Long-term effect of farmyard manure and mineral fertiliser on the yield and yield stability of maize (Zea mays L.) in dry and wet years

Abstract

The effect of mineral fertilisation, farmyard manure and their combinations on the yield and yield stability of maize was studied in a long-term maize monoculture experiment set up in Martonvásár, Hungary in 1959. The experiment, laid out as a Latin square, included two fertilisation levels [35 t ha−1 or 70 t ha−1 farmyard manure (FYM) every four years] and seven treatments. The yield results were evaluated using analysis of variance, cumulative yield analysis and stability analysis. The year effect was analysed by dividing the 51 years (1959–2009) into wet (32) and dry (19) years. The rainfall sum for the months Apr.–Sep. averaged 361 mm in the wet years and 232 mm in the dry years.Among the fertiliser treatments the FYM + mineral fertiliser combination and NPK mineral fertilisation alone gave the highest yields. In more than 50% of the years the higher fertiliser level had no significant yield-increasing effect. The yield differences between the two fertiliser levels were twice as high in wet years as in dry years (0.543 vs. 0.274). Averaged over all seven treatments, the maize yield was 3.959 t ha−1 in dry years and 6.250 t ha−1 in wet years, giving a yield increment of 2.291 t ha−1 in favourable years. Yield stability was greatest when the NPK content of 35 t ha−1 FYM was replaced in part (17.5 t ha−1 FYM + N1/2P1/2K1/2) or in full (N1P1K1) by mineral fertiliser, or when 70 t ha−1 FYM was applied. Yield stability is an important indicator of the sustainability of crop production.