Sowing Density Research Articles

Sowing density rather than row spacing influences chia radiation use and yield

AbstractChia (Salvia hispanica L.) production worldwide has been encouraged due to its high essential fatty acid content that is effective for reducing cardiovascular affections. However, few studies have assessed the sowing density and row spacing to maximize chia grain yield (GY) and found controversial results. None of them reported effects on radiation interception and use efficiency that could help to clarify the controversial results. The objective of this study was to determine the effects of sowing density and row spacing on radiation interception and radiation use efficiency (RUE) of chia and their effects on chia growth and yield. Two field trials were conducted in Salta, Argentina, during 2017 and 2018, combining two factors: sowing density (5, 9, 13, 17, and 21 plants m−2) and row spacing (0.26 and 0.52 m). Photosynthetically active radiation (PAR) interception (PARi), RUE, biomass and GY components were measured. There was a clear effect of sowing density on the main growth and yield attributes, whereas there were no effects of row spacing. Sowing density had a greater impact on PARi than row spacing. Increasing sowing density increased PARi and RUE through earlier time of maximum PARi, accumulating more PAR producing more biomass and GY. Grain yield, which increased by 73 kg ha−1 per unit increase in plant density, was closely associated with biomass, grain number, and verticillaster number (VN), and negatively associated with 1,000‐grain weight (TGW). Summarizing sowing density rather than row spacing had a greater impact on growth and yield attributes of chia.

Beneficial effects of antitranspirants on water stress tolerance in maize under different plant densities in newly reclaimed land

BackgroundThe global freshwater shortage is an important issue threatening the sustainable development of agriculture and food security. A field study was conducted in two seasons, i.e., 2019 and 2020, in the newly reclaimed land at Village 8, El-Minia Governorate, Egypt, to evaluate maize crop response to three irrigation levels (IL1 = 80, IL2 = 70, and IL3 = 60% of the crop evapotranspiration “ETc”), three plant densities (PD1 = 17.500, PD2 = 23.333, and PD3 = 35.000 plants fed−1), and three antitranspirants treatments (An1 = control, An2 = kaolin at 6%, and An3 = chitosan at 150 L fed−1). The experiment was designed as a randomized complete block design (RCBD) using a split plot in strips.ResultsResults revealed that the irrigated maize plants with IL1 (80% of ETc) recorded the maximum values for all traits such as vegetative growth, phenology, and yield and its attributes in both seasons. The heaviest value of grain yield (3.15 and 3.10 tonnes fed−1, where 1 feddan = 0.42 hectare) was realized from IL1 treatment in the 1st and 2nd seasons, respectively. Plant density of 35.000 plants fed−1 (PD3) produced the greatest values of leaf area index (6.70 and 6.85), more days to 50% for each of tasseling (62.16 and 61.99 days), and silking (63.63 and 63.73 days), heaviest grain yield (3.11 and 3.16 ton fed−1) and greater water use efficiency WUE (1.46 and 1.48 kg m−3) in both seasons, respectively.ConclusionsFoliar spraying with antitranspirants, i.e., kaolin at 6%, led to a tremendous impact on all studied traits by alleviating the water stress and reducing the rate of transpiration. The effect of second-order interaction among IL1 × PD3 × An3 indicated a significant increase in grain yield by 69.91% as compared with the interaction of IL3 × PD1 × An1 in the 2020 season only. CS 10 single-cross maize realized the highest productivity and most efficient use of available resources via using a sowing density of 35.000 plant fed−1, foliar spraying with kaolin at 6%, and irrigation level (80% of ETc) under El-Minia conditions.

Nitrogen Fertilizer and Sowing Density Affect Flag Leaf Photosynthetic Characteristics, Grain Yield, and Yield Components of Oat in a Semiarid Region of Northwest China

Oat has been gaining renewed interest due to its role in a healthy human diet, in animal feed, and as a source of high value compounds with industrial applications. Nitrogen fertilization and planting density are two of the most important crop management practices that affect the formation of yield components and final yield of oat. A 2 year 3 × 5 factorial field experiment was conducted to investigate the effects of nitrogen (N) fertilizer and planting density on the flag leaf photosynthetic characteristics, grain yield, and yield components under rainfed conditions. The experiment consisted of three sowing densities (60, 180, and 300 kg·ha−1) and five nitrogen fertilizer rates (0, 45, 90, 135, and 180 kg·ha−1). Results showed that the grain yield was significantly (p < 0.05) correlated with the leaf net photosynthesis rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (Tr), water-use efficiency (WUE), stomatal limitation value (Ls), chlorophyll content (SPAD value), leaf area index (LAI), panicle length, number of spikelets per panicle (NSP), number of grains per panicle (NGP), weight of grains per panicle (WGP), and 1000-kernel weight. Among the yield components, grain yield was driven by number of spikelets per panicle (NSP) and number of grains per panicle (NGP) at low (or high) planting density with low N supply, whereas, at high N supply, 1000-kernel weight was also an important factor for yield. Nitrogen fertilizer and sowing density had significant (p < 0.05) effects on the flag leaf photosynthetic characteristics, grain yield, and yield components of oat. The yield components increased and then decreased with the increase in nitrogen fertilizer, while they decreased with the increase in planting density. The maximum values (p < 0.05) of grain yield were observed in the nitrogen fertilization of 90 kg·ha−1 and sowing density of 180 kg·ha−1 treatment in both growing seasons, mainly contributing to the improved leaf photosynthesis traits (Pn, Gs, Tr, Ls, SPAD, and LAI). The combination of nitrogen fertilization of 90 kg·ha−1 and sowing density of 180 kg·ha−1 is suitable for oat production on a cool semiarid plateau or other agroecozones with similar environmental conditions.

Eficácia do tratamento de sementes com fungicidas no controle do tombamento de plântulas de soja causado por Rhizoctonia solani sob condições casa de vegetação

ABSTRACT The present study was conducted to evaluate the efficacy of fungicide seed treatment in the control of soybean seedling damping-off caused by Rhizoctonia solani under greenhouse conditions. The experiment was carried out in Dourados, Mato Grosso do Sul State, Brazil. Treated and untreated soybean seeds were sown in previously sterilized sand, contained in plastic trays, in equidistant individual wells at 3cm depth. The soybean sowing density was 200 seeds/plastic tray. Inoculation with R. solani was done by homogeneous distribution of the fungal inoculum onto the substrate surface (5.0g/tray). The fungus was grown for 35 days on autoclaved black oat seeds ground to powder with a mill (1mm). Seedling emergence, pre and post-emergence damping-off, injured seedlings and disease index (severity) were evaluated according to McKinney formula. Fungicide seed treatments had a significant effect (P ≤ 0.05) on seedling emergence, pre and post-emergence damping-off, injured seedlings and disease index (severity). The best results were obtained for fludioxonil+metalaxyl-M+thiabendazole and fipronil+pyraclostrobin+thiophanate-methyl, followed by carbendazim+thiram+pencycuron and thiophanate-methyl+fluazinam. The least efficient treatments were carbendazim+thiram, fludioxonil+metalaxyl-M and carboxin+thiram. Pearson correlation analysis indicated that injured seedlings and disease index were positively correlated (R=0.92). This means that the greater the number of injured seedlings, the greater the disease index and the less efficient the fungicide. The fungicides used in the present study did not have any phytotoxic effect on soybean seedlings.

Corn yield components in function of the regulation of the seeder-fertilizer in a conventional planting system in amazon biome

The correct seeder-fertilizer adjustment is responsible for increasing the efficiency of corn cultivation's implementation process. This work aimed to evaluate transmission system regulation of seeder-fertilizer seed deposition unit in maize crop implantation in the Eastern Amazon. The experiment was carried out after the sowing process with a seeder-fertilizer for conventional planting with a mechanical seed distributor. The treatments resulted in five size combinations of driven gears (8, 10, 12, 15, 17) with the motor gear of size 7, which resulted in the respective corn sowing densities, 64.978, 62.311, 52.444, 44.977, 38.665 plants ha-1. Each treatment consisted of a 200 m seeding strip divided into 20 plots per strip (treatment). The agronomic variables analyzed were: average Number of Days to Emergence (NDE), longitudinal distribution of plants in the standard (N), Fault (F) and Double (D) fields, Initial Plant population (IP), Final Plant population (FP), Stem Diameter (SD), Plant Height (PH), Number of Leaves (NL), Number of Ears (NE), Mass of one hundred grains (MG), Number of Grains per row (GR), Number of Ear rows (ER), Ear Length (EL), Ear Diameter (ED) and Productivity (P). Data were submitted to statistical analysis, correlation test and decision tree analysis. The decision tree showed which initial population was more important to classify the most relevant agronomic variables in corn planting. The initial stand of 62.442 plants ha-1 was the most suitable for corn in the Amazon region. There is potential to reach corn productivity of 5.14 to 5.33 t ha-1 when combined with a drive gear 12 and driven gear 7 seeder-fertilizer machine transmission system

Determination of Grain Yield and Some Forage Quality Traits of Rye Genotypes at Different Sowing Densities

Çalışmasın amacı, çavdar genotiplerinde farklı ekim sıklığı uygulamalarının (350, 425, 500, 575, 650, 725 tohum m-2) tane verimi ve kalite üzerine etkisini belirlenmektedir. Çalışma, birer tescilli tritikale (Karma-2000) ve çavdar (Aslım-95) çeşidi ile iki yerel çavdar hattı (Bayburt ve Yozgat) olmak üzere dört genotip kullanılarak 2014-2015 ve 2015-2016 yetiştirme sezonlarında yürütülmüştür. Deneme bölünmüş parseller deneme deseninde; ana parsellere genotipler, alt parsellere ekim sıklıkları yerleştirilerek üç tekrarlamalı olarak yürütülmüştür. Yıllar üzerinden birleştirilerek yapılan varyans analizi sonuçlarına göre, tane verimi, bitki boyu, bin tane ağırlığı, nişasta oranı, ham protein oranı, ham yağ oranı, asit deterjanda çözünmeyen lif (ADF) ve nötr deterjanda çözünmeyen lif (NDF) değerleri üzerine genotip ve ekim sıklıklarının (yağ oranı hariç) etkisi istatistiki olarak önemli bulunmuştur. Tane verimi en yüksek 3.94 ton ha-1 ile m2’de 575 tohum sıklığı uygulamasından elde edilirken, regresyon denklemine göre en uygun ekim sıklığı 563 tohum m-2 olarak tespit edilmiştir. Çavdar genotiplerini kendi içinde değerlendirdiğimizde yerel genotiplerin kalite özellikleri bakımından Aslım-95 çeşidinden daha iyi değerlere sahip olduğu sonucuna varılmıştır.

Вплив елементів технології на врожайність насіння ліній — батьківських компонентів гібридів кукурудзи в умовах краплинного зрошення

Goal. To determine the influence of plant density and treatment with preparation Retenho® on the weight of 1000 grains and the seed yield of lines — parental components of corn hybrids under irrigation conditions. Methods. The research was carried out using field (determining the yield of lines — parental components), laboratory (weight of 1000 grains), and analytical and mathematical-statistical methods. Results. The maximum yield of the mid-early line DK 247 on average at a plant density factor of 90,000 plants/ha was 4.70 t/ha, of the medium-ripe line DK 205710 at a density of 80,000 plants/ha — 5.42 t/ha, of the mid-late line DK 445 for the density of 70 thousand plants/ha — 7.08 t/ha of seeds. The most productive mid-late line DK 445 — the parent component of the Vira, Hileia, Arabat hybrids reacts negatively to the density of crops. The seed yield at a density of 100,000 plants/ha decreased by 1.03 t/ha, or by 15% compared to the yield at an optimal density of 70,000 plants/ha. When plants were treated with Retenho®, the weight of 1000 grains increased by 10–12 g, or by 3.7–5.4% compared to the untreated control. Treatment of plants with the growth-regulating fungicide Retenho® contributed to an increase in seed yield by 0.29–0.41 t/ha, or by 6.3–7.9%. Sowing density affected the weight of 1000 grains: the maximum weight of 1000 grains on average over the years of research (252 g) was obtained at a density of 60 thousand plants/ha in all lines. Conclusions. The trait «weight of 1000 grains» of lines — parental components were affected by FAO group, sowing density, and treatment with Retenho®. Each parent line has an optimal seeding density to obtain the highest seed yield by maintaining the optimal feeding area of one plant. The maximum yield of the mid-early line — the parental component DK 247 was observed at a density of 90 thousand plants/ha and treated with Retenho® — 4.94 t/ha. In the medium-ripe line —parent component DK 205710 formed the maximum yield at a sowing density of 80,000 plants/ha and treatment with Retenho® — 5.61 t/ha. In the mid-late line — the parental component DK 445 showed the maximum yield at a density of 70,000 plants/ha and treatment with Retenho® — 7.08 t/ha.

Yield, intercepted radiation and morphology of crotalaria (Crotalaria juncea L.) at different densities

Objetive: The objective of this study was to evaluate the yield, intercepted radiation and morphology of crotalaria (Crotalaria juncea L.) at different planting densities, in the dry tropics of the state of Guerrero, Mexico.
 Desing / Methodology / Approach: The treatments were: four planting densities at 400,000, 200,000, 100,000 plants ha-1 and a stream. A growth analysis was also evaluated at 30, 38, 45, 52, 60, 68 and 75 days of growth, understanding that the pod was fully developed. The variables evaluated were: dry matter yield, intercepted radiation and morphological composition.
 Results: The dry matter yield, regardless of the cutting age, was obtained in descending order at the planting densities of: 400,000 ˃ chorrillo ˃ 200,000 ˃ 100,000 plants ha-1 with 19,837, 17,918, 8,786 and 4,074 kg DM ha-1,
 Study Limitations / Implications: In the tropics it is necessary to broaden the panorama with the producers, in the use of forage legumes to improve the feeding of cattle.
 Findings / Conclusions: It is recommended to sow at a sowing density of 400,000 plants ha-1 and to cut after 45 days of growth in crotalaria since it is when the best structural characteristics of the meadow and 95% of intercepted radiation are found

Intercropping of sorghum with congo grass (Brachiaria ruziziensis) on soybean succession at the rainy season

Sorghum intercropping with Brachiaria has the potential to improve grain yield and dry matter in the Cerrado region, but there are no studies on the ideal density of Brachiaria seeds for adoption in intercropping when the system is deployed at the beginning of the rainy season. Thus, the objective of this study was to determine the intercropping of sorghum with Brachiaria ruziziensis that may provide higher yield of grain sorghum and dry mass of both crops. We also evaluated the performance of soybeans in succession after intercropping. The test was conducted in 2013/14 and 2014/15 in tropical climate region with wet and dry seasons. The experimental design followed a randomized complete block in a factor 3 x 5 + 1 + 5, corresponding to three intercropping Brachiaria ruziziensis seeding systems (row, inter-row and broadcast sowing) associated with five densities of Brachiaria (2, 4, 6, 8 and 10 pure viable seeds m-2) plus the additional treatments related to monocultures of the grain sorghum and the five densities of the Brachiaria. The Brachiaria ruziziensis association with sorghum cultivation proved to be a promising technique for improving grain yield and dry matter at different times of the year without affecting the development and yield of the soybean crop culture. The best results were achieved with planting of Brachiaria ruziziensis in the line at the sowing density of 8 viable pure m-2 seeds and the inter-row sowing density of 6 viable pure m-2 seeds

The effects of different sowing density and harvest periods on dry matter yield and some quality traits of safflower (Carthamus tinctorius L.)

Amaç: Bu çalışma, farklı ekim sıklıkları ve gelişme dönemlerinin aspirin kuru madde verimi ve bazı kalite özelliklerini belirlemek amacıyla yürütülmüştür. Materyal ve Yöntem: Araştırma, tesadüf bloklarında faktöriyel deneme desenine göre üç tekerrürlü olarak 2021 yılında Uşak’ta yürütülmüştür. Çalışma kapsamında aspir 30, 60, 90, 120 ve 150 bitki m-2 ekim sıklıklarında yetiştirilmiş ve tabla çıkarma, çiçeklenme başlangıcı ve tam çiçeklenme dönemi olmak üzere 3 farklı gelişme döneminde hasat edilmiştir. Araştırmada aspirin bitki boyu, yeşil ot verimi, kuru madde verimi, ham protein oranı, ham protein verimi, NDF ve ADF oranları belirlenmiştir. Araştırma Bulguları: Araştırmadan elde edilen sonuçlara göre aspirde uygulamalara bağlı olarak bitki boyu 72.35-77.67 cm, yeşil ot verimi 1333.54-2001.87 kg/da, kuru madde oranı %16.53-40.73, kuru madde verimi 303.72-585.86 kg/da, ham protein oranı % 8.36-12.29, ham protein verimi 37.40-55.23 kg/da, NDF oranı % 31.30-47.92 ve ADF oranı % 27.61-38.59 arasında değişim göstermiştir. Çalışmada artan bitki sıklığı yeşil ot, kuru madde ve ham protein verimini artırırken ilerleyen hasat dönemi kalite özelliklerinde azalmalara neden olmuştur. Sonuç: Çalışma sonunda kaba yem amacıyla yetiştirilen aspirde m2’ de 90 bitkinin yer alması ve hasadın çiçeklenme başlangıcı dönemde yapılmasının yüksek ot verimi ve kalite için daha uygun olduğu ancak sonuçlar hakkında daha sağlıklı bir karar verebilmek için denemenin en az bir yıl daha yürütülmesinin uygun olduğu sonucuna varılmıştır.

AGRONOMIC PERFORMANCE OF LINSEED AS A FUNCTION OF PLANT ARRANGEMENT

The objective of this work was to understand the agronomic performance of flaxseed cultivated in different spacings between rows and plant density, identifying associations between traits for indirect selection. The experiment was carried out in the municipality of Augusto Pestana - RS, in the years 2020 and 2021, using a randomized block experimental design organized in a 6x3x2 three-factor scheme, with six sowing densities (30, 60, 90, 120, 150 and 180 plants per linear meter), three spacings between rows (0.18 m, 0.36 m, .0.54 m), and two crop seasons (2020 and 2021). In ten plants per plot, plant height, height of insertion of the first capsule, number of basal branches, stem diameter, number of branches on the stem, number of main branches, number of capsules, mass of capsules, number of grains per plot were measured. plant, weight of one hundred grains and weight of grains per plant. In addition, grain yield and plant stand were estimated. Grain yield is enhanced in row spacing of 18 cm with densities of 65 seeds per linear meter in crops with favorable conditions. In flaxseed, the number of capsules, number of grains and the mass of grains per plant exhibit a linear association with grain yield and can be used for indirect selection.

ADJUSTING THE OPTIMAL ARRANGEMENT OF PLANTS TO MAXIMIZE THE PRODUCTIVITY AND QUALITY OF FLAXSEED GRAINS

The aim of this work was to highlight the effects of row spacing and seed densities on the agronomic performance of flaxseed. The trial was developed in the experimental area of the Regional Institute of Rural Development, which belongs to the Regional University of the Northwest of the Brazilian State of Rio Grande do Sul. The experimental design was randomized blocks, and the treatments were structured in factorial scheme three (spacings) x six (densities) with three replications per treatment, totaling 54 experimental units. We used three spacings between rows, 18 cm, 36 cm and 54 cm, and densities of 30, 60, 90, 120, 150 and 180 seeds per linear meter. The experimental units were three meters wide by 10 meters long, totaling 30 square meters. Morphological and productive variables of the flaxseed crop were evaluated, as well as meteorological variables. Increased spacing contributes to reduced grain yield regardless of the sowing density. The row spacing of 18 cm shows the best results for grain yield in relation to the seed densities used. High magnitude linear associations such as number of stem branches, productive branches, number and mass of capsules and grains per plant, and plant population define grain yield per unit of area.

Сошниковая секция с дисковым рассеивателем семян

The issue of seed distribution during strip sowing of agricultural crops by using a disk seed disperser in the design of the joint is considered. The development of an optimal design of a coulter for strip sowing of vegetable seeds with a technologi-cally expedient method of sowing is presented. In confirmation of the advantages of strip sowing over ordinary, compara-tive experimental studies on the quality of seed distribution were conducted and the following results were obtained: - with an increase in the seeding rate, the coefficients of uniformity of sow-ing KV and density of sowing KP increase; - the feeding area of one plant SP at the seeding rate Q = 3 kg / ha in a two-disc coulter is greater and equal to 6.11 cm2, and at Q= 4 kg / ha it is greater in a coulter with an active seed disperser and is 5.01 cm2. Keywords: VEGETABLE CROPS, STRIP SOWING, PLANT FEEDING AREA, DISC SEED DISPERSER, COULTER, SOWING UNIT

Sowing rate effect the performance and seed quality of pea cultivars in the eastern forest-steppe of Ukraine

Sowing rate effect the performance and seed quality of pea cultivars in the eastern forest-steppe of Ukraine

The Effect of Different Nitrogen Fertilizer Rates, Sowing Density, and Plant Growth Regulator Application on the Quality and Milling Value of Triticum durum Desf. Grain

Agronomic treatments and environmental conditions of cultivation affect the nutritional value and technological quality of durum-wheat-based products. The aim of this study was to determine the effect of 18 agronomic treatments that differed in nitrogen rate, sowing density, and growth regulator application on variability in the quality and milling parameters of durum wheat grain, and the interrelationships between these parameters. The study demonstrated that the investigated parameters were modified by the agronomic treatments. However, environmental variance resulting from differences in soil characteristics and climatic conditions dominated in most cases (44–93%). The percentage of variance induced by differences between treatments in total variance was distinctly higher only in the case of the gluten index (59%). The treatments without nitrogen fertilization and with or without the application of the growth regulator, and the treatments with the application of the growth regulator and the nitrogen rate of 120 kg N ha−1, discriminated between the milling parameters associated with sifting (bran, type 1 semolina) and grading of milling products (flour, type 2 semolina, and type 3 semolina), respectively.

Effects of paclobutrazol application on plant architecture, lodging resistance, photosynthetic characteristics, and peanut yield at different single-seed precise sowing densities

The key to high-yielding peanut cultivation is the optimization of agricultural production practices. Regulating single-seed precise sowing (SSPS) density and paclobutrazol (Pbz) application concentration are effective practices that increase peanut yield by improving plant architecture, lodging resistance, and photosynthetic characteristics. Therefore, we conducted a two-factor field optimization experiment for the sowing density (D1: 1.95 × 105 plants ha−1, D2: 2.40 × 105 plants ha−1, D3: 2.85 × 105 plants ha−1, and D4: 3.30 × 105 plants ha−1) and Pbz application concentration (P0: 0 mg L−1 and P1: 100 mg L−1). The objective was to optimize agricultural production practices and provide a theoretical basis for high-yielding peanut cultivation by evaluating the effects of sowing density and Pbz application on plant architecture, lodging resistance, photosynthetic characteristics, and yield. The results showed that at the same Pbz application concentration, increasing sowing density increased lodging percentage and reduced leaf photosynthetic capacity. At the same sowing density, Pbz application reduced lodging percentage by decreasing plant height (PH), improving lignin biosynthesis-related enzyme activities, and enhancing stem puncture strength (SPS) and breaking strength (SBS). The paclobutrazol-induced alterations in plant architecture and lodging resistance improved light transmission at the middle and bottom leaf strata, resulting in the increase in relative chlorophyll content and net photosynthetic rate (Pn) of leaves. Furthermore, D3P1 treatment had the highest peanut yield among all treatments. In summary, the production strategy combining the sowing density of 2.85 × 105 plants ha−1 with the application of 100 mg L−1 Pbz was found to be the optimal agricultural production practice for giving full play to production potential and achieving higher peanut yield.

Response of Bread Wheat Cultivar to Different Sowing Densities for Yield and Yield Traits

This study was conducted at Edirne, Tekirdağ and Kırklareli locations in 2017-2018 growing season. The experiment was arranged in a randomized complete block design with four replications. In the study, it was aimed to determine the effects of five different sowing densities (200, 300, 400, 500 and 600 seed m-2) on grain yield and yield components of bread wheat cultivar Aslı. In the experiment, the effect of sowing density and location on grain yield and yield components was found significant. In addition, sowing density × location interaction was found to be statistically significant in terms of grain yield. Grain yield was found among 693.2-849.7 kg da-1, while spike length was ranged from 8.3 to 9.5 cm. However, number of spikelets per spike was in the range of 17.4-19.7, while number of grains per spike was 35.2 to 44.1 and grain weight per spike was 1.43 to 1.75 g. Among the locations, the highest grain yield was determined at Edirne location. In terms of grain yield, the most appropriate sowing density was determined as 400 seed m-2 rate.

Potencijal prinosa sjemena i biomase bijele lupine (Lupinus albus L.) u ekološkoj proizvodnji

Lupin is a very promising crop for seed and biomass production in organic farming. The aim of this research, conducted in 2018 and 2019 at the experimental facility of the Faculty of Agriculture, University of Zagreb, was to determine the white lupin seed and biomass yield, depending on the sowing density. The trial was laid out according to a randomized block design with four replications. The research included two white lupin varieties, Feodora and Energy, respectively, and three sowing densities: 50, 70, and 90 seeds m-2. In 2018, the Energy variety achieved a higher green mass and dry matter yield than the Feodora variety, and tended to produce the insignificantly higher yields than Feodora over all the tested sowing densities in 2019. The green mass and the dry matter yield increased with an increase in the sowing density. In 2019, the weather conditions were more favorable for the lupin growth and development, and a higher yield was achieved if compared to that of 2018. The Energy variety achieved a significantly higher seed yield in 2018. The seed yield increased with an increase in the sowing density. In both research years, the number of pods and seed weight per plant decreased with an increase in the sowing density. These parameters’ lowest values were achieved at the sowing density of 90 seeds m-2. A tendency of a harvest index decrease was detected along with an increase in the sowing density, but the differences were very small.

A Balanced Sowing Density Improves Quality of Rapeseed Blanket Seedling

Mechanized transplanting of rapeseed (Brassica napus L.) blanket seedling is an effective strategy to cope with the seasonal conflict and large labor cost in rapeseed production. The sowing density is a key factor to cultivate high-quality seedlings suitable for mechanized transplanting. An experiment was conducted to investigate the effects of different sowing density levels of 638, 696, 754, 812, 870 and 928 seeds per tray (referred as D1, D2, D3, D4, D5 and D6, respectively) on agronomic traits and survival rate after mechanized transplanting of two rapeseed cultivars (Zheyouza108 and Heza17) in 2020 and 2021. The results showed that high sowing density increased plant height but decreased leaf area, collar diameter, biomass accumulation, the ratio of root to shoot and seedling fullness. These negative effects jointly decreased the seedling rate and survival rate after mechanized transplanting. However, the seedlings under D1 and D2 posed a great plant survival rate of more than 95% after mechanized transplanting, suggesting that the seedlings under the two densities were perfect for mechanized transplanting. In addition, hierarchical analysis grouped D1 and D2 into the same class, indicating that their seedling qualities were not significantly different, though the blanket seedlings under D1 outperformed those under D2 in some traits. A sowing density of 696 seeds per tray (D2) is then recommended in this study, altogether considering its high-quality seedlings suitable for mechanized transplanting, and economically, fewer seedling trays required.

Can sowing density facilitate a higher level of forb abundance, biomass, and richness in urban, perennial “wildflower” meadows?

Forb species abundance and richness determine both ecological and social values in naturalistic meadows in urban landscapes. However, species loss and dominance through competition are naturally part of meadow ecological processes often leading on productive soils to large grass biomass in the absence of appropriate management. Sowing density is a design tool to manipulate the initial number of emergents of each component species however high sowing densities may not benefit community performance in terms of species richness and diversity in the longer term. This study investigated the effect of sowing density on forb species abundance, biomass and richness. Two sowing densities approximating to 500 and 1,000 emerged seedlings/m2 were employed with 29 forb and one grass species. The higher sowing density did not lead to a larger grass biomass that dominated the community, as the grass species used was ultimately less competitive than the forb dominants. Increasing sowing density increased the number of forb seedlings initially but this declined, as did species richness in the longer term. In terms of subordinate forb survival, ability to access light resources to survive intense competition from dominants was key. Tall, and native species were more likely to maintain higher seedling numbers in the longer term. The research suggest that lower sowing rates are likely to be most useful on soils which are either unproductive, do not contain a significant weed seed banks, where weed free sowing mulches are employed or in rural situations where there is less immediate political pressure for rapid development of forb rich meadows.