Teff (Eragrostis tef (Zucc.) Trotter) fodder yield and quality as affected by cutting frequency

Teff (Eragrostis tef (Zucc.) Trotter) is a well-adapted, fast-growing crop with competitive forage quality as its nutritive value for livestock fodder is similar to other grasses utilized as hay or ensiled feeds. Two field experiments were conducted from May to October 2017 in order to determine the effect of cutting frequency on yield and quality of teff (Eragrostis tef) as fodder crop under Mediterranean climatic conditions. The agronomic performance and nutritive value of teff was analyzed in order to define alternatives to local forages for animal feeding in the Mediterranean region. The experiments conducted at two sites (Western and Central Greece) were laid out in a completely randomized design with three replicates and three cutting frequencies (10, 20, 30 days’ interval between cuttings - F10, F20, and F30, respectively). The results of this study demonstrate that the cutting interval has a marked effect on the fodder yield and quality. The highest total dry matter yield (6,322–6,778 kg ha-1) was found in F10 treatment. In terms of qualitative characteristics, the highest fat levels and lowest ADF levels was found in F30 treatment, the highest protein levels and the lowest NDF levels in F10 treatment, and the highest levels of fibrous substances, ADF and NDF, in F20 treatment. Data suggest that teff could be successfully integrated into Mediterannean grasslands with the prospect for improving their nutritional quality and the possibility for increasing protein yield through the application of frequent cuttings

Self-assembly of telechelic tyrosine end-capped PEO and poly(alanine) polymers in aqueous solution

The self-assembly in aqueous solution of three novel telechelic conjugates comprising a central hydrophilic polymer and short (trimeric or pentameric) tyrosine end-caps has been investigated. Two of the conjugates have a central poly(oxyethylene) (polyethylene oxide, PEO) central block with different molar masses. The other conjugate has a central poly(l-alanine) (PAla) sequence in a purely amino-acid based conjugate. All three conjugates self-assemble into β-sheet based fibrillar structures, although the fibrillar morphology revealed by cryogenic-TEM is distinct for the three polymers—in particular the Tyr5-PEO6k-Tyr5 forms a population of short straight fibrils in contrast to the more diffuse fibril aggregates observed for Tyr5-PEO2k-Tyr5 and Tyr3-PAla-Tyr3. Hydrogel formation was not observed for these samples (in contrast to prior work on related systems) up to quite high concentrations, showing that it is possible to prepare solutions of peptide–polymer-peptide conjugates with hydrophobic end-caps without conformational constraints associated with hydrogelation. The Tyr5-PEO6k-Tyr5 shows significant PEO crystallization upon drying in contrast to the Tyr5-PEO2k-Tyr5 conjugate. Our findings point to the remarkable ability of short hydrophobic peptide end groups to modulate the self-assembly properties of polymers in solution in model peptide-capped “associative polymers”. Retention of fluidity at high conjugate concentration may be valuable in potential future applications of these conjugates as bioresponsive or biocompatible materials, for example exploiting the enzyme-responsiveness of the tyrosine end-group

Effect of three tillage systems on weed flora in a 3-year rotation with four crops

Field experiments were conducted to determine the effect of tillage on the dry weight, frequency (PF), density (PD) and species composition of the weed population. Three tillage systems (CT: conventional tillage, MT: minimum tillage and NT: no tillage) were compared in a 3-year rotation [wheat - Vetch (green manure) - Cotton - Barley]. Decreases in PF, mean PD and number of species were observed under NT because in this system the soil remains undisturbed, and conditions are not suitable for seed germination. In contrast, annual weeds had a higher PF under the CT system, because they mainly propagate by seed and soil tillage creates more favourable growth conditions; thus they also had a higher PD. The highest PF and PD were found for the species Sinapis arvensis and Solanum nigrum. Perennial weeds had higher PD under the NT system, because their roots cannot be destroyed by soil tillage. The number of species was not altered in CT and MT, but was decreased in NT. In winter crops, annual species under CT and MT, and perennial species under NT were observed. In cotton crops, perennial species under CT and MT, and annual species under NT were observed. The mean PD of weed species in the first crop followed the sequence NT > MT > CT and in subsequent crops followed the reverse sequence CT > MT > NT

The phytotoxicity of various graminicides in durum wheat in Greece

The effect of three herbicides, diclofop-methyl (DM), imazamethabenz-methyl (TM) and fenoxaprop-ethyl (FE), was investigated at the recommended rate (x) and double the recommended rate (2x) in a durum wheat crop. FE had the smallest effect on root system characteristics, while IM had the greatest effect. For all herbicides, the double rate treatment gave a greater statistical reduction than the single rate for root system characteristics. FE had the smallest effect on the activity of aerobic microorganisms, while DM gave the greatest reduction, 10 days after application, and all three herbicides reduced earthworm abundance. DM gave the smallest reduction in the number of tillers and in plant height, while the double rate of IM gave the greatest reduction. For all three herbicides, double the recommended rate resulted in a significant reduction in the weight of 1000 seeds, while no statistically significant deviations were noted at the recommended rate. Finally, the use of all three herbicides resulted in significantly lower statistical yields compared to the sample (control plot), although there were no significant statistical differences among them, for either recommended or double recommended rates

The phytotoxicity of various graminicides in durum wheat in Greece

The effect of three herbicides, diclofop-methyl (DM), imazamethabenz-methyl (TM) and fenoxaprop-ethyl (FE), was investigated at the recommended rate (x) and double the recommended rate (2x) in a durum wheat crop. FE had the smallest effect on root system characteristics, while IM had the greatest effect. For all herbicides, the double rate treatment gave a greater statistical reduction than the single rate for root system characteristics. FE had the smallest effect on the activity of aerobic microorganisms, while DM gave the greatest reduction, 10 days after application, and all three herbicides reduced earthworm abundance. DM gave the smallest reduction in the number of tillers and in plant height, while the double rate of IM gave the greatest reduction. For all three herbicides, double the recommended rate resulted in a significant reduction in the weight of 1000 seeds, while no statistically significant deviations were noted at the recommended rate. Finally, the use of all three herbicides resulted in significantly lower statistical yields compared to the sample (control plot), although there were no significant statistical differences among them, for either recommended or double recommended rates

Controlled nitroxide-mediated and reversible addition-fragmentation chain transfer polymerization of N-vinylpyrrolidone: Synthesis of block copolymers with styrene and 2-vinylpyridine

An approach to control the polymerization of N-vinylpyrrolidone (NVP) with nitroxide-mediated polymerization (NMP) and reversible addition-fragmentation chain transfer (RAFT) polymerization techniques was analyzed. The polymerizations were conducted at 95 °C to avoid the thermal decomposition of the monomer, in presence of acetic anhydride. Three different chain-transfer agents (CTA) were employed under various experimental conditions for the RAFT polymerization of NVP. The living character of the poly(N-vinylpyrrolidone) (PNVP) chains produced by RAFT polymerization was confirmed by the synthesis of block copolymers by the sequential addition of another monomer