Crop Density Research Articles

Are Wheat Hybrids More Affected by Weed Competition than Conventional Cultivars?

Seeding rates of hybrid wheat varieties are typically much lower than conventional varieties due to their higher seed costs, which could potentially delay canopy development leading to greater weed pressures. To test whether hybrid wheat crops are more affected by weed pressure than conventional cultivars, a conventional variety (“Illico”) and a hybrid (“Hystar”), were compared in a three-year (2012–2016) field study at two sites in Northern Italy. Weed infestation was mainly characterized by weeds with an early growth pattern, and in only a few seasons did the hybrid crops show a higher weed density than the conventional cultivar. Despite the lower sowing rate, hybrids were able to achieve a similar crop density to the conventional cultivar even in years of delayed sowing or dry weather conditions. Normalized Difference Vegetation Index values were generally similar between cultivars across the years, regardless of the presence of weeds, except during the springtime. Occasionally, the test weight was significantly higher in weeded plots than un-weeded plots. Overall, the two cultivars showed similar yields within the same year. These results indicate that on fields with a low weed burden, and where these weeds emerge early, cultivars may not be significantly affected by productivity losses.

Production and multiplication of national potato varieties in family farming systems

Potato is the main vegetable in terms of production volume at national level. In Uruguay, two agricultural cycles are carried out every year, in autumn and in spring. Potato small-scale family farmers represent 80% in number and cover only 10% of national area. The current system of seed multiplication allows for two crops in two years, involving the conservation of seed tubers for six months. An alternative scheme for family farmers has been proposed, based on the use of national short dormancy varieties. With proper management, it is possible to obtain four crops in two years. In order to support the insertion of family farmers in a multiplication scheme of national varieties and to identify the main management factors to be improved, the monitoring of seed production was carried out in 2016. Farms were visited every 15 days to assess crop growth and health and support decision making. Total yield was estimated and classified into categories. Critical management factors discussed with farmers were crop design and density, emergence, harvest and post harvest management. We found harvest date is a bottleneck for family farmers, where delays in harvest are frequent. The delay of the spring harvest would not allow using these seeds for the autumn crop since they would not reach an adequate sprouting state. In spite of the fact that national varieties have short dormancy, for this scheme of seed multiplication, the spring harvest date is a key factor to ensure a proper sprout status for the next planting season.

Features of the protection of winter wheat crops from weed rotation after sunflower

Goal. The of the research was to conduct field studies of new formulations of herbicides in winter wheat crops and to optimize the phytotoxic composition of tank mixtures consisting of different-spectrum active substances.
 Methods. In carrying out the work, general scientific and special research methods were used.
 Results. Species diagnostics of weed phytocenoses in winter wheat crops showed that high potential weed caused dominance in the agrophytocenoses of ragweed wormwood and sunflower scavenger. The deformation of the classic wintering type of weed was observed in the direction of the annual seed species composition. The phytotoxic properties of tank mixtures of Granstar Gold and Hammer herbicides and combined preparations were studied, their technical efficiency, the dynamics of depression and the death of weeds during the growing season were established, the individual resistance of certain types of weeds was revealed. A biometric analysis (crop density, linear growth, grain yield from an ear) of winter wheat was carried out depending on the toxicity of the herbicides. The scientific conclusion was made that the most effective mixture of herbicides was Granstar Gold 30 g/ha + Hammer 20 g/ha.
 Conclusions. As a result of the studies, it was found that winter wheat responded positively to reducing the degree of clogging by improving biometric and productive indicators. The yield of winter wheat grain is in a natural dependence on the degree of weediness of crops and phytotoxic effectiveness against weeds. The maximum increase in grain yield of 0.34 t/ha was achieved in comparison with the control when processing wheat crops of the winter mixture of herbicides Granstar Gold 30 g/ha + Hammer 20 g/ha.

Spatiotemporal mapping mangroves of Tengragiri wildlife sanctuary under Barguna district of Bangladesh using freely available satellite imagery

Naturally grown mangrove forest is the south coastal community’s green barrier from any type of hydro-meteorological hazard and disasters. South-western coastal area of Bangladesh is covered by the Sundarbans, and mid-central zone is covered by Tengragiri wildlife sanctuary which is taken as a protected area in this recent era but not mapped properly with considering different species diversification and temporal changes pattern which is required for successful co-management of this mangrove forest. This study identifies species composition, plant diseases, degradation of the mangrove forests and further focuses on mapping mangroves by conducting plotting-based primary field visit, variability analysis using different indices and cross-matching with secondary databases. Existing mangrove forest boundary’s 200 m buffering with three-time series satellite imagery 2000, 2010 and 2017 is considered for further analysis. Including all buffering zone, this protected area considered 9 major classes that included four subclasses for presenting result like Baen (Avicennia officinalis), Gewa-Goran (Excoecaria agallocha, Ceriops decandra), Keora (Sonneratia apetala), Sundri (Heritiera fomes), Plantation trees Samanea Saman (Raintree), agriculture-grassland (agri-grass) and homestead settlement, sandbar and waterbody. Mapping accuracy assessment purpose automatically generated 996 points cross-matched with previously mangrove species level detailed survey results and found highest accuracy in Sundri species (70%) and all others above 50%. During 2000–2017, the Keora area showed the highest increase 129% over 2000 and increasing rate 13.17 ha/yr. About 26% Sundri and Baen–Passur increased around 13.45 ha/yr. In case of Sundri, 70% area coverage remained intact during 2000–2017, while other 25% classified in 2017 as Avicennia officinalis, Gewa-Goran classes. Furthermore, using refracted electromagnetic energy from various physical characteristics of plants application, four indices (NDVI, DVI, MSAVI-2, RVI) are usable where single-species-level crop density analysis has limitations, but identification of Sundri and Keora by MSAVI-2 and NDVI found significant and alternately lower accuracy values from RVI. Identification of dominant mangrove species groups as well as area gains and losses over 2000–2017 is a robust biophysical baseline for management of the sanctuary. Natural hearts of this area and working as first-step warriors against natural disasters originated from Indian Ocean and Bay of Bengal; so far, it is very much required to save this forest and the coastal communities as well. The results of the study and maps will be helpful for the scientific community, planners, government-international bodies and the activists, Forest Department and the local community in effective planning, monitoring the effectiveness of co-management in conservation of the sanctuary.

Crop design for improved robotic harvesting: A case study of sweet pepper harvesting

Current harvesting robots have limited performance, due to the unstructured and dynamic nature of both the target crops and their environment. Efforts to date focus on improving sensing and robotic systems. This paper presents a parallel approach, to ‘design’ the crop and its environment to best fit the robot, similar to robotic integration in industrial robot deployments. A systematic methodology to select and modify the crop ‘design’ (crop and environment) to improve robotic harvesting is presented. We define crop-dependent robotic features for successful harvesting (e.g., visibility, reachability), from which associated crop features are identified (e.g., crop density, internode length). Methods to influence the crop features are derived (e.g., cultivation practices, climate control) along with a methodological approach to evaluate the proposed designs. A case study of crop ‘design’ for robotic sweet pepper harvesting is presented, with statistical analyses of influential parameters. Since comparison of the multitude of existing crops and possible modifications is impossible due to complexity and time limitations, a sequential field experimental setup is planned. Experiments over three years, 10 cultivars, two climate control conditions, two cultivation techniques and two artificial illumination types were performed. Results showed how modifying the crop effects the crops characteristics influencing robotic harvesting by increased visibility and reachability. The systematic crop ‘design’ approach also led to robot design recommendations. The presented ‘engineering’ the crop ‘design’ framework highlights the importance of close synergy between crop and robot design achieved by strong collaboration between robotic and agronomy experts resulting in improved robotic harvesting performance.

Influence of luminous flux parameters on the formation of re-weeding of hemp crops

Light (energy) growing conditions of hemp plants have a direct effect on both crop plants and their habitat, as well as on new seedling plants of weeds that began their vegetation after soil herbicides weakened their protective function. The appearance of such weeds in crops is called re-weeding. Re-weeding is difficult to control. 
 It is fair to say that the density of hemp crops and, consequently, their optical density is a very effective, cheap and environmentally friendly factor influencing weeding processes. The application of such factors of influence on the indicators of re-weeding of crops is especially effective, when the application of any agronomic or chemical methods on new weed seedlings is very difficult or simply impossible.
 Studies conducted during 2014‒2016 in the field experiment of the Institute of Bast Crops of NAAS to determine the influence of light regimes of hemp sowing on the formation of re-weeding crops provided five options with different stocking densities of hemp sowing, which formed different indicators of optical density of crops. The experiment determined such indicators of the light regime as the incident energy flux of the headlights and the transmission of light by sowing to the ground. Weed surveys were performed according to the requirements of the "Pesticide Test and Application Methods". Crop weeds were determined quantitatively and quantitatively by weight.
 As a result of the conducted researches the regularities of weed formation at different density of stems, as well as between weed parameters and light regimes of sowing hemp crops were established. There is a direct linear relationship between the transmission of light to the soil by sowing hemp and the number and weight of weeds. The critical dates for the release of FAR energy into the soil for re-weeding were the third decade of July and the third decade of September. With a standing plant density of 1.65 million units/ha, conditions developed under which most weed plants in repeated weeding could not reach the virgin stage of organogenesis. That is, it can be argued that it is in crops with a stem density of 1.65 million units/ha conditions are achieved for the least development of re-weeding due to the minimum energy input of the headlights required for full generative productivity of weeds.
 Thus, the development of methods for controlling the processes of re-weeding of hemp crops based on phytocenotic factors deserve widespread introduction into agricultural production, as quite effective and environmentally friendly.

Рост и продуктивность лесных культур сосны С.В. Алексеева на Европейском Севере России

Sowing and planting of forests in the European North are the most important silvicultural treatment that guarantee the regeneration of coniferous species in present-day conditions. Lack of relevant information on the historical experience of forest crop development and current state of such objects is an indicator of a certain information vacuum. The research purpose was to assess growth and productivity of experimental forest crops of pine of the northern arborist S.V. Alekseev developed by the sowing method in 1927–1930 and to compare them with natural stands. The research was carried out at the stationary site “Experimental Forest Crops of Pine named after S.V. Alekseev”, which is located in the central part of Arkhangelsk region. The oldest experimental forest crops in the European North of Russia grow on the site. S.V. Alekseev used different forest crops in order to choose rational ways of their development. We examined forest crops at 4 permanent sample plots in 2018. Collection, processing and analysis of field data was carried out according to the methods generally accepted in forest inventory. The following parameters were determined: average diameter and height, relative and absolute density, quality class, standing volume, stand composition, mean increment, and current mean periodic increment. The dynamics of inventory parameters of forest crops for the period from 1999 to 2018 shows that all forest elements are in a phase of active growth. Over the 19-year period, the share of pine in the stand decreased by 3–10 %, while the share of spruce and birch increased by 3–7 % and by 2–3 %, respectively. Herewith the number of trees of all species decreased by 3–36 % and amounted to 1420–1952 pcs/ha in forest crops. The total cross-sectional area increased by 3.6–11.6 m2/ha. The standing volume increased by 88–133 m3/ha. The current mean periodic increment of forest crops ranged from 4.6 to 7.0 m3/ha. Analysis of the inventory parameters of the studied stands shows that forest crops are not inferior in growth to normal pine stands of Arkhangelsk region. The total density of forest crops exceeds the density of normal pine stands by 29.4–125.7 %. The total standing volume of forest crops have reached high levels by the age of 90. The total standing volume of forest crops is 416–444 m3/ha, including pine (284–342 m3/ha). The mean increment of forest crops is 4.6–5.0 m3/ha, including pine (3.2–3.8 m3/ha). Forest crops growing on the 3rd sample plot (option 8) are the best option among those examined by productivity according to the complex of inventory parameters (density, standing volume, increment, pine share in the composition). The experiments of S.V. Alekseev show that the sowing method can provide guaranteed reforestation of pine in the European North. For citation: Soldatova D.N., Ilintsev A.S. Growth and Productivity of Pine Forest Crops Named after S.V. Alekseev in the European North of Russia. Lesnoy Zhurnal [Russian Forestry Journal], 2020, no. 1, pp. 99–112. DOI: 10.37482/0536-1036-2020-1-99-112 Funding: The study was carried out with the financial support from the Ministry of Education and Science of Arkhangelsk Region within the framework of the competition of scientific projects “Young Scientists of Pomorye” (project No. 11-2019-02a). Acknowledgments: We gratefully acknowledge A.P. Bogdanov, R.A. Ershov, Yu.S. Bykov, and A.V. Paramonov for participation in the collection of field material, as well as scientificsupervisors prof. N.A. Babich and prof. S.V. Tret’yakov for methodological assistance.

Computer based production of Saffron (Crocus sativus L.): From mechanical design to electronic control

The article describes the design and implementation of a computer based industrial system for production of saffron. The proposal is based on an automated greenhouse with temperature, light and irrigation control together with harvesting and stigma separation devices. The harvesting device has been specifically developed using scalability properties and computer vision. The greenhouse is designed to increase the crop density if required generating a more sustainable and continuous production. The main advantages of the proposed method are as follows: the harvesting of the saffron flower and the procedure to get the stigmas are carried out in the same process; the greenhouse allows to significantly extend the flowering time of the saffron plant; and higher productivity per worker and per planting area is achieved. In order to show the feasibility and applicability of the proposed approach, real experimentation has been carried out for the extension of the flowering time and for the harvesting and stigma separation devices and successful results have been obtained.

Серебряноборское опытное лесничество – основная база биогеоценологических работ Института лесоведения РАН в средней полосе России

Изложена краткая история биогеоценотических исследований Института лесоведения РАН на территории Серебряноборского опытного лесничества под Москвой. Создана сеть постоянных пробных площадей, на которых ведутся регулярные наблюдения за древостоем и напочвенным покровом. Изучается рост сосновых и лиственничных культур различного происхождения. Ведутся наблюдения за микобиотой Серебряноборского лесничества. The history and results of long-term silvicultural and geobotanical studies, begun in 1947 on the territory of the Serebryanoborsky experimental forest district of Institute of Forest Science RAS, are presented. Descriptions of the main types of the forest vegetation area were made and their map was compiled. Also compiled soil map of forest district. In 1947, the first permanent sample plot was laid to monitor all layers of vegetation. Later, a system of 53 permanent sample plots was created, covering the whole variety of indigenous and derived forest types. Regularly checkups of the forest district flora composition have been being conducted. Protected plant species have been identified and are regularly monitored at permanent sites. One of the main causes of vegetation dynamics in forest district was changes in anthropogenic influence. Livestock grazing was prohibited, but at the same time, recreational loads increased in a large part of the territory. The maps of recreational disturbance of the forest district were made twice. It has been established that the age of natural maturity of forest stands of complex boron does not occur earlier than 200-220 years. Studies of geographical cultures of pine and larch, created in 1948-1950, allowed to establish comparative features of different provenances of pine and different species and forms of larch, including the unique Far Eastern ones, in the conditions of the Moscow region. The study of the growth dynamics of experimental different density pine plantations, established in 1948, led to the conclusion about the optimal planting crop density of 28 thousand trees per ha. At the Experimental Test Site, established in 2002, the influence of recreation of different intensity on the dynamics of all components of pine forests is studied. Over the years, a study of the mushroom biota of the Serebryanoborsky experimental forestry was conducted. As a result of the research, data on the diversity of forest mycobiota have been accumulated, the most important tree species pathogens have been identified, information on their distribution and harmfulness has been obtained, and a phytopathological assessment of the success of growing Scots pine climatypes has been carried out in experimental geographical cultures that have reached adulthood. An inventory of dendrotrophic fungi species composition is currently being carried out, an information base is being formed in order to monitor the diversity of fungal biota and phytopathological monitoring in the territory of an experimental forest range.

Plant diversity and density in cocoa-based agroforestry systems: how farmers’ income is affected in the Dominican Republic

Cocoa-based agroforestry systems (AFS) provide a variety of products, either sold or self-consumed. The choice of crop species and planting density in cocoa AFS has an impact on the quantities and the economic value of the agricultural products sold and consumed by producers. We characterized 140 cocoa AFS in three main production areas in the Dominican Republic, together with farmer’s management practices, to construct a typology of cocoa AFS based on their structure, and evaluate their performances. The sum of the sales of cocoa, other products, and self-consumption did not differ significantly among AFS types. However, a high degree of diversification combined with a high density of associated fruit species reduced cocoa sales, but increased fruit sales and self-consumption. In contrast, a low diversity of associated plants including nitrogen-fixing trees increased cocoa sales but reduced fruit sales and self-consumption. The highest economic performance was obtained with intermediate diversity (three to seven species) and density (100–400 associated plants ha−1). Our results provide food for thought for optimizing crop diversity and density to adjust the economic balance between sales and self-consumption of the products harvested in cocoa AFS.

ПРОБЛЕМЫ ВЕДЕНИЯ ЛЕСНОГО ХОЗЯЙСТВА В ЛЕСАХ РАЗЛИЧНОГО ЦЕЛЕВОГО НАЗНАЧЕНИЯ

Legal and technical documents on the implementation of forest management in the Russian Forest Fund have been analysed. It is established that the current regulatory technical documents do not provide practical forestry, management on a zonal (subzonal) typologic basis. Selected forest areas often combine completely different forest conditions to the areas of forest fund which does not contribute to the forest management optimisation. There are a lot of contradictions and recommendation in the normative and technical documents as concerns mature and over mate stands felling, sanitary felling, improvement felling, forest restoration and forest growing that are not substantiated on factual material. That has resulted in conflicts between forest users and control authorities, reduced efficiency of forestry activities and unjustified financial costs. Elaboration of normative and technical documents is required to improve forest management in protective forests, taking into account their intended purpose. The current recommendation does not take into account the latter and only regulate the relative completeness and composition of stands. Reforestation and afforestation are noteworthy in particular. The requirements for the transition to use when creating forest crops only planting material with a closed root system cannot be considered correct for all regions of the country. Also, specifications on the density of the forest crops created require clarifications as well as correlation artificial and natural reforestation. Relevant is the development of tables of trees attrition having in view the operational appointment of sanitary felling. We believe that improving the regulatory framework for forestry in the forest for various purposes will contribute to increasing their productivity and sustainability.

Model of creation of productive agrocenosis of Echinacea

The results of many years of field research on the effect of stocking density of different types of Echinacea spp. on its productivity are discussed. It was found that when the Echinacea purpurea crops were thickened, the collected raw material had a high percentage (more than 50%) of stems, which negatively affected its quality. An increase in the density of Echinacea pallida crops has less effect on the formation of generative shoots. Long-term research has revealed patterns that determine the productivity of Echinacea spp. at different planting densities. This made it possible to calculate and recommend for production the density of plants at which the optimal yield of the agrocenosis will be achieved: for Echinacea purpurea – 100-110 thousand/ha, and for Echinacea pallida – 120-140 thousand/ha.

Plant density and weediness of clary sage crops depending on the effect of winter hardiness and years of use of the crop in the southern Ukraine

Plant density and weediness of clary sage crops depending on the effect of winter hardiness and years of use of the crop in the southern Ukraine

Overviewing of weed management practices to reduce weed seed bank and to increase maize yield

Background: Weeds are unwanted and undesirable plants which deteriorate the quality of agricultural products and interfere with farming activities. Most of the weeds (indigenous and invasive) seeds get preserved in soil horizons as weed seed bank which ensure their survival leading to the spoilage of quantitative and qualitative functioning of agricultural farms. Objective: To keep weeds below threshold level, elimination of weeds seed before germination can be a viable and pro-ecological approach. To achieve this objective, weed seeds reserved in the soil which serve as an effective pool to ensure their survival necessitate weed-seed bank management. Thus the ultimate goal was to synthesize and analyze research findings on weed seed bank management leading to formulating the most effective strategy encompassing viable control of weeds in maize. Methods: This study reviewed and analyzed the characteristics which impart botanical superiority to weeds and impact of all prevalent weed control strategies on weed seed bank, weeds density and maize yield. The research findings pertaining to different agronomic practices and technological packages were critically analyzed to sort out the most effective and eco-friendly approach to control weed-seed bank and weeds density in maize crop. Results: The synthesis and critical evaluation of research findings pertaining to weed control methods revealed that manual and mechanical methods were eco-friendly but involved expensive labor, while the chemical approach involving the use of herbicides led to serious deterioration of agro-environmental resources. Two or more techniques used in coherence which encompassed deep tillage to burry weeds seed and prevented their germination through mulches of biotic and synthetic materials along with optimizing sowing method especially raised bed technique reduced weed seed bank and weeds density in maize. Conclusions: It is inferred that integrated approach entailing cultural, manual, mechanical and chemical control can be developed as a pro-environmental and farmer friendly approach for weed control by reducing weed seed reserves which can potentially lead to higher economic returns through higher maize yield.

Plant density and weediness of clary sage crops depending on the effect of winter hardiness and years of use of the crop in the southern Ukraine

Plant density and weediness of clary sage crops depending on the effect of winter hardiness and years of use of the crop in the southern Ukraine

Crop density affects weed suppression in organically managed Sunflower

AbstractA field experiment in central New York evaluated the effect of sunflower (Helianthus annuus L.) density on weed biomass and yield in organic sunflower production. Two varieties of sunflower, Badger DMR and N5LM307, were seeded at 6.1 and 8.6 seeds m−2, and grown using organic management practices at one site in 2016 and two sites in 2017. Sunflower density, weed biomass, and sunflower yield were quantified at crop maturity. Weed biomass was lower (P < .05) in plots with sunflower seeded at 8.6 seeds m−2 compared to 6.1 seeds m−2 in only one variety in one site‐year. However, a negative relationship (P < .05) was observed between sunflower density and weed biomass when data were pooled over site‐years. No difference was observed in sunflower seed yield between varieties or seeding rate treatments. Sunflower seed yield was higher in 2016 (354 g m−2) when conditions were extremely dry, and in one site‐year in 2017 (308 g m−2), when conditions were extremely wet and seeding was delayed by a month. In the other site‐year in 2017, sunflower seed yield was lower (225 g m−2), which was likely due to weed competition as weed biomass was an order of magnitude greater in this site‐year than the other two site‐years. Although more research is needed to refine management recommendations for organic sunflower production, our results suggest that increasing sunflower density can contribute to weed suppression.

Variety and weed management effects on organic chickpea stand establishment and seed yield

AbstractThe need for organic produce is increasing worldwide but weed control remains a critical problem for organic crop production. Three types of weed control practices were evaluated for two organic chickpea (Cicer arietinum L.) varieties at the Western (Corvallis) and Eastern (Sidney) Agricultural Research Centers of Montana State University. Treatments included two chickpea varieties (Black and CDC Orion chickpeas), two seeding rates (standard seeding rate or 1× at 43 seeds m−2 and 50% increase over the standard rate or 1.5×), and two pre‐emergent weed control practices (flame weeding and shallow tillage). Results revealed that Black chickpea was associated with greater stand densities and grain yield with lower weed biomass than CDC Orion. Increasing seeding rate for Black chickpea improved crop density and increased grain yield to the extent of 26% compared with the standard seed rate. Flaming increased chickpea grain yield only at Corvallis in 2016. The combined effects of shallow tillage and increased seeding rates resulted in reduced weed biomass. Shallow tillage can be successfully integrated to improve yields and reduce weed pressure in organic chickpea. However, precaution must be taken for the tillage timing to avoid damage to emerging chickpea seedlings. More research is needed to select chickpea varieties that have improved vigor and are more competitive to weed pressure commonly seen in organically managed fields.

Interseeding cover crops in corn

AbstractFarmers benefit from ecosystem services that cover crops provide, but time constraints limit the opportunity to seed cover crops following corn (Zea mays L.) harvest in the upper Midwest. Interseeding cover crops in corn during the early vegetative growth stages lengthens the cover crop growing season; however, cover crops may have difficulty establishing in standing corn, or conversely, compete with corn and reduce yield. The objectives of this research were to determine cover crop establishment when broadcast interseeded in corn from the V2–V7 growth stages, suppression of weeds by cover crops, and effects of cover crops on corn grain yield. Annual ryegrass (Lolium multiflorum Lam.), crimson clover (Trifolium incarnatum L.), oilseed radish (Raphanus sativus L.), and a three‐species mixture were interseeded in four site‐years in Michigan. Annual ryegrass density was highest compared with oilseed radish and crimson clover 30 d after interseeding and at harvest in October. Cover crop density was highest at the V4–V7 interseeding timings. Annual ryegrass produced more fall biomass (186 kg ha−1) compared with crimson clover (112 kg ha−1), and fall biomass was greatest at the V2, V3, and V5 interseeding timings. Spring biomass was 384 and 180 kg ha−1 for annual ryegrass and the cover crop mixture, respectively; these treatments reduced winter annual weed biomass. Corn grain yield was unaffected by cover crops at any interseeding timing. Crimson clover did not establish well in this experiment. Annual ryegrass and oilseed radish interseeded in V2–V7 corn did not reduce corn grain yield.

Growth and development of Alfalfa depending on the type of nitrogen nutrition

Mineral and symbiotrophic types of nitrogen nutrition of plants were compared in experiments with the blue-hybrid alfalfa. Variants with seed inoculation by high-mountain strains of nodule bacteria (In-1800 and N30+In) had the maximum height of plants during all experimental years (40-70 cm), which is explained by the better nitrogen provision of plants. At the same time, the effect of the mineral forms of nitrogen appeared only in the year of sowing at the beginning of the growing season to the first mowing, in the future the differences between these options were neutralized. The foliage intensity of plants was in the range of 41.4-54.8%, increasing due to the improved availability of biologically bound nitrogen in plants. Mineral forms of nitrogen reduced plants’ foliage coverage in all experimental years, however, this decrease was noted only in the initial periods of vegetation. The maximum indicators of foliage coverage were noted in the In-1800 variant. By the end of the third year of crops use, the plant stand density was 980-1100 thousand units/ha, and the total thinning of alfalfa crops reached 45-51%. At the same time, the symbiotrophic type of nitrogen nutrition made it possible to significantly increase the competitiveness of plants, which ultimately affected the persistence of the crop density.

Eksperimentalna procena organskih podloga za ispitivanje klijavosti semena soje

High germination of seeds and seedling establishment are critical for soybean production since it determines crop density and eventually affects the yield. Accurate evaluation of the germination potential of sowing material is valuable, as well as initial quality assessment of newly harvested seed. ISTA Rules prescribe alternative methods for soybean seed germination: sand, between paper, top of paper covered with sand and since 2020 organic growing media. In the Seed Testing Laboratory at the Maize Research Institute soybean germination is conducted in the sand at 20<=>30°C. The objective of this study was to evaluate several available organic growing media and compare results obtained with the standard laboratory method. Five soybean seed lots of different quality were tested in four germination growing media (3 organic and sand), at two temperature regimes (25 °C and 20<=>30°C). Statistical analyses showed that all types of organic growing media were of the same quality. Slightly higher germination in organic growing media was obtained in the experiment at 20<=>30°C compared to sand, but those differences were not statistically significant. When testing was done in germinator with 25°C positive effects of organic growing media were identified and this impact was significant, especially for low-quality seed lots. The experimental outcome was to continue with routine practice and use organic growing media for retesting of seed lots with lower germination as an alternative substrate.