Wpływ następczy nawożenia kompostem z osadów komunalnych oraz częstotliwości koszenia na architekturę łanu wierzby energetycznej w dalszych latach uprawy

Celem pracy jest ocena efektu następczego nawożenia kompostem z osadów komunalnych i azotem mineralnym oraz wariantów koszenia w latach 2006–2009 na architekturę łanu dziewięciu klonów wierzby energetycznej w latach 2012–2014. W latach 2006–2009 zastosowano nawożenie: (A) obiekty bez nawożenia, (B) nawożone kompostem z osadów komunalnych (10 t·ha⁻¹ s.m.), (C) nawożone kompostem z osadów komunalnych (10 t·ha⁻¹ s.m.) i azotem mineralnym w ilości 90 kg N·ha⁻¹ oraz (D) nawożone kompostem z osadów komunalnych (10 t·ha⁻¹ s.m.) i azotem mineralnym w ilości 180 kg N·ha⁻¹. W latach 2010–2014 nie stosowano żadnego nawożenia. Zastosowano trzy warianty koszenia wierzby na poletkach. Pomiary biometryczne na wierzbie wykonano w latach 2012– –2014. Badania wykazały, że intensyfikacja uprawy wierzby w latach 2006–2009 na glebie lekkiej wpływała negatywnie na architekturę łanu w latach 2012–2014, ponieważ został osłabiony odrost pędów na długość i grubość oraz zmniejszyła się liczba pędów w karpie i liczba żywych karp na poletku.

The aim of the study was to evaluate the successive effect of fertilization with compost from municipal sewage sludge and the frequency of mowing in the first 4-year rotation on architecture of field of nine energetic willow clones in subsequent years of cultivation on sandy soil. In the years 2006–2009 following fertilization was applied: (A) object without fertilization, (B) object fertilized with compost from municipal sewage sludge (10 t·ha⁻¹ dm), (C) fertilized with compost from municipal sewage sludge (10 t·ha⁻¹ dm) and nitrogen (90 kg N·ha⁻¹) and (D) fertilized with compost from municipal sewage sludge (10 t·ha⁻¹ dm) and nitrogen in the amount of (180 kg N·ha⁻¹). Compost was applied once in the spring of 2006, and nitric fertilizer – annually in 2006–2009. In 2010–2014 no fertilization was applied. In the experiment, four fertilizer combinations were the sub-blocks of the first order, and nine clones of willow cultivated at planting of cuttings 32100 cuttings per hectare were the sub-blocks of the second order. The experiment involved following willow clones: 1047, 1054, 1023, 1013, 1052, 1047D, 1056, 1033 and 1018, which were planted on plots of 34.5 m² in three repetitions. Each plot was divided into 3 parts 11.5 m² each, on which 40 cuttings were planted. Growths of shoots were mowed after the second, third and fourth year of growing. In the first 4-year rotation willow shoots mowed: once on plot „a” (26.11.2009), twice on plots: „b” (25.02 and 26.11.2009) and „c” (02.08.2008 and 26.11.2009). In the years 2012–2014 on each plot measurements of field were performed. Following parameters were assessed: height and thickness of shoots, number of live shoots in the bush and number of live bushes. Analysis of variance was performed for the studied parameters and significance of variance components was determined and the significance of effects was assessed using F test. Percentages of main effects and their interactions were assessed and the successive effect of combination of fertilization and mowing frequency was determined and compared to effects of years of cultivation and willow clones. Studies showed that intensive fertilization of willow with compost and mineral nitrogen in the first 4 years from plantation establishment on sandy soil, in the direct effect caused increase of increments of length and thickness of willow shoots and 40.3–55.6% increase of yield of dry mass during experiment. Although successive effect, without fertilization, in 7th –9th year of vegetation, affected negatively cultivation architecture. The negative successive effect of willow fertilization with compost and mineral nitrogen was caused by a weakened regrowth of shoots in the length and thickness and reduced number of live shoots in bushes and live bushes on the plot.