Weed management in soybean with a special focus on the control of purple nutsedge (Cyperus rotundus)

Purple nutsedge (Cyperus rotundus L.) is globally an important perennial weed. Infestations from this species lead to significant losses in yield and quality of crop production. A field study was conducted at Kopaida region in Greece, to evaluate the efficacy of different herbicides for the weed management in soybean. The evaluation of the herbicides was based on the efficacy against purple nutsedge and the effect on soybean biomass production and crop seed yield. Treatments included an untreated control, two pre-emergence applications (with S-metolachlor and pendimethalin), as well as three post-emergence applications (with trifloxysulfuron, bentazone and pyrithiobac sodium). A single application of S-metolachlor maintained the density of purple nutsedge at 15 plants per m2 in soybean and allowed the crop to compete adequately with the weed. S-metolachlor also resulted in a seed yield of 3.26 tn ha-1 , a value 52% higher than the untreated control and 38–45% higher than the other herbicides. The results from this study demonstrated that a combination of high seed density in soybean and effective application of herbicides like S-metolachlor can lead to economically acceptable yields

The effect of nitrogen fertilization on root characteristics of Camelina sativa L. in greenhouse pots

Climate change has made mandatory the introduction of new crops in Greece, such as the cultivation of camelina [Camelina sativa (L.) Crantz]. Nitrogen (N) and the development of root system are two important factors affecting crop growth and yield. Camelina has been studied mainly for its composition and oil. In the present study, root development of camelina crop was thoroughly investigated; mainly in terms of Nitrogen fertilization. Therefore, a camelina greenhouse experiment was established in Western Greece, in the region of Agrinio, in March 2019 in completely randomized design with four treatments, (control 0 ppm N, 30 ppm N, 60, ppm N and 90 ppm N). The N rates had statistically significant affected root density and root surface from 40 to 120 days after treatment (DAT) with highest values at 100 DAT and 90 ppm N, 52.54 cm of root 100 cm-3 and 27.59 cm2 of root 100 cm-3 , respectively. The root volume was significantly affected by N fertilizer from 40 to 100 DAT and highest value was 13.18 cm3 of root 100 cm-3 soil in the 90 ppm at 120 DAT. The plant leaf area was significantly affected by the highest rate of N. Yield per plant had not statistically significant difference with the 60 and with the 90 and highest weight per plant 292.25 g plant-1 in 90 ppm. In conclusion, Ν fertilization significantly affected growth or camelina’s root system after 40 DAT. Plant growth was significantly affected by fertilization and the highest yield and 1,000 seed weight were recorded with the highest amount of N

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

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

Seed and Saponin Production of Organic Quinoa (Chenopodium quinoa Willd.) for different Tillage and Fertilization

Field experiment was conducted to determine the effects of tillage systems and fertilization on growth, yield and quality of quinoa crop (Chenopodium quinoa Willd.). The experiment was laid out in a split-plot design with four replicates, two main plots [conventional tillage (CT) and minimum tillage (MT)] and three sub-plots (fertilization treatments: control, cow manure and compost). The soil porosity (45.5-49.75%) and total nitrogen (0.144-0.173%) were higher in soils subjected to MT system than under CT. In soil porosity, an interaction between fertilization and tillage system was found. The highest leaf area index (4.47-5.03), dry weight (8650-9290 kg ha-1) and root density (1.03-1.21 cm cm-3) were also found in MT. Moreover, there were significant differences between the organic fertilization treatments concerning the LAI, dry weight and root density. The highest seed yield (2485-2643 kg ha-1) and saponin content (0.42-0.45%) were found in cow manure and compost treatments. Also, the highest saponin yield (7.70-12.05 kg ha-1) was found in the MT system. Saponin yield had positive and significant correlation with total N (r=0.866, p<0.001). In quinoa measurements, an interaction between fertilization and tillage system was not found. The present results indicated that MT and organic fertilization increase saponin yield of quinoa

Effects of cropping system (organic and conventional) on the fiber quality index, spinning consistency index and multiplicative analytic hierarchy process of cotton (Gossypium hirsutum L.)

Markets for organically produced high quality cotton (Gossypium hirsutum L.) are projected to increase. Field experiments were conducted in Palamas, Karditsa in Central Greece, to compare the effects of two cropping systems on fiber quality of three cotton cultivars. The experiments, conducted during three years, were laid out in a split plot design with four replicates, two main plots (organic and conventional system) and three sub-plots (cotton cultivars). Findings suggest that fiber quality index (FQI), spinning consistency index (SCI) and multiplicative analytic hierarchy process (MAHP) are three indices that could be integrated in a useful protocol for the evaluation of different cropping systems for cotton cultivation. In particular, our results indicate that in general there was not any superiority of conventional compared to the organic cropping system regarding fiber quality as shown by the above mentioned indices. Regarding the length of the cotton fiber, this was positively correlated with micronair and the uniformity index of the cotton fiber. The organic system resulted to higher values of SCI than the ones of the conventional (1547.9 and 1522.3, respectively). The present 3-years study shows that organic cultivation of cotton can ensure high fiber quality and this was clearly confirmed by means of the several important indices

Effect of Tillage System and Rimsulfuron Application on Weed Flora, Arbuscular Mycorrhizal (AM) Root Colonization and Yield of Maize (Zea mays L.)

Field experiments were conducted to determine the effects of tillage system and rimsulfuron application on weed flora and growth of maize (Zen mays L. Mitic F1) at a site with no history of pesticide use for the last 5 years. A randomized complete block design was employed with three replicates per treatment (conventional tillage without rimsulfuron application (control), no-tillage with rimsulfuron application (NT+Rim) and conventional tillage with rimsulfuron application (CT+Rim)). The lowest leaf area index, dry weight and yield of maize were recorded in NT+Rim plots. In addition, the highest soil bulk density was determined in NT+Rim plots. Moreover, the rimsulfuron application resulted in significant reduction in the root growth and arbuscular mycorrhizal (AM) colonization. The lowest root biomass, root length density, root surface and AM root colonization was found in CT+Rim plots. The lowest weed number and biomass was also observed at CT+Rim plots. Sustainability yield index (SYI) shown that the maize crop is more stable under conventional tillage compared with no-tillage. Our results indicated that root growth was reduced significant by rimsulfuron application but statistically significant lower maize yield was obtained in no-tillage system

MAIZE AND LEGUMES ROOT GROWTH AND YIELD AS INFLUENCED BY ORGANIC FERTILIZATION, UNDER MEDITERRANEAN ENVIRONMENTAL CONDITIONS

Field experiments were conducted to determine the effects of green manures on growth and yield of maize crop. This study also evaluated the effects of two different composts on nitrogen fixation and growth of legume crops. The experiments used a split-plot design with three replicates, three main plots (control - no treatment, compost 1 and compost 2) and three sub-plots (vetch, faba bean and pea). The legumes root growth was affected by the compost application. The highest root diameter, density and dry weight was found under organic fertilization treatments (compost 1 and 2). Nitrogen fixation was also affected by the compost application. The highest root and above-ground N % was found under compost 1 treatment. Moreover, the highest above-ground biomass was found under organic fertilization treatments (compost 1 and 2). Faba bean and vetch had higher biomass in comparison to pea, and both these species accumulated significantly more N than pea. The maize root growth was affected by the organic fertilization. The highest leaf area index, root and aboveground dry weight were found in the plots where vetch was used as a green manure. The lowest yield was found in the plots where pea was used as a green manure. The main reason for differences in maize growth between green manure treatments may be attributed to the rate of N mineralization of each green manure. The results suggest that vetch is the optimum species for use as green manure

Effects of nitrogen fertilizers with two different inhibitors (urease and nitrification) on the survival and activity of earthworms (Octodrilus complanatus)

Earthworms are among the most important species of the soil macrofauna. However, they are very sensitive to inorganic fertilization, more specifically to urea, which makes them a well-known bio-indicator. The objective of this study was to test if a fertilizer with inhibitors could be less destructive to earthworms than urea. In two consecutive years, we studied how new type fertilizers with urea (urea + urease inhibitor, urea + nitrification inhibitor and urea + urease inhibitor + nitrification inhibitor) can differ from urea applied alone and be closer to control (no fertilizer) in terms of the impact on earthworms, verified on different days after application. The measurements concerned earthworms’ mortality, casts and weight. Moreover, some soil properties which are affected by earthworms’ activity, such as exchangeable Ca, cation exchange capacity (CEC) and soil CO2 respiration, were studied. The inhibitors that were used comprised nitrification inhibitor, dicyandiamide (DCD), urease inhibitor, N-(n-butyl) thiophosphoric triamide (NBPT), and double inhibitors, both urease and nitrification inhibitor. The study revealed how a fertilizer with inhibitors could be less destructive to earthworms than urea. Urea with urease inhibitor and urea with urease inhibitor and nitrification inhibitor had the least negative impact on earthworms’ activities. In contrast, urea and urea with nitrification inhibitor caused higher mortality among earthworms than the other fertilizers used

Effects of fertilization and tillage system on growth and crude protein content of quinoa (Chenopodium quinoa Wild.): An alternative forage crop

A field experiment was conducted to determine the effects of fertilization and tillage on growth, yield and quality of quinoa crop (Chenopodium quinoa Willd.). The agronomic performance and nutritive value of quinoa was analyzed in order to define alternatives to local forages for dry-season feeding of ruminants in the Mediterranean region. The experiment was laid out in a split-plot design with two replicates, two main plots [conventional tillage (CT) and minimum tillage (MT)] and sub-plots (fertilization treatments: control, cow manure, inorganic fertilization 100 kg ha(-1) (N1) and inorganic fertilization 200 kg ha(-1) (N2)). The results indicated that quinoa growth was influenced by both tillage and fertilization. The lowest height and dry weight were found under MT. Moreover, the lowest height and dry weight (8205 kg ha(-1) and 8020 kg ha(-1) for CT and MT, respectively) were found under control treatment (no-fertilization). Concerning the nitrogen content there were no significant differences between CT and MT systems. In addition, the highest quinoa nitrogen content was observed for N2 treatment (200 kg N ha(-1)). Moreover, the highest nitrogen content was measured at 150 DAS. Concerning the crude protein content, there were no significant differences between CT and MT systems. In addition, there were significant differences in crude protein between fertilization treatments. The greatest value was observed for N2 treatment. Moreover, the highest crude protein yield (2481 kg ha(-1) and 2356 kg ha(-1) for CT and MT, respectively) and acid detergent fibre (ADF) were found under N2 treatment. In addition, ash was not influenced by both tillage systems and fertilization treatments. Data indicate that quinoa crop could be used as alternative to legumes for protein production to feed ruminant animals