engleski

Response of soybean to phosphorus fertilization under drought stress conditions

The field experiment was conducted on clay soil with five phosphorus (P) fertilization rates (a = 75, b = 225 ; c = 375 ; d = 525 ; e = 975 kg P2O5 ha-1) on March 12, 2011 in Prud (Posavian Canton, Federation B&H, Bosnia and Herzegovina). The choice of experimental plots was based on previous soil test. The source of P was monoammonium phosphate or MAP (13% N + 53 % P2O5). The experiment was conducted in four replicates (basic plot 60 m2). The type of experimental soil was calcareous alluvial, low in plant available P and rich in K. Soybean (cultivar Lucija, originating from Agricultural Institute Osijek, Croatia) was sown on April 30, 2011 and harvested on September 14, 2011. The 2011 growing season was less favorable for soybean because of water shortage and higher air-temperatures. For example, precipitation quantity in August (Gradiste: about 20 km distance from the experiment) was only 4 mm (mean 1971-1990: 66 mm) accompanied by mean air-temperature 23.4 °C (mean 1971-1990: 20.7 °C). Moreover, in the second 10-day period of July mean air-temperature was 25.5 °C and without precipitation. Under these conditions achieved soybean yields were low (mean 2111 kg ha-1). However, P fertilization alleviated this type of abiotic stress. Increase P fertilization from 75 to 375 kg P2O5 ha-1, soybean yield was increased up to 20%, whereas further increase of P rates resulted with lower yield to the control level.

soybean yield ; oil ; protein ; phosphorus fertilization ; drought stress

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