Soil phosphorous and potassium apparent recovery by field crops
2015
Karklins, A., Latvia Univ. of Agriculture, Jelgava (Latvia). Inst. of Soil and Plant Sciences | Lipenite, I., Latvia Univ. of Agriculture, Jelgava (Latvia). Inst. of Soil and Plant Sciences | Ruza, A., Latvia Univ. of Agriculture, Jelgava (Latvia). Inst. of Agrobiotechnology
Data from 72 field trials using the same layout was carried out in four locations in Latvia during 2008-2012 was used. Experimental crops: winter and spring wheat, winter rye, winter and spring rape, spring barley and potatoes. In each experiment soil before planting of crops was tested in two depths: 0-20 cm and 20-40 cm and plant available phosphorous and potassium (Egner-Riehm method) was determined. Using data of bulk density, PK content was transformed on 0-20 and 0-40 cm soil layer and expressed as tons per ha. Apparent recovery of soil PK (soil PK recovery efficiency) was calculated as the difference in PK uptake in plots not receiving fertilisers and PK content in the soil (kg haE-1) within the depth of 0-20 or 0-40 cm and expressed as a proportion of these two values. It was found that soil phosphorous apparent recovery in average consisted as 8.68% if calculated based on 0-20 cm soil layer or 4.96% – if calculated based on 0-40 cm soil layer and has small differences depending on crops. Soil potassium recovery was significantly different depending on crops. In average cereals and rape utilised 12.76% from its content in 0-20 cm soil layer or 6.79% from content in 0-40 cm soil layer. Potatoes - 62.04% and 32.81% subsequently. It is possible to use the developed soil phosphorous and potassium recovery factors for fertilising planning in situations where PK containing fertilisers are used regularly and residual effect of its is applications is prospective.
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