Economic effects of summer catch crops application in sweet corn cultivation

The work presents the results of investigations conducted in 2004- 2007 to evaluate the residual effect of summer catch crops ploughed as green manures on productive-economic effects of sweet corn cultivation. The experiment was carried out in east-central Poland (52°03’N, 22°33’E). The following summer catch crops were grown: phacelia, amaranth, sunflower, serradella and faba bean. The catch crop seeds were sown in 2004-2006 at three dates: on the 21stJuly, 4th and 18th August. The effect of summer catch crops was compared to FYM applied at the rate of 40 t·ha-1. The catch crops biomass (roots + above ground parts) and FYM were incorporated in the third decade of October. Sweet corn seeds (6 kg·ha-1) were sown in mid-May, in the years 2005-2007, at the between – and inter- row spacing of 65 × 20 cm. Sweet corn ears were hand-harvested at the stage of milk maturity of kernels, at the turn of August and September. During the harvest marketable yield of ears (t·ha-1) and number of marketable ears per 1 ha were determined. Economic evaluation of sweet corn cultivation under diversified organic fertilization was conducted according to the standard gross margin method. The calculation was based on the 2014 prices. The highest yield and number of ears were obtained after catch crops with faba bean and phacelia sown on the 21st July and after FYM. Delaying the sowing date of catch crops resulted in a decrease in the successive yielding effect. The highest gross margin (25267.66 PLN·ha-1 and 0.56 PLN per 1 ear) and profitability index (332%) were achieved in the sweet corn cultivation after catch crop with faba bean sown on the 21st July. Compared to the plot with FYM, a higher level of gross margin and profitability index were obtained after all catch crops sown on the 21st July and the 4th August. Irrespective of investigated factors, profitability index was on a very high level amounting to 211-332%.