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To investigate the response of maize hybrids to plant population and nitrogen fertilization rates. Two field experiments were conducted at the Experimental Farm, Faculty of Agriculture (Saba Basha), Alexandria University during 2018 and 2019 seasons. Factorial experiments (two factors) in randomized complete block design (RCBD). Whereas, the first factor was plant population (50000, 75000, 100000 plant/ha), while, the second factor was nitrogen fertilization rates (216, 288, 360, and 432 kg N/ha). The results revealed that ear length (cm), number of rows/ear, number of grains/row, number of grains/ear, 100-grains weight (g), grain yield (t/ha), straw yield, biological yield (t/ha), harvest index (%) and grain protein content (%) of maize hybrid were, significantly, affected by plant population and nitrogen fertilizer rates, where the highest grain yield was obtained by growing maize plant hybrid 3444 at a population of 75000 plant/ha under the application of 360 kg N/ha under the environmental conditions of Alexandria, Egypt. [ABSTRACT FROM AUTHOR]

The paper presents the results of the field experiments dedicated to investigation of chickpea reaction on cultivation technology elements in the South of Ukraine. The study was carried out during 2012-2014 on the dark-chestnut soil in the semi-arid climate conditions. The design of the study included research of the crop reaction on the following agrotechnological factors: plowing depth (20-22, 28-30 cm), fertilization dose (N0P0; N45P45; N90P90), plants population (50, 100, 150 plants per m²), and humidification conditions (sprinkler irrigation applied or not). The study was conducted in four replications by the split plot design method with the crop variety Rosanna of Kabuli type. Chickpea yielding data were processed by ANOVA procedure, the differences obtained in the experiments are significant and reliable at the probability level of 95%. The results of the experiments testify that the best crop productivity could be obtained at the irrigated variants with the highest fertilization dosage, the maximum plants population, and plowing at the depth of 28-30 cm - 3600 kg per ha. However, the best water resource use efficiency was obtained at the variants with plowing at the depth of 20-22 cm - 36.66 kg per mm. Absence of water supply by irrigation also worsened the water use efficiency and productivity of the crop. Mineral fertilizers and optimum plants population significantly enhanced the crop water use efficiency and productivity both at the irrigated and non-irrigated conditions. [ABSTRACT FROM AUTHOR]

The adequate combination of row spacing with the number of plants per meter in front of different edaphoclimatic conditions is fundamental to obtain greater common bean yields. This work aimed to identify the best spatial arrangement and dose of monoammonium phosphate (MAP) to maximize the productive potential of very early BRS FC104 common bean cultivar. The experiments were conducted in Formosa, Cristalina, Santa Helena de Goiás, and Santo Antônio de Goiás, Goiás, in a randomized block design with split plots and four replications. In the plots, five doses of MAP, 100, 150, 200, 250, and 300 kg ha-1, and, in the subplots, five plant populations, 6, 8, 10, 12, and 14 plants per meter were evaluated. Two experiments were carried out in each locality, one at 0.38 m spacing and another at 0.50 m spacing. Among the grain yield components, the number of pods per plant was the most affected by the spatial arrangement of plants, increasing its value with the increase in row spacing and the reduction in plant population. The response of common bean yield to row spacing was variable, depending on the local and the dose of MAP. The plasticity of the grain yield components kept the common bean yield stable in relation to changes in the plant population, except in Santa Helena de Goiás, where greater grain yield was obtained with about 14 plants per meter. Phosphate fertilization increased common bean yield in Santo Antônio de Goiás. [ABSTRACT FROM AUTHOR]

Crop growth models including CERES-Maize and CROPGRO-Soybean have been used in the past to evaluate causes of spatial yield variability and to evaluate economic consequences of variable rate prescriptions. In this work, a nitrogen prescription program has been developed that simulates the consequences of different nitrogen prescriptions using the DSSAT crop growth models. The objective of this paper is to describe a site-specific nitrogen prescription and economic optimizer program developed for computing spatially optimum N rates over long periods of weather and plant population for maize (Zea mays L.) using the CERES-Maize model. The application of the model was demonstrated on a field in Germany and another one in the USA to evaluate the concept across different environmental conditions. The user can determine the short- and the long-term optimal spatial nitrogen prescription based on crop price and nitrogen cost. The program simulated short-term optimum N applications that averaged 9% (McGarvey field, USA) and 48% (Riech field, Germany) lower than the uniform rates actually applied in the fields. The program indicated different site-specific N management options for low and high yielding fields under the assumed prices for maize and N. The implementation of a site-specific plant population management was investigated. A site-specific-optimization of plant population showed a higher profitability in the heterogeneous field in Germany. Hard pan depth, hard pan factor, root distribution factor and the percentage of available soil water across the heterogeneous field were useful indicators in predicting the magnitude of site-specific plant population benefits over uniform rates. [ABSTRACT FROM AUTHOR]

The process of improving crop management inputs by use of remote sensing devices is a new technology. This study presents the use of the normalized-difference vegetative index (NDVI) combined with the coefficient of variation (CV) to predict plant populations in corn (Zea mays L.) over different growth stages and different locations. About 76 plots were selected from the two sites to conduct this research. The results showed that we were not able to reliably predict plant population at lately growth stages because the canopy covered the soil with overlapping leaves. However, at early growth stages, the results suggest that as the corn plant emerged from the soil, the biomass per unit area was small and the sensor technology application for prediction of plant population was possible. Further studies may be designed based on this observation to investigate the possibility at early growth stages such as V2 and V3. [ABSTRACT FROM AUTHOR]

In‐row plant densities have not been studied for common beans with type II growth habit and contrasting reactions to white mould. Advanced breeding lines with partial resistance or susceptibility to white mould were combined with 4, 7, 10 or 13 plants m−1 and with or without fungicide at a constant between‐row spacing of 0.5 m in five sprinkler‐irrigated field trials conducted during the autumn–winter season in Brazil. White mould pressures in the trials covered the whole range from zero to moderate/high (46–60% of white mould severity index). In all trials, means of white mould incidence, severity and yield did not vary significantly between 7 and 13 plants m−1 for the partially resistant line, regardless of the fungicide levels. For the susceptible line, 13 plants m−1 increased white mould incidence and severity under moderate disease, regardless of the fungicide levels, and decreased yield compared with 10 plants m−1 when fungicide was applied twice under moderate/high disease pressure. For the susceptible line, 7 or 10 plants m−1 maximized yield in all trials, with or without fungicide applications. The results suggest that the current recommendation of 11–13 plants m−1 could be used for type II beans with partial resistance to white mould in either a conventional or organic system. For susceptible genotypes, 7–10 plants m−1 seems to be the most appropriate in‐row plant density. This study may improve the recommendation of in‐row plant density for type II beans cultivated under white mould pressure. [ABSTRACT FROM AUTHOR]

Farmers in Bangladesh are always seeking an optimal seed rate to reduce production costs and increase wheat yield. The Wheat Research Centre (WRC) of Bangladesh has developed new wheat varieties over several years. To reduce production costs and obtain higher grain yield (GY) from these varieties, optimum seeding rates are needed. In this context, a two-year field experiment was conducted with five newly released wheat varieties (‘BARI Gom 24’, ‘BARI Gom 25’, ‘BARI Gom 26’, ‘BARI Gom 27’ and ‘BARI Gom 28’) and three seeding rates (100, 120 and 140 kg ha─1). These treatments were performed under irrigation in the WRC research field in Northern Bangladesh to determine the optimum seeding rates for these varieties. Significantly higher GY (p≤0.05) was obtained with a seeding rate of 140 kg ha─1 for all varieties, compared to other rates. A seeding rate less than the recommended rate (120 kg ha─1) for all varieties failed to produce comparable GY in both years. Among all varieties, ‘BARI Gom 26’ had the highest GY while ‘BARI Gom 25’ had the lowest GY in both years. Although the interaction effect of variety and seeding rate on GY did not vary significantly (p≤0.05) in both years, surplus GY was 467 and 233 kg ha─1, respectively for ‘BARI Gom 24’, 63 and 75 kg ha─1 for ‘BARI Gom 25’, 81 and 93 kg ha─1 for ‘BARI Gom 26’, 23 and 66 kg ha─1 for ‘BARI Gom 27’, and 152 and 220 kg ha─1 for ‘BARI Gom 28’ in the first and second year when seeded at 140 kg ha─1. For the same seed rate, the GY of ‘BARI Gom 24’ increased by 5.3 to 9.6% and that of ‘BARI Gom 28’ increased from 2.8 to 5% over the two years. Therefore, a seeding rate of 140 kg seed ha─1 is recommended for ‘BARI Gom 24’ and ‘BARI Gom 28’, while the current recommended rate (120 kg ha─1) should be continued for the other three varieties when grown under irrigation on the Old Himalayan Piedmont Plain of Bangladesh. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Highlights • Oil yields in the 0.7 m row-spacing treatment increased over the whole of the 2.0-14.3 plants m-2 range of populations explored. • This increase was a reflection of a continuous increase of total crop biomass with increased plant population, together with an unchanging harvest index. • Over the 2-7 plant m-2 range of plant populations shared between 0.7 m and 1.40 m the row-spacing treatments yields did not differ between row spacings. • Vegetative and reproductive plasticities did not vary for the range of plant populations greater than 2.0 plant m-2 in either row spacing Abstract Attempts have not been made to increase the potential yield of sunflower via the combined use of high plant populations and crowding-tolerant cultivars, an approach that has been successful in maize -another strong apical dominance crop. This may be due to the negative effects of increased disease pressure and increased susceptibility to lodging at high sunflower plant populations. Information on crop yield responses to plant populations higher than usual recommended commercial plant populations is also limited. Wide inter-row spacing could shift crop water consumption towards later developmental stages with positive effects on yield in seasons of low rainfall, but might also limit crop yields in years with good rainfall. Here we report on studies aimed at examining yield (both oil and total biomass) responses to changes in plant population at two inter-row spacings: 0.7 and 1.4 m, in crops grown without restrictions due to water or nutrients, and protected from insects and diseases. Oil yields in the 0.7 m row spacing treatments increased over the whole of the 2.0-14.3 plants m-2 range, reaching values much greater than those obtainable at the current commercial plant population of around 5.1 plants m-2. This increase reflected a continuous increase with increased plant population for total crop biomass, together with an unchanging harvest index. Over the 2-7 plant m-2 range of plant populations shared between the two row spacing treatments yields were not affected by spacing. Vegetative and reproductive plasticities, as reflected in the responses of biomass and plant leaf area at mid-anthesis to ground surface area per plant (vegetative plasticity indicators) and oil yield per plant to ground surface area per plant (reproductive plasticity indicator) did not vary over the 2.0-14.3 plant m-2 plant population range in either row spacing. In the 0.7-m row-spaced crops, reproductive plasticity was less than vegetative plasticity and a similar tendency was observed at the 1.4-m row spacing. Floret number and achene number per plant together with unit achene weight decreased over the 2.0-14.3 plant m-2 range for both row spacings, while fertility ratio over the same range was stable. Over the same range of plant population, achene oil concentration fell slightly, while achene oil content increased slightly and then stabilised. The study of the genetic basis of the plasticities found in this work should contribute to breeding programs aimed at increasing crop tolerance to high plant population densities. [ABSTRACT FROM AUTHOR]

Establishing an adequate plant population is one of the first challenges of sugar beet production. Reduced sugar beet emergence results in a decision between a lower than desired plant population or replanting the field. The objective of this study was to determine the plant population that warrants replanting a field to maximize extractable sugar ha-1. The study was conducted in three environments during the 2016 and 2017 growing seasons. Two planting dates and six plant populations were utilized in each environment. The two planting dates were separated by 19 or 20 days to simulate a replant situation. Sugar beets in each planting date were hand thinned to six populations of 44,000, 58,700, 73,400, 88,100, 102,800, and 117,400 plants ha-1. Planting date and plant population did not significantly affect sugar concentration. However, planting date and plant population influenced yield and extractable sugar ha-1. Extractable sugar yieldwas maximized with the first planting date and populations of 102,800 and 117,400 plants ha-1. A population of 58,700 plants ha-1 in the first planting date had similar extractable sugar yield to the second planting date populations of 88,100, 102,800, and 117,400 plants ha-1. Sugar beet populations above 58,700 plants ha-1 should not be replanted based on the results from this study. [ABSTRACT FROM AUTHOR]

Conflicting reports of the responsiveness of carrots (Daucus carota L.) to nitrogen (N) fertiliser have been rationalised on the basis of the climatic zones in which the experiments were conducted. We tested this explanation with two experiments under temperate conditions, where yield increases were predicted to be unlikely, yet growers frequently apply N fertiliser. Our results show that in temperate regions carrot yields may indeed respond to N fertiliser when the yield potentials are c. 140 t ha−1 of fresh roots, if soil mineral N to 0.6 m depth and readily mineralisable N add to less than c. 190 kg N ha−1. With normal experimental precision, such responses may be undetected unless soil water deficit is kept small and variations in plant population are accounted for. Carrots have strong potential for luxury uptake of N. This has implications for marketing and the possible use of carrots as catch crops. [ABSTRACT FROM AUTHOR]

Copyright of Anbar Journal of Agricultural Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Despite breeding advancements in high carotenoid maize, impacts of common crop management on carotenoid levels remain unclear. Our objective was to identify possible crop management options, other than genotype selection, for increasing maize grain carotenoid concentration and to relate them with the resulting flour color. We were also interested in understanding what environmental factors help explain variations in grain carotenoid concentration. The effects of plant population, sowing date, genotype selection, and N fertilization on total grain carotenoid concentration and flour color were tested in different field experiments under rainfed conditions. Genotypes had 25% higher values when sowing date was delayed. However, the response to sowing date was genotype dependent (p < 0.05; an increase from 6 to 57%). Plant populations higher than 8.5 plant m-2 decreased carotenoid concentration by 5% (p < 0.05), while N fertilization showed inconsistent effects (+5 or −12% depending on the environment). The higher concentrations in later sowings were associated with cooler temperatures and a better water balance during grain filling. The impact of management over carotenoid concentration also affected the resulting flour color, modifying its lightness and chromaticity. Results suggest that, in addition to genotype selection, late sowing dates and moderate plant populations can help increase grain carotenoid concentrations. [Display omitted] • High plant population reduce carotenoid levels, while N fertilization showed inconsistent results. • Delayed sowing dates increased ∼25% carotenoid concentration. • Cooler and wetter conditions during grain filling promoted higher carotenoid levels. • Carotenoid levels showed no yield negative trade-offs. [ABSTRACT FROM AUTHOR]

The second crop narrow row cotton under rainfed conditions, after soybean or common bean harvest, has increased in the Midwest Brazilian Savannah. This change in sowing date exposes cotton plants to adverse environmental conditions. This study aimed at evaluating the effect of cotton cultivars, plant densities and sowing dates on cotton yield. The experiments were conducted over three consecutive years. In each year, the treatments were two sowing dates (second half of January and first half of February), cultivars (early and mid-cycle) and plant densities (8.9-33.3 plants m-2). Cotton was sowed in the second crop, after the early soybean harvest. In each sowing date, experiments were conducted in a split-plot randomized blocks design, with cultivars arranged in plots and densities in subplots. Cotton yield in the second crop growth season was little affected by plant densities and cultivars. Late sowing reduced plant height, number of bolls per unit area and cotton lint yield. In the second sowing date, lint yield decreased nearly 25 %, 17 % and 41 %, respectively in 2009, 2010 and 2011. Sowing date is the most important factor for cotton production in a second crop.

Within the context of precision agriculture, goods insurance, public subsidies, fire damage assessment, etc., accurate knowledge about the plant population in crops represents valuable information. In this regard, the use of Unmanned Aerial Vehicles (UAVs) has proliferated as an alternative to traditional plant counting methods, which are laborious, time demanding and prone to human error. Hence, a methodology for the automated detection, geolocation and counting of crop trees in intensive cultivation orchards from high resolution multispectral images, acquired by UAV-based aerial imaging, is proposed. After image acquisition, the captures are processed by means of photogrammetry to yield a 3D point cloud-based representation of the study plot. To exploit the elevation information contained in it and eventually identify the plants, the cloud is deterministically interpolated, and subsequently transformed into a greyscale image. This image is processed, by using mathematical morphology techniques, in such a way that the absolute height of the trees with respect to their local surroundings is exploited to segment the tree pixel-regions, by global statistical thresholding binarization. This approach makes the segmentation process robust against surfaces with elevation variations of any magnitude, or to possible distracting artefacts with heights lower than expected. Finally, the segmented image is analysed by means of an ad-hoc moment representation-based algorithm to estimate the location of the trees. The methodology was tested in an intensive olive orchard of 17.5 ha, with a population of 3919 trees. Because of the plot’s plant density and tree spacing pattern, typical of intensive plantations, many occurrences of intra-row tree aggregations were observed, increasing the complexity of the scenario under study. Notwithstanding, it was achieved a precision of 99.92%, a sensibility of 99.67% and an F-score of 99.75%, thus correctly identifying and geolocating 3906 plants. The generated 3D point cloud reported root-mean square errors (RMSE) in the X, Y and Z directions of 0.73 m, 0.39 m and 1.20 m, respectively. These results support the viability and robustness of this methodology as a phenotyping solution for the automated plant counting and geolocation in olive orchards.

Variations in response pattern of maize (Zea mays)grown at plant populations, defoliated at post-anthesis in the rainforest were tested. Two field trials were conducted at Abeokuta, (Longitude 3025’E, Latitude 7015’N; 144 m a.s.l) and Ibadan (3056’E, 7033’N: 168 m a.s.l), Nigeria in 2015. The trials consisted of maize variety {2009 TZE-W DT STR [open pollinated variety (OPV)] and TZEI 124 × TZEI 25 (hybrid)]} in the main plot, plant population (71111, 80000 and 106666 plant ha-1) in sub plot and defoliation (+ defoliation and – defoliation) as sub-sub plot. It was laid out in a split-split plot arrangement fitted into randomised complete block design with three replicates. OPV had significantly higher assimilatory surface, rate of current photosynthesis, reduced dry matter translocation efficiency, reduced days to 50 % anthesis and more 1000 grain massthan the hybrid maize, with similar grain yields. Both locations experienced increased leaf area index with increased plant population. Reduced 1000 grain massat both locations when maize was defoliated suggested a disruption in source:sink balance.

Seed spacing directly affects crop revenue because the number of potato seeds planted determines the final plant population density. The analysis presented in this 5-page publication was extracted from a series of field trials that looked at improved potato plant arrangement in the field by adjusting seed piece spacing for Florida growing conditions. Written by Fernanda Souza Krupek, Steven A. Sargent, Peter J. Dittmar, and Lincoln Zotarelli and published by the UF/IFAS Horticultural Sciences Department, May 2018. https://edis.ifas.ufl.edu/hs1317

Quantitative estimation of genotypic structure dynamic of three plant species: Nicotiana tabacum L., Anacamptus pyramidalis (L.) Rich., Teucrium chamaedrys L. in different ecological conditions has been conducted. The effectiveness of systemic analyses of the trait complex with the aim of ecologo-genetic monitoring of the plant population has been established.

To further unification of approaches to the terminology and methodology of research in the demographic ecology, it is important to seek consensus on a number of issues, including the concept of “population vitality”. There is a need to develop a consolidated approach to the assessment of a population-based set of characteristics – individual and group. Based on current views, we can assume that the vitality of population is an integral characteristic that reflects the current state of a population on the basis of major individual and group parameters of structure, growth, development and reproduction. Vitality represents the actual position of population in the realized ecological niche and corresponds to the norm of reaction that reflects actual habitat conditions at a particular time. The main parameters to establish the vitality of a population are its size, age, vital and sex structure, population density, the intensity of generative and vegetative propagation, phytomass and others. Evaluation of the vitality does not provide long-term prognosis instead of population viability, which means the establishment of perspectives. Monitoring of population vitality should form the basis for population viability assessment.

The objective of this work was to study the influence of different seeding rates and cultivars over flooded rice yield at the west border of Rio Grande do Sul State. The experimental design was a randomized blocks with four replicates. The treatments were arranged in factorial scheme 4 x 3, in which factor A was the seeding rate (40, 60, 80 and 100kg ha-1) and B the cultivars (BR-IRGA 409, Olimar and Puitá Inta-CL). The increase in seeding rate from 40 to 100 kg ha-1 reduces linearly the tilled number, filled, total grains for panicle and number of panicle per m2. The greater rice grains yield in cultivars Olimar and Puitá Inta-CL is obtained in seeding rate of 66 and 77 kg ha-1 respectively. On the other hand, the yield of cultivar BR-IRGA 409 was not influenced by seeding rate. The yield grain was greater in cultivar Puitá Inta-CL, except with the seeding rate of 80 kg ha-1, in which it was the second most productive cultivar.

Our aim was to evaluate agronomic and chemical characteristics of corn hybrids to ensiling. It were evaluated nine corn hybrids (MX 300, RB 9308, 2B655, XB 6012, GNZ 2500, PL6890, PRE 32D10, PRE 22T10 e AG 1051), with three replicates. The higher fresh matter yield were observed in the hybrids PL6890 and PRE 32D10, while the dry matter yield was observed in the hybrid PRE 32D10 (13.43 t ha-1). The hybrids PRE 32D10 and PRE 22T10 stood out to present higher percent of leaf in relation to whole plant, while the lower percent of stems was found in the hybrids MX 300, 2B655 and XB 6012, however the higher leaves: stems relation was found in XB 6012 (0.49). There was higher CP content in the hybrid PRE 32D10 (9.10% of DM), while the lower NDF (57.78% of DM) and cellulose content (24.27% of DM) were observed in the hybrid GNZ 2500. The hybrid PL6890 presented higher ADF and lignin contents, the others hybrids had values lower. The lower NDIN content was observed in the hybrid RB 9308, while the lower AIDN content occurred on the hybrid 2B655. The lower buffer capacity was observed in the hybrid 2B655 (0.29). There are some differences on chemical composition among the corn hybrids used in this study, however, it is recommended to use the hybrids MX 300, PL6890 and PRE 32D10 for showing higher dry matter yield, which may reflect in the amortization of silage production costs.

Cover crops have been recognized as a vital part of conservation agriculture, but they need to be managed appropriately to avoid planting problems related to the large amounts of biomass. Typically, cover crops are rolled in the same direction as the travel direction of the planter, but producers have been inquiring if other rolling directions are also effective. To answer this question, replicated field experiments (split-plot design) were conducted at two locations in Alabama during three growing seasons to evaluate different rolling directions of a cereal rye cover crop, i.e., non-rolled (standing rye), 0° (cotton planting direction), 180° (opposite of planting direction), 15° (offset from 0°), and 195° (15° offset from 180°), using a roller/crimper. A no-till cotton planter with different row cleaners, i.e., a commercially available row cleaner (Dawn with coulter), a residue pusher with and without a coulter, and no row cleaner (control), was used to determine the effects of rolling direction and row cleaners on cotton population, emergence rate, and yield. The rye cover crop was terminated with a roller/crimper and glyphosate. Among growing seasons, significant differences existed in rye production, cotton population, emergence rate index (ERI), seed cotton yield, amount of residue accumulated on the planter, and the time required to remove residue from the planter. For the rolling direction treatments, higher cotton population was found for 0° and non-rolled rye, and the lowest population was found with 195°. The ERI was higher for 0° and non-rolled rye, and the lowest ERI was observed for 195°. For the row cleaner treatments, the cotton population and ERI were both higher for Dawn with coulter and pusher with coulter. Across three growing seasons, cotton yield was not affected by rolling direction but was affected by row cleaner. Significantly higher cotton yield was associated with Dawn with coulter and pusher with or without coulter, compared to lower yield for no row cleaner. The important findings were that residue accumulation was not problematic when the cover crop was rolled. When the cover crop was not rolled, the pusher accumulated more residue than Dawn with coulter; however, the time required to remove the residue was more than 3 times higher for Dawn with coulter as compared to the pusher. The data indicated that, across all growing seasons and locations, rolling direction and row cleaner affected the cotton population, ERI, residue accumulation on the planter, and the time required to remove residue. In contrast, rolling direction did not affect seed cotton yield, but row cleaner had an effect on seed cotton yield. Based on the results, the best combination of rolling direction and row cleaner was 15° offset to the cotton planting direction and Dawn with coulter, which resulted in higher cotton population, ERI, and seed cotton yield without residue accumulation on the row cleaner. However, the 0° and 180° Dawn with coulter and 15° pusher with coulter combinations were also effective in producing relatively higher cotton population, ERI, and seed cotton yield. [ABSTRACT FROM AUTHOR]

Copyright of Nativa is the property of Revista Nativa and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The standard row width for potato production in the Columbia Basin of Washington and Oregon is 86 cm (34 in.), but the reasons for this are unclear. The goal of this research was to identify a row width that maximizes potato grower revenue by optimizing land use efficiency. A 2012 pilot study conducted in central WA with four potato varieties (Alturas, Ranger Russet (R.), R. Burbank, and Umatilla R.) and four row width treatments (76, 81, 86, and 91 cm (30, 32, 34, and 36 in.)) indicated that row widths <86 cm had several advantages over those ≥86 cm. The protocol and methods were refined and a larger study conducted between 2013 and 2015. Russet Norkotah, Chieftain, and Teton R. were planted with the four varieties mentioned above into 71, 76, 81, and 86 cm (28, 30, 32, and 34 in.) row-width treatments; in-row seed piece spacing was 25.4 cm (10 in.). When data were averaged across years and varieties, a quadratic regression provided the best fit for total yield and adjusted gross return; the values for each peaked at 79 cm and 80 cm, respectively. Row widths of 76 and 81 cm produced 6 and 7 t ha−1 higher yields, respectively, than the 86 cm industry standard. The 81 cm treatment produced 7.3% higher adjusted gross than the industry standard. Compared to the industry standard, plants from the 71 cm rows performed poorly; this 15 cm (6 in.) reduction in row width caused a 9.3% loss of adjusted gross income. Tuber weight and number per plant and were maximized when rows were ≥81 cm wide. These data suggest that the industry standard row width of 86 cm is an inefficient use of land and that an inter-row spacing of 80-81 cm (31.5-32.0 in.) could improve economic return to Columbia Basin growers by as much as $937 ha−1. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the productivity and quality of grains under different sowing densities in irrigated rice hybrids. The hybrids BRSCIRAD 302 and BRSCIRAD AH703 CL were analyzed at sowing densities of 10, 20, 30 and 40 kg ha-1, in the municipalities of Capão do Leão and Capivari do Sul, in the state of Rio Grande do Sul. The characteristics assessed were: productivity, components of grain production, agronomic characteristics, industrial and commercial quality of irrigated rice grains. The data were submitted to analysis of variance and F test, using for the comparison of hybrids the Tukey test at a 5% significance level, and for sowing, density regression analysis was applied. Sowing densities of 20 kg ha-1 and higher show no effect on productivity. The grain quality of hybrids is not influenced by the variation in sowing density, and reduction in sowing density up to 10 kg ha-1 does not affect the commercial quality of the grains. Thus, it is possible to recommend the cultivation of irrigated rice hybrids with reduced sowing densities, starting from 20 kg ha-1, without affecting grain yield and quality. [ABSTRACT FROM AUTHOR]

Large animal species, which provide important ecological functions such as dispersal of seeds or top–down control of seed predators, are very vulnerable in fragmented forests, being unable to survive in small fragments, and facing increasing hunting pressure. The loss of large animals affects two main ecological processes crucial for the tree reproductive cycle: seed dispersal of large seeds (e.g. provided by tapirs) and control of seed predator population (e.g. provided by large cats). The changes in both processes are expected to increase seed mortality since seeds are not dispersed away from conspecifics (causing increased pre‐dispersal mortality due to negative density dependent effects) and/or face increased predation after a dispersal event (post‐dispersal mortality). Although an extensive body of empirical knowledge exists on seed predation, the link between seed loss and adult tree community composition and structure is not well established, as well as the temporal scale seed changes affect adults. Using an individual‐based forest model (FORMIND), we evaluate the long‐term consequences of increased pre and post‐dispersal seed mortality on the future forest biomass retention of a Brazilian northeastern Atlantic forest. Our results show that forest biomass is significantly affected after 80–93% pre‐dispersal loss of large seeds, or post‐dispersal predation densities of 20–25 predators per parent tree. Large‐seeded tree species are at increased risk of local extinction causing up to 26.2% loss of forest biomass when both pre and post‐dispersal processes are combined. However, these changes can last up to 100 years after the occurrence of defaunation. In summary we conclude that large animal loss has the potential to reduce future forest biomass and tree species‐richness by impacting seed survival, and should be considered in the planning of biodiversity friendly landscapes as well as in calculations of the global carbon budget. [ABSTRACT FROM AUTHOR]

In plant–arthropod associations, the first herbivores to colonise a plant may directly or indirectly affect community assembly on that particular plant. Whether the order of arrival of different arthropod species further modulates community assembly and affects plant fitness remains unclear. Using wild Brassica oleracea plants in the field, we manipulated the order of arrival of early‐season herbivores that belong to different feeding guilds, namely the aphid Brevicoryne brassicae and caterpillars of Plutella xylostella. We investigated the effect of herbivore identity and order of arrival on community assembly on two B. oleracea plant populations during two growth seasons. For this perennial plant, we evaluated whether foliar herbivory also affected herbivore communities on the flowers and if these interactions affected plant seed production. Aphid infestation caused an increase in parasitoid abundance, but caterpillars modulated these effects, depending on the order of herbivore infestation and plant population. In the second growth season, when plants flowered, the order of infestation of leaves with aphids and caterpillars more strongly affected abundance of herbivores feeding on the flowers than those feeding on leaves. Infestation with caterpillars followed by aphids caused an increase in flower‐feeding herbivores compared to the reversed order of infestation in one plant population, whereas the opposite effects were observed for the other plant population. The impact on plant seed set in the first reproductive year was limited. Our work shows that the identity and arrival order of early season herbivores may have long‐term consequences for community composition on individual plants and that these patterns may vary among plant populations. We discuss how these community processes may affect plant fitness and speculate on the implications for evolution of plant defences. [ABSTRACT FROM AUTHOR]

Copyright of Revista Caatinga is the property of Revista Caatinga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nitrogen fertilizer and plant density are considered some of the most important factors affecting phenology and grain yield of maize. Therefore, current study was conducted to assess the effects of nitrogen fertilizer application and plant density on phenology (days to tasseling, silking and maturity) and grain yield of maize (Variety: Rampur Composite) at Mangalpur VDC-3, Anandapur, Chitwan, Nepal during 2006-07 winter season. The fve levels of nitrogen as 0, 50, 100, 150 and 200 kg N/ha and three levels of the plant population as 55555, 66666 and 83333 plants/ha were evaluated using two factorial randomized complete block design with three replications. The days of fowering (tasseling and silking) decreased with increasing nitrogen level up to 200 kg N/ha and increased with increasing level of plant population up to 83333 plants/ha). Physiological maturity and grain yield increased with increasing level of nitrogen up to 200 kg N/ha and plant population up to 83333 plants/ha. The highest grain yield (6925.79 kg/ha) was obtained with 200 kg N/ha + 66666 plants/ha. This study suggested that maize production can be maximized by cultivating maize with the use of 200 kg N/ha and maintaining the plant density of 66666 plants/ha. [ABSTRACT FROM AUTHOR]

Copyright of Cientifica is the property of Fundacao de Apoio a Pesquisa e Extensao and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background and Aims Global agriculture is facing the challenge of a phenotyping bottleneck due to large-scale screening/breeding experiments with improved breeds. Phenotypic analysis with high-throughput, high-accuracy and low-cost technologies has therefore become urgent. Recent advances in image-based 3D reconstruction offer the opportunity of high-throughput phenotyping. The main aim of this study was to quantify and evaluate the canopy structure of plant populations in two and three dimensions based on the multi-view stereo (MVS) approach, and to monitor plant growth and development from seedling stage to fruiting stage. Methods Multi-view images of flat-leaf cucumber, small-leaf pepper and curly-leaf eggplant were obtained by moving a camera around the plant canopy. Three-dimensional point clouds were reconstructed from images based on the MVS approach and were then converted into surfaces with triangular facets. Phenotypic parameters, including leaf length, leaf width, leaf area, plant height and maximum canopy width, were calculated from reconstructed surfaces. Accurate evaluation in 2D and 3D for individual leaves was performed by comparing reconstructed phenotypic parameters with referenced values and by calculating the Hausdorff distance, i.e. the mean distance between two surfaces. Key Results Our analysis demonstrates that there were good agreements in leaf parameters between referenced and estimated values. A high level of overlap was also found between surfaces of image-based reconstructions and laser scanning. Accuracy of 3D reconstruction of curly-leaf plants was relatively lower than that of flat-leaf plants. Plant height of three plants and maximum canopy width of cucumber and pepper showed an increasing trend during the 70 d after transplanting. Maximum canopy width of eggplants reached its peak at the 40th day after transplanting. The larger leaf phenotypic parameters of cucumber were mostly found at the middle-upper leaf position. Conclusions High-accuracy 3D evaluation of reconstruction quality indicated that dynamic capture of the 3D canopy based on the MVS approach can be potentially used in 3D phenotyping for applications in breeding and field management. [ABSTRACT FROM AUTHOR]

Florida cabbage production is dominated by a bare ground production with sub optimal plant populations under seepage irrigation system. Previous studies used plasticulture to increase the plant population and maximize cabbage production per area. The present research was conducted to; determine the optimum nitrogen fertilizer application rate range, determine the transport and fate of applied nitrogen fertilizer and to examine the effects of two irrigation strategies for the proposed plasticulture system with high plant population. The soil moisture sensor based irrigation treatment used 11% and 33% less irrigation water in 2013 and 2014, respectively compared to the evapotranspiration based irrigation with no significant difference in cabbage yield. In 2014, the soil moisture sensor based irrigation also led to an increased retention time of nitrogen fertilizer in the crop rootzone. The optimum fertilizer rate range was determined to be between 400 and 570 kg ha −1 of N (5–7 g plant −1 of N), respectively. Cabbage yields obtained using fertilizer rates within the optimum range under high plant population plasticulture were on average 71% greater than the average bare ground yield under seepage irrigation. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Kirkuk University for Agricultural Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Field trial was conducted during the 2012 and 2013 wet seasons at Institute for Agricultural Research, Ahmadu Bello University, Zaria Farms at Kadawa and Minjibir, (110 39'N, 080 20'E) and Kano (12° 08' N, 08° 40' E)500m above sea level in the Semi arid ecological zone of Nigeria, to study the influence of weed control treatment and plant population on yield and yield attributes of sweet sorghum (Sorghum bicolor (L.)Moench. sub-species, saccharatum) varieties. The treatments consisted of four levels of weed control treatment (one rate each of atrazine and primextra gold at 2.1 kg a.i/ha, hoe-weeded control at 3 and 6 weeks after sowing (WAS) and weedy check), three plant densities (53,333, 106,667, and 160,000 plants/ha), and two varieties(NTJ2 and Ex-Daura). The treatments were laid out in a split plot design with three replications. The combination of weed control treatment and the plant population were assigned to main plot while the two varieties to sub-plot. The study revealed that primextra gold at 2.1 kg a.i/haand two hoe-weeding at 3 and 6 WAS resulted in significantly longer panicle length, higher1000-grain weight, stalk, grain, and brix yields in both seasons and locations. The performance of this herbicide was comparable to hoeweeding in keeping the trial fields weed free and lower competition for nutrients at both location seasons. Weedy check reduced all yields and yield attributes. The 160,000plants/ha significantly suppressed weed infestation and resulted in longer panicles, higher 1000-grain weight, stalk, grains and brix yields at the two the locations and seasons.NTJ2 performed better in term yield and yield attributes, with higher stalk yield at Kadawa and grain yield at Minjibir. Based on the result obtained from this, it can be concluded that the use of NTJ2 variety, with application of primextra gold at 2.1 kg a.i/ha, and 160,000plant population and NTJ2 variety had resulted gave season long weed control, the highest stalk and grain yields at Kadawa and Minjibir. [ABSTRACT FROM AUTHOR]

Thirty million hectares of maize (Zea maysL.) in the developing world are planted and harvested by hand. Indigenous planting encumbers placing two to three seeds per hill and this results in uneven spacing and decreased yields. Oklahoma State University (OSU) built a new hand planter to deliver single seeds with each strike (singulation). This planter includes a range in cavity sizes so as to accommodate different seeds. At all sites, the OSU internal drum resulted in similar emergence as the checks were planted by hand, and a John Deere vacuum planter. Developing world maize producers can use the OSU hand planter with drum “450S” if seeds are in the 2500–4000 seeds/kg range using a conventional metal tip. This planter also removes the chemically treated seed from producer's hands, reduces health risks, and serves as a mid-season fertilizer applicator. [ABSTRACT FROM PUBLISHER]

There is little quantitative information available on the responses of carrots (Daucus carotaL.) to water deficits. We tested the hypothesis that root yield decreases with increases in the maximum potential soil water deficit (DØmax, mm). Field crops of carrot (Chantenay Red Core) were grown under a rain-out shelter near Lincoln, New Zealand, using trickle irrigation to achieve six treatments that differed in the timing (early-, mid- and late-season) and intensity (moderate and high) of water stress. There were also unirrigated and fully irrigated (minimal water stress) treatments. Total biomass and root yields declined linearly with increasingDØmax, supporting the hypothesis under test. Storage root diameter, but not length, also decreased, so that process-grade packouts of roots fell sharply with DØmax. There was no significant relationship between root soluble solids concentration andDØmax. Minimising water deficits is crucial for achieving high yields of quality carrots. [ABSTRACT FROM AUTHOR]