Impact of rainfall, liming, nitrogen (N), phosphorus (P2O5), potassium (K2O), calcium (CaO), magnesium (MgO) mineral fertilization on triticale (x Triticosecale Wittmack) yield in a monoculture in Hungary

The natural climate variability may be masked by the anthropogenic made global warming, today. With a warmer climate, drought and excess rainfall conditions could become more frequent and longer lasting. The potential increase of the hazards result stresses and high costs in cereal production. For this reason a long-term study was conducted on a sandy acidic lessivated brown forest soil; WRB: Haplic Luvisol in the 44 year old Nyirlugos Field Trial (NYFT) in a Hungarian fragile agroecosystem in Nyirseg region (N: 470 41' 60, and E: 220 2' 80) on triticale (x Triticosecale Wittm.) yield between 1999 and 2006. In 1962, at the trial set up the soil had the following agrochemical properties: pH (H2O) 5.9, pH (KCl) 4.7, hydrolytic acidity 8.4, hy 10.3, humus 0.7%, total N 34 mg kg(-1), ammonlactate (AL) soluble-P2O5 43 mg kg(-1), AL-K2O 60 mg kg(-1) in the plowed (0-25 cm) layer. The trial consisted of 32 x 4 = 128 plots in randomised block design. The gross plot size was 10 x 5 = 50 m(2). The average fertilizer rates in kg ha(-1) year(-1) were nitrogen 75, phosphorus 90 (P2O5), potassium 90 (K2O), calcium 437.5 (CaCO3) and magnesium 140 (MgCO3). The groundwater table had at a depth of 2-3 m below the surface. During drought conditions the respective yield of the control areas was -25% less than for average years. The application N alone or NP and NK treatments led to yield reduction of -19.7%, while that of NPK, NPKCa, NPKMg and NPKCaMg caused an -28.3% yield drop. In the wet years the yield decreased by -22.2% on the unfertilized soils; in case of the N, NP and NK nutrition the yield dropped with an -14.1%; and the yield increased at 13.8% on NPK, NPKCa, NPKMg and NPKCaMg treated plots. Yield dropped in the very wettest year -43.1% on control soils; -39.3% of N, NP and NK loadings, and -35.8% on NPK, NPKCa, NPKMg and NPKCaMg treatments to those in the average year. The relationship between rainfall quantity during the vegetation period and N, P, K, Ca, Mg nutrition and yield was characterised by polynomial correlation (control: R = 0.7212***, N: R = 0.7410***, NP: R = 0.6452***, NK: R = 0.6998***, NPK: R = 0.5555***, NPKCa: R = 0.5578***, NPKMg: R = 0.4869**, NPKCaMg: R = 0.4341**). However, total regression coefficients ranged from 0.43 to 0.74 in depence on the different nutrient application. Maximum yields of 5.8-6.0 t ha(-1) were achieved in the rainfall range of 580-620 mm. At values above and below this domain of the precipitation the grain yield reduced quadratically. So, it can be stated that both drought and excess rainfall conditions resulted dramatically significant negative effects between fertilization (N, P, K, Ca, Mg) and triticale yield.