The influence of crop deėnsity on spring oilseed rape agrocenosis under different supply of nutrients

Field experiment was conducted in 2010 at Experimental Station of the Aleksandras Stulginkis university on a Calc(ar)i-Endohypogleyic Luvisol. The objective of the current study was to determine the influence of crop density_on spring oilseed rape {Brassica napus L.J agrocenosis under different supply of nutrients. Treatments of the investigations: factor A - fertilization: 1) without fertilization, 2) fertilization before rape sowing 64 kg ha"1 N, 64 kg ha"1 P2O5, 94 kg ha"1 K20 and at the budding stage 70 kg ha"1 N. Factor B - crop density: 1) 2 kg ha"1 (50.1-100 plants m"2), 2) 4 kg ha"1 (100.1- 150 plants m"2), 3) 6 kg ha"1 (150.1-200 plants m"2), 4) 8 kg ha"1 (200.1-250 plants m"2), 5) 10 kg ha"1 (250.1-300 plants m"2), 6) 12 kg ha"1 (300.1-350 plants m"2), 7) 14 kg ha1 (350.1-400 plants m"2), 8) 16 kg ha"1 (400.1-450 plants m"2). In spring rape without fertilization a direct, very strong and statistically significant relationship (r = 0.97, P<0.01) was determined between rape crop density and above-ground plant massVytauto Didžiojo universitetasŽemės ūkio akademij

After-effect of long-term soil management on soil respiration and other qualitative parameters under prolonged dry soil conditions

Climatic conditions of environmental zone Nemoral 2 of Europe are favorable for agricultural development. However, more frequent events of hot air-waves and prolonged droughts occurring as a consequence of climate change lead to soil moisture content reduction down to the plant wilting point. Dry soil conditions may have negative consequences for soil as a habitat. The goal of this study was to evaluate the cumulative after-effect of long-term conventional (CT) and no-tillage (NT) application in combination with or without crop residues on soil physicochemical properties, microbiological activity, and soil respiration (SR) under prolonged dry soil conditions. Long-term CT with residue returning created a soil environment that was more resistant to dry conditions than NT. Longterm CT with residue returning created a qualitative soil environment in which the main direct determinants for SR were fungal (F) and bacterial (B) community and carbon/nitrogen ratio (C/N). Slightly weaker contributors for SR were available phosphorus (PAL), plant wilting point (PWP), plant available water (PAW), and urease activity (UR); however, they acted as indirect factors. Long-term spreading of residues on soil surface under NT determined the decrease in water capacity in mesopores and micropores. Significant reduction in field capacity and PWP was revealed, while PAW remained unchanged compared to NT with residues removed. Main direct determinants for SR were F and PAL. Slightly weaker indirect contributors for SR were B, dehydrogenase, UR, and PAWLietuvos agrarinių ir miškų mokslų centro Žemdirbystės institutasVytauto Didžiojo universitetasŽemės ūkio akademij