Spatial Arrangement Of Plants Research Articles

Role of cover crop roots in soil organic carbon accrual—A review

AbstractAppropriate cover crop (CC) management is an important tool for the improvement of soil carbon stock; however, the relationships between carbon accumulation and CC root traits remain unclear. A literature review was performed to identify the extent and focus of recent research and to answer questions about the role of root traits of CCs in soil C accumulation with regard to species selection, mixture composition and agronomic management. The findings based on the analysis of 69 publications show that a range of root traits such as root biomass, architecture, depth of rooting, root chemical composition, as well as quantity and quality of rhizodeposition, can contribute to soil structure formation and C accumulation. These traits are usually species specific, and it seems that appropriate species combinations in the mixtures can offer the highest potential for optimization of C stock across various environments. However, there has been twice as much recent research on roots of CC monocultures than on mixtures, with little attention paid to agronomic aspects such as plant spatial arrangement or soil tillage in relation to CC root development. Considerations of real management under field conditions could be beneficial in providing greater accuracy of estimation of the contribution of CCs in increasing the SOC stock in croplands.

Lonesome plants: How isolation affects seed set of a threatened dioecious shrub.

Plant reproductive failure is a critical concern for conserving rare and endangered species that typically have low-density and sparse populations. One important factor contributing to reproductive failure is the spatial arrangement of plants within a population, which can lead to isolation and negatively affect seed production, particularly in obligate outcrossers. Additionally, plant size can compound this effect, influencing seed production via multiple processes. Here, we investigate how spatial distribution and size influence the reproductive success of Vasconcellea chilensis, an endemic-threatened papaya species in Chile. We first examined whether V. chilensis can produce seeds via apomixis using pollinator exclusion experiments. We then used Spatial Point Pattern Analysis (SPPA) in three populations to explore the spatial arrangement of plants. Finally, we assessed whether plant size and neighbor distance influence the reproductive success V. chilensis is a dioecious shrub unable to produce fruits through apomixis. The SPPA revealed significant clustering of female and male plants at different spatial scales, indicating a non-random distribution. Moreover, a significant spatial association between the sexes was observed. In two populations, closer proximity to male plants was linked to higher seed production. Our study revealed that the reproductive system of V. chilensis is susceptible to distance-dependent reproductive failure due to pollen limitation. While the species' spatial structure may partially mitigate this risk, female plants isolated from male counterparts will likely experience reduced seed set.

Sorghum Densification with Changes in Plant Spacing Arrangement: Productivity and Qualitative Characteristics of Silage Material

The aim of this study was to evaluate the agronomic performance of sorghum grown in different combinations of row spacing and plant density, as well as possible interferences on silage quality. No other study dedicated to identifying the interference of plant spatial arrangement on the cultivation of silage material has been developed in the productive context of the Amazon Biome, making it necessary to understand the behavior of the studied factors. The treatments were arranged in a split-plot scheme: the plots corresponded to three row spacings (0.45 m, 0.60 m, and 0.75 m) and subplots at four densities (105,000, 120,000, 135,000, and 150,000 plants ha−1). The agronomic and productivity characteristics of sorghum and the fermentative and bromatological characteristics of forage and silage were evaluated. The sorghum plants showed an increase in plant height and green and dry mass yield when using higher densities (p < 0.05). For the culm diameter variable, an isolated effect of the factors was observed, with reduced diameter when grown closer to inter-row spacing or using higher plant densities. No effect of the factors was found (p > 0.05) for morphological plant components. In silage, wider spacing promoted higher dry matter content. Regarding crude protein in the silage, higher percentages were obtained at closer spacing and higher plant density. The sorghum growing in dense conditions is indicated, given the positive performance in productivity and bromatological composition.

Physiological quality of soybean seeds produced under different spatial arrangements of plants

The present study aimed to evaluate the physiological effect of seeds on soybean genotypes in the southern region of Rio Grande do Sul. The test was developed in the field, in two agricultural crops, on a farm located in the District of Monte Bonito - Pelotas (RS, Brazil), in eutrophic haplic planosol soil, with geographic coordinates 31° 40' 27"S and 52°23' 28 "W. The experiment consisted of twelve treatments involving two factors: factor A - 3 soybean genotypes (NA 5909 RR (super early, growth indeterminate and maturation group A), NS 6006 IPRO (high grain weight, growth indeterminate and maturation group B 5.9), and NS 5959 IPRO (precocity, indeterminate growth and maturation group C) and factor B - 4 line spacing (0.17; 0.30; 0.45 and 0.60 meters). The experimental design used was randomized blocks in a factorial scheme (3x4) with four blocks. The plant population used was 330.000 plants ha-1. The evaluations of the physiological performance of seeds were germination, first germination count, length and dry matter of aerial part, root, and a total of seedlings, accelerated aging, and emergence in the field. Soybean plants better distributed in the cultivation area, in spacings of 0.17 and 0.30 meters, present greater plant height, stem diameter, and productive performance.the only genotype that presented a reduction in germination as the row spacing increased was 'NS 6006 IPRO', resulting in seeds with lower germination in the spacings of 0.45 and 0.60 m compared to the other genotypes under study. The reduction in the spacings, 0.17 and 0.30 meters, produced seeds with better physiological quality, evidenced in years with rain preceding the harvest.

Adjusting spatial use to establish productive and stable Elymus nutans monocultures and mixed sowing systems

Community arrangement plays a critical role in maintaining forage community production and stability. To explore reasonable management for efficient community production in alpine regions, three monoculture communities composed of Elymus nutans, Cross row (S_C), Double row (S_D), and Single Row (S_R), and three mixed communities consisting of Elymus nutans and Onobrychis viciifolia, Broadcast(M_B), Dependent row (M_D) and Independent row (M_I) were established in Tianzhu County on the Qinghai Tibetan Plateau during 2018–2019. The results showed S_C was the most productive monoculture community, with less intraspecific competitiveness and higher population density after establishment, which could reduce the influence of lodging on yield loss. The maximum forage yield was attained at the end of 2018 (5187.6 kg·ha−1) and August 2019 (26190.9 kg·ha−1). In mixed communities, the relationship of natural height between E. nutans and O. viciifolia was relatively stable, but growth rate displayed asynchronous traits. Besides, mixed communities had higher lodging resistance compared with monoculture communities; E. nutans showed higher competitiveness than O. viciifolia, but O. viciifolia competivity when the community natural height decreased. M_B (3015.3 kg·ha−1 in 2018; 4804.6 kg·ha−1 at the flowering of 2019), and M_D (7686.2 kg·ha−1 in 2019) had better performance in forage yield. Our study has demonstrated the feasibility of adjusting plant spatial arrangements as a means to enhance forage production in alpine regions. It is crucial to consider the interaction of growth rates, as this factor determines the optimal utilization time for monocultural and mixed communities. Additionally, this study highlights the influence of changes in sowing patterns on forage growth and yield, while enriching the grassland establishment mode, thus supporting the development of sustainable livestock systems in the Qinghai Tibet Plateau.

Landscape composition and pollinator traits interact to influence pollination success in an individual‐based model

Abstract The arrangement of plant species within a landscape influences pollination via changes in pollinator movement trajectories and plant–pollinator encounter rates. Yet the combined effects of landscape composition and pollinator traits (especially specialisation) on pollination success remain hard to quantify empirically. We used an individual‐based model to explore how landscape and pollinator specialisation (degree) interact to influence pollination. We modelled variation in the landscape by generating gradients of plant species intermixing—from no mixing to complete intermixing. Furthermore, we varied the level of pollinator specialisation by simulating plant–pollinator (six to eight species) networks of different connectance. We then compared the impacts of these drivers on three proxies for pollination: visitation rate, number of consecutive visits to the focal plant species and expected number of plants pollinated. We found that the spatial arrangements of plants and pollinator degree interact to determine pollination success, and that the influence of these drivers on pollination depends on how pollination is estimated. For most pollinators, visitation rate increases in more plant mixed landscapes. Compared to the two more functional measures of pollination, visitation rate overestimates pollination service. This is particularly severe in landscapes with high plant intermixing and for generalist pollinators. Interestingly, visitation rate is less influenced by pollinator traits (pollinator degree and body size) than are the two functional metrics, likely because ‘visitation rate’ ignores the order in which pollinators visit plants. However, the visitation sequence order is crucial for the expected number of plants pollinated, since only prior visits to conspecific individuals can contribute to pollination. We show here that this order strongly depends on the spatial arrangements of plants, on pollinator traits and on the interaction between them. Taken together, our findings suggest that visitation rate, the most commonly used proxy for pollination in network studies, should be complemented with more functional metrics which reflect the frequency with which individual pollinators revisit the same plant species. Our findings also suggest that measures of landscape structure such as plant intermixing and density—in combination with pollinators' level of specialism—can improve estimates of the probability of pollination. Read the free Plain Language Summary for this article on the Journal blog.

Plant spatial aggregation modulates the interplay between plant competition and pollinator attraction with contrasting outcomes of plant fitness

Abstract. Ecosystem functions such as seed production are the result of a complex interplay between competitive plant–plant interactions and mutualistic pollinator–plant interactions. In this interplay, spatial plant aggregation could work in two different directions: it could increase hetero- and conspecific competition, thus reducing seed production; but it could also attract pollinators, increasing plant fitness. To shed light on how plant spatial arrangement modulates this balance, we conducted a field study in a Mediterranean annual grassland with three focal plant species with different phenology, Chamaemelum fuscatum (early phenology), Leontodon maroccanus (middle phenology) and Pulicaria paludosa (late phenology), and a diverse guild of pollinators (flies, bees, beetles and butterflies). All three species showed spatial aggregation of conspecific individuals. Additionally, we found that the two mechanisms were working simultaneously: crowded neighborhoods reduced individual seed production via plant–plant competition, but they also made individual plants more attractive for some pollinator guilds, increasing visitation rates and plant fitness. The balance between these two forces varied depending on the focal species and the spatial scale considered. Therefore, our results indicate that mutualistic interactions do not always effectively compensate for competitive interactions in situations of spatial aggregation of flowering plants, at least in our study system. We highlight the importance of explicitly considering the spatial structure at different spatial scales of multitrophic interactions to better understand individual plant fitness and community dynamics.

The Movement Ecology of Mutualism (CSEE/ESA 2022, OOS17)

The Movement Ecology of Mutualism (<scp>CSEE</scp>/<scp>ESA</scp> 2022, <scp>OOS17</scp>)

Intraspecific competition in common coastal dune grasses overshadows facilitation on the dune face

Restoration of degraded dunes through revegetation of native dune building species is critical to preserve multiple ecosystem services (i.e., coastal protection, habitat). As dunes exhibit high levels of abiotic stress, it is likely that facilitative interactions among plants occur, reducing stress caused by harsh abiotic conditions, and benefiting restoration efforts. The research was to determine how plant spatial arrangement (clumped vs. dispersed) at the dune slope affects the growth of two dominant dune grasses along the United States Atlantic coast, Ammophila breviligulata (American beachgrass) and Uniola paniculata (sea oats). We determined the local distribution and density of each species through field surveys to inform a manipulative study of planting arrangement and to assess plant growth and survival under different spatial arrangements. Planting arrangement did not influence the survival of U. paniculata, but dispersed plantings had a positive effect on growth parameters (height, stem number, ramet number), compared to the clumped arrangement. No plantings of A. breviligulata survived by the end of the second season, regardless of planting arrangement. Clumped arrangements did not improve growth of U. paniculata or growth and survival of A. breviligulata over the two growing seasons studied; thus, creating clumped arrangements may not be necessary for revegetation efforts. However, observing natural spatial patterns and using this information to guide restoration planting may be beneficial as climate change may impact revegetation results due to increased abiotic stress. Further research focusing on biotic interactions and density of plantings at multiple locations along dunes will contribute to dune restoration planning.

Influence of plant spatial arrangement and water supplementation on soybean productivit

The present study aims to evaluate the influence of plant spatial arrangement and water supplementation on soybean yield for the 2020/21 crop year, in the edaphoclimatic conditions of the central region of Rio Grande do Sul (Brazil). The field experiment was installed in an experimental area of ​​ the Rio Grande do Sul State University (UERGS) in the city of Cachoeira do Sul. Supplementary irrigation provided positive increases in soybean yield between 13% (row spacing of 0.75 m) and 35% (row spacing of 0.50 m). The conventional row spacing of 0.50 m can be recommended as a spatial arrangement strategy for both irrigated areas (productivity 5,196.6 kg ha-1) and rainfed areas (productivity 3,360.0 kg ha-1), optimizing costs regarding the mechanization of farming.

Spatial arrangements between rows x radish plants

Given the importance of this crop and the need for phytotechnical knowledge about the plant spatial arrangement. The objective of this study was to evaluate the productive parameters of the radish culture when submitted to different spatial arrangements between plants and rows. To achieve this aim, the hybrid cultivar Red Pearl was used as a test in a randomized block experimental design, in a 4 x 6 factorial scheme, with four replications. The factors comprise the combination of crop spacing between “rows” and “plants”. The factor levels correspond to the distances between rows: 8, 16, 24, and 32 cm; and between plants: 4, 6, 8, 10, 12, and 14 cm. Root yield, average root mass, longitudinal and transverse diameters, and non-commercial roots were determined. The data obtained were tabulated to obtain the averages, which were submitted to the Shapiro-Wilk residual normality test, at 5% significance, followed by the analysis of variance. When the residual was normal and the response variable was significant, the data was analyzed using linear regression and the appropriate polynomial model was adjusted to present the results. Statistical analyzes were carried out using the R Software. The results show that there was no interaction between the spacing factors for the analyzed parameters, and the spacing between rows and plants influenced the attributes evaluated independently. The spatial arrangements with lower plant densities provided greater root mass and diameter. The importance of new studies involving fixing the spacing between rows and varying the spacing between plants is suggested to better understand the effect of new spatial arrangements on the productive parameters of the radish crop.

The contribution of plant spatial arrangement to bumble bee flower constancy.

Floral constancy of foraging bees influences plant reproduction. Constancy as observed in nature arises from at least four distinct mechanisms frequently confounded in the literature: context-independent preferences for particular plant species, preferential visitation to the same species as the previous plant visited (simple constancy), the spatial arrangement of plants, and the relative abundances of co-flowering species. To disentangle these mechanisms, we followed individual bee flight paths within patches where all flowering plants were mapped, and we used step selection models to estimate how each mechanism influences the probability of selecting any particular plant given the available plants in a multi-species community. We found that simple constancy was positive: bees preferred to visit the same species sequentially. In addition, bees preferred to travel short distances and maintain their direction of travel between plants. After accounting for distance, we found no significant effect of site-level plant relative abundances on bee foraging choices. To explore the importance of the spatial arrangement of plants for bee foraging choices, we compared our full model containing all parameters to one with spatial arrangement removed. Due to bees' tendency to select nearby plants, combined with strong intraspecific plant clumping, spatial arrangement was responsible for about 50% of the total observed constancy. Our results suggest that floral constancy may be overestimated in studies that do not account for the spatial arrangement of plants, especially in systems with intraspecific plant clumping. Plant spatial patterns at within-site scales are important for pollinator foraging behavior and pollination success.

Effect of plot size and plant spatial arrangement on the efficiency of family selection in sugarcane

The purpose of this study was to identify the ideal sample size representing a family in its potential, to identify superior families and, in parallel, determine in which spatial arrangement they may have a better accuracy in the selection of new varieties of sugarcane. For such purpose, five families of full-sibs were evaluated, each with 360 individuals, in the randomized blocks design, with three replications in three different spacing among plants in the row (50 cm, 75 cm, and 100 cm) and 150 cm between the rows. To determine the ideal sample size, as well as the better spacing for evaluation, the bootstrap method was adopted. It was observed that 100 cm spacings provided the best average for the stalk numbers, stalk diameter and for estimated weight of stalks in the stool. The spacing of 75 cm between the plants allowed a better power of discrimination among the families for all characters evaluated. At this 75 cm spacing was also possible to identify superior families with a sample of 30 plants each plot and 3 reps in the trial. Highlights The bootstrap method was efficient to determine the ideal sample size, as well as the best spacing for evaluation. The 75-cm spacing had the highest power of discrimination among families, indicating that this spacing is the most efficient in evaluating sugarcane families for selection purposes. From all the results and considering selective accuracy as the guiding parameter for decision making, the highest values obtained considering the number of stalks and weight of stalks in the stools were found at the 75-cm spacing.

Emergent spatial structure and pathogen epidemics: the influence of management and stochasticity in agroecosystems

Organisms susceptible to disease, from humans to crops, inevitably have spatial geometry that influence disease dynamics. Understanding how spatial structure emerges through time in ecological systems and how that structure influences disease dynamics is of practical importance for natural and human management systems. Here we use the perennial crop, coffee, Coffea arabica, along with its pathogen, the coffee leaf rust, Hemileia vastatrix, as a model system to understand how spatial structure is created in agroecosystems and its subsequent influence on the dynamics of the system. Here, we create a simple null model of the socio-ecological process of death and stochastic replanting of coffee plants on a plot. We then use spatial networks to quantify the spatial structures and make comparisons of our stochastic null model to empirically observed spatial distributions of coffee. We then present a simple model of pathogen spread on spatial networks across a range of spatial geometries emerging from our null model and show how both local and regional management of agroecosystems interact with space and time to alter disease dynamics. Our results suggest that our null model of evolving spatial structure can capture many critical features of how the spatial arrangement of plants changes through time in coffee agroecosystems. Additionally, we find small changes in management factors that can influence the scale of pathogen transmission, such as shade tree removal, and result in a rapid transition to epidemics with lattice-like spatial arrangements but not with irregular planting geometries. The results presented here may have practical implications for farmers in Latin America who are in the process of replanting and overhauling management of their coffee farms in response to a coffee leaf rust epidemic in 2013. We suggest that shade reduction in conjunction with more lattice-like planting schemes may result in coffee being more prone to epidemic-like dynamics of the coffee leaf rust in the future.

Increasing the efficiency of spring wheat selection for resistance to soil infection

The aim of the research was to substantiate the need to take into account the factors that have a significant impact on the root rot infestation of spring wheat in the process of practical selection for resistance. The studies were carried out in 2019–2020 with the application of generally accepted and author’s methods. A systemic restructuring of work is needed to increase the efficiency of practical breeding for resistance to root rot. The damaging factor is cereal flies which “open the gates” to all soil phytopathogens after the tillering phase. It should be eliminated, and the ability of varieties to induce the suppression of rhizosphere soil to main phytopathogens should be taken into account. According to the results of two years of research, the smallest, within two biological thresholds of harmfulness (PV), the infestation by root rot at the germination phase was shown by the spring wheat varieties Novosibirskaia 15 and Manu. The development of root rot in comparison with the germination phase in 2019 increased by an average of 2.5, and in 2020 - by 5.6 times. There was an equalization of differences in damage between varieties during the growing season. In the germination phase, the coefficient of variation in the development of root rot by varieties was 24.1 ± 4.0, in the phase of maturity, it decreased 2.5 times to 9.4 ± 1.5. The main reason for smoothing out the differences between varieties in terms of root rot infestation was strong (up to 100%) damage by intra-stem pests. The economic threshold of harmfulness for damage to spring wheat stems by cereal flies was exceeded in 2019 up to 4.8 times, and in 2020 up to 7.8 times. The correlation coefficient between the development of root rot and damage by intra-stem pests in 2019 was R = 0.744 ± 0.185 (P &lt;0.01), in 2020 R = 0.713 ± 0.092 (P &lt;0.01). Analysis of variance showed that the power of the influence of the spatial arrangement of plants on their damage by cereal flies was 30.9% and was reliable at the 1% level, while the influence of the variety itself on this indicator was almost 2 times lower (16.8%) and was significant at the 5% level. The induction of soil suppression to phytopathogens by the rhizosphere of spring wheat varieties influenced their representation in the pathogenic complex of root rot. The correlation coefficient of induction by cultivars of suppressiveness to F. poae and its representation in pathogenic complexes was R = - 0.638 ± 0.318 and was significant at the 5% level. The correlation coefficient of induction of suppressiveness to F. oxysporum and its presence in pathogenic complexes of root rot of varieties was R = - 0.844 ± 0.203 (P &lt;0.01).

Tracking native small mammals to measure fine-scale space use in grazed and restored dry woodlands

The degradation of dry woodlands in South America by agricultural activities affects wildlife through a decrease in available habitat and fine-scale changes in habitat structure. The impact of land use can be perceived by small, mobile organisms as preventing or facilitating their movement through and among habitats, consequently altering ecosystem functions. By tracking with radiotelemetry we describe for the first time the pattern of movement of a small mammal (Graomys griseoflavus) that inhabits dry woodland ecosystems in South America and its relationship with environmental features that affect movement. We measured environmental variables linked to the ecological requirements of the species (e.g., plant cover and patches of forage species consumed) in restored and grazed woodlands and compared movements between seasons (dry and wet). We found that the fine-scale differences in the vegetation cover associated with livestock grazing changed the mobility and use of space of this small mammal. The step-lengths and used area for G. griseoflavus were greater under passive restoration compared to the area grazed by livestock. Small rodents moved between patches of similar mean size of forage species, avoiding large inter-patches of bare ground. Although both management conditions showed seasonal variations in plant cover, the step-lengths decreased significantly in the grazed woodland during the wet season, while step-lengths in the restored area were unaffected by season. The fine-scale spatial arrangement of plants in restored woodlands elucidated notable changes in animal movement on grazed lands, suggesting that space use by small mammals may be an important tool to identify habitat structures that facilitate the movement of animals in restoration of degraded systems.

Spatial arrangement of maize plants aiming to maximize grain yield in the hybrid BRS-3046

The objectives of this study were to: (i) evaluate the effect of different spatial arrangements on morpho-physiological characteristics and (ii) determine the optimal spatial arrangement to maximize grain yield of the maize hybrid BRS-3046 grown in the Mid-North region of Brazil. We tested two row spacings (0.5 and 1 m) and five plant densities (2, 4, 6, 8, 10 plants m-2), which corresponded to 10 different plant spatial arrangements. Different morphophysiological variables, gas exchange rates and grain yield were measured. The increased planting density led to a linear increase in LAI, regardless of row spacing, while the net CO2 assimilation rate increased until the density of 4 and 6 plants m-2, under a row spacing of 0.5 and 1.0 m, respectively. On the other hand, we found a linear reduction in the stomatal conductance with increasing planting density. The intercellular CO2 concentration and the transpiration rate were higher in the widest row spacing. The instantaneous efficiency of carboxylation, in turn, showed a slight increase up to the density of six plants m-2, then falling, regardless of row spacing. Increasing plant density resulted in a linear increase in plant height and ear insertion height, regardless of row spacing. However, it had an opposite effect on stem diameter. Grain yield, in turn, increased up to 7.3 plants m-2 at a row spacing of 0.5 m and 8 plants m-2 at a row spacing of 1.0 m. This spatial arrangement was considered as ideal for achieving maximum yield

Correlation between grain yield in maize plant densities

When assessing genotypes in different environments, the result depends on the genotype-environment interac­tion. Among the environmental factors, the spatial arrangement of plants is among the most important manage­ment practices to achieve higher grain yield. This arrangement involves changes in the spacing between rows and between plants. The present study evaluates the correlation between the grain yield of maize genotypes and different plant populations. We conducted the experiments in the 2012/2013 harvest season and in the 2012/13 off-seasons at UNESP - Jaboticabal Campus, in Jaboticabal county, São Paulo State, Brazil, and in the 2013 off-season at Cambuhy Farm, in Matão county, São Paulo State, Brazil. The experimental design was in randomized blocks, with three replicates. For the 0.50 m spacing between rows, the spacing between plants was 0.25 m (80,000 pl ha -1 ), 0.30 m (66,667 pl ha -1 ), and 0.40 m (50,000 pl ha -1 ). For the 0.90 m spacing between rows, the spacing between plants was 0.20 m (55,556 pl ha -1 ). We assessed the treatments for grain yield (six genotypes), analyzing the correlations between grain yield averages and plant population densities for each environment using the Pearson correlation coefficient. The 2012/2013 harvest season in Jaboticabal county provided the highest average yield, regardless of population density. The 2012 off-season in Jaboticabal county provided the lowest average yield. As for population densities, the one that provided the highest yield was 80,000 plants ha -1 . The present study found several types of correlation, which allows us to say that population density recommendations must be specific.

Plant spatial arrangement on growth, weed control, and yield of okra

ABSTRACT Light interception by okra [Abelmoschus esculentus (L.) Moench] can be altered by changing row and plant spacing and plant/row orientation. In okra, reduction in yield can occur due to improper planting arrangement, use of inappropriate cultivar, weed interference, and ineffective weed control. A field experiment was conducted at the Federal University of Agriculture, Abeokuta, Nigeria, to assess the effects of planting arrangement on okra and on its ability to control weeds. Cultivars NHAe 47–4 and LD 88 were established at a population of 40,000 plants∙ha−1 as a result of spatial arrangement using 100 cm inter-row distance and respective intra-row distances of: 25 cm with 1 plant/stand; 50 cm with 2 plants/stand, and 75 cm with 3 plants/stand. Data were collected on number of leaves, plant height, stem diameter, leaf area, days to first flowering, days to 50% flowering; total fruit yield, weed density, weed fresh weight, and weed dry matter content. Cultivar and planting arrangement affected growth, yield, and weed interference. More and wider, leaves with taller plants were produced by cv. NHAe 47–4 planted at 1 plant/stand. Cultivar LD 88 planted at 1 plant/stand produced wider stems, higher yields and best weed suppression (7 weeds.m2) while earlier flowering was observed at 2 plants/stand. The days to 50% flowering was similar for cv. NHAe 47–4 planted at 1 or 2 plants/stand and ‘LD 88ʹ planted at 2 plants/stand. Cultivar LD 88 planted at 1 plant/stand had higher yield and suppressed weeds best, 7 weeds∙m2. Plant spatial arrangement can affect growth and yield. The best planting arrangement for a crop could have impact on productivity and cost of production. The late-maturing cv. LD 88 planted at 100 × 25 cm at 1 plant/stand produced optimum okra growth, yield, and efficient weed control in a traditional cropping system in the tropics.

Spatial arrangement of plants on leaf growth and development and the yield potential of soybean

This study aimed at determining the effect of a variety of plants arrangements on foliar growth and development as well as the productive potential in soybean. The field experiments were performed over two agricultural years (2015/16 and 2016/17) on Argisoil in subtropical environment. The two selected cultivars, viz., BMX Tornado RR and FPS Urano RR were sown in four spatial distribution of the plants such as conventional spacing (0.45 m spacing between rows), reduced spacing (0.225 m spacing between rows), paired spacing (two rows with 0.225 m and 0.45 m spacing from the other rows) and crossed spacing (0.45 m spacing between the rows with crosses of two rows, at a 90° angle). The randomized block design was adopted for the experiments with the treatments in a 2x4 factorial distribution and four replications. The first factor was the cultivar and the second types of plant distribution. The results showed that plant arrangement affected the plant profile regarding the behavior of the ecophysiological variables like plastochron, leaf lifetime and yield distribution. Leaf life in each stratum was caused by the foliar senescence rhythm, explained by a 4th degree polynomial model, revealing two peaks in the senescence rate, one during pre-flowering stage and the other when the grain filling stage was completed. According to the results, we do not recommend changes in conventional spacing.