Plant Population Density Research Articles

Response of Newly Released Late Maturing Maize Variety to Nitrogen and Plant Population Density at Jimma, Southwestern Ethiopia

Response of Newly Released Late Maturing Maize Variety to Nitrogen and Plant Population Density at Jimma, Southwestern Ethiopia

Response of Maize Variety to Nitrogen and Plant Population Density in Jimma Zone, Southwestern Ethiopia

Response of Maize Variety to Nitrogen and Plant Population Density in Jimma Zone, Southwestern Ethiopia

Sowing Management and Plant Population in Organic Quinoa Production for Food and Nutrition Security

Purpose: The objective of this study was to evaluate the population density of quinoa plants sown by broadcasting or in rows to improve agronomic indicators of an organic farming system focused on increasing food and nutrition security of the population. Method/design/approach: The study was conducted in 2020, in Augusto Pestana, RS, Brazil, using a randomized block experimental design with four replications, in a 2×4 factorial arrangement consisted of 2 sowing methods (sowing in rows spaced 0.20 m apart and by hand broadcasting) and 4 plant population densities (10, 40, 80, and 120 plants m-2). Thinning was performed in the plots of both sowing methods approximately 20 days after emergence for achieving the desired plant densities. Grain yield and other traits of agronomic interest were evaluated under an organic cropping system. Results and conclusion: The arrangement of 70 quinoa plants m-2 through sowing in rows or by broadcasting ensures satisfactory crop yields without using pesticides and synthetic fertilizers. The incorporation of these more sustainable practices into quinoa production systems contributes to the promotion of agroecological and organic agriculture, resulting in a high-quality nutraceutical food. Originality/value: This study provides significant contribution to the advancement of research on quinoa in Brazil, bringing new information benefiting farmers, technical assistance agents, and the food industry and improving the production system efficiency to ensure food and nutrition security and care for the environment and society.

A study of plant community stability in the lower Tarim River based on MLR and MLP and improved Morneau dynamics model

Taking the lower reaches of Tarim River as the research area, drought adaptability and species number of plant communities were studied. Due to the simple, dry and water-scarce topography, the plant community structure in this region is relatively uncomplicated, so it is a good area for analysis. In this paper, Monod model, a macroscopical internal mechanism of long-term interaction between plant community and environment, is proposed. The Monod model is derived from the growth of microorganisms and therefore needs to be optimized when considering plants: self-inhibition characteristics are introduced to obtain an optimized mechanism model. Based on this model, the conditions to be met when the change rate of plant population density is positive are solved in this paper. Combined with the actual number of species, it is considered that the community needs at least three different plant species to benefit, and the situation caused by the increase of species is discussed. Different types of plants have different NDVI, so they have different effects on the model. In this paper, the analysis is divided into three types of plants, and the effect of changing drought frequency is considered. Since there are only two regions with different drought frequency and easy to be divided, this paper introduced multiple linear regression models in the two regions respectively, extracted the general model from the regression coefficient relationship between the two regions, and analyzed the NDVI regression coefficient of the two regions at the same time, to obtain the general rule of the effect of less drought on the number of species. Due to the lack of pollution data and habitat data in the study area, this paper derived a model of negative environmental factors from the mechanism model, and finally combined with the easily available pm2.5 index. Based on the established model, this paper hopes to help ensure community survival in terms of increasing resource growth rates and preserving diversity.

An Outlook on Processing Sweet Corn Production from the Last Three Decades (1990s–2010s)

Sweet corn (Zea mays L. var. rugosa or saccharate), consumed both fresh and processed (primarily canned or frozen), is a popular vegetable crop in the United States. Recent nationwide data have reported declining trends in sweet corn production, which poses serious challenges for the US processing sweet corn producers. Here, we evaluated a processing sweet corn dataset that represents nearly 3 decades (1992–2018) of commercial production in the Upper Midwest and the Pacific Northwest regions in an attempt to understand national trends in US processing sweet corn. The objectives of this study were to (a) quantify trends in processing sweet corn production (harvest area and total green ear mass production); (b) understand trends in planting date, plant population density, and hybrid lifespan; and (c) estimate interannual yield deviations in green ear mass yield. Our results reveal declining trends in sweet corn hectares, particularly in rainfed production systems of the Upper Midwest. For the past 3 decades of commercial sweet corn production, plant population density and planting dates used by vegetable processors have remained unchanged. Our analysis revealed a large range (1 to 20 years) in hybrid lifespan, which can be attributed to wide differences in hybrid yield stability across the diverse production environments in the United States. Rainfed production systems are becoming scarcer because sweet corn yields under rainfed conditions are particularly susceptible to severe weather, including heat and drought stress events. Future research is needed to understand sweet corn yields as a function of climatic and nonclimatic variables to stabilize the industry, particularly given predictions of a future with more frequent weather extremes.

Source-specific risk judgement and environmental impact of potentially toxic elements in fine road dust from an integrated industrial city, North China

The contamination of potentially toxic elements (PTEs) in road dust of large industrial cities is extremely serious. Determining the priority risk control factors of PTE contamination in road dust is critical to enhance the environmental quality of such cities and mitigate the risk of PTE pollution. The Monte Carlo simulation (MCS) method and geographical models were employed to assess the probabilistic pollution levels and eco-health risks of PTEs originating from different sources in fine road dust (FRD) of large industrial cities, and to identify key factors affecting the spatial variability of priority control sources and target PTEs. It was observed that in FRD of Shijiazhuang, a typical large industrial city in China, more than 97% of the samples had an INI > 1 (INImean = 1.8), indicating moderately contaminated with PTEs. The eco-risk was at least considerable (NCRI >160) with more than 98% of the samples, mainly caused by Hg (Ei (mean) = 367.3). The coal-related industrial source (NCRI(mean) = 235.1) contributed 70.9% to the overall eco-risk (NCRI(mean) = 295.5) of source-oriented risks. The non-carcinogenic risk of children and adults are of less importance, but the carcinogenic risk deserves attention. The coal-related industry is a priority control pollution source for human health protection, with As corresponding to the target PTE. The major factors affecting the spatial changes of target PTEs (Hg and As) and coal-related industrial sources were plant distribution, population density, and gross domestic product. The hot spots of coal-related industrial sources in different regions were strongly interfered by various human activities. Our results illustrate spatial changes and key-influencing factors of priority source and target PTEs in Shijiazhuang FRD, which are helpful for environmental protection and control of environmental risks by PTEs.

Early Sowing on Some Soybean Genotypes under Organic Farming Conditions.

The demand for soybeans in Europe motivates breeders, researchers, and growers to find suitable cultivars to adapt and extend the soybean crop to improper climate areas. Weed control is a crucial aspect of crop technology in organic agriculture, but particularly for soybean crops. In laboratory conditions, the cumulative stress index for seedlings was determined to identify the susceptible cultivars. A field experiment with 14 soybean accessions and 2 sowing dates was conducted under organic farming conditions over the course of three years, from 2020 to 2022. Plant population density was found to be significantly (p < 0.01 and p < 0.1) negatively correlated to the degree of resistance to low temperature as well as infestation degree with weeds (for p < 0.05 and p < 0.1), with the exception of early sowing in 2021. Yield was significantly (p < 0.05, p < 0.01, p < 0.1) correlated with plant population density, with the exception of optimal sowing in 2022. Early sowing variants emerged with vigor in the first two years, breeding lines and registered varieties showed low input, and organic agriculture systems showed low yields in the drought years of 2020 and 2022. Although early sowing even in the first two years proved to be a practice that increased the cultivars' performance, in 2022, due to the long period of chilling stress in the field, this option had negative effects on yield due to the high weed frequency. Therefore, the early sowing strategy for the soybean crop in this particular case of non-irrigated conditions in a temperate continental area proved to be a risky practice.

Effect of plant population density of black maize on plant growth, baby-corn yield, and biomass

The aim of the study was to determine the effect of black maize plant population density on plant growth, baby-corn yield, and biomass. The research was carried out from September to November 2021 on the plot of the Merang Mushroom Center and Integrated Farming of Lestari Makmur, Kepuhan Hamlet, Argorejo, Sedayu, Bantul, Yogyakarta with vertisol soil type and an altitude of 87.5 meters above sea level. The plant population density implemented in the number of plants per hole, namely 1, 2, 3, and 4 plants per hole, was tested using Completely Randomized Block Design with 3 replications. Each experimental unit measuring 3m × 3.5m with a plant spacing of 75cm × 25cm. Maintenance of experimental plants following the standard recommendations for corn cultivation. Cow manure 15 tons ha−1 was sown before planting, while NPK fertilizer of 300 kg ha was given 2 times on 2 and 4 weeks after planting, by making a whole, put fertilizer in, then covered with soil again. Detasseling was done before the tassels bloom. Baby corn was harvested up to maximum of 6 days after the ears appear. Biomass was harvested by cutting the plant stand after all baby-corn had been harvested. The observed variables were plant height (cm), number of leaves (strands), stem diameter (mm), days to tasseling (days after planting), fresh and dry weight of plant (g), weight and diameter of ears, baby corn yield ha−1, and biomass yield ha−1. Data collected were analized by analysis of variance and DMRT at α= 5%. The results showed that the population density of black maize had an effect on stem diameter, plant fresh weight, baby-corn yield, and biomass yield per hectare. The largest stem diameter at a population density of 1 plant/hole. The yield of baby-corn per hectare was highest at a density of 3 or 4 plants per hole, and the highest biomass yield per hectare was at a density of 4 plants per hole. The weight, length, and diameter of baby-corn did not differ at various population densities.

Yield and Yield Components of Onion as Influenced by Intra-Row Spacing and Nitrogen Fertilizer Levels in Rift Valley, Ethiopia

Background and Objectives: Farmers currently employ nationally approved fertilizer rates and plant spacing when growing onions, but knowledge of plant population density and fertilizer rates that may produce the best bulb production for different cultivars and locations is limited. As a result, gardeners frequently use nonspecific plant population densities for various cultivars, resulting in sub-optimal bulb yields.&#x0D; Materials and Methods: A field experiment was conducted in 2019 from August to December to study the effects of intra-row plant spacing and levels of nitrogen on yield and quality of onion (Allium cepa L.) variety Nafis under irrigation.&#x0D; Results: The main effect of intra-row spacing on stand count and both nitrogen levels and intra-row spacing on plant height and the number of leaves per plant was observed. The interaction of nitrogen level and intra-row distance affected days to maturity, leaf length, leaf diameter, bulb diameter, mean bulb weight, marketable and unmarketable bulb yield, and all bulb size categories. Increased intra-row spacing to 10.5 cm and N rate of 82 kg ha-1 increased marketable and total bulb yield by approximately 3.14 and 3.21 t ha-1, respectively, spacing and decreased unmarketable bulb yield by 1.38 t ha-1.&#x0D; Conclusion: The use of 82 kg ha-1 N at the intra-row spacing of 10.5 cm was optimum for bulb production of onions. 82 kg ha-1 N at 10.5 cm intra-row spacing resulted in the highest net benefit.

Regulation Mechanism of Plant Growth Process

Aims: Non-native plantation and grass can effectively conserve soil and water and improve ecological environment but sometime soil desiccation occurs, led to severe soil degradation, vegetation decline and crop failure, which influence forest and grass high-quality sustainable development and Agriculture high quality production, so it is necessary to regulate the plant resources relationship and get maximum yield and benefits. However, there is a lack of a universally accepted theory to provide guidance of sustainable use of soil water resources and high-quality sustainable management of forest and Agriculture high quality production p in such regions. Purpose of the paper is to introduce the theory of plant resources relationship regulation. Methods: Different caragana plant density experiment plot was established in the same condition, the precipitation, plant growth, soil water content at different depth was investigated, the wilt coefficient at different soil depth, the maximum infiltration, soil water resources use limit by plants and the theory of soil water vegetation carrying capacity was dealt with. Results: The results showed that the theories of plant resources relationship regulation include the Resources Use Limit by Plants and Vegetation Carrying Capacity. Resources Use Limit by Plants and Vegetation Carrying Capacity include Space Resources Use Limit by Plants and Space Vegetation Carrying Capacity in soil water and soil nutrient rich regions, Soil water Vegetation Carrying Capacity and Soil Nutrient Resources Use Limit by Plants and Soil Nutrient Vegetation Carrying Capacity. The Soil water Vegetation Carrying Capacity is the population in a plant population or plant density of indicator plants in a plant community when the resources supply is equal to soil water consumption in the root zone and a given time, especially and changes with plant community type, location and time. Conclusions: The degree of coverage, productivity and benefits of a plant community when population quantity of an indicator plant equals SWVCC should be the theoretical basis for sustainable use of soil water resources, high-quality sustainable management of forest and grass and Agriculture high-quality production.

Long-term assessments of cotton fiber quality in response to plant population density: Reconciling fiber quality and its temporal stability

Regulation of plant population density is crucial for optimizing cotton fiber quality. However, the relationship between plant density and fiber quality stability under contrasting climatic conditions remains unclear, and the compromise between fiber quality and temporal stability is unknown. In this study, based on a long-term field experiment with various plant densities (1.5–10.5 plants m–2) conducted from 2008 to 2021, cotton fiber quality variability, including fiber length, fiber strength, elongation, uniformity index, and micronaire, and their temporal stability, were evaluated. We determined the optimal plant density for cotton cultivation and elucidated the contributions of plant density and climatic conditions to the variability of cotton fiber quality and its temporal stability in China’s Yellow River Valley. The results revealed that cotton maintained its upper-intermediate quality throughout the study period, with fiber length, strength, elongation, uniformity index, and micronaire values ranging between 28.04 and 30.03 mm, 26.15–30.05 cN tex–1, 5.90–6.83%, 83.85–85.44%, and 4.24–5.14, respectively. An increase in plant density improved fiber quality but impaired temporal stability (P < 0.01), and slight increases in stability at lower plant densities resulted in substantially decreased probabilities of years with major declines in fiber quality class. Plant density and climatic conditions regulated the quality traits (23.5% and 69.3% of the explained variance, respectively), including fiber length, fiber strength, and micronaire, while climate was the most important factor (75.9% of the explained variance) in determining their temporal stability. Photosynthetically active radiation and maximum and mean temperature exhibited significant positive effects on fiber quality, whereas mean diurnal temperature range had the opposite effect. A plant density of 3.3–5.1 plants m–2 ensures the highest temporal stability of cotton fiber quality without declines in the fiber quality class. This study first provides insights into balancing cotton fiber quality and temporal stability through agronomic interventions, with implications for the quantitative prediction of future crop quality changes owing to climatic variation.

The Relationship Between Plant Roots and Population Density of Soil Fauna in Some Vegetable Crops

The Relationship Between Plant Roots and Population Density of Soil Fauna in Some Vegetable Crops

Influence of Plant Population Density and Variety on the Growth and Yield Components of Carrot (Daucus Carota L.)

Influence of Plant Population Density and Variety on the Growth and Yield Components of Carrot (Daucus Carota L.)

English

A study was carried out at two sites in Tanzania to assess the effect of different planting densities on growth and yield of five recently released bush bean varieties. The experiment was laid out in a split-plot design in a factorial arrangement with three replications during long and short rainy seasons of 2019/20 and 2020/21. The treatments comprised five bean varieties; TARIBEAN 1, 2, 3, 4 and 5 and five plant population densities; 200000, 222222, 250000, 266666 and 333333 plants/ha. Variables evaluated were plant height, angular leaf spot and common bacterial blight disease scores in leaves, number of pods per plant, number of seeds per pod, hundred seed weight and grain yield. The variables were subjected to ANOVA and means of statistically significant variables to plant density, variety, and environment were analyzed by Tukey HSD test and &ldquo;which-won-where&rdquo; view of the GGE biplot. The interaction of factors only affected significantly plant height and yield. Highest grain yield of 1,353 and 1,607 kg/ha were recorded by plant density of 200,000 plants/ha and TARIBEAN 1 variety at Maruku site during short rainy seasons (E2). Therefore, a plant density of 200,000 plants/ha and TARIBEAN 1 variety are recommended in all four environments. Key words: Plant density, bean varieties, grain yield, environment, GGE biplot, &ldquo;which-won-where&rdquo;.

The vegetation cover dynamics and potential drivers of habitat change over 30 years in the Free State National Botanical Garden, South Africa

As a conservation strategy, the South African National Biodiversity Institute (SANBI) establishes biodiversity gardens in areas with unique vegetation types that are vulnerable to extinction. The study aimed to (1) determine the vegetation cover dynamics of the Free State National Botanical Garden (FSNBG) over a 30-year period (1987–2017), focusing on different vegetation classes; (2) evaluate the ecological integrity of the Critical Biodiversity Area 1 (CBA1) vegetation using species abundance and vegetation cover; and (3) quantify potential conservation threats that may be drivers of vegetation cover changes. The “moderate vegetation cover” and “dense vegetation cover” had increased by 25.1 ha and 8.6 ha respectively in the FSNBG. Woody vegetation cover expanded significantly over the past 30-year period, suggesting “bush” encroachment. Shannon–Wiener diversity indices showed high overall plant species diversity of CBA1 vegetation type (H = 3.5), with the vegetation cover remaining high (79.6 ± 15.9%), 50 plant species no longer existing, suggesting reduced taxonomic richness. Major conservation threats included the presence of 27 alien and invasive plant species interspersed within different vegetation patches and anthropogenic habitat fragmentation in the past 19 years (i.e. covering ~ 18% of the buffer zone). We conclude that increased vegetation cover is associated with bush encroachment and we recommend interventions to reduce the population density of woody plants and establish permanent vegetation monitoring plots.

Genotype-dependent responses of Andean and Coastal quinoa to plant population density for yield and its physiological determinants in Northwest Argentina

Context In quinoa, similar yields are found under a wide range of plant population densities due to its phenotypic plasticity. Aims This study aimed to identify optimal plant population densities for achieving attainable yields, in relation to the most adapted genotype for a given environment. Methods Andean (RQ252 and RQ420) and Coastal (Titicaca and Puno) genotypes were tested at conventional (14 plants/m2) and low (7 plants/m2) plant population densities, in Dry Valley and Highland mega-environments for 2 years. Key results More than 64% of total variation was explained by genotype, location, and interaction effects for grain yield, biomass, and harvest index. For these variables, the genotype × location × plant population density term presented the highest percentage of variation among triple and quadruple interaction terms. In the Highlands, grain yields decreased with plant population density for Andean genotypes (30–40%), in contrast to lower reductions for Coastal genotypes (9–20%). In the Dry Valleys, no effect of plant population density was found for all genotypes. In the Highlands, reductions in biomass and harvest index explained grain yield response, in parallel with increases in small grain percentage of up to 16% when frosts came early, related to uneven maturity at low plant population density. Conclusions Attainable yields in Northwest Argentina were achieved by exploring local adaptation and response to plant population density of Andean genotypes in the Highlands, in contrast to stable yields of Coastal genotypes through locations and plant population densities. Implications Understanding genotype-dependent responses to plant population density according to Northwest Argentina mega-environments can reduce yield gaps in quinoa production and refine breeding strategies.

Plant population density in cotton: Addressing knowledge gaps in stand uniformity and lint quality under dryland and irrigated conditions

A recent literature review and data synthesis better defined the yield curve with plant population density in cotton (Gossypium hirsutum L.), but it also highlighted gaps in knowledge. Few cotton plant population studies have been conducted in relatively low-yielding dryland conditions; fewer have considered the impact of uneven crop stands, which are common in actual field conditions due to planting equipment errors and seed/plant mortality; and population reports that include fiber quality measurements by Advanced Fiber Information System (AFIS) testing are lacking (rather than just the standard High Volume Instrument (HVI) measurements). To address these issues, a study was conducted in North Texas, USA with treatment combinations of two irrigation levels (0% and 90% ET replacement), five plant population densities (15,000, 30,000, 60,000, 90,000, and 120,000 plants ha-1), and two stand uniformities (even and uneven plant-to-plant spacing within rows). Canopy development was tracked by unmanned aircraft system (UAS) measurements, late-season measurements were taken of boll density and size, and lint yield and quality measurements were collected at maturity. Lint yield was unaffected by plant population density in 2020 (i.e. 15,000–120,000 plants ha-1), whereas an interaction between irrigation and plant population occurred in 2021. Lint yield was reduced by 19% with 15,000 plants ha-1 relative to 120,000 plants ha-1 under only irrigated conditions in 2021. There was no substantial or consistent effect of stand uniformity on any response variable in either year. Poor stand quality is often the basis for terminating and replanting or replacing troubled cotton crops, but these results suggest this is not justified when overall population density is 30,000 plants ha-1 or greater, depending on production environment. The risk of yield loss is clearly greater when overall plant density decreases below this level, especially in higher-yielding conditions, but the economic tradeoffs of replanting or replacing the crop must be considered. In the cotton plant, yield compensation for low plant density and uneven stands occurred primarily by increased boll number per plant and secondarily by increased boll size. Fiber quality parameters as measured by HVI and AFIS were minimally and inconsistently affected by population density and stand uniformity, suggesting that population dynamics are not critical factors cotton producers must consider in optimizing the fiber quality of their product.

Effects of radiation and plant population on growth and yield attributes of wheat

Radiation plays a crucial role for growth and yield of wheat. A field experiment was conducted at the Field Laboratory of Agrotechnology Discipline of Khulna University in Bangladesh during November 2018 to March 2019 to study the effect of radiation levels and plant population on growth and yield attributes of wheat. The study was set out in the randomized complete block design with four radiation levels (full sunlight, 75% light, 55% light, 25% light) and three plant population densities (160 plant/m2, 200 plant/m2, 230 plant/m2) that replicated thrice. Growth and yield attributes of wheat were generally similar between two light levels (full sunlight, 75% light) and two plant densities (200 plant/m2, 230 plant/m2). However, the attributes were usually minimum at 25% light. The interaction effect of full sunlight or 75% light with optimal (200 plant/m2) or maximal (230 plant/m2) plant densities produced statistically similar plant height, leaf number, tiller number, total dry matter, grain yield, straw yield, and biological yield. Therefore, combination of 75% light with 230 plant/m2 is suggested for growing wheat in light limited areas and in agroforestry system with acceptable yield.

First steps toward developing Lewis flax (Linum lewisii Pursh) as an agronomic crop

Abstract Perennial Lewis flax (Linum lewisii Pursh) has the potential to be grown as a new oilseed crop that could simultaneously meet commodity production, ecosystem service provisioning, and farm resiliency goals. Despite many potential benefits, Lewis flax remains minimally explored as an agronomic crop. Determining agronomic best practices for producing economically relevant stands of Lewis flax is critical to its adoption as an oilseed crop. Several aspects of Lewis flax agronomic production were explored through the lens of adaptive management between 2020 and 2022. Initial field trials aimed at assessing spring-seeded Lewis flax row spacing, plant population density, and intercropping strategies with legumes and grasses failed due to poor establishment. Heavy rains and excessive weed pressure further complicated attempts to reestablish these initial trials. We established additional Lewis flax plots via fall and dormant seeding in response to the failure of our first experiment. This second experiment focused on exploring row spacing, population density, and seeding timing impacts on flax production. Flax yield did not differ among our treatments, averaging 59 kg ha−1. The low yields realized by our field trials may be due to several factors including need for harvest technology optimization, high weed pressure, and need for Lewis flax genetic improvement. Our study is a first step toward developing recommendations for optimal production strategies for Lewis flax in an agronomic context. Continued exploration of methods to improve management and yield of Lewis flax will be critical to its successful development as an agronomic crop.

Growth of Red Amaranth (Amaranthus cruentus L.) Cultivated on Soil-Based Substrate Amended with a Residue of the Black Soldier Fly Larvae Containing Heavy Metals

Red amaranth (Amaranthus cruentus L.) is a fast-growing and nutritious leafy vegetable. The seed population density needs to be known appropriately to obtain the optimal yield of marketable sizes plants. The residue of black soldier fly (BSF) larvae culture has been recognized as a potential source of nutrients for cultivating red spinach plants. This study was designed to search for the best combination of plant population density and BSF concentration to obtain the optimal marketable yield of the red amaranth plant. In addition, an accurate leaf area estimation of the red amaranth plant was also developed using leaf dimensions as a predictor with several regression models. Two experiments were conducted. Firstly, the BSF residue was applied at a high rate (up to 50%) using a floating culture system. Application of the residue at the rate of 30% and higher significantly inhibited the growth of the red amaranth. Secondly, the application rate was reduced to 10% and 20%, and the experiment was conducted using the conventional cultivation system. Results indicated that the optimum application rate of the BSF residue was 10% for enhancing growth. Application of seed density at 30 mg/dm2 produced an optimum marketable yield of the red amaranth since a higher population density causes plant-plant competition. Thus, creating high size variability within the population or reducing the average size of the harvested plants. Lastly, the leaf area of red amaranth can be accurately estimated using the leaf length x width (LW) as a predictor using the zero-intercept linear regression model.