Small-plot Field Trials Research Articles

The effect of nitrogen fertilisation, biostimulant application and extra-root phosphorus fertilization on yield and quality of malting barley grain

A series of small-plot field trials were conducted between 2019 and 2021 with the spring barley variety Francin. The impact of Vital Root and YaraVita KOMBIPHOS on the grain quality of malting barley at varying nitrogen fertilization rates (50 kg·ha-1 N, 70 kg·ha-1 N, 90 kg·ha-1 N, and 110 kg·ha-1 N) was investigated. The following parameters were evaluated: grain size, thousand grain weight, specific weight, starch content, and protein content. The portion of grain <2.5 mm, weight of thousand grains, and specific weight decreased with increasing nitrogen fertilization. Additionally, a decrease in starch content was observed with an increase in protein content in the grain. The application of Vital Root and YaraVita KOMBIPHOS at lower nitrogen fertilization rates up to 70 kg·ha-1 N had a positive effect on grain quality.

Cotton host resistance as a tool for managing Rotylenchulus reniformis in Louisiana.

The reniform nematode, Rotylenchulus reniformis, is a major yield-limiting pest of upland cotton (Gossypium hirsutum) in the United States that has been steadily increasing in incidence in many states. Reniform nematode-resistant cotton cultivars have recently become commercially available for cotton producers; however, few field trials have evaluated their efficacy as a nematode management tool. The aim of this study was to evaluate reniform nematode population development, plant growth, and seed cotton yield of reniform nematode-resistant cotton cultivars in two nematode-infested fields in Louisiana. Replicated small-plot field trials were conducted in St. Joseph, LA (NERS field) and Winnsboro, LA (MRRS field) during the 2022 and 2023 growing seasons. In 2022, cultivars evaluated included: (1) DP 1646 B2XF (susceptible/tolerant), (2) DP 2141NR B3XF (resistant), (3) PHY 332 W3FE (resistant), (4) PHY 411 W3FE (resistant), and (5) PHY 443 W3FE (resistant). In 2023, an additional susceptible cotton cultivar, PHY 340 W3FE, was also included. All nematode-resistant cotton cultivars evaluated provided suppression of reniform nematode population development relative to that of the susceptible cotton cultivars, with suppression of nematode soil population densities at harvest ranging from 49 - 81% relative to DP 1646 B2XF. The resistant cultivar PHY 411 W3FE provided the most consistent suppression of reniform nematode population development, reducing reniform nematode soil population densities at harvest in both field locations and both trial years. In contrast, DP 2141NR B3XF only reduced soil population densities at harvest in the NERS field in 2023. Despite relatively consistent nematode suppression and improvements in plant vigor ratings and canopy coverage associated with the resistant cotton cultivars, a yield increase was only observed with PHY 332 W3FE and PHY 411 W3FE planted at the NERS field in 2023. Despite strong resistance to reniform nematode in the evaluated cotton cultivars, nematode soil population densities still increased during the growing season in plots planted with resistant cotton cultivars, emphasizing the need for additional management tactics to use alongside host resistance. This study indicates that new reniform nematode-resistant cotton cultivars show promising potential to reduce nematode population development during the growing season in Louisiana.

Effects of SmartStax® and SmartStax® PRO maize on western corn rootworm (Diabrotica virgifera virgifera LeConte) larval feeding injury and adult life history parameters.

Field-evolved resistance of the western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, to Bacillus thuringiensis Berliner (Bt) proteins Cry3Bb1 and Cry34/35Ab1 (now classified as Gpp34Ab1/Tpp35Ab1) expressed in the pyramid SmartStax® has been documented in areas of the United States (U.S.) Corn Belt. SmartStax® PRO is a recently registered rootworm-active pyramid containing the same Bt proteins expressed in SmartStax® plus DvSnf7 dsRNA. Little to no published data is available comparing efficacy of the technologies or potential effects of dietary exposure on adult WCR fitness. Therefore, experiments were conducted to compare effects of adult WCR dietary exposure to SmartStax® and SmartStax® PRO on life history parameters and efficacy of the technologies in the field with both Bt-susceptible and Bt-resistant WCR populations. WCR life history parameters evaluated included adult longevity, head capsule width, egg production, and egg viability. Results of small-plot field trials indicated that both technologies provided a high level of root protection when a Bt-susceptible WCR population was present. Root protection was reduced on SmartStax® but maintained on SmartStax® PRO when WCR Bt resistance occurred. Lifetime egg production was the key life history parameter that was significantly reduced when either Bt-susceptible or Bt-resistant adult WCR were fed SmartStax® or SmartStax® PRO diet. A potential fitness advantage was apparent as egg production was significantly higher in the Bt-resistant than Bt-susceptible population. The similar response by the Bt-susceptible WCR population to SmartStax® and SmartStax® PRO indicates that results were caused by sublethal dietary exposure to Bt proteins. Adult size (males < females) and egg viability (high: >95%) were not significantly different among treatments but longevity results were inconsistent between years. Collectively, the field efficacy and life history parameter data expand existing knowledge of SmartStax® and SmartStax® PRO technologies, which will inform practical WCR resistance management programs.

Assessment of the influence of soil inoculation on changes in the adaptability of maize hybrids

The aim of this paper is to present the results of the field trial carried out to collect and assess data on the interaction of maize (Zea mays L) genotypes and beneficial microorganisms. The small plot field trial consisting of untreated control plots and plots treated with biostimulants was conducted in three consecutive years (2019, 2020 and 2021). Yield is a particularly important trait from the aspect of maize breeding as well as maize production; therefore, the present study focused more closely on how it was influenced by the biostimulant treatments. The level of grain yield, grain moisture content at harvest and grain dry-matter content were observed and recorded as the components of yield. The nutritional value of kernels was also tested, and protein, oil and starch contents were analysed as the most important components of this trait. The results reflected that the treatment with biostimulants constituted from beneficial microorganisms can be listed among the factors influencing the grain yield, in addition to the seasonal effect, the genotype and the nutrient supply of the soil. The treatment with biostimulants, even on its own among the factors, had an impact on the quantity and components of yield, and on the characteristics determining the kernel nutritional value. The interaction between the genotypes and the interacting microorganisms is of specific importance. The most spectacular result was attained with the application of one of the biostimulants leading to elevated grain yield in 75% of the maize genotypes in the study, along with a kernel nutritive value equal to the control group over all of the three years of the trial.

The effect of drip irrigation for potatoes on soil nitrogen dynamics

The effects of potato drip irrigation on soil nitrogen dynamics and potato yield was studied in small-plot field trials. The trials were evaluated at during three experimental times seasons (2016-2018). Four variants of irrigation were determined, ie non-irrigated, 60, 65 and 70 ASWC (Available Soil Water Capacity). At the same time, two pre-planting fertilization dates were set at a maximum of 120 kg N/ha a in divided i.e. 60 kg N/ha before planting and 60 kg N/ha by fertigation during vegetation. Pre-planting crop fertilization or in-season fertigation did not have any significant effect on the potato yields of most variants. In all studied parameters, the positive beneficial effect of irrigation was recorded and compared to the non-irrigated control. The mitigation of drought stress in plants during the growing season is the most important advantage of irrigation. In the trials, on average across all years and varieties, the yield of the irrigated variant increased by 41 % compared to the non-irrigated variant. Maintaining optimal soil moisture has a favourable effect use of applied fertilizers. The highest mineral nitrogen content in the soil was recorded for the variant without irrigation. Considering the increased use of nitrogen fertilizers, the subsurface drip line appeared to be optimal for the creation of suitable conditions for nitrogen availability to plants in the root zone.

Effects of plant density, seed spacing, and seed treatment on thrips injury to cotton

Previous observations in small-plot field trials in Tennessee suggest that thrips injury is higher in plots with lower plant densities and when singular plants are spatially isolated and uniformly distributed compared to a group of plants that are clumped together; however, research documenting this is limited. Thus, studies were performed in Jackson and Milan, TN across two years (2020, 2021). Both studies had fungicide-treated seed planted with or without an imidacloprid insecticide seed treatment. The first study investigated the effects of plant density by planting seed at rates considered to be low, normal, high, and very high. The second study investigated the effects of seed placement strategies with seed planted at the same density. Cotton plates were used to plant seed to result in singular plants that were spatially isolated and uniformly planted or clumped, “hill-dropped” plants. Results from the plant density tests showed thrips injury ratings were higher as the plant density decreased. At two test sites, the number of adult thrips was higher in plots with lower plant densities, indicating that thrips were more concentrated on individual plants. However, high thrips pressure and unfavorable growing conditions at the other sites seemed to overwhelm the potential effects of plant populations. Results from initial thrips injury ratings in the seed spacing study showed significantly higher injury for singular, uniformly distributed plants than plants in a hill (i.e., cluster); however, additional research is needed because one test was lost. Future research evaluating oviposition rates on recently emerged seedlings could help explain why decreased thrips injury occurs when plant densities are relatively high.

Building a UAV Based System to Acquire High Spatial Resolution Thermal Imagery for Energy Balance Modelling

High spatial resolution and geolocation accuracy canopy evapotranspiration (ET) maps are well suited tools for evaluation of small plot field trials. While creating such a map by use of an energy balance model is routinely performed, the acquisition of the necessary imagery at a suitable quality is still challenging. An UAV based thermal/RGB integrated imaging system was built using the RaspberryPi (RPi) microcomputer as a central unit. The imagery served as input to the two-source energy balance model pyTSEB to derive the ET map. The setup’s flexibility and modularity are based on the multiple interfaces provided by the RPi and the software development kit (SDK) provided for the thermal camera. The SDK was installed on the RPi and used to trigger cameras, retrieve and store images and geolocation information from an onboard GNSS rover for PPK processing. The system allows acquisition of 8 cm spatial resolution thermal imagery from a 60 m height of flight and less than 7 cm geolocation accuracy of the mosaicked RGB imagery. Modelled latent heat flux data have been validated against latent heat fluxes measured by eddy covariance stations at two locations with RMSE of 75 W/m2 over a two-year study period.

Supporting wild pollinators in agricultural landscapes through targeted legume mixtures

Insect-pollinated legumes are rich in plant-based proteins making them a vital constituent of sustainable healthy diets for people and livestock. Furthermore, they deliver or support a range of ecosystem services that underpin agricultural production and their prevalence in agricultural landscapes is likely to increase. Under typical implementation and management, the value of legumes to pollinators has, however, been questioned. Through exploring a range of legume crops, grown as monocultures and mixtures, this study aims to identify multifunctional legume cropping systems that optimise forage availability for a diversity of wild pollinators whilst delivering a wide range of agronomic and environmental benefits. This study innovatively explores legume mixtures concurrently with monocultures of the component species using replicated small-plot field trials established in two geographical locations. Observational plots assessed the richness and abundance of floral resources, and wild pollinators (i.e. bumblebees and hoverflies) throughout the peak flowering period. Densely flowering, highly profitable legumes (e.g. Trifolium incarnatum and Trifolium mixes) supported abundant and rich pollinator assemblages. The functional makeup of floral visitors was strongly influenced by flower structure and hoverflies, with their shorter proboscises, were largely constrained to legumes with shallower corolla and open weed species. Floral richness was not a key driver of pollinator assemblages; however, clear intra-specific differences were observed in flowering phenology. Combining functionally distinct legumes with respect to flower structure and phenology, will support a wider suite of pollinating insects and help stabilise the temporal availability of forage. For highly competitive legumes (e.g. Vicia faba and Vicia sativa), planting in discrete patches is recommended to reduce the risk of less competitive species failing in mixtures. Legumes can provide valuable forage for pollinators; however, they fail to meet all resource requirements. They should therefore be used in combination with agri-environmental measures targeted to promote early-season forage (e.g. hedgerows and farm woodlands), open flowers for hoverflies, saprophytic hoverfly larval resources (e.g. ditches and ponds) and nesting habitats (e.g. undisturbed field margins).

ОБ ЭФФЕКТИВНОСТИ ОБРАБОТКИ СЕМЕННЫХ КЛУБНЕЙ КАРТОФЕЛЯ ЭТИЛЕНОМ

Potato (Solanum tuberosum L.) is one of the most important agricultural crops in Russia. Potato tubers contain protein of high biological value, starch and vitamins necessary for humans. There are various ways to increase the yield of the crop, currently, it is mainly due to application of mineral fertilizers. However, this method has limitations, since an increase in doses of fertilizers is associated with deterioration of consumer quality and culinary indicators of tubers. One possible alternative is the gassing of seed tubers with ethylene. This phytohormone is widely used on various crops, but its effect on potatoes has not yet been fully studied. It is known that depending on the treatment modes it can act as both a stimulator and an inhibitor of tuber germination. We have developed a new method for increasing potato yield based on the property of phytohormone ethylene to suppress apical dominance at the beginning of tuber germination and thereby promote the formation of a larger number of lateral sprouts from which additional stems are formed. The aim of the research was to determine the effect of seed potato tubers treatment with ethylene on their biochemical parameters, as well as on the growth, development and tuber yield of the crop. The experiments were conducted on the basis of storage facilities of JSC Ozyory (Ozyorsky District, Moscow Province). For gassing, the adapted technology of the company «Restrain Company Ltd» (Great Britain) was used. The storage temperature for seed potatoes was 4 °С; the period of ethylene gassing was from November to the end of April. The treatment with ethylene was stopped 3-5 days before planting. Ethylene-treated potatoes were planted in 2015-2017 on the territory of the Moscow region. A two-factor small-plot field trial was conducted in the Lyuberetsky District at the Korenevo experimental base, the soil was sod-podzolic sandy loam. Seed tubers of potato varieties Lady Claire (early), Gala (mid-early) and Saturna (mid-late) were treated with ethylene. In the control, ethylene was not applied. A three-factor large-scale (40 ha) field trial was performed during commercial potato growing of the same varieties (JSC Ozyory, Ozyorsky District, Moscow Province, sod-podzolic loamy soil). We used the same treatment as in experiment 1 added with 2-3 irrigation (200 m3/ha). In both experiments, the potatoes were planted in the first decade of May (45 thousand tubers per hectare, row spacing width of 75 cm; N60P120K120 applied locally). Biochemical, biometric parameters, and potato yield were measured.It was found that the treatment of potato seed tubers with ethylene at 4 °С changes their biochemical parameters, i.e., dry matter content decreases by 0.2-0.5 % while sucrose increases by 0.03-0.08 %, which indicates the breakdown of tubers’ dormancy. There was a suppression of apical dominance and the formation of more lateral sprouts on tubers, a greater number of stems per plant (by 19.9-36.0 %), and an increase in number of tubers per plant (by 6.3-19.0 %, especially in the Gala variety). Potato yield increased by 9.9-19.0 % depending on the variety, growing area and irrigation. The produced potato tubers were more uniform and marketable. Depending on the common agricultural level and the technology used at a farm, a differentiated approach is proposed in choosing the planting rate. If low agricultural technology and no irrigation, the planting rate of ethylene-treated tubers reduced by 10-15 % allows for the same yield as that for high technology and irrigation.

EFFICIENCY OF ETHYLENE APPLICATION ON SEED POTATO TUBERS

Potato (Solanum tuberosum L.) is one of the most important agricultural crops in Russia. Potato tubers contain protein of high biological value, starch and vitamins necessary for humans. There are various ways to increase the yield of the crop, currently, it is mainly due to application of mineral fertilizers. However, this method has limitations, since an increase in doses of fertilizers is associated with deterioration of consumer quality and culinary indicators of tubers. One possible alternative is the gassing of seed tubers with ethylene. This phytohormone is widely used on various crops, but its effect on potatoes has not yet been fully studied. It is known that depending on the treatment modes it can act as both a stimulator and an inhibitor of tuber germination. We have developed a new method for increasing potato yield based on the property of phytohormone ethylene to suppress apical dominance at the beginning of tuber germination and thereby promote the formation of a larger number of lateral sprouts from which additional stems are formed. The aim of the research was to determine the effect of seed potato tubers treatment with ethylene on their biochemical parameters, as well as on the growth, development and tuber yield of the crop. The experiments were conducted on the basis of storage facilities of JSC Ozyory (Ozyorsky District, Moscow Province). For gassing, the adapted technology of the company «Restrain Company Ltd» (Great Britain) was used. The storage temperature for seed potatoes was 4 °С; the period of ethylene gassing was from November to the end of April. The treatment with ethylene was stopped 3-5 days before planting. Ethylene-treated potatoes were planted in 2015-2017 on the territory of the Moscow region. A two-factor small-plot field trial was conducted in the Lyuberetsky District at the Korenevo experimental base, the soil was sod-podzolic sandy loam. Seed tubers of potato varieties Lady Claire (early), Gala (mid-early) and Saturna (mid-late) were treated with ethylene. In the control, ethylene was not applied. A three-factor large-scale (40 ha) field trial was performed during commercial potato growing of the same varieties (JSC Ozyory, Ozyorsky District, Moscow Province, sod-podzolic loamy soil). We used the same treatment as in experiment 1 added with 2-3 irrigation (200 m3/ha). In both experiments, the potatoes were planted in the first decade of May (45 thousand tubers per hectare, row spacing width of 75 cm; N60P120K120 applied locally). Biochemical, biometric parameters, and potato yield were measured.It was found that the treatment of potato seed tubers with ethylene at 4 °С changes their biochemical parameters, i.e., dry matter content decreases by 0.2-0.5 % while sucrose increases by 0.03-0.08 %, which indicates the breakdown of tubers’ dormancy. There was a suppression of apical dominance and the formation of more lateral sprouts on tubers, a greater number of stems per plant (by 19.9-36.0 %), and an increase in number of tubers per plant (by 6.3-19.0 %, especially in the Gala variety). Potato yield increased by 9.9-19.0 % depending on the variety, growing area and irrigation. The produced potato tubers were more uniform and marketable. Depending on the common agricultural level and the technology used at a farm, a differentiated approach is proposed in choosing the planting rate. If low agricultural technology and no irrigation, the planting rate of ethylene-treated tubers reduced by 10-15 % allows for the same yield as that for high technology and irrigation.

Dynamics of the Degradation of Acetyl-CoA Carboxylase Herbicides in Vegetables.

(1) Background: Aryloxyphenoxy-propionates and cyclohexanediones are herbicides most widely used in dicot crops worldwide. The main objective of the study was to determine the dynamics of herbicide residues in carrot, lettuce, cauliflower, and onion in order to suggest a low level of residues in harvested vegetables. (2) Methods: Small plot field trials were carried out in four vegetables in the Czech Republic. The samples of vegetables were collected continuously during the growing season. Multiresidue methods for the determination of herbicide residues by LC-MS/MS were used. Non-linear models of degradation of individual herbicides in vegetables were calculated using the exponential decay formula. Action GAP pre-harvest intervals for the 25% and 50% maximum residue limit (MRL) and 10 µg kg−1 limit (baby food) were established for all tested herbicides. (3) Results: The degradation dynamics of fluazifop in carrot, onion, and cauliflower was significantly slower compared to quizalofop and haloxyfop. The highest amount (2796 µg kg−1) of fluazifop residues was detected in cauliflower 11 days after application. No residue of propaquizafop and cycloxydim was detected in any vegetable samples. (4) Conclusions: Aryloxyphenoxy-propionate herbicide (except propaquizafop) could contaminate vegetables easily, especially vegetables with a short growing season. Vegetables treated with fluazifop are not suitable for baby food. Lettuce and cauliflower treated by quizalofop are not suitable for baby food, but in onion and carrot, quizalofop could be used. Propaquizafop and cycloxydim are prospective herbicides for non-residual (baby food) vegetable production.

Progress Toward an Attract-and-Kill Device for Asian Citrus Psyllid (Hemiptera: Liviidae) Using Volatile Signatures of Citrus Infected With Huanglongbing as the Attractant.

Asian citrus psyllid, Diaphorina citri (Kuwayama), preferentially orient toward citrus hosts infected with the phytopathogenic bacterium, Candidatus liberibacter asiaticus (CLas) the agent of citrus greening (Huanglongbing, HLB), compared to uninfected counterparts. We investigated whether this preference for the odors of infected plants could be useful for the development of an attract-and-kill (AK) device for D. citri. Twenty-nine blends of volatile organic compounds derived from the odor of citrus infected with CLas were tested in laboratory olfactometer tests, and two blends were also assessed under field conditions. A seven component blend of tricosane: geranial: methyl salicylate: geranyl acetone: linalool: phenylacetaldehyde: (E)-β-ocimene in a 0.40: 0.06: 0.08: 0.29: 0.08: 0.06: 0.03 ratio released from a proprietary slow-release matrix attracted twice more D. citri to yellow sticky traps compared with blank control traps. The attractive blend was subsequently co-formulated with spinosad insecticide into a slow-release matrix to create a prototype AK formulation against D. citri. This formulation effectively reduced the population density of D. citri up to 84% as measured with tap counts when deployed at a density of eight 2.5 g dollops per tree as compared with untreated controls in small plot field trials conducted in citrus orchards. Psyllid populations were not statistically affected at a deployment rate of four dollops per tree. Our results indicate that an AK formulation incorporating spinosad and a volatile blend signature of citrus greening into a slow-release matrix may be useful to suppress D. citri populations.

In-furrow fluopyram nematicide efficacy for Rotylenchulus reniformis management in cotton production

In-furrow nematicide application is a primary method for managing Rotylenchulus reniformis (Linford and Oliveira, 1940) in cotton (Gossypium hirsutum L.). Fluopyram is a relatively new non-fumigant nematicide and field data is needed to determine its efficacy at managing R. reniformis (reniform nematode, RN) in cotton production. To investigate, two experiments, consisting of multiple small plot field trials per experiment, were conducted in Quincy, FL. The first experiment evaluated optimal fluopyram application rate by comparing 0, 105, 131, 158, 184, and 236 g a.i./ha. The second experiment compared aldicarb, a common non-fumigant nematicide in cotton, with two fluopyram formulations, one at 184 g a.i./ha and another at 199 g a.i./ha. In the first experiment, fluopyram reduced RN abundances in 2 of 3 trials, and 236 g fluopyram/ha provided the most consistent management of RN soil populations, while 158 and 184 g fluopyram/ha were effective in one trial each. At 131 g a.i./ha or above, any fluopyram rate tested improved cotton yield compared with untreated in one trial, but did not affect yield in any other trial. In the second experiment, aldicarb reduced RN egg abundances in roots compared with untreated or fluopyram treatments. None of the nematicides affected yield in the second experiment. In summary, fluopyram was inconsistent for managing RN on cotton.

Cyantraniliprole: A new insecticidal seed treatment for U.S. rice

Current pest management practices for the rice water weevil (Lissorhoptrus oryzophilus Kuschel) and the Mexican rice borer (Eoreuma loftini Dyar) in U.S. rice rely heavily on a small number of insecticides. Thus, additional products are needed to delay resistance development and replace products no longer available to farmers. Evaluation of novel and widely used insecticidal seed treatments was conducted in eight small plot field trials from 2015 to 2019 in Louisiana and Texas. Treatments evaluated included the insecticides cyantraniliprole, chlorantraniliprole, thiamethoxam, and clothianidin. Seed treated with chlorantraniliprole and seed treated with both cyantraniliprole and thiamethoxam together provided the best control of L. oryzophilus across trials. Thiamethoxam and clothianidin seed treatments did not provide satisfactory control of L. oryzophilus. Only chlorantraniliprole seed treatment controlled E. loftini. Improved yield was recorded from plots treated with chlorantraniliprole or cyantraniliprole + thiamethoxam across trials from 2017 to 2019 over fungicide only controls. Yield differences among treatments were not detected in 2015–2016 trials. Registration of cyantraniliprole seed treatment for use in U.S. rice provides a new tool for diversification of pest management practices and insecticide resistance management.

Chlorophyll Fluorescence Kinetics May Be Useful to Identify Early Drought and Irrigation Effects on Photosynthetic Apparatus in Field-Grown Wheat

To assess the reliability and sensitivity of non-invasive optical methods to detect the early effects of water deficit in the field, we analyzed the time-series of non-invasive measurements obtained in a dry season in a representative collection of wheat genotypes grown in small-plot field trials, in non-irrigated and irrigated variants. Despite a progressive water deficit and significant yield loss, the measurements indicated very minor changes in chlorophyll content or canopy cover. This corresponded well to the insignificant differences in spectral reflectance normalized difference vegetation index (NDVI) values. On the other hand, we identified the significant and rapid response of fast fluorescence kinetics data following the onset of irrigation. Analysis of parameters showed the main effects of drought were associated with changes in the amplitude of the I–P phase of the OJIP transient, indicating changes at the level of photosystem I and beyond. Statistical analyses identified the integrative parameter performance index PItot as the most sensitive parameter, which well-reflects the differences in responses of the genotypes to water deficit. Our results suggest that focusing on photosynthetic functions detected by the rapid chlorophyll fluorescence records can provide more accurate information on the drought stress level, compared to the structural data obtained by absorbance or reflectance measurements.

Examination of drought stress of two genotype maize hybrids with different fertilization

In the growing season of 2019, we analysed stress resulting from climatic factors on maize hybrids of different genotypes, with the aim of gaining a better understanding of the physiological responses of each hybrid, which might support the elaboration of a cost-effective irrigation plan.&#x0D; Our experiments were carried out at the Látókép Experimental Station of the University of Debrecen on calcareous chernozem soil in a small-plot long-term field trial with strip plot design. In the scope of the experiment, N-fertilizer doses were applied as basic fertilizer and top-dressing in addition to the non-fertilized (control) treatment. The 60 and 120 kg N/ha doses applied as basic fertilizers in the spring were followed by top-dressing in the V6 phenophase with a +30 kg N/ha dose. Measurements were carried out with the involvement of the Renfor early (FAO 320) and Fornad (FAO 420) late maturity hybrids-&#x0D; The stomata of the plants became more and more closed with the progression of the phenological phases; their stomatal conductance decreased. However, the hybrids responded differently to environmental stress. In the case of the Renfor hybrid, the highest conductance (669 mmol/m2-s) was recorded in the V12 phenophase with the 150 kg N/ha treatment. The stomata were more open due to the high turgor pressure, allowing plants to evaporate properly. The plant was in its worst physiological condition on 2nd July, at the time of the appearance of the last leaf in the case of the 120 kg N dose (224 mmol/m2-s). The value measured in the V12 phenophase has already shown that the stomata were closing due to the self-regulating system of the plant. It would have been necessary to dispense irrigation water following the measurement. This confirms the finding that water stress can be prevented by measuring stomatal conductance.&#x0D; In the case of the Fornad hybrid, stomatal conductance was the highest on 12th June (630 mmol/m2-s) in the 90 kg N/ha treatment and it was the lowest (183 mmol/m2-s) in VT (emergence of the last leaf) phenophase in the 60 kg N/ha treatment. In this case, the appropriate time for applying irrigation water would have been early July, when the conditions for the plants were still adequate. Subsequently, the stomata began to close due to a reduction of the water resources available to them.&#x0D; There was a significant correlation between soil moisture and stomatal conductance, as well as between temperature and stomatal conductance.

Effect of Sulphur Foliar Application on Yield and Grain Quality of Selected Malting Barley Varieties

The aim of the experiment was to assess the influence of foliar application of sulphur on grain yield, N-substances and sulphur content in the grain. The content of dimethylsulphide (DMS) and its precursors (PDMS) of malt were determined. The study was performed in the form of a small-plot field trial between the years of 2010 and 2012, at a field trial station in Žabčice (South Moravia). Three malting barley varieties for the production of Czech beer (Aksamit, Bojos and Radegast) and three malting barley varieties for the production of export beer (Prestige, Jersey and Sebastian) were tested in that period. Sulphur (8 kg S per ha) was applied on leaves in the form of a suspension of micronized elementary sulphur with bentonite in stem elongation – first node (BBCH 31) and before end of heading (BBCH 57) of growth stages. Sulphur fertilization in both vegetation phases increased significantly grain yield and the most significant increase was detected after the application in BBCH 57. On the other hand, there was no accumulation of sulphur in the grain nor an increase in N‑substances content. Sulphur fertilization did not increase DMS and PDMS content of malt as well.

The effect of stand structure on the grain quality of spring barley

The results of 81 different crop management practices in spring barley grown in small-plot field trials on fertile soils in central Moravia were assessed during 2014–2016 with the aim to achieve the highest gross margin (GM – calculated as the difference between revenues and direct costs). GM was most affected by protein content in the grain below 12% corresponding to malting quality. Analyses identified greater determination level of non-linear relationships between stand structure elements and the content of nitrogen substances in the grain. This indicates that the probability of obtaining high quality malting barley is increased when a high level of sinks (number of grains/m&lt;sup&gt;2&lt;/sup&gt;) corresponding to availability of sources, mainly water, is formed by optimal plant density (300–400/m&lt;sup&gt;2&lt;/sup&gt;) and balanced combination of both structural elements of crop stand, i.e. – number of spikes per plant (2–4) and number of grains per spike (18–26). In case that the high level of sinks will be formed predominantly by one element, the risk of higher protein content in grain increases. This constitutes the requirement of early sowing and uniform, synchronized tillering and efficient use of nitrogen fertilizers.

Szarvasi-1 and Its Potential to Become a Substitute for Maize Which Is Grown for the Purposes of Biogas Plants in the Czech Republic

The domestic biogas market has been developing rapidly, and legislation (The Act) supporting the use of renewable energy sources has come into force. In light of this act and investment support from national programs co-financed by the European Union (EU), the total number of biogas plants has recently increased from a few to 600. The total capacity of electricity generation of those 600 installed plants exceeds 360 Megawatts (MW) (as of mid-2018). Such dynamic growth is expected to continue, and the targets of the National Renewable Energy Action Plan are projected to be met. The use of waste material, which was urgently needed, was the original aim of biogas plants. However, in certain cases, the original purpose has transformed, and phytomass is very often derived from purpose-grown energy crops. Maize is the most common and widely grown energy crop in the Czech Republic. Nevertheless, maize production raises several environmental issues. One way to potentially reduce maize’s harmful effects is to replace it with other suitable crops. Perennial energy crops, for example, are possible alternatives to maize. A newly introduced species for the conditions of the Czech Republic, Elymus elongatus subsp. ponticus cv. Szarvasi-1, and some other well-known species—Phalaris arundinacea L. and Miscanthus × giganteus—are suitable for Czech Republic climate conditions. This paper presents the findings of the research and evaluation of environmental, energy-related, and economic aspects of growing these crops for use in biogas plants. These findings are based on 5-year small-plot field trials. The energy-related aspects of producing Elymus elongatus subsp. ponticus cv. Szarvasi-1, Phalaris arundinacea L., and Miscanthus x giganteus are reported on the basis of experiments that included measuring the real methane yield from a production unit. The economic analysis is based on a model of every single growing and technological operation and costs. The environmental burden of the individual growing methods was assessed with a simplified life cycle assessment (LCA) using the impact category of Climate Change and the SimaPro 8.5.2.0 software tool, including an integrated method called ReCiPe. The research findings show that Szarvasi-1 produces 5.7–6.7 Euros (EUR) per Gigajoule (GJ) of energy, depending on the growing technology used. Szarvasi-1 generates an average energy profit of 101.4 GJ ha−1, which is half of that produced by maize (214.1 GJ ha−1). The environmental burden per energy unit of maize amounts to 16 kg of carbon dioxide eq GJ−1 compared with the environmental burden per energy unit of Szarvasi-1, which amounts to 7.2–15.6 kg of CO2 eq GJ−1, depending on the yield rate. On the basis of the above-mentioned yield rate of Szarvasi-1, it cannot be definitively recommended for the purpose of biogas plants in the Czech Republic.

Effect of different drip irrigation regimes on tuber and starch yield of potatoes

Small-plot field trials monitored the effect of drip irrigation of potatoes on tuber and starch yield. The trials were performed at two different localities in two trial years, 2016 and 2017. The subject of the evaluation included two cultivars with different vegetation periods (the very early cv. Monika and the semi-early cv. Jolana). Four repeated trials studied 4 irrigation treatments according to the available water capacity (AWC) of the soil, i.e. without irrigation, irrigation when soil humidity decreased below 60, 65 and below 70% AWC. All monitored parameters reflected a positive effect of irrigation in comparison to the non-irrigated control. The Žabčice locality showed the highest tuber and starch yields mostly after medium-intensity irrigation. The Valečov locality achieved the highest tuber and starch yields after the highest-intensity irrigation. Subject to the locality and the cultivar, the recommendation is to introduce automatic irrigation start when the soil humidity drops to 65% AWC for heavy soils and 70% AWC for medium heavy soils.