate - KNO3) in nutrient solutions, increases growth and the accumulation of dry material in peach and apple tree nurseries.

Bud length of the trees in nurseries may be increased when K Plus is applied (potassium nitrate - KNO3) as a source of potassium to the fertigation mix, instead of potassium chloride (KCl) or potassium sulfate (K2SO4) (Oosthuyse et al. 2014).