Fibre hemp is grown for a multitude of end products derived from its cannabinoids, seed, fibre and wooden core. A key factor that influences the quantity and quality of the production of hemp is nitrogen fertilization. The aim of this study was to determine the response of five well-adapted industrial hemp cultivars to different nitrogen fertilization rates during the 2016 growing season. The experiment was laid out in a split-plot design with two replicates, five main plots (hemp cultivars: 'Bialobrzeskie', 'Tygra', 'Felina 32', 'Sanhtica 27', 'Futura 75') and sub-plots [fertilization treatments: control (N0), fertilizer 46-0-0 at 120 kg ha -1 (N1), 180 kg ha -1 (N2), 240 kg ha -1 (N3)]. For the computation of height, biomass yield, stem dry weight, length and weight of the inflorescences and mean seed weight, 10 plants were randomly selected in each plot. In general, increasing N fertilization rate positively impacts hemp biomass yield, stem dry weight, plant height, and inflorescence indices. Biomass yield, stem dry weight and inflorescence weight increased by 37.3%, 48.2% and 16%, respectively, with the application of 240 kg N ha -1 when compared with the unfertilized control. Plant height and inflorescence length increased from 1.66 to 1.76 m and from 66.2 to 82.9 cm, respectively, with the application of the higher N rate compared with the control, while there were no significant differences between the fertilization treatments for mean seed weight. The varieties 'Tygra' and 'Futura 75' showed the highest values for all the measurement characters. Our results indicate that hemp responded well to the addition of N fertilizer.

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). 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.

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 -1for 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.

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In recent years, quinoa (Chenopodium quinoa Willd.) has attached the interest as a multi-purpose crop. A 3-year field experiment was conducted to determine the effects of tillage systems and fertilization on nitrogen uptake and use efficiency of quinoa crop. The experiment was laid out in a split-plot design with two replicates, two ) were found in N2. Nitrogen harvest index and nitrogen utilization efficiency were up to 60% lower and 40% lower, respectively, in inorganic treatments than in the control. Rates of nitrogen higher than 100 kg N ha -1 (N1) did not increase the nitrogen agronomic efficiency. Regarding apparent nitrogen recovery efficiency, the higher values observed under inorganic fertilization and being greater than 100%. The highest rates of change of nitrate reduction in soil (-0.108 to -0.188 N% day -1 ) and nitrogen increase in plant (0.025 to 0.027 N% day -1 ) were observed under N2 treatment. As a conclusion, quinoa has a high capacity to take up nitrate from the soil, but presents lower nitrogen remobilization from the vegetative parts into the seeds under high nitrogen supply.

There is growing consideration among farmers and researchers regarding the development of natural herbicides providing sufficient levels of weed control. The aim of the present study was to compare the efficacy of four different pelargonic acid products, three essential oils and two natural products’ mixtures against L. rigidum, A. sterilis and G. aparine. Regarding grass weeds, it was noticed at 7 days after treatment that PA3 treatment (pelargonic acid 3.102% w/v + maleic hydrazide 0.459% w/v) was the least efficient treatment against L. rigidum and A. sterilis. The mixture of lemongrass oil and pelargonic acid resulted in 77% lower dry weight for L. rigidum in comparison to the control. Biomass reduction reached the level of 90% as compared to the control in the case of manuka oil and the efficacy of manuka oil and pelargonic acid mixture was similar. For sterile oat, weed biomass was recorded between 31% and 33% of the control for lemongrass oil, pine oil, PA1 (pelargonic acid 18.67% + maleic hydrazide 3%) and PA4 (pelargonic acid 18.67%) treatments. In addition, the mixture of manuka oil and pelargonic acid reduced weed biomass by 96% as compared to the control. Regarding the broadleaf species G. aparine, PA4 and PA1 treatments provided a 96–97% dry weight reduction compared to the corresponding value recorded for the untreated plants. PA2 (pelargonic acid 50% w/v) treatment and the mixture of manuka oil and pelargonic acid completely eliminated cleaver plants. The observations made for weed dry weight on the species level were similar to those made regarding plant height values recorded for each species. Further research is needed to study more natural substances and optimize the use of natural herbicides as well as natural herbicides’ mixtures in weed management strategies under different soil and climatic conditions.

E. colona is a C4 annual summer grass which is troublesome to major summer annual and perennial crops. Due to recent complaints by the farmers, the objectives of the present study were to evaluate the efficacy of penoxsulam, profoxydim, cycloxydim, cyhalofop-butyl, florpyrauxifen-benzyl and glyphosate against six E. colona accessions, and also to evaluate the response of these accessions to different rates of glyphosate in a dose-response experiment. In the first experiment, herbicides were applied at their maximum recommended label rates, while in the dose-response experiment, glyphosate was applied at six doses corresponding to 0, 1/4X, 1/2X, X, 2X, and 4X of the recommended rate. The dry weight of the biotypes TH8 and TH7 treated with profoxydim was 66% and 68% of the untreated control, respectively. The efficacy of cyhalofop-butyl against three accessions was lower than 30%, while two accessions were susceptible to this herbicide. The efficacy of penoxsulam against the biotypes ET2 and ET4 was lower than 10%, while dry weight of FT5 and TH8 was only reduced by 23%–28% as compared to the control. Cycloxydim application provided control higher than 75% at 21 days after treatment (DAT) of three accessions, while the majority of E. colona accessions was adequately controlled by the application of florpyrauxifen-benzyl. The response of the different accessions to glyphosate varied. The results of the glyphosate dose-response experiment revealed that the GR50 values of the resistant E. colona accessions ET2 and ET4 were up to 1098 and 1220 g a.e. ha−1 of glyphosate, respectively, whereas the GR50 value of the susceptible accession (FT5) was only 98 g a.e. ha−1. The resistance indices of ET2 and ET4 were 12.4 and 11.2, respectively, indicating that they have already developed resistance to glyphosate. Three more accessions could be also of developing resistant to glyphosate. This is the first report of glyphosate resistance from E. colona accessions in Greece, with indications of multiple resistance also present. Further research is needed in order to evaluate the efficacy of several herbicides under different soil and climatic conditions, conduct baseline sensitivity studies, reveal the evolvement of resistance patterns to glyphosate from accessions of Echinochloa spp., and search for alternative options of weed management in annual and perennial crops due to the clear indications of multiple resistance situations.

Nitrogen (N) management remains a global challenge for the sustainability of diversified farming systems. Field crops are often over-supplied with nitrogen by farmers aiming to high productivity. Although the increase of nitrogen rates leads in many instances to high yields, degree of effectiveness for nitrogen use remains low. Urease and nitrification inhibitors are technologies which have been present in the fertilizers market at least 50 years. Inhibitors exploitation ensures long-term nitrogen release and improved N-uptake by plants and N-storage in seeds and silage. Avail of inhibitors, such as the decline of nitrogen leaching in form of NO3−, reduction of emissions in NH3 form, and rise of yield, are some of the desirable attributes that are derived from their integration in fertilization schedules. This review reports the evaluation of applied nitrogen, with inhibitors, and field crops based on nitrogen indices. The examined N-indicators include Nitrogen use efficiency (NUE), Nitrogen Utilization Efficiency (NUtE,) Nitrogen Agronomic Efficiency (NAE), Nitrogen Harvest Index (NHI), and N uptake. This review gathered all, to the best of our knowledge, available data regarding the utilization of nitrification and urease inhibitors under an exclusively agronomic perspective. Either dual or single use of nitrification and urease inhibitors has been reported to significantly increase yield components and promote nitrogen uptake. To conclude, the assessment of N-related indices is vital to promoting sustainability in diversified farming systems, while the integration of inhibitors in national N fertilizations schemes may contribute to system profitability through enhancement of N-supply to crops.