PROXIMITY EFFECT OF SPRING CEREALS AND LEGUMES IN STRIP INTERCROPPING. PART II. RESPONSE OF PEA TO THE PROXIMITY OF WHEAT, TRITICALE, BARLEY, AND YELLOW LUPINE
Background. Strip intercropping brings together the advantages of pure sowing and intercropping, but its production value depends on the reciprocal effect of the various species at the contact point of adjacent rows. The aim of the experiment was to establish the response of pea to the neighbouring occurrence of spring wheat, spring triticale, spring barley, and yellow lupine and the estimation of the production effect of strip intercropping of pea in the proximity of those species.
Material and methods. In the experiment, the results of field experiments on mixed sowings carried out in the years 2008–2010 at the experimental station in Mochełek near Bydgoszcz (53°13’ N; 17°51’ E) were used. Experimental factor was the position of plant row on the plot: four rows into the plot away from the outermost row with respective neighbouring species. First row of pea (contact row) was situated 12.5 cm away from the first row of respective neighbouring species. Experimental unit was subsequent plant rows, each 4 meters long.
Results. Proximity of wheat, triticale, barley, and lupine was unfavourable to pea. It occurred the most strongly in the first plant row and decreased in the subsequent, farther rows. The most unfavourable proximity for pea in strip intercropping proved to be barley. In the row adjacent to this species, pea grain yield was lower than in the fourth row by 59.4%. In the subsequent rows, also a tendency for seed yield decrease was noted, namely in the second row by 26.9% and in the third row by 9.2%. Confirmed unfavourable proximity effect for wheat and triticale included first and second pea rows. The least unfavourable vicinity for pea was that of yellow lupine.
Conclusion. When introducing pea to strip intercropping with cereals, its yield may be lower by 3.5% (one-sided proximity of triticale) to 7.9% (proximity of barley), which decreases the proportion of pea seeds in the total yield of strip intercropping.