Small Field Plots 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.

Effect of plant spacing on pigeonpea grain yield in Northern Uganda

The aim of crop production is to achieve the highest possible yield per unit area. One way of increasing productivity per unit area is through plant spacing optimization. The effect of plant spacing (90 cm x 60 cm, 150 cm x 120 cm and 150 cm x 180 cm) on yield of three pigeonpea genotypes (KAT 60/8, ICEAP 00540 and ICEAP 00554) was investigated on-station in a small-plot field experiments in 2018. Significant differences were recorded in grain yield of all the three genotypes. The highest yield for all the three genotypes was recorded for row spacing of 90 cm and inter plant spacing of 60 cm, and the lowest for row spacing of 150 cm and inter plant spacing of 180 cm. Plant spacing effect on other yield parameters (number of pods per plant and 100 seed weight) were not significant. Similar effects were recorded for plant growth parameters (plant height and number of primary branches). Thus, it can be concluded that row spacing of 90 cm and interplant spacing of 60cm is appropriate for pigeonpea grain production in Uganda.

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.

The effect of plant growth regulators on the growth, development, and incidence of fungal diseases of black currant in conditions of the city of Moscow

Small-plot field experiments were laid on the territory of the Educational and Experimental Farm of the FSBEI HE RSAU-MAA named after K.A. Timiryazev on the territory of the city of Moscow. The following plant growth regulators were used in the experiments: Zavyaz, KRP (5.5 g/l gibberellic acid sodium salts); Obereg, R (0.15 g/l arachidonic acid), Zircon, R (0.1 g/l hydroxycinnamic acids), Epin-Extra, R (0.025 g/l 24-epibrassinolide). As part of the study, for two years, young blackcurrant plantings of three varieties with different maturation periods were treated with plant growth regulators. During the growing season, plant growth and development were recorded, the development of fungal diseases was recorded – powdery mildew (Sphaerotheca mors-uvae) and blister rust (Cronartium ribicola). Accounting for the yield of berries in various experiment options was carried out in comparison with the control version. The results of the study showed that the double use of growth regulators Zavyaz, KRP, Obereg, R, Zircon, R, and Epin-Extra, R positively influenced the formation of growth of black currant shoots and significantly reduced the development of fungal disease - powdery mildew on the leaves and berries of this crop.

Content of Toxic Elements after Introduction of Phosphogypsum and Litter into Slightly Eroded Agrochernozem

When using by-products and wastes of industrial and agricultural production (phosphogypsum (PG) and turkey litter (TL)) as a fertilizer, it is necessary to take into account not only the content of nutrients, but also environmental safety, including the presence of toxic elements. A small-plot field experiment was conducted on slightly eroded agrochernozem in the forest-steppe zone of the Bashkir Cis-Urals. PG was applied once at doses of 5, 10, and 20 t/ha; TL – in doses of 40 and 60 t/ha; organo-mineral fertilizer (OMF) – 40 and 60 t/ha at ratios of PG and TL 1 : 10, 1 : 5 and 1 : 2. After applying of PG, TL, or OMF into the soil, the content of As, Cd, Hg, Se, Mo, Sb, W, and V remained at the trace level. The content of Zn, Ni, Cu, Ba, and Mn remained practically unchanged compared to the control variant, but was significantly higher than in the initial PG. The content of Pb and Sr increased mainly with the addition of high doses of PG, while those of Co and Cr increased with high doses of TL. In general, the content of elements of three toxicity classes did not exceed the MPC, the total effect of pollution was assessed as permissible.

Small Field Plots Can Cause Substantial Uncertainty in Gridded Aboveground Biomass Products from Airborne Lidar Data

Emerging satellite radar and lidar platforms are being developed to produce gridded aboveground biomass (AGB) predictions that are poised to expand our understanding of global carbon stocks and changes. However, the spatial resolution of AGB map products from these platforms is often larger than the available field plot data underpinning model calibration and validation efforts. Intermediate-resolution/extent remotely sensed data, like airborne lidar, can serve as a bridge between small plots and map resolution, but methods are needed to estimate and propagate uncertainties with multiple layers of data. Here, we introduce a workflow to estimate the pixel-level mean and variance in AGB maps by propagating uncertainty from a lidar-based model using small plots, taking into account prediction uncertainty, residual uncertainty, and residual spatial autocorrelation. We apply this workflow to estimate AGB uncertainty at a 100 m map resolution (1 ha pixels) using 0.04 ha field plots from 11 sites across four ecoregions. We compare uncertainty estimates using site-specific models, ecoregion-specific models, and a general model using all sites. The estimated AGB uncertainty for 1 ha pixels increased with mean AGB, reaching 7.8–33.3 Mg ha−1 for site-specific models (one standard deviation), 11.1–28.2 Mg ha−1 for ecoregion-specific models, and 21.1–22.1 Mg ha−1 for the general model for pixels in the AGB range of 80–100 Mg ha−1. Only 3 of 11 site-specific models had a total uncertainty of <15 Mg ha−1 in this biomass range, suitable for the calibration or validation of AGB map products. Using two additional sites with larger field plots, we show that lidar-based models calibrated with larger field plots can substantially reduce 1 ha pixel AGB uncertainty for the same range from 18.2 Mg ha−1 using 0.04 ha plots to 10.9 Mg ha−1 using 0.25 ha plots and 10.1 Mg ha−1 using 1 ha plots. We conclude that the estimated AGB uncertainty from models estimated from small field plots may be unacceptably large, and we recommend coordinated efforts to measure larger field plots as reference data for the calibration or validation of satellite-based map products at landscape scales (≥0.25 ha).

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.

Symbiotic interaction between a mixture of Bradyrhizobium japonicum strains and different soybean cultivars

Aim. To study the mutual relations between different soybean cultivars and two Bradyrhizobium japonicum strains after mixed inoculation, to evaluate the impact of the introduced microorganisms on the local rhizobial communities in soil, the formation and functioning symbiotic systems, and productivity of soybean. Methods. Microbiological and serological methods; field experiment, gas chromatography and mathematical-statistical methods. Results. A small- plot field experiment demonstrated that the use of a mixture of B. japonicum 46 and B. japonicum КВ11 strains pro- moted a more even distribution of the local and introduced rhizobia in the nodule populations of 12 soybean cultivars of different geographic origin. There was no domination of particular strains in the nodules, and the symbiotic systems formed were more balanced than the control without inoculation. After inoculation of the above-mentioned mixture, in most cultivars there was a considerable increase in the number of nodules (10–45 % more) and their mass (11–86 % increase). There was also an increase in the level of symbiotic nitrogen fixation with 1.2–4.2 times and an increase in the weight of grain per plant by 6–29 % (depending on the cultivar). The efficiency of a mixture of B. japonicum 46 and КВ11 strains in a preparation Rizogumin was confirmed in extensive field trials with soybean on an area of about 60 thousand ha in different regions of Ukraine. In the background of the local populations of the soybean nodulating bacteria in the areas, the application of the formulated mixture of the two rhizobia strains ensured a stable increase by 15–33 % in the soybean yield as compared with the control without the inoculation. Conclusions. A novel approach was investigated, which lies in the application of a mixture of B. japonicum 46 (genetic group USDA 6) and B. japoni- cum КВ11 (genetic group USDA 123) strains for different soybean cultivars inoculation. Combining these two strains and their introduction into agrocenoses ensured the formation of a balanced symbiotic systems (without clear domina- tion of some strains in the nodules). This was expressed in an intensified nodulation, symbiotic nitrogen fixation, and increased yield of different cultivars of soybeans by 15–33 % as compared to the control (without inoculation).

Effects of Planting Pre-Germinated Buds on Stand Establishment in Sugarcane

Sugarcane (a complex hybrid of Saccharum spp.) is propagated vegetatively by using stem pieces of mature cane with healthy buds. Abiotic and biotic stress may cause pre-germination of these buds, which may have an impact on both emergence and plant cane stand establishment. There is very limited information available in the literature. A greenhouse study was conducted with single-budded seed pieces of three levels of bud germination (ungerminated buds, Pop-eyes, and Lalas) from three different cultivars (CP 96-1252, CPCL 05-1201, and CPCL 02-0926) planted in pots and repeated over time. Data on growth parameters (tiller count, primary shoot height, SPAD, and dry biomass of shoots and roots) at early growth showed that Lalas produced more tillers and higher shoot dry biomass than Pop-eyes and ungerminated buds. Both Lalas and Pop-eyes produced higher root dry biomass than ungerminated buds in one of the two experiments. The cultivar had a significant effect on primary shoot height and SPAD. A small plot field experiment was conducted with cultivar CP 96-1252 to validate the results of greenhouse experiments, and similar results were reported for tiller count. The results indicate that pre-germinated buds may have a neutral or positive effect on early sugarcane growth and establishment. Further on-farm research needs to be conducted to confirm these results before using pre-germinated buds as a potential seed source for the late season planting of sugarcane.

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.

Reduced Sensitivity to Fluopyram in Meloidogyne graminis following Long-Term Exposure in Golf Turf.

In recent years, some golf course superintendents in Florida have reported that the turf health is no longer as great, and nematode responses to fluopyram have decreased. The objective of this research was to determine if the mechanism of the reported reduced efficacy was attributable to either: i) enhanced degradation accelerating its breakdown in the soil, or ii) reduced sensitivity to the nematicide in the nematode populations. In a field experiment, soil and nematodes were collected from small plots that had been treated multiple times over four years, for only one year, or never treated. Soil and nematodes were additionally collected from commercial turf sites where either multiple applications of fluopyram had been made for numerous years, or it had never been used. Bioassay experiments found no evidence of enhanced degradation. However, M. graminis collected from small field plots and commercial sites with long-term use of fluopyram were less sensitive to fluopyram in-vitro than those from small plots and commercial sites where fluopyram had not been used. These results indicate that nematicide resistance is a likely cause of reduced fluopyram efficacy on golf-course turf in Florida.

Belonolaimus longicaudatus management using metam potassium and fluensulfone in potato.

Belonolaimus longicaudatus (sting nematode) is an important pest in Florida potato production and is managed primarily by fumigation using 1,3-dichloropropene (1,3-D). Other effective nematicides are needed for more flexibility in managing this pest. The objective of this study was to evaluate fluensulfone, metam potassium, and mixtures of the two products, relative to 1,3-D and untreated control, for efficacy at managing sting nematode, and for non-target effects on free-living nematodes in potato. To test this objective, a small-plot field experiment was conducted in northeast Florida in 2020 and repeated in 2021. Metam potassium fumigation (390 kg a.i./treated ha)-with or without fluensulfone-managed sting nematode soil abundances but was phytotoxic to potato. Strategies that mitigate metam potassium phytotoxicity, such as reduced application rates, are needed before efficacy of metam potassium in this system can be determined. As a preplant soil spray, fluensulfone alone (403 g a.i./treated ha) did not manage sting nematode abundances and had an inconsistent effect on yield. Fumigation with 1,3-D (88.3 kg a.i./treated ha) was the only treatment that consistently managed sting nematode and increased potato yield. Nematicides did not consistently affect free-living nematodes.

Beneficial effects of silicon fertilizers on indicators of seed germination, grain yield of barley and soybean and silage corn biomass

The aim of the study was to determine the optimal doses and methods of the application of silicon fertilizer in barley, silage corn, and soybean under the climatic conditions of Ukraine. A series of laboratory and field experiments were carried out, as along with statistical and analytic data processing. The small-plot field experiment was conducted on chernozem podzolic soil at the NSC ?Institute for Soil Science and Agrochemistry Research named after O.N. Sokolovsky? (Kharkiv region, Forest-Steppe of Ukraine). The laboratory experiments were set up in Petri dishes using a preparative form of different concentrations (0%, 0.5%, 0.75% and 1.0%) of potassium silicate for their assessment of the germination indicators of barley and corn seeds. The significant stimulating effect of potassium silicate on the germination capacity and germination energy of barley and corn seeds was shown, and the optimal concentration of the solution for pre-sowing seed treatment was established. A high positive correlation was determined between the amount of SiO2 application and the yield of the studied crops (P &lt; 0.01; R = 0,7479-0,8682). The optimal levels of the pre-sowing application of SiO2 into the soil were established to obtain maximum crop yields on chernozem podzolic soil (105 kg SiO2 ha-1 for barley, 92 kg SiO2ha-1 for silage corn, and 76 kg SiO2ha-1 for soybean). Also, for each of the studied crops, the most optimal methods of the application of silicon fertilizers were determined, which will improve their productivity on chernozem soils.

Improvement of Anther Culture to integrate Doubled Haploid Technology in Temperate Rice (Oryza sativa L.) Breeding.

Doubled haploid (DH) plant production, such as anther culture (AC), is an effective tool used in modern rice breeding programs. The improved efficient protocols applied can shorten the process of breeding. The effect of combinations of plant growth regulators (2.5 mg/L NAA, 1 mg/L 2,4-D and 0.5 mg/L kinetin; 2 mg/L 2,4-D and 0.5 mg/L BAP) in the induction medium were compared in AC for five rice breeding materials and combinations. Induction of calli ranged from 264.6 ± 67.07 to 468.8 ± 123.2 calli/100 anthers in AC of rice genotypes. Two basal media (MS and N6) and two combinations of growth regulators (1 mg/L NAA, 1 mg/L BAP and 1 mg/L kinetin; 1.5 mg/L BAP, 0.5 mg/L NAA and 0.5 mg/L kinetin) were used as regeneration media. The in vitro green plant production was the highest with the application of the N6NDK induction medium (NAA, 2,4-D and kinetin) and the MS-based regeneration medium (1 mg/L NAA, 1 mg/BAP and 1 mg/L kinetin) in anther culture of the '1009' genotype (95.2 green plantlets/100 anthers). The mean of five genotypes was 24.48 green plantlets/100 anthers for the best treatment. Flow cytometric analyses conducted identified the microspore origin of the haploid calli produced in AC, while the uniformity of spontaneous DH plants was checked in the DH1 and DH2 generations. Spontaneous chromosome doubling ranged from 38.1% to 57.9% (mean 42.1%), depending on the breeding source. The generated and selected DH lines were tested in micro- and small-plot field experiments to identify promising lines for a pedigree breeding program. The improved AC method was integrated in a Hungarian temperate rice pedigree breeding program.

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.

Application of Callopian clay to improve the productivity of zinc-contaminated soils in lawn ecosystems

Pollution of lawn soils with heavy metals leads to the suppression of life and activity of living organisms inhabiting these ecosystems. The use of various means of soil detoxification will make it possible to neutralize the effect of technogenic pressure on the functional properties of urban ecosystems. The article presents data on the sorption-fertilizing properties of Callovian clay when used in zinc-contaminated soils of lawn ecosystems. The study used a small-plot field experiment, which simulated artificial contamination of agro-gray soil with zinc. The article discusses 2 methods of tillage and 4 doses of fertilizer-sorbent. It was found that the use of Callovian clay led to an increase in the production of raw and dry phytomass of lawn grasses by 3.7 - 33.2%, microbiological activity of soils by 0.9 - 132.5 times, as well as a decrease in zinc toxicity by 10 - 25%. The sorption-fertilizing effect and the optimal doses of the applied Callovian clay were determined by the time when the Callovian clay was introduced into the soil (autumn or spring).

A reassessment of the fungicidal efficacy of 1,3-dichloropropene, chloropicrin, and metam potassium against Macrophomina phaseolina in strawberry.

The effectiveness of metam potassium, 1,3-dichloropropene, chloropicrin, and different ratios of 1,3-dichloropropene and chloropicrin on the reduction of natural and artificial inoculum of Macrophomina phaseolina were investigated in laboratory and field experiments. Additionally, a multivariate meta-analysis with data from six field trials conducted in Florida from 2012 to 2018 was performed. In small-plot field experiments using drip stakes, the highest rate (468 L ha-1 ) of metam potassium was most effective in controlling M. phaseolina in infected crowns buried at 15.2cm from the point of fumigant injection, whereas none of the rates was able to reduce inoculum buried at 30.5cm. In closed-container experiments, use of the highest rate of 1,3-dichloropropene (168 kg ha-1 ) resulted in the highest level of pathogen control. Different rates of chloropicrin also reduced inoculum when compared to the non-treated control. 1,3-dichloropropene + chloropicrin at different ratios were also highly effective in controlling M. phaseolina. Results from the meta-analysis of open-field experiments indicated that metam potassium and 1,3-dichloropropene + chloropicrin (63:35, v:v) treatments were significantly more effective in reducing M. phaseolina than the 1,3-dichloropropene + chloropicrin (39:60, v:v) treatment; however, metam potassium was not as effective at the side of the beds. 1,3-dichloropropene alone and in mixture with chloropicrin were more effective in reducing inoculum of M. phaseolina than chloropicrin alone, indicating the fungicidal efficacy of 1,3-dichloropropene. Formulation with higher 1,3-dichloropropene concentration performed better than the formulation with higher chloropicrin concentration in field trials. Metam potassium was effective when applied at the highest rate, but with limited lateral movement perpendicular to the drip irrigation line. © 2022 Society of Chemical Industry.

Correlation analysis of relative chlorophyll content and yield of maize hybrids of different genotypes

In 2021, correlation between relative chlorophyll content and yield in three maize hybrids of different genotypes was examined. The data were collected at the Látókép Experimental Station of the University of Debrecen located on the Hajdúság loess ridge in Hungary. The soil of the small plot field strip plot trial, which was set up in 2011, was calcareous chernozem. Apart from the control treatment (without fertilisation), N fertiliser is applied in the form of base and top dressing. The base fertiliser containing 60 and 120 kg ha-1 N of nutrient applied in spring was followed by top dressing containing +30–30 kg ha-1 N in V6 and V12 phenophases. SPAD values measured at different phenological stages of the growing season increased by an average of about 28% up to 10 leaf stage for all three hybrids. In the pre-silking period (Vn), the relative chlorophyll content decreased by 8% on average. After an average increase of 14% in the tasselling and silking period, SPAD decreased by an average of about 29% at full maturity (R6). For the different fertiliser treatments, higher N doses resulted in higher yields. In the basal fertiliser treatment, the A 60 N dose resulted in an average 34% increase in yield, and the A 120 N dose resulted in an average 94% increase in yield compared to the control. The 60 kg ha-1 N basal fertiliser (A60) increased in the V6 phenophase with an additional 30 kg ha-1 N resulted in an average yield increase of 26%. When 120 kg ha-1 N of basal fertiliser (A120) was increased by an additional 30 kg ha-1 N in the V6 phenophase, only the Merida hybrid showed a significant yield increase (7%). No further yield increase was observed when V690 and V6150 treatments were increased by an additional 30 kg ha-1 N in the V12 phenophase. The yield of the Armagnac hybrid decreased by almost 20%, the yield of Fornad by 3% and the yield of Merida by 1%.

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.