Close Spacing Research Articles

Strategic agronomic interventions for leaf yield and quality improvement in moringa (Moringa oleifera L.) under high density planting system

Moringa leaves are rich in minerals, vitamins, proteins, and soluble fiber, making them an ideal dietary supplement for addressing undernourishment, as well as iron and vitamin A deficiencies. The presence of high concentrations of potassium, iron, calcium, and magnesium, and natural antioxidants are particularly beneficial for pregnant mothers and young children. The current study carried out in 2021 and 2022, sought to standardize crop geometry and harvesting heights to enhance leaf biomass and quality in Moringa under High-Density Planting Systems . The research trial employed four different spacing configurations, incorporating single-row and double-row triangular planting at both wider and closer spacing, and included three harvesting heights. The experiment was arranged in a split-plot design with three replications. Observations on growth parameters, physiological traits, and yield characters were recorded at each harvest. Leaf quality parameters were analyzed in dried Moringa leaf powder. Pooled results indicated that double-row triangular planting with narrower intra-row spacing, combined with a 45 cm harvesting height, yielded substantially higher fresh and dried leaf yields of 42.76 t/ha and 7.83 t/ha, respectively. This treatment also produced superior leaf quality parameters, attributed to enhanced growth, physiological responses, and yield outcomes, leading to greater economic returns through enhanced fresh leaf yield.

High-resolution electron energy analyzer with wide acceptance angle for hard X-ray photoelectron holography: integrating PESCATORA and retarding field analyzer

Abstract Photoelectron holography requires measuring the photoelectron angular distribution across a wide acceptance angle, typically exceeding ±45°. This necessitates an electron analyzer that offers both a large acceptance angle and high energy resolution for kinetic energies ranging from several hundred to several thousand eV. Our previously developed high-resolution retarding field analyzer (RFA) achieves excellent energy resolution. However, its close electrode spacing limits operation at high voltages (several thousand eV). To address this limitation, we propose a novel electron analyzer that combines a parallelizing electron lens (PESCATORA) with an RFA. The PESCATORA lens parallelizes the trajectories of photoelectrons. Subsequently, the RFA decelerates and analyzes their energy. This two-stage approach allows for a sufficient distance between the RFA electrodes, enabling high-voltage operation. The resulting analyzer functions as a high-pass filter with a sharp energy cut-off. By incorporating lock-in detection, this system can be further worked as a bandpass electron analyzer. Our simulation also suggests that a specially designed mesh electrode within the RFA allows bandpass operation without the need for lock-in detection.

Investigation of band-beam slabs subjected to close-in blast loading - Experimental and numerical study

"Band-beam slab" or "slab with a shallow beam" are widely used in contemporary multi-level building construction and are particularly common in lower levels and basements. These slabs are favoured for conserving space and reducing floor-to-floor heights. Consequently, understanding how band-beam slabs perform when exposed to close-range detonations is essential for critical infrastructure projects and has not been previously studied in the literature. With recent terrorism events where portable explosives ranging from 2 kg to 10 kg are more common, a close-in detonation can significantly affect the structural integrity of civil infrastructure. Thus, this study aims to examine the behaviour of band-beam slabs when subjected to close-in detonations. The paper presents both experimental results and validated Arbitrary Lagrange-Euler (ALE) numerical framework to study and assess the damage of the slabs under various loading conditions and slab designs. A total of six band-bean panels are subjected to close-in detonations of Composition-4 (C4) charges. Initially, validation of the numerical modelling is performed where damage in terms of spall crater sizing and crack patterns are observed. It was shown that the numerical modelling technique could predict crater sizes within 15 % of the area, and crack propagation, including patterns, was appropriately captured. Through numerical modelling parametrisations, it was shown that confinement detailing, such as the use of C-hooks, close spacing of shear reinforcement, and additional reinforcement in the beam-to-slab transition zone can drastically improve the performance of the panel in terms of spalling damage and deflections. Finally, it was shown that the spalling, global and local deformation can be minimised with appropriate detailing. Design recommendations for additional reinforcement to control and mitigate spalling, cracking and scabbing were proposed.

Fundamental effects of array density and modulation frequency on image quality of diffuse optical tomography.

Diffuse optical tomography (DOT) provides three-dimensional image reconstruction of chromophore perturbations within a turbid volume. Two leading strategies to optimize DOT image quality include, (i) arrays of regular, interlacing, high-density (HD) grids of sources and detectors with closest spacing less than 15mm, or (ii) source modulated light of order ∼100MHz. However, the general principles for how these crucial design parameters of array density and modulation frequency may interact to provide an optimal system design have yet to be elucidated. Herein, we systematically evaluated how these design parameters effect image quality via multiple key metrics. Specifically, we simulated 32 system designs with realistic measurement noise and quantified localization error, spatial resolution, signal-to-noise, and localization depth of field for each of ∼85000 point spread functions in each model. We found that array density had a far stronger effect on image quality metrics than modulation frequency. Additionally, model fits for image quality metrics revealed that potential improvements diminish with regular arrays denser than 9mm closest spacing. Further, for a given array density, 300MHz source modulation provided the deepest reliable imaging compared to other frequencies. Our results indicate that both array density and modulation frequency affect the spatial sampling of tissue, which asymptotically saturates due to photon diffusivity within a turbid volume. In summary, our results provide comprehensive perspectives for optimizing future DOT system designs in applications from wearable functional brain imaging to breast tumor detection.

Impact of Tree Geometry on the Growth and Yield Performance of Black Gram (Vigna mungo L.) under Kadam (Neolamarckia cadamba Roxb.) based Agroforestry System

Agroforestry is an environmentally conscious and comprehensive method of land management that entails cultivating agricultural crops, forest trees, and animals in conjunction on the same parcel of land through the implementation of suitable management strategies. The present study entitled “Impact of tree geometry on the growth and yield performance of Black Gram (Vigna mungo L.) under Kadam (Neolamarckia cadamba Roxb.) based Agroforestry System” was conducted during the Kharif season of 2022-23 within an already established 2-year-old plantation situated at Forestry research farm, RLBCAU, Jhansi. The study encompasses three different spacings, i.e., S1- 5 m x 5 m, S2- 5 m x 4 m and S3- 5 m x 3m. A randomized block design having four treatments each replicated five times was laid out, Outcomes of research revealed that sole cropping of black gram exhibited higher plant height (77.44 cm), leaf and branch numbers (6.38 and 5.32, respectively), dry matter accumulation (17.05 g/plant for above-ground and 2.12 g/plant for below-ground), leaf area (2183.06 cm2), root nodules (11.54), shorter phenological duration viz., 50% flowering, 50% pod setting and maturity (40.11 days, 54.49 days, and 70.84 days, respectively). It also demonstrated significantly higher yield attributes such as number of pods and seeds per pod (27.28), number of seeds per pod (5.82), test weight (36.73 g), grain yield (0.79 t ha-1), straw yield (1.78 t ha-1), biological yield (2.57 t ha-1), harvest index (30.63 %), and grain-to-straw ratio (0.44) compared to the intercropped. Among all the agroforestry treatments Neolamarckia cadamba at 5 m × 5 m with Vigna mungo, found to perform better than closer spacing (i.e., 5 m x 4 m and 5 m x 3 m) spatial arrangements. The study encountered challenges in achieving an optimal balance between tree-crop interactions and resource competition, which are critical factors in agroforestry systems. Nevertheless, it provides significant contributions by offering insights into the optimization of tree geometry, enhancing both yield performance and the sustainability of such integrated systems.

Effect of Spacing and Planting Time on Growth, Yield and Yield Components of Mustard (Brassica nigra L.) Cultivar in Unwana, Ebonyi State, Nigeria

A field experiment was conducted at the Department of Horticulture and Landscape Technology teaching and research farm during 2022 cropping season, to investigate the effect of spacing and planting time on the growth, yield and yield components of mustard in Unwana agro-ecology of Southeastern Nigeria. Two (2) planting time and six (6) plant spacings were evaluated in a split-plot fitted in a randomized complete block design (RCBD) with three (3) replications. The factor A was time of planting (March and August), which occupied the main plot while factor B which was plant spacing (20x15cm, 30x15cm, 40x15cm, 50x15cm, 60x15cm and 70x15cm) occupied the sub-plots. Data were collected on plant height, leaf number, total yield, straw yield, oil yield and oil content at harvest. Result obtained showed that the growth, yield and yield components of mustard were significantly (P˂0.05) improved by time of planting and plant spacing used. March time of planting increased seed yield and yield components seed yield (102.90gha-1), straw yield (25.97gha-1), oil yield (654.10kg/ha), and oil content (41.56%) than August planting time (39.40gha-1, 20.93gha-1, 477.50kg/ha and 39.02% seed yield, straw yield, oil yield and oil content, respectively. On the other hand, result revealed that the plot planted with 20x15 plant spacing significantly increased the plant height and leaf number (18.98cm and 16.62) at 4WAP, respectively with the corresponding total yield (103.20gha-1) than other plant spacing used. The result showed that it was more productive to grow mustard at closer spacing (20x15cm) as depicted by the yield and yield components advantages.

Synthesis of dynamic modelling framework and optimal control strategy for virtually coupled train sets with guaranteed safety

Virtual coupling represents a novel railway operational mechanism, wherein several trains share state information and adjust their behaviours based on control objectives, which include safety (collision avoidance) assurance and stability (uniform velocity and constant spacing between trains) maintenance. However, the conflict between safety and stability requirements becomes more apparent, as the closer spacing between trains. Moreover, the hybrid nature of the train platoon operation, which involves both discrete events and continuous dynamics, also poses a significant barrier to the control strategy synthesis. This paper presents the Virtually Coupled Train Sets (VCTS) dynamic modelling framework and strategy synthesis approach to address these problems. A Hybrid Markov Decision Process (HMDP) is adopted for relative longitudinal dynamics modelling of trains, considering the influence of the uncertainty dynamic of trains ahead. A Stackelberg game-based strategy synthesis algorithm is applied for the safe guarantee by overcoming the uncertainty, and a Q-learning method is used for stability strategy selection from the safe strategy. The results showed a 17.95% expansion in the safe state space when compared to the general relative braking scheme (which assumes maximal acceleration during the delay horizon). In a four-train tracking operation scenario, compared with Q-learning without safe constraints, our approach gives similar stability performance; compared with Q-learning with general relative braking safe constraints, our approach not only assurance safety but has a better stability performance.

Correlation Between Mother’s Nutritional Expertise and Toddler’s Stunting Incidence in Wainyapu Village

Stunting is one of the world's nutritional challenges, particularly in impoverished and emerging countries. Stunting is an issue since it is connected with a higher risk of morbidity and mortality, as well as inadequate brain development, which leads to delayed motor development and stunted cerebral growth. The mother's health and nutritional status before and throughout pregnancy, the mother's body posture, the close spacing of pregnancies, the mother's adolescence, and poor dietary intake during pregnancy all have an impact on fetal growth and stunting risk. Stunting is influenced by the mother's nutritional expertise. This study aimed to evaluate the correlation between mothers’ nutritional expertise and the toddlers’ stunting incident in Wainyapu Village. This quantitative study employed an analytical survey design and a cross-sectional approach method. The population in this study were mothers who had toddlers 12-59 months and lived in Wainyapu Village. This study employed total sampling technique, with a questionnaire on mothers’ nutritional expertise as the research instrument. The Spearman correlation test was employed during data analysis. The findings yielded that the level of mothers’ nutritional expertise was mostly in the poor category (76.9%), with the incidence of stunting in toddlers as high as (75%), and there was a significant correlation between mothers’ nutritional expertise and the toddlers’ stunting incident as shown by Spearman correlation results were 0.945 with Sig p-value <0.01. It is expected that this study can provide mothers some information to better understand the importance of toddlers’ nutritional expertise in order to avoid stunting

Effects of Reynolds number and surface modification on wake-induced vibrations of two staggered circular cylinders

This study explores the role of Reynolds numbers (Re) in wake-induced vibrations (WIVs) of two cylinders, specifically wake galloping and two-degree-of-freedom coupled flutter on the downstream cylinder. The center-to-center distances between the cylinders were 3.0D −5.0D in along-flow direction and 0.0D −2.0D in cross-flow direction (D is the diameter of the cylinders). The Re ranged from 1.4 × 104–6.7 × 104, within the subcritical Re regime of a smooth cylinder. The supercritical Re regime was realized by winding 12 spiral protuberances along the cylinders to lower the critical Re. Descriptions of wake interference of two smooth cylinders at Re = 850–6.5 × 105 were summarized from the literature. Wake interference strongly depended on Re, even within the subcritical Re regime. WIVs mostly occurred in the upper subcritical Re regime with strong wake interference. In the supercritical Re regime, the wakes of the cylinders were narrowed and vortex shedding was suppressed. Consequently, the wake interference and WIVs were weakened or completely disappeared. The cylinders fitted with 12 spiral protuberances reportedly reached the supercritical Re regime at Re = 3.1 × 104. Resultantly, they were stable against WIVs above this Re even at close spacing, and suitable for stay cable applications.

Morphological Diversity in Litchi Based on Tree and Leaf Characteristics

On the basis of tree and leaf characteristics, twenty litchi genotypes were evaluated to select promising genotypes. Numerous differences have been observed between the genotypes. The genotypes KT-1 and GC-2 recorded the highest (5.35 m) and lowest (4.50 m) height, respectively. The girth was greatest for the genotype KD-1 (63.01 cm) and lowest for the genotype GC-2 (49.99 cm). The genotype DP-2 had the smallest canopy diameter (5.29 m) and the genotype KS-1 the greatest (6.40 m) among the ones investigated. In GC-2 and KT-1, the plant volumes ranged from 20.35 m3 to 26.79 m3. Leaf exhibited a great deal of variability among them, nine genotypes showed vivid pink in their new leaves, whereas eleven genotypes showed yellowish green. Comparably, the colour of the leaves varied among the genotypes; nine had dark green, whereas eleven had green. Nine genotypes showed a downward curve from the midrib, whereas eleven genotypes showed an upward curve. According to an analysis of the number of leaflets on each compound leaf, Shahi had the most (7.24), while GC-1 had the fewest (6.16). The longest rachis measured 11.10 cm in KD-2 and the shortest 9.75 cm in GP-2. The genotype DT-1 exhibited the smallest petiole length, while the genotype KS-1 had the longest. The length of the leaflets varied significantly between genotypes, ranging from 10.86 cm (KD-1) to 13.81 cm (China). The genotype DP-2 had the shortest breadth (3.70 cm), while genotype KD-1 had the widest (4.36 cm). The genotypes GC-2, GP-2 and KD-1 can be promoted in close spacing orchard.

How Cropping System Influences Robusta Coffee Leaf Gas Exchange Efficiency via Stomatal Regulation

Background: Robusta coffee leaves regulate gas exchange in response to climatic factors like full sun and shaded conditions. To fully understand the reasons behind the variations in photosynthetic rates and water-use efficiency, exploring the underlying mechanisms of stomatal regulation in the maximum photosynthetic efficiency of Robusta coffee trees, especially in a shade condition is necessary. Methods: This study aimed to evaluate how stomatal regulation in Robusta coffee leaves affects gas exchange under different cropping systems. The Robusta coffee trees were grown in four different cropping systems: monoculture (full-sun condition) (S1), intercropped (single row) with rubber trees (S2), intercropped (double spacing) with rubber trees (S3), and intercropped in a mixed orchard (S4). Result: The results revealed that Robusta coffee trees grown between rubber tree rows with closer spacing (S2) exhibited the largest stomata sizes. These stomata sizes had a statistically significant increase in width, length, and area (ranging from 12.04 to 14.74 µm, 19.22 to 25.55 µm, and 202.37 to 296.05 µm², respectively) compared to Robusta coffee grown in S1, S3, and S4 systems. On the other hand, Robusta coffee grown in S1 system displayed the highest stomatal density, ranging from 310 to 540 stomata/mm². Interestingly, coffee trees grown between rubber rows (S3) and in the mixed orchard (S4) exhibited both high rates of photosynthesis (9.18 and 9.35 µmol/m²/s) and photosynthetic water-use efficiency (3.78 and 5.15 mmol/mol). Notably, these values were statistically different from those observed in other planting conditions. Additionally, Robusta coffee grown in S1 system exhibited the highest canopy temperature (ranging from 30.8 to 47.4°C). It also had the lowest Fv/Fm value (ranging from 0.706 to 0.759) compared to other planting conditions. This study indicates that Robusta coffee leaves exhibited varying stomatal responses to changes in light and temperature depending on the cropping system. By understanding how these leaf traits influence adaptation, we could potentially optimize Robusta coffee trees to thrive in full sun and shaded conditions, particularly within intercropping systems.

Channel‐Spanning Logjams and Reach‐Scale Hydraulic Resistance in Mountain Streams

AbstractLogjams create an upstream backwater of deepened, slower water, locally reducing bed shear stress. We compared hydraulic impact of logjam series across 37 geomorphically diverse reaches of mountain streams observed over 11 years in the US Southern Rockies. To enable reach‐scale comparison of logjam structure and spacing, we identified the modeled best‐fit effective resistance coefficient minimizing difference between outflow exiting a 1D channel with logjams present, and the same model channel with elevated channel resistance. Effective resistance increased with ratio of jam upstream depth to depth without a logjam, ratio of backwater length to average spacing, and decreased for randomly distributed jams due to close spacing, which reduced backwater impact. An analytic approximation and boundaries for region of relative spacing with steepest increase in effective resistance are provided. Our results can assist in targeting interventions to areas where hydraulic impact is greatest, providing value for money in nature‐based solution design.

Theoretical simulation study of laser-induced plasma bombardment on bacteria

With the rapid advancement of laser decontamination technology and growing awareness of microbial hazards, it becomes crucial to employ theoretical model to simulate and evaluate decontamination processes by laser-induced plasma. This study employs a two-dimensional axisymmetric fluid dynamics model to simulate the power density of plasma bombardment on bacteria and access its decontamination effects. The model considers the transport processes of vapor plasma and background gas molecules. Based on the destructive impact of high-speed moving particles in the plasma on bacteria, we investigate the bombardment power density under various conditions, including different laser spot sizes, wavelengths, plate’s tilt angles, and plate-target spacing. The results reveal that the bombardment power density increases with a decrease in laser spot size and wavelength. For instance, when the plate is parallel to the target surface with a 1 mm spacing, the bombardment power density triples as the laser spot size decreases from 0.8 mm to 0.5 mm and quadruples as the wavelength decreases from 1064 nm to 266 nm. Notably, when the plate is parallel to the target with a relatively close spacing of 0.5 mm, the bombardment power density at 0° inclination increases sevenfold compared to 45°. This simulation study is essential for optimizing optical parameters and designing component layouts in decontamination devices using laser-induced plasma. The reduction of laser spot size, wavelength, plate-target spacing and aligning the plate parallel to the target, collectively contribute to achieving precise and effective decontamination.

Apparent Joint Swarms Formed by the Crack‐Jump Process

ABSTRACTJoint swarms can be important components of fractured reservoirs. They are often explained as damage around faults or related to mechanical differences between layers, although this does not explain the close spacing of the joints. Joint swarms around Bergen (Norway) are described, which are not related to exposed faults and are not influenced by layering or foliation in the Lower Palaeozoic gneisses. We suggest an evolution whereby: (1) a zone of microcracks develops; (2) one microcrack propagates and becomes connected to a source of mineralising fluid; (3) the fracture becomes a microvein, with a higher tensile strength than the microcracked host rock; (4) another microcrack propagates and the cycle is repeated, producing a zone of microveins; (5) the veins are partly weathered out, producing an apparent joint swarm, or the microveins crack at or near the ground‐surface. Joint swarms in exposed analogues may therefore not occur at reservoir depths.

A potential cause for extensive dieback of Acacia mearnsii plantation in highland districts of Awi zone, northwestern Ethiopia

Although Acacia mearnsii De Wild has rapidly expanded for economic and ecological purposes in the highland districts of the Awi zone, northwestern Ethiopia, recent plantations have suffered from severe defoliation, dieback, and stunted growth. We conducted this study in four districts that hold potential for A. mearnsii plantations. The study examined the identification of the causal agent, its occurrence, and local community perceptions of the plantation's significant dieback. Most respondents (75.8 %) indicated that the substantial dieback began in the rainy season of 2020 and spread rapidly. They also noted that close spacing of plantings and limited silvicultural measures exacerbated the damage. We discovered in this study that the wattle rust disease caused by the Uromycladium acacia fungus was the root cause of significant dieback for A. mearnsii plantations. The incidence and severity of this wattle rust varied significantly (p = 0.001) between districts, seasons, and plantation age groups. In Fegita-Lekuma district, the maximum disease severity was over 72 % in plantations up to two years after planting during the rainy season. The progression of the wattle rust disease caused by U. acacia has led to the loss of A. mearnsii plantations in the Awi zone, resulting in a severe economic and environmental crisis. Consequently, we should apply fungicides to seedlings at nursery sites in the short term. Eventually, however, the focus should shift towards prioritizing disease-resistant species and implementing proper forest management practices. This should be achieved through scientific initiatives that engage key stakeholders in areas where this tree species could potentially grow.

Sensitivity of rainfed okra (Abelmoschus esculentus L. Moench) to mulch material and plant spacing in drought-prone tropical soils

Mulch regulates soil hydrothermal regime while suppressing weed growth, effects of which may depend on mulch material and/or similar to that of closed crop canopy. Combined use of organic or inorganic material as surface mulch and appropriate plant spacing may produce synergistic agronomic effects in water-stressed environments. This study evaluated the sensitivity of rainfed okra to mulch-spacing variants in droughty derived-savannah soils. With dry-grass mulch (DGM) and sawdust mulch (SDM) representing organic mulch material and black polythene (BPM) as inorganic/plastic, treatments were factorial combinations of surface-applied DGM, SDM and BPM with close (60 cm × 30 cm), intermediate (60 cm × 45 cm) and wide (60 cm × 60 cm) spacings. Crop growth/performance and fruit yield data were collected. Mulch material affected okra growth (with overall better results in BPM than SDM), but not flowering/fruiting and fruit yield. For plant spacing, sum of weights of pods and fruit yield were higher in close than intermediate and wide spacings, with fruit yields as 2.42, 1.21 and 0.76 t ha-1, respectively. Mulch-spacing interaction effects showed that BPM with close spacing gave the highest values for stem girth 8 weeks after sowing (SDM treatments gave the lowest), sum of weights of pods and fruit yield (2.93 t ha-1). Fruit yield, however, depended not on stem girth but on certain okra yield attributes. The BPM or, where not feasible, either of DGM and SDM, could be effectively combined with close spacing to improve okra productivity in droughty soils of the derived savannah.

Incidence of insect-pests in response to plant density and nutrient levels in Desi cotton (Gossypium arboreum) under rainfed condition

The field experiment was conducted to study the effect of spacing and nutrients on insect-pests infestation on compact desi cotton (Gossypium arboreum) grown under rainfed condition during kharif seasons of 2019–20 to 2021–22 at the Main Cotton Research Station, Navsari Agricultural University, Surat. The experiments were carried out in factorial randomized block design with nine treatment combinations with three replicates comprised of three levels of spacing viz., 60 cm × 15 cm, 60 cm × 30 cm and 120 cm × 45 cm and three nutrient levels, viz. 120, 150 and 180 kg N/ha. The population of sucking pests viz., leafhopper, thrips, whitefly and mealy bug as well as open boll and locule damage by bollworms was recorded significantly lower in plant density at normal (recommended) spacing, 120 cm × 45 cm and vice a versa. Only the aphid population was found significantly lowest in closer spacing (60 cm × 15 cm). Amongst nitrogen levels, there was a significant difference with respect to N levels and the highest population of sucking pests as well as open and locule damage was recorded at N level of 180 kg N/ha. With respect to treatment combinations, there was no significant difference in sucking pests (aphids, thrips, whitefly and mealybugs) and open boll and locule damage amongst different treatment combinations of spacing and nitrogen levels. However, the treatment combination comprising the spacing of 120 × 45 cm and 120 kg N/ha recorded significantly lowest population of leafhopper followed by treatment combination of spacing 120 cm × 45 cm with nitrogen level of 150 kg/ha. Hence, proper interventions for leafhopper control is required when compact desi cotton was sown at closer spacing under rainfed condition.

Experimental and numerical investigations on the bending capacity of cold-formed steel box headers

The study investigates the bending strength of tracks of box headers beyond AISI, which considers the capacity of individual channels alone. Both experimental and FEM are used, and the results are compared to AISI. The findings highlight tracks' significant role in the overall bending capacity. AISI is found to be conservative by 34% to 152%. Failure mode is different from code theoretical expectations for a single channel. Fastener close spacing marginally improves the capacity, while side fasteners offer significant enhancement, but track widening limits this enhancement. A modification to AISI is proposed considering track strength, with outcomes showing good accuracy.

Optimizing seaweed biomass production - a two kelp solution

Interest in farming kelps has grown beyond using kelp for food, feed or biofuels. There is considerable interest in generating biomass from seaweed for use in bioplastics and other products that would substitute for petroleum-derived products. For these uses to be viable, large amounts of biomass are needed. Very large kelp farms can be expensive to build and maintain, leading to the need to optimize the biomass per unit area. Although close spacing of growlines can lead to poor growth, a viable approach may be to grow two species of kelps together: one that hangs down and one that is buoyant, growing up. This system would increase the spacing in three dimensions. In Alaska, Saccharina latissima is commonly grown hanging down from longlines. One of the buoyant Alaskan kelps is Nereocystis luetkeana. Because there are commercial uses for wild-harvested Nereocystis in Alaska, we undertook a preliminary trial in Kodiak, Alaska, that grew both Saccharina and Nereocystis in the same longline array. Closely spaced lines were seeded the first week of February 2023 and set at 3 m below the surface. The arrays were harvested in late June 2023. Total yields were greatest on the combined arrays, followed by the Nereocystis only and Saccharina only arrays. Despite having 45% fewer grow-lines, the total yield of the Nereocystis on the combined arrays was statistically similar to the Nereocystis only arrays. These results may have significance for large scale macroalgal production.

Ridge and Furrow Sowing Method with Close Spacing Reduces the Salinity Effect of Sunflower Production in the Ganges Delta

Ridge and Furrow Sowing Method with Close Spacing Reduces the Salinity Effect of Sunflower Production in the Ganges Delta