Effects of Crop Geometry and Nutrient Management On Nutrient Uptake and Quality Parameters of Potato Under Winter Maize + Potato Intercropping System

Effects of crop geometry and nutrient management on nutrient uptake and quality parameters of potato under winter maize + potato intercropping system were studied during two consecutive years (2015-2016 and 2016-17) at BHU, Varanasi, India. Results revealed that under different crop geometry the nutrient uptake (NPK kg/ha) were obtained significantly higher with 1 : 2 row ratio in additive series as compared to other row ratio due to maximum plant population. The minimum nutrient uptake (NPK kg/ha) were obtained with 1:1 row ratio in replacement series. However, quality parameters (protein and starch) did not vary significantly by different crop geometry during both the years of investigation. Amongst nutrient management, the highest nutrient uptake (NPK kg/ha) and quality parameters (protein and starch) were obtained significantly with the application of 100% RDF + 25% N through poultry manure followed by the application of 100% RDF + 25% N through vermicompost. Thus, the results suggest that 1:2 row ratio (crop geometry) in additive series with 100% RDF + 25% N through poultry manure (nutrient management) followed by 100% RDF + 25 % N through vermicompost were feasible and practicable during both the years of investigations. Bangladesh J. Bot. 50(4): 1011-1019, 2021 (December)

Competitive ability of canola (Brassica napus var. oleifera) hybrids with black oat (Avena strigosa) in a subtropical environment

The objective of this study was to assess the competitive ability of canola (Brassicanapus var. oleifera) hybrids in competition with black oat (Avena strigosa) in a subtropical environment. The experiments were conducted in a greenhouse where canola hybrids ‘Hyola 61,’ ‘Hyola 76,’ ‘Hyola 433,’ and ‘Hyola 571’ were tested individually for their competitive performance with black oat. The plant proportion between black oat and the canola hybrid was changed (100%:0%; 75%:25%; 50%:50%; 25%:75%; and 0%:100%) while keeping the total population of plants constant (20 plants plot‑1). Photosynthesis rate (μmol m-2 s-1), internal CO2 concentration (μmol mol-1), and transpiration rate (mol H2O m-2 s-1) were assessed using an infrared gas analyzer 55 days after emergence. Leaf area (m2 m-2) and dry matter (g m-2) were also assessed on the same day. The data set was analyzed by the replacement series method for competition studies. There was evidence of intense competition between canola and black oat, independent of plant proportion. The competitive ability of canola was distinct among hybrids; Hyola 571 performed better than the others in the competition against black oat. Choosing the most competitive hybrid, such as Hyola 571, helps maintain high canola grain yield levels in areas infested with black oat. Highlights: There is difference in competition among canola hybrids against black oat; Hyola 571 performed better in the competition; Preference should be given for most competitive canola genotypes against weeds, and weed control should be carried out early in the critical period of interference; Aggressiveness is the most preponderant parameter in determining canola genotypes with superior ability in competition against weeds.

PERTUMBUHAN DAN HASIL DUA VARIETAS KACANG TANAH DALAM TUMPANGSARI REPLACEMENT SERIES DENGAN PADI BERAS HITAM SISTEM IRIGASI AEROBIK PADA BEDENG

This study aimed to determine growth and yield of two varieties of peanut in a 2:2 replacement series intercropping system with black rice under aerobic irrigation system on raised-beds. The experiment, carried out on irrigated rice fields in South Kediri village (West Lombok, NTB) from May to August 2019, was arranged according to Split Split-Plot Design with three treatment factors, namely intercropping system as the main plots (T1: intercropping 2:2 rows between peanuts and black rice; T2: peanut monocrop), peanut varieties as the sub-plots (V1: Bison; V2: Hypoma-1 variety), and combinations of inorganic-organic-bio-fertilizers for black rice as the sub-sub-plots (P1: NPK fertilizer only; P2: NPK+Petroganik; P3: NPK+Petroganik+mycorrhiza bio-fertilizer). The intercropped peanut was fertilized only with 200 kg/ha Phonska (NPK). The results indicated that the most influencing treatment factors were intercropping systems and combinations of inorganic-organic-bio-fertilizers. However, there were significant two-factor-interactions, namely between varieties and intercropping systems on peanut leaf number, dry stover weight and dry filled-pod weight, and between intercropping systems and fertilizer combinations on seed yield and harvest index. Dry seed yields were not significantly different between varieties, but were higher under P3 (21.17 g/clump) or P2 (20.67 g/clump) compared to P1 (19.35 g/clump), while peanut intercropped with black rice resulted in higher seed yield (22.10 g/clump) than monocroped peanuts (18.69 g/clump). Based on the interaction between intercropping systems and fertilizer combinations, the highest seed yield was obtained in peanuts intercropped with black rice fertilized with NPK+organic+bio-fertilizer (23.65 g/clump) and the lowest average was in monocropped peanuts (17.87 g/clump).

RELATIVE COMPETITIVENESS BETWEEN MAIZE HYBRIDS AND WILD POINSETTIA

ABSTRACT Maize is one of the main cereals cultivated worldwide and wild poinsettia is among the weeds that cause damage in grain production. The objective of this study was to evaluate the relative competitive ability of maize hybrids in the presence of a wild poinsettia biotype through experiments in replacement series. In preliminary experiments, it was determined the plant population in which the dry mass becomes constant. For the maize hybrids ‘Agroeste’, ‘Morgan’, ‘Nidera’, and ‘Velox’, as well as the wild poinsettia, the population was 20 individuals vase-1. Subsequently, experiments were carried out in replacement series in different combinations of species that varied the relative proportions (100:0, 75:25, 50:50, 25:75, and 0:100%). The analysis of the species' competitiveness was carried out using diagrams applied to the replacement experiments and by the relative competitiveness indexes. The height (PH), chlorophyll index (CI), leaf area (LA), and the shoot dry mass (DM) of the plants were evaluated 50 days after emergence. There was competition between the maize hybrids and the wild poinsettia; both were negatively affected, regardless of the proportion of plants, causing reductions in the species' PH, CI, LA, and DM. The competition between maize and wild poinsettia occurs for the same resources in the environment, and interspecific competition caused greater damage to maize and wild poinsettia than intraspecific competition. In general, it was observed that only the hybrids ‘Nidera’ and ‘Velox’ were more competitive than the wild poinsettia.

Environmental Factors Effects on Winter Wheat Competition with Herbicide-Resistant or Susceptible Silky Bentgrass (Apera spica-venti L.) in Poland

Environmental factors, including weather and soil conditions, can affect the competitive effects of weeds on crops. This work aimed at a comparison of the competitive abilities of winter wheat toward bentgrass (Apera spica-venti (L.) P. Beauv) with single herbicide resistance, multiple herbicide resistance, or a susceptible biotype in different environmental conditions of Poland. A replacement series competition model was applied in field conditions in 2017–2018 and 2018–2019 across the country. A competitive ratio (CR) was calculated for the relative biomass of plants and grain number. A canonical variate analysis (CVA) was performed for biological parameters and a day-difference in emergence between winter wheat and bentgrass with the hydrothermal coefficient and soil texture in all of the sites in each season separately. Winter wheat emergence was correlated with the amount of precipitation after seeding, and was fastest for five days in humid conditions, and slowest up to 22 days, when the precipitation in October was low. The CVA proved that winter wheat’s competitive effects toward the susceptible or herbicide-resistant biotypes of bentgrass are site-specific. During the dry season, the bentgrass biotype with multiple herbicide resistance was more competitive toward winter wheat than the susceptible one. The wheat CR < 1 with regard to biomass and both biomass and the grain number was in 64% and 50% of all the combinations with the resistant biotype. In conclusion, weather affects the competitive effects of winter wheat toward herbicide-susceptible or resistant bentgrass.

Productivity of Chickpea (Cicer arietinum. L.) and Mustard (Brassica juncea) Intercropping System as Influenced by Different Row Ratios and Liquid Manures

A field experiment was conducted during two consecutive rabi seasons of 2018-2019 and 2019-2020 at Crop Research Farm, Department of Agronomy, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj (U.P.). The present experiment comprising with five intercropping systems viz. sole chickpea, sole mustard, chickpea + mustard (1:1), chickpea + mustard (2:1), chickpea + mustard (3:1) row ratios in replacement series and four liquid manures viz. control (no spray), panchagavya 3%, cow urine 10% and vermiwash 10%. Results revealed that among the row arrangements maximum plant height and dry weight of both crop (Chickpea and mustard) were recorded under chickpea + mustard 3:1 row ratio. However sole stand of both crop produced maximum yield attributes and yield. Whereas among the liquid manures foliar application of panchagavya 3% found to be superior over rest of the liquid manures.

Species Interactions and Nitrogen Use during Early Intercropping of Intermediate Wheatgrass with a White Clover Service Crop

Perennial grain crops intercropped with legumes are expected to use nitrogen (N) resources efficiently. A pot experiment using the 15N isotope dilution method demonstrated interspecific competition and use of N from the soil and N2 fixation in intermediate wheatgrass (Thinopyrum intermedium (Host) Barkworth & D.R. Dewey, IWG) and white clover (Trifolium repens L., WC) intercrops at five species-relative frequencies and four levels of inorganic N fertilizer in a replacement series design. The proportion of N in WC derived from the atmosphere increased from 39.7% in a sole crop to 70.9% when intercropped with IWG, and 10.1% N in IWG transferred from WC. Intermediate wheatgrass showed high fitness with maintained high total dry matter production at low relative frequencies. Decreasing IWG-relative frequency only increased dry matter and N accumulation of WC, resulting in increased amounts of N2 fixed. Increased levels of N fertilization increased the proportion of N acquired from the fertilizer in IWG and WC but decreased the N fixed by WC and N absorbed by IWG from the soil. Our study indicates that WC supply sufficient fixed N2 for IWG intercrop biomass yields under appropriate levels of soil N fertility and species-relative frequencies.

Effect of Water Exchange Rate on Interspecies Competition Between Submerged Macrophytes: Functional Trait Hierarchy Drives Competition

Aims: Although the relative contributions of the “competition-trait similarity” and “competition-trait hierarchy” hypotheses in predicting competitive outcomes in response to environmental variation has recently been investigated in terrestrial plants, their validity in aquatic plants remain poorly understood, particularly in terms of variation in the water exchange rate (WER). Methods: To this end, this study investigated the influence of WER variation on interspecies competition and functional traits in two pairs of submerged macrophytes (Vallisneria natans vs. Myriophyllum aquaticum and V. natans vs. Myriophyllum spicatum) under three levels of WER using the replacement series experiment. Results: Results showed that V. natans was a stronger competitor than either Myriophyllum species in static waterbodies. However, the relative competitive ability of V. natans consistently decreased with increasing WER and decreasing its planting proportion, which would eventually change it from a stronger to weaker competitor. Between species pairs, most functional traits showed competently opposite patterns to increasing WER and decreasing the planting proportion of V. natans. Conclusions: Our results indicate that WER affected the outcome of interspecies competition between submerged macrophyte species, and moreover, the relative competition ability of each species within a pair was linked strongly to species’ competition-trait hierarchy than to competition-trait similarity.

Invasive plant benefits a native plant through plant-soil feedback but remains the superior competitor

Plant soil feedback (PSF) occurs when a plant modifies soil biotic properties and those changes in turn influence plant growth, survival or reproduction. These feedback effects are not well understood as mechanisms for invasive plant species. Eragrostis lehmanniana is an invasive species that has extensively colonized the southwest US. To address how PSFs may affect E. lehmanniana invasion and native Bouteloua gracilis growth, soil inoculant from four sites of known invasion age at the Appleton-Whittell Audubon Research Ranch in Sonoita, AZ were used in a PSF greenhouse study, incorporating a replacement series design. The purpose of this research was to evaluate PSF conspecific and heterospecific effects and competition outcomes between the invasive E. lehmanniana and a native forage grass, Bouteloua gracilis. Eragrostis lehmannianaPSFs were beneficial to B. gracilis if developed in previously invaded soil. Plant-soil feedback contributed to competitive suppression of B. gracilis only in the highest ratio of E. lehmanniana to B. gracilis. Plant-soil feedback did not provide an advantage to E. lehmanniana in competitive interactions with B. gracilis at low competition levels but were advantageous to E. lehmanniana at the highest competition ratio, indicating a possible density-dependent effect. Despite being beneficial to B. gracilis under many conditions, E. lehmanniana was the superior competitor.