Effect of nitrogen fertilizations, with and without inhibitors, on cotton growth and fiber quality

Considering cotton, one of the most non environmentally friendly crops, new types of fertilizers, such as the urease inhibitor, are now being used for fertilization. Furthermore, the need of increasing the nutrient use efficiency which is an important contributor to yield has arisen. The objective of this study was to assess the impacts of four different urea combinations (Urea, Urea+NI+UI, Urea+NI, Urea+UI) on cotton (Gossypium hirsutum L.) yield and fiber traits. For this purpose, different inhibitors used on urea fertilizer such as nitrification inhibitor (NI), dicyandiamide (DCD), urease inhibitor (UI), N-(n-butyl) thiophosphoric triamide, and a combination of urease (UI) and nitrification inhibitor (NI) (double inhibitor). Additionally, Nitrogen indicators were also used to evaluate the efficiency of these combinations. Two field experiments were conducted in Agrinio and Copaida region, Central Greece during 2019. The total dry weight ranged from 13,027 to 14,481 kg ha-1 in Agrinio area and from 12,567 to 14,136 kg ha-1 in Copaida area. The highest seed cotton yield was recorded under Urea+NI+UI fertilization at 5,145 kg ha-1 application in Copaida area and 5,318 kg ha-1 application in Agrinio area. Also, the total plant nitrogen uptake (kg N ha-1) was affected by the inhibitors NI and UI. The range for Nitrogen Utilization Efficiency (NUtE) index was 9.27 to 23.06. Moreover, results indicated that NI and UI inhibitors have a marked effect on fiber quality such as strength (g Tex-1). In the Mediterranean region of Greece, the combined use of inhibitors UI and NI resulted in higher yield and finest fiber quality

Block Copolymers of Macrolactones/Small Lactones by a "Catalyst-Switch" Organocatalytic Strategy. Thermal Properties and Phase Behavior

Poly(macrolactones) (PMLs) can be considered as biodegradable alternatives of polyethylene; however, controlling the ring-opening polymerization (ROP) of macrolactone (ML) monomers remains a challenge due to their low ring strain. To overcome this problem, phosphazene (t-BuP_4), a strong superbase, has to be used as catalyst. Unfortunately, the one-pot sequential block copolymerization of MLs with small lactones (SLs) is impossible since the high basicity of t-BuP_4 promotes both intra- and intermolecular transesterification reactions, thus leading to random copolymers. By using ROP and the “catalyst-switch” strategy [benzyl alcohol, t-BuP_4/neutralization with diphenyl phosphate/(t-BuP_2)], we were able to synthesize different well-defined PML-b-PSL block copolymers (MLs: dodecalactone, ω-pentadecalactone, and ω-hexadecalactone; SLs: δ-valerolactone and ε-caprolactone). The thermal properties and the phase behavior of these block copolymers were studied by differential scanning calorimetry and X-ray diffraction spectroscopy. This study shows that the thermal properties and phase behavior of PMLs-b-PSLs are largely influenced by the PMLs block if PMLs components constitute the majority of the block copolymers

Block Copolymers of Macrolactones/Small Lactones by a "Catalyst-Switch" Organocatalytic Strategy. Thermal Properties and Phase Behavior

Poly(macrolactones) (PMLs) can be considered as biodegradable alternatives of polyethylene; however, controlling the ring-opening polymerization (ROP) of macrolactone (ML) monomers remains a challenge due to their low ring strain. To overcome this problem, phosphazene (t-BuP_4), a strong superbase, has to be used as catalyst. Unfortunately, the one-pot sequential block copolymerization of MLs with small lactones (SLs) is impossible since the high basicity of t-BuP_4 promotes both intra- and intermolecular transesterification reactions, thus leading to random copolymers. By using ROP and the “catalyst-switch” strategy [benzyl alcohol, t-BuP_4/neutralization with diphenyl phosphate/(t-BuP_2)], we were able to synthesize different well-defined PML-b-PSL block copolymers (MLs: dodecalactone, ω-pentadecalactone, and ω-hexadecalactone; SLs: δ-valerolactone and ε-caprolactone). The thermal properties and the phase behavior of these block copolymers were studied by differential scanning calorimetry and X-ray diffraction spectroscopy. This study shows that the thermal properties and phase behavior of PMLs-b-PSLs are largely influenced by the PMLs block if PMLs components constitute the majority of the block copolymers

Pulsed electromagnetic field - a cultivation practice used to increase soybean seed germination and yield

The aim of the research was to test the effect of pulsed electromagnetic field (PEMF) on soybean seed germination and yield depending on specific field conditions, years of study, exposure duration and frequency. Field trial was conducted on an experimental field of Institute of Field and Vegetable Crops in Novi Sad, Serbia in 2010-2013. Seeds of the soybean (Glycine hispida (Moench)) medium-early cultivar. Valjevka 'were exposed to the PEMF therapy using the impulse generator and strip. Low-frequency (16, 24, 30 and 72 Hz) PEMF was used in the duration of 0, 30, 60 and 90 minutes. Research results indicate that this method can increase seed germination up to 8.00% and yield by 960.5 kg, or 21% in field conditions, which is a significant increase and a solid basis to introduce this practice, primarily in organic production with a very limited use of seed treatment preparations. However, the practice can have an inhibitory effect under an unfavourable combination of exposure duration and frequency. The obtained data were processed using the analysis of variance of three-factorial trials considering all years of study. Due to different meteorological conditions in the study years, analysis of variance was conducted for each year of study and correlations between the tested traits were examined

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