Influence of nitrogen fertilization, seed inoculation and the synergistic effect of these treatments on soybean yields under conditions in south-western Poland

Soybean, belonging to legumes, has a specific ability to biological nitrogen fixation, which can be reinforced by seeds inoculation. However, support with a starter dose of mineral nitrogen fertilizer may be necessary to achieve high seed yields. A four-year field experiment was conducted to determine the effect of mineral N fertilization (0, 30, 60 kg ha-1), seed inoculation with two commercial inoculants and combinations of these treatments on yield components and yielding of soybean in conditions of south-western part of Poland. The synergistic effect of mineral fertilization at dose 30 kg ha-1 and inoculation on soybean productivity was the most beneficial. Similar effects were observed when 60 kg N ha-1 was applied both separately and with inoculation. However, due to the environmental impact of mineral fertilizers and to promote plants to biological nitrogen fixation (BNF), it is advisable to use lower doses of N fertilizer (at 30 kg ha-1) and inoculate soybean seeds in agro- climatic conditions of south-western Poland. Therefore, based on this study we recommend to apply starter dose of N and inoculation.

Chalcone Synthase (CHS) Gene Suppression in Flax Leads to Changes in Wall Synthesis and Sensing Genes, Cell Wall Chemistry and Stem Morphology Parameters

The chalcone synthase (CHS) gene controls the first step in the flavonoid biosynthesis. In flax, CHS down-regulation resulted in tannin accumulation and reduction in lignin synthesis, but plant growth was not affected. This suggests that lignin content and thus cell wall characteristics might be modulated through CHS activity. This study investigated the possibility that CHS affects cell wall sensing as well as polymer content and arrangement. CHS-suppressed and thus lignin-reduced plants showed significant changes in expression of genes involved in both synthesis of components and cell wall sensing. This was accompanied by increased levels of cellulose and hemicellulose. CHS-reduced flax also showed significant changes in morphology and arrangement of the cell wall. The stem tissue layers were enlarged averagely twofold compared to the control, and the number of fiber cells more than doubled. The stem morphology changes were accompanied by reduction of the crystallinity index of the cell wall. CHS silencing induces a signal transduction cascade that leads to modification of plant metabolism in a wide range and thus cell wall structure.

Response of Prairie cordgrass (Spartina pectinata Link) to a residual effect of municipal sewage sludge application

The objective of our study was to assess the residual effect of sewage sludge on the growth and yield of Prairie cordgrass and the content of crude ash, macroelements and heavy metals in the plant biomass. Field trials conducted in the years 2011 to 2013 focused on the assessment of the impact of municipal sewage sludge applied from 2008 to 2010on the growth and yield of Prairie cordgrass. The experiments followed the split-plot design with two variables: the rate of sewage sludge (DM-dry matter) at 0, 1.4, 2.8 and 4.2 t ha-1, corresponding to nitrogen fertilization with: 0, 50, 100, 150 kg ha-1, and the harvest time - fall and winter. The total dose of sewage sludge applied in 2008−2010 was 0, 4.2, 8.4 and 12.6 t DM ha-1, which corresponded to the total dose of nitrogen fertilization: 0, 150, 300 and 450 kg ha-1, respectively. The municipal sewage sludge at a rate of 8.4 t DM ha-1, compared to the Control, significantly increased the number of leaves per plant, the leaf and culm matter, the number of shoots per 1 m2, the dry matter yield, crude ash deposition and uptake of macroelements and heavy metals.