engleski

Changes in Chemical Soil Properties after 11 Years of Different N and Regular P and K Fertilization

Fertilization with different amounts of mineral nitrogen (0 to 300 kg N ha-1) have been applied continuously, in eleven years investigation period, from 1996 till 2006, in stationary field experiment established on drained Stagnosol. Trial treatments included annual fertilization with different mineral nitrogen rates, respectively with 0, 100, 150, 200, 250 and 300 kg N ha-1 what imply total nitrogen input in eleven years investigation period of 0, 1100, 1650, 2200, 2750 and 3300 kg N ha-1. Fertilization with phosphorus and potassium has been equal for all trial treatments in the same year of investigation, excluding check treatment. This paper presents results of changes of pH value, humus content and plant available phosphorus and potassium content in soil at three investigation depths (0-30 cm, 30-55 cm and 55-80 cm) for soil samples taken before establishment of field trial in May 1996 and 11 years later, after the harvest of winter wheat in July 2006. Chemical soil properties in 2006 have been measured in frame of EU LIFE Project, Development of the Croatian soil monitoring programme with a pilot project. During the investigation period, mean pH value in soil at selected treatments decreased in average. At the depth 0-30 cm average soil pH decreased from 4.25 to 4.18, at depth 30-55 cm from 4.84 to 4.59 and at depth 55-80 cm from 5.04 to 4.70. At the same time, average humus content in soil increased, at the depth 0-30 cm from 2.06 to 2.29, at the depth 30-55 cm from 1.57 to 2.14, and at the depth of 55-80 cm from 0.61 to 1.20 %. In studied period plant available phosphorus and potassium content in soil generally increased, because of consistent fertilization with single P and K and complex NPK fertilizers.

fertilization; chemical soil properties

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