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

Fitossociologia de plantas daninhas do cafezal consorciado com leguminosas

O objetivo deste trabalho foi avaliar a fitossociologia de plantas daninhas em cafezais sob diferentes períodos de consórcio com leguminosas em dois anos de cultivo. Os tratamentos corresponderam à combinação fatorial entre as leguminosas feijão-de-porco (Canavalia ensiformis) e lablabe (Dolichos lab-lab) e períodos de consorciação com cafeeiros aos 30, 60, 90 e 120 dias após o plantio, mais uma testemunha sem leguminosa. O experimento foi composto por nove tratamentos em delineamento de blocos casualizados com quatro repetições. As leguminosas foram semeadas em dezembro de 2007 e outubro de 2008 e cortadas conforme os períodos de consorciação, sendo removidas da entrelinha, para ficarem sob a copa dos cafeeiros. As plantas daninhas foram amostradas nas entrelinhas e na projeção das copas dos cafeeiros, em outubro de 2008 e em outubro de 2009, refletindo o efeito dos tratamentos após um e dois anos de consorciação, respectivamente. As avaliações constaram da similaridade da comunidade, do índice do valor de importância e da importância relativa das plantas daninhas mais frequentes. Nos dois anos agrícolas foram identificadas 17 espécies de plantas daninhas, distribuídas em dez famílias botânicas, sendo mais frequentes as espécies Cyperus rotundus, Paspalum conjugatum, Amaranthus retroflexus e Oxalis latifolia. No primeiro ano, o feijão-de-porco (2,65 t ha-1) produziu mais massa que a lablabe (1,89 t ha-1), e no segundo ano a lablabe produziu mais massa (4,21 t ha-1) que o feijão-de-porco (2,73 t ha‑1). Nas entrelinhas, a diferença da flora de plantas daninhas em relação à testemunha foi maior do que na projeção da copa dos cafeeiros, no final dos dois anos. Em 2008, quando a lablabe ficou por 90 ou 120 dias nas entrelinhas, houve crescimento da importância da tiririca, enquanto em 2009 a importância relativa desta foi mais elevada na testemunha. As entrelinhas do cafeeiro apresentaram massa de matéria seca de plantas daninhas maior do que a projeção da copa, possivelmente devido ao sombreamento proporcionado pelos cafeeiros. A espécie Cyperus rotundus foi a de maior importância nos dois anos, seguida de Paspalum conjugatum, que teve sua importância aumentada de 2008 para 2009, devido à sua adaptação às condições de baixa luminosidade

Allelopathy for Weed Management

A large number of plant and weed species produce secondary metabolites known as allelochemicals, and the process is known as allelopathy. Allelochemicals can be used to control weeds in agricultural systems by using allelopathic crops for intercropping, crop rotation, or mulching. A few important examples of crop species with high allelopathic potential may include (but not limited to) wheat, rice, sorghum, rye, barley, and sunflower. The naturally produced allelochemicals in these crops could be manipulated to suppress weeds and witness an environment-friendly and sustainable agricultural production system. © 2020, Springer Nature Switzerland AG

Carbon nanotube buckypaper reinforced polymer composites: a review

Abstract This review provides valuable information about the general characteristics, processing conditions and physical properties of carbon nanotube buckypaper (BP) and its polymer composites. Vacuum filtration is the most common technique used for manufacturing BP, since the carbon nanotubes are dispersed in aqueous solution with the aid of surfactant. Previous works have reported that mechanical properties of BP prepared by vacuum filtration technique are relatively weak. On the other hand, the incorporation of polymer materials in those nanostructures revealed a significant improvement in their mechanical behavior, since the impregnation between matrix and BP is optimized. Electrical conductivity of BP/polymer composites can reach values as high as 2000 S/m, which are several orders of magnitude greater than traditional CNT/polymer composites. Also, BP can improve remarkably the thermal stability of polymer matrices, opening new perspectives to use this material in fire retardant applications