On the course of three vegetation periods 2009/2010-2010/2011-2011/2012 the effect of applied mineral fertilizers and post harvest residues of precrop of common pea (Pisum sativum L.) on yields and content of crude protein in grain of winter wheat (variety Istrodur) was investigated. Field experiment was established at the experimental site of the Slovak University of Agriculture in Nitra. Under the conditions of organic fertilizers deficit the primary aim of the experiment was to evaluate the effect of post harvest residues (as alternative source of organic matter) on uptake of nutrients by aboveground phytomas, balance of nutrients and energetical effectiveness of nitrogen fertilizers. There were examined four treatments of fertilization in the experiment: 0 – unfertilized control, PZ – post harvest residues of precrop incorporated into soil by ploughing, PH – rational fertilization with mineral fertilizers based on soil and plant analyses, PH+PZ – rational fertilization with mineral fertilizers + incorporation of precrop postharvest residues into soil. Grain yields were highly significantly influenced by experimental year and ferttilization, respectively. On the average of three experimental years the highest yield of grain (4.63 t.ha-1) was gained in treatment fertilized by mineral fertilizers. Incorporation of post harvest residues into soil (treatment PZ and PH+PZ) decreased the average grain yields to 3.88 and 3.99 t.ha-1, respectively which were lower ones in comparison to control unfertilized treatment. There was found out high significant correlation between nutrients uptake by aboveground phytomass and grain yield (r = 0,8766xxx). Energetical effectiveness of nitrogen fertilizers achieved value E = 4.65 on the average of experimental years and fertilization treatments. The highest energetical effectiveness was calculated in treatment PH (E = 6.2)in year 2011. The highest average content of crude protein in grain (11.81%) was determined in treatment PH+PZ and the highest production of crude protein per hectare (544 kg) in treatment fertilized by mineral fertilizers. Rational fertilization with mineral fertilizers in combination with pea post-harvest and root residues ploughing down into soil represents treatment which is getting closest to the sustainable farming on soil. On the average of three experimental years balance surplus of nitrogen was low (10.3 kg.ha-1.yr-1), phosphorus medium (18.4 kg.ha-1.yr-1) and potassium high (51.7 kg.ha-1.yr-1). Decrease of potassium inputs into soil through the mineral fertilization application in year 2012 seems to be very effective measure for reducing high balance surplus of potassium in treatment PH+PZ.

post-harvest residues, mineral fertilization, grain yield, crude protein, balance of nutrients

Presentation: oral