Variability of basic soil characteristics on selected arable land

Na območju Celja smo izbrali 8 njiv, kjer je od zadnje obdelave pretekel najmanj 1 mesec. Vse vzorce tal smo odvzeli isti dan (20. 3. 2020), po krajšem obdobju suhega vremena. Vzorčili smo na njivah s poljedelskim kolobarjem, kjer je bila v jeseni 2019 posajena koruza. Glede na velikost njive smo odvzeli od 3 do 21 površinskih vzorcev tal na posamezni njivi, skupaj 93 vzorcev. Predvidevali smo, da je variabilnost meritev odvisna od heterogenosti tal na površini njiv in od izvedbe vzorčenja. Ugotovili smo, da je bila najmanjša povprečna vrednost rastlinam dostopnega fosforja 2,3 mg/100 g, največja pa 15,1 mg/100 g. Najmanjša povprečna vrednost rastlinam dostopnega kalija je bila 8,2 mg/100 g, največja pa 46,3 mg/100 g. Povprečne vrednosti so se torej precej razlikovale. Pri pH so se povprečne vrednosti za različne njive gibale od 4,6 do 6,9. Vrednosti deleža organske snovi pa so se gibale od 3,2 % do 4,8 %. Koeficient variacije (KV) je bil za pH vrednost od 3,2 do 12 %, pri deležu organske snovi pa je bil 6,5 – 34,7 %. Precej večja je bila variabilnost v meritvah rastlinam dostopnega fosforja in kalija. Koeficient variacije za kalij je bil od 11,5 do 73 %pri fosforju pa od 6,3 do 87,9 %. Vrednosti za rastlinam dostopen fosfor in kalij sta bila bolj variabilna kot za pH in organsko snov.We selected 8 fields in the Celje area, where at least 1 month had passed since the last cultivation. All samples were taken on the same day (March 20, 2020) after a short dry period. Samples were collected from fields with crop rotation where corn had been grown in the fall of 2019. Depending on the size of the field, between 3 and 21 soil samples were collected per field, resulting in a total of 93 soil samples. We assumed that the variability of the measurements depended on the heterogeneity of the soil on the field surface and sampling. We found that the lowest average value of plant-available phosphorus was 2.3 mg/100 g and the highest was 15.1 mg/100 g. The lowest average value of plant-available potassium is 8.2 mg/100 g and the highest was 46.3 mg/100 g. Thus, the average values vary considerably. For pH, the average values for different fields ranged from 4.6 to 6.9, and the percentage of organic matter varied from 3.2% to 4.8%. The coefficient of variation (KV) for pH ranged from 3.2 to 12%, and for the percentage of organic matter from 6.5 to 34.7%. The variability in the measurement of phosphorus and potassium available to plants was much greater. The coefficient of variation for potassium ranged from 11.5 to 73%, and that for phosphorus ranged from 6.3 to 87.9%. The data for plant available phosphorus and potassium were more variable than for pH and organic matter