Seeds Ha-1 Research Articles

Effect of spraying with silicon, humic acid, and proline on the safflower tolerance (Carthamus tinctorius L.) to salt stress

The experiment was carried out in the winter of season 2021-2022 in the research field of the College of Agriculture - University of Basra (latitude 30.57° North and longitude 47.80°) to study the effect of foliar spraying of silicon, humic acid, and proline on the endurance of safflower (Carthamus tinctorius L.) to salt stress. The experiment was carried out by distributing eight treatments of foliar spraying. Silicon (Si) was sprayed at a concentration of 800 ppm, humic acid (H) at a concentration of 80 ppm, and proline (P) at a concentration of 100 ppm. The studied treatments included control (C), Si, H, P, SiH, SiP, HP, and SiHP) on two soils with salinity (7.63 and 14.24 ds m-1) randomized complete block design with three replicates. The seeds of safflower (Cv. Gila) were planted in the two soils. The results showed significant superiority of the triple treatment (SiHP) in all studied traits, as it recorded the highest mean of height (156.3 cm), number of bells in the plant 59.11, number of seeds in the bell (59.17), weight of 500 seeds (24.30 g), seeds yield (10549 kg seeds ha-1) and biological yield (27582 kg ha-1) with a significant increase over the control treatment, which amounted to 64.2 cm, 26.08 bell plant-1, 24.90 seed bell-1, 14.03 g, 1725 kg seeds ha-1 and 6594 kg.ha-1 respectively—superiority of the proline treatment in all studied traits. Salinity decreased the number of seeds in the plant, the weight of 500 seeds, and seed yield. The foliar spray with the above treatments has proven its effectiveness and efficiency in growth and yield and increased salinity tolerance, in addition to the fact that these materials are environmentally friendly. Keywords: Foliar Spraying; Salinity; Silicon; Humic acid; proline.

Soybean Population Management Seeking Greater Grain Productivity

Objective: The objective of this research was to evaluate plant growth, soybean grain yield and production cost depending on the use of different populations. Theoretical reference: Among management practices, plant population is an extremely important stage for the establishment of soybean crops. In many cases, just changing the plant population is enough to result in high gains in crop grain productivity. Methodology: A randomized block design was used, with four treatments and four replications. The treatments consisted of densities of 200, 250, 300 and 350 thousand seeds ha-1. Plant height, insertion height of the first pod, number of pods per plant, number of grains per pod, mass of one thousand grains and grain productivity were evaluated. Results and conclusion: Populations influenced grain productivity, with the highest productivity being achieved in the population of 250 thousand, 5905 kg ha-1. It was concluded that sowing density affects the number of pods per plant and soybean grain productivity. The density of 250 thousand seeds ha-1 was the one that provided the highest productivity of soybeans and the lowest sowing cost. Research implications: Determining the best population of soybean plants in different locations is essential to reduce producer costs. Originality/value: Most research works focus on the use of inputs, disregarding that the plant population can affect crop performance and production costs.

Soybean cultivars subjected to narrow row spacing and plant populations in early sowing in subtropical region in southern Brazil

Spatial arrangement between plants and sowing time used are decisive practices for obtaining adequate agronomic performance in soybean crop. The aim of this work was to evaluate morphological attributes, yield components and grain yield of soybean cultivars installed with different row spacing and seeding densities, in early (10/04/2017) and conventional (11/08/2017) sowing dates in subtropical climate region in southern Brazil. The experimental design was in a 2×2×4 factorial arrangement: soybean cultivars BRS 433 RR (MG 5.8) and BRS 1003 IPRO (MG 6.3) installed with row spacing of 25 and 50 cm and seeding densities of 160,000; 240,000; 320,000; and 400,000 viable seeds ha-1. Morphological attributes and yield components are altered by spatial arrangement between plants and cultivar, with variable responses according to the sowing date. In the early sowing date, soybean has yield raise due to the increase in seeding density with different responses between cultivars. In the conventional sowing date, soybean installed with 25-cm row spacing has an increase in 1000-grains weight. In the conventional sowing date, there is an increase in soybean yield installed with 25-cm row spacing associated with a seeding density of 320,000 to 400,000 viable seeds ha-1.

Rye cover crop and in-furrow fertilizer and fungicide impacts on corn optimum seeding rate and grain yield

Higher corn seeding rates and in-furrow fertilizer and fungicide combinations may be effective tools to overcome early-season corn (Zea mays L.) stress, stand reductions, and yield loss following a rye (Secale cereale L.) cover crop (RCC). The objective of this research trial was to evaluate corn growth and yield response and optimum seeding rate requirement following a RCC and different in-furrow starter treatments. Trials were established at three Kentucky, USA locations (2017–20), 7 site-years to evaluate corn response to seeding rate (49,421–108,726 seeds ha-1) following a RCC and no cover crop, and in-furrow fertilizer (10-34-0) + fungicide (pyraclostrobin) and no in-furrow starter. At 2 of 3 locations, a RCC reduced corn V5 chlorophyll content and grain yield by 3.1% and 2.7%, respectively. The inclusion of an in-furrow starter failed to increase corn yield at any location and no interaction with a RCC was observed. Furthermore, an in-furrow starter reduced corn plant stand by 3.2% at 2 of 3 locations. At Lexington, quadratic regression analysis revealed that a higher corn agronomic optimum seeding rate (AOSR) and economic optimum seeding rate (EOSR) was required to maximize corn following a RCC compared to no cover crop. However, no significant stand loss was observed at this location. Overall, these results suggest that in-furrow fertilizer and fungicide do not ameliorate negative effects from a RCC and may cause negative impacts when applied simultaneously in-furrow. In addition, a higher corn AOSR and EOSR may be required following a RCC to maximize corn yield. However, because the effects of a RCC on AOSR were inconsistent among locations, further research may be required.

Influence of Phosphorus Fertilization and Seed Rates on Yield Components and Yield of Black Cumin (Nigella sativa L.)

The experiment was carried out at the “Horticulture Farm” of Sher-e-Bangla Agricultural University, Dhaka, Bangladesh from November 2019 to March 2020 to study the influence of phosphorus fertilization and seed rates on yield components and yield of black cumin. The experiment consisted of two factors. Factor A: Four levels of phosphorus viz., P0= control, P1= 35 P kgha-1, P2= 40 P kgha-1 and P3= 45 P kgha-1and Factor B: Three seed rates viz., R1= 8 kg seeds ha-1, R2= 10 kg seeds ha-1and R3= 12 kg seeds ha-1. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications. Data were recorded on growth, yield components and yield of black cumin and significant variation was observed for most of the studied characters. Growth related data was maximum on P3 (45 P kgha-1) treatment but in case of seed yield, P2 (40 P kgha-1) treatment showed the best result. In case of growth characters, R1 (8 kg seeds ha-1) treatment revealed the best result but in case of seed yield, R2 (10 kg seeds ha-1) treatment showed the best result. The highest seed yield (1.27 t ha-1) was obtained from P2R2 (40 P kgha-1+ 10 kg seeds ha-1) treatment combination. On the other hand, the lowest seed yield (0.94 t ha-1) was obtained from of P0R3 (control + 12 kg seeds ha-1) treatment combination. So, it was revealed that the P2R2 treatment combination appeared to be best for achieving the higher growth and seed yield of black cumin.

Pre- and Post-anthesis Deficit Irrigation of Corn in the West Central Great Plains— Working with Less Water

HighlightsConcentrating deficit irrigation during the post-anthesis period optimized grain yield and water productivity, while minimizing the seasonal irrigation amount.Corn grain yields were not greatly affected by deficit irrigation strategy, but irrigation amounts varied as much as 62%.Seeding rates ranging from 62,000 to 74,000 corn plants per hectare were acceptable under deficit irrigation.Corn hybrid effects were not consistent across years and location.Abstract. A three-year study (2018 to 2020) was conducted in west central and northwestern Kansas on silt loam soils to determine corn grain yield and yield component response, water use, and crop water productivity as affected by irrigation capacity and timing, corn hybrid, and seeding rate. A range of four irrigation treatments concentrated greater application amounts in either the pre-anthesis or post-anthesis period. The Pre-38 treatment applied 38 mm weekly pre-anthesis as needed (limited by weather-based scheduling) and only applied 38 mm every two weeks during the post-anthesis period. The Pre-25 treatment applied 25 mm weekly as needed pre-anthesis, followed by 25 mm applications every two weeks post anthesis. Post-38 and Post-25 treatments had application amounts similar to Pre-38 and Pre-25, respectively, but had the weekly applications concentrated during the post anthesis period and less frequent (every two weeks) applications pre-anthesis. Two corn hybrids (Pioneer 1197 and Pioneer 0801) were planted at seeding rates of 62 and 74 thousand seeds ha-1. Averaged across location and year, the Pre-25 irrigation treatment had approximately 5% less yield than the other three treatments but received approximately 28% less irrigation. Overall, when averaged across all irrigation, hybrid and seeding rate treatments, the yield components of kernels ear-1 and kernel mass varied approximately 2% and 3%, respectively and were responsible for nearly all of the grain yield variation. The Pre-25 and Post-25 treatment had the greatest water productivity and generally had similar yields to the other deficit irrigation treatments and thus should be considered as effective strategies to reduce irrigation in this region. Seeding corn at 74 thousand seeds ha-1 increased yield only 2% compared with 62 thousand seeds ha-1 indicating that a considerable range of seeding rates produce similar yields when using deficit irrigation strategies in this region. Hybrid effects were not consistent across years and locations. Keywords: Crop water productivity, Evapotranspiration, Irrigation scheduling, Limited irrigation, Maize.

Optimizing the Seed Rate for Maximized Yield And Benefits of Wheat Under Strip Tillage In Bangladesh

An on-farm experiment was conducted at the farmer's field located at the Durbachara village of Gauriopur upazilla under the Mymensingh district of Bangladesh from November 2015 to March 2016 to study the effect of seed rate on yield performance of wheat under strip tillage. Wheat cv. BARI Gom-26 was sown under conventional tillage (CT) vs. strip tillage (ST), including four seeding rates viz. 100, 110, 120, and 130 kg ha-1. The CT was done with a two-wheel tractor and consisted of two primary tillages followed by two secondary tillages. The ST was done using a Versatile Multi-crop Planter (VMP) machine in a single pass process. A pre-plant herbicide, glyphosate was applied 3 days before of ST operation @ 3.7 L ha-1. The experiment was laid out in a randomized complete block design with four replications. The impact of tillage methods on the seed rate was found significant in the yield and economic profit of wheat. The longest spike with the highest number of grains spike-1, the highest weight of 1000-grain, grain yield, and BCR was recorded when 120 kg seeds of wheat sown with strip tillage. This practice produced a 25% higher yield and earned 51% higher profit than the practice of seeding 100 kg seeds ha-1 with conventional tillage. SAARC J. Agric., 19(1): 45-56 (2021)

Growth, Yield and Its Attributes of Durum Wheat as Affected by Sowing Dates and Seeding Rates under Libyan Conditions

A field experiment was carried out during 2020/ 2021 winter season in a private farm at Al-Maamorah district, El-Ghafara, Tripoli, Libya to evaluate four planting dates (1st and mid November and 1st and mid December) and four seeding rates (80, 100, 120 and 140 kg ha-1) on growth, grain yield, yield attributes and grain protein content of Sidi Almsry durum wheat variety. Randomized complete block design in split plot arrangement in three replications was used, where the four sowing dates were randomly allocated in the main plots and the four seeding rates were randomly distributed within each main plot. Obtained results indicated that planting the studied variety at mid November produced the tallest plants, highest LAI, number of tillers and spikes m-2, number of grains spike-1, grain yield, H.I. and heaviest 1000-grain weight. However, 140 kg seeds ha-1 produced the tallest plants, highest LAI, number of tillers and spikes m-2, lodging percentage and grain protein content. Meanwhile, planting Sidi Almsry variety at mid November with 100 kg seeds ha-1 produced maximum grain yield, H.I and 1000-grain weight, while 140 kg seeds ha-1 at mid November produced the tallest plants and highest LAI, number of tillers and spikes m-2. The highest grain protein content resulted from sowing at mid December with 140 kg seeds ha-1.

Podridões de colmo estão associadas à precocidade de híbridos de milho

As podridões de colmo do milho são responsáveis por significativas reduções em rendimento de grãos. O objetivo deste estudo foi avaliar a relação existente entre a incidência de podridões de colmo e o ciclo de seis híbridos de milho. O experimento foi conduzido a campo, semeados no mês de outubro nas safras 2012/2013 e 2013/2014 utilizando-se 70.000 sementes ha-1 dos híbridos comerciais P32R22 YHR e AG9045 VT PRO (superprecoces) e P30F53 Hx, DKB250 VT PRO2, AS1656 VT PRO2 e AG8025 VT PRO (precoces). O delineamento utilizado foi de blocos casualizados com quatro repetições avaliando-se, em cada parcela cinco metros lineares. A incidência de podridões foi determinada pela presença de descoloração e menor resistência do colmo. Espigas provenientes de plantas sadias e doentes foram trilhadas separadamente para determinação do dano percentual. Danos ocasionados por podridões de colmo, em função da severidade da doença podem ser variáveis em função dos híbridos, mesmo com características semelhantes de ciclo. Os fungos detectados nos colmos foram Stenocarpella sp., Colletotrichum graminicola, Fusarium graminearum e F. verticillioides. Todos os híbridos avaliados expressaram sintomas de podridão de colmo demonstrando não haver resistência, mas sim, apenas diferentes graus de suscetibilidade entre os materiais testados. O híbrido AG8025 VT PRO demonstrou ser o menos suscetível a podridões de colmo. Os híbridos superprecoces P32R22 YHR e AG9045 VT PRO apresentaram maior incidência do que híbridos de ciclos precoces, indicando que a maior precocidade está associada à maior suscetibilidade a podridões de colmo.

A Decision Support System to Guide Grower Selection of Optimal Seeding Rates of Wheat Cultivars in Diverse Environments.

Seeding rate in hard red spring wheat (HRSW; Triticum aestivum L.) production impacts input cost and grain yield. Predicting the optimal seeding rate (OSR) for HRSW cultivars can eliminate the need for costly seeding rate research and growers using OSRs can maximize yield and seeding efficiency. Data were compiled from seeding rate studies conducted in 32 environments in the Northern Plains United States to determine the OSR of HRSW cultivars grown in diverse environments. Twelve cultivars with diverse genetic and phenotypic characteristics were evaluated at five seeding rates in 2013–2015, and nine cultivars were evaluated in 2017–2018. OSR varied among cultivar within environments. Cultivar x environment interactions were explored with the objective of developing a decision support system (DSS) to aid growers in determining the OSR for the cultivar they select, and for the environment in which it is sown. A 10-fold repeated cross-validation of the seeding rate data was used to fit 10 decision tree models and the most robust model was selected based on minimizing the value for model variance. The final decision tree model for predicting OSR of HRSW cultivars in diverse environments was considered the most reliable as bias was minimized by pruning methods, and model variance was acceptable for OSR predictions (RMSE = 1.24). Findings from this model were used to develop the grower DSS for determining OSR dependent on cultivar straw strength (as a measure of lodging resistance), tillering capacity, and yield of the environment. Recommendations for OSR ranged from 3.1 to 4.5 million seeds ha–1. Growers can benefit from using this DSS by sowing at OSR relative to their average yields; especially when seeding new HRSW cultivars.

Late-season surveys to document seed rain potential of Palmer amaranth (Amaranthus palmeri) and waterhemp (Amaranthus tuberculatus) in Texas cotton.

Weed escapes are often present in large production fields prior to harvest, contributing to seed rain and species persistence. Late-season surveys were conducted in cotton (Gossypium hirsutum L.) fields in Texas in 2016 and 2017 to identify common weed species present as escapes and estimate seed rain potential of Palmer amaranth (Amaranthus palmeri S. Watson) and waterhemp [A. tuberculatus (Moq.) J.D. Sauer], two troublesome species with high fecundity. A total of 400 cotton fields across four major cotton-producing regions in Texas [High Plains (HP), Gulf Coast (GC), Central Texas, and Blacklands] were surveyed. Amaranthus palmeri, Texas millet [Urochloa texana (Buckley) R. Webster], A. tuberculatus, ragweed parthenium (Parthenium hysterophorus L.), and barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.] were reported as the top five weed escapes in cotton fields. Amaranthus palmeri was the most prevalent weed in the HP and Lower GC regions, whereas A. tuberculatus escapes were predominantly observed in the Upper GC and Blacklands regions. On average, 9.4% of an individual field was infested with A. palmeri escapes in the Lower GC region; however, 5.1 to 8.1% of a field was infested in the HP region. Average A. palmeri density ranged from 405 (Central Texas) to 3,543 plants ha–1 (Lower GC). The greatest seed rain potential by A. palmeri escapes was observed in the upper HP region (13.9 million seeds ha–1), whereas the seed rain potential of A. tuberculatus escapes was the greatest in the Blacklands (12.9 million seeds ha–1) and the upper GC regions (9.8 million seeds ha–1). Seed rain from late-season A. palmeri and A. tuberculatus escapes is significant in Texas cotton, and effective management of these escapes is imperative for minimizing seedbank inputs and impacting weed species persistence.

Nitrogen fertilization changes the productivity and chemical composition of Brown and Golden flax grains

Nitrogen fertilization can be used to increase production for area, as well as to improve the grains nutritional value. The aim of this study was to evaluate the chemical composition of two linseed cultivars (Brown and Golden) submitted to increasing doses of nitrogen fertilization in a completely randomized design. The Brown and Golden flax sowing was in April 2014, using 40 kg of viable seeds ha-1 and 100 kg ha-1 of diammonium phosphate (16-46-00) as fertilizer. It was evaluated the increasing doses of N fertilization in the cover: 0, 50, 100, 150 and 200 kg of N ha-1, applied in the urea form. For the fatty acids (FA) analysis, a composite sample of each variety was performed for the treatment 0 and 200 kg N ha-1. The composite samples were grounded in a multi-use mill with cooling jacket. The cooling was aimed to avoid the heating of the samples during their processing, in order to reduce the chances of FA profile alterations. The application of nitrogen positively influenced the production of grains and oil ha-1 of the cultivars, improved the Brown flax dry matter in vitro digestibility and the Golden flax neutral detergent fiber, ether extract and crude protein amounts. The cultivar Brown flax presented higher production of grains and oil ha-1 when compared to Golden flax, which presented lower neutral detergent fiber, crude protein, total carbohydrates and higher amounts of ether extract. The Golden flax was nutritionally healthier, as it presented higher proportions of C18:3 n3, unsaturated fatty acids, unsaturated/saturated fatty acids and hypocholesterolemic index. Both cultivars have potential ingredients to be used in animal feed, aiming to improve the quality of the final product.

Yield performance of soybean cultivars with indeterminate growth habits in response to plant spatial arrangement

Modifications in plant spatial arrangements, such as the use of narrow rows, twin rows, and crossed rows, may favor the development and productivity of soybeans due to the morphophysiological changes occurring in the plants. The aim of this research was to assess yield components, mortality rate, harvest index, and the yield, of two soybean cultivars, with indeterminate growth habits, in response to alternative plant spatial arrangements. The experiment was conducted in Londrina, Paraná State, Brazil, in the 2013/14 and 2014/15 growing seasons, with randomized complete block design, in a 4 × 3 × 2 factorial scheme, with three replications. The treatments were composed of four row spacings, at 0.2 m (narrow rows); 0.2/0.8 m (twin rows); 0.5 m (traditional); and 0.5 m (crossed rows); at three seeding rates (150, 300, and 450 thousand viable seeds ha-1) in two cultivars (BMX Potência RR and BRS 359 RR). In both growing seasons, there was a water deficit, and climatic conditions that would restrict soybean growth and development. The narrow rows, twin rows, and crossed rows did not favor yield performance compared to traditional spacing in either cultivar. The tested cultivars showed high phenotypic plasticity, allowing large changes in row spacing and seeding rate without major changes in the yield. The narrow rows, when associated with a high seeding rate, favored plant mortality. Grains per pod and harvest index were not influenced by the plant spatial arrangement.

Field Validation of Seed Meter Performance at Varying Seeding Rates and Ground Speeds

Abstract. High planter performance requires achieving near-perfect seed meter performance in the field during planting. In-field meter performance can be impacted by several factors including meter setup, ground speed, seeding rate, planter vibration, and field conditions. A study was conducted to evaluate the field performance of two different seed meters (John Deere Standard and Precision Planting eSet) at varying seeding rates and ground speeds during planting. Study treatments consisted of planting corn at seeding rates of 49,000, 59,000, 69,000, 79,000, and 89,000 seeds ha-1 at four different ground speeds of 6.1, 7.1, 8.2, and 9.5 km h-1. These ground speeds and seeding rates were implemented in a strip-split plot design in the field with seeding rates blocked within the individual ground speed replications. Field tests were performed by uploading a variable-rate seeding prescription map into the planter rate controller and then travelling at the desired ground speed for each planter pass. Field data collection consisted of measuring plant population and plant spacing in the plots separately for each seed meter. Meter performance was evaluated by computing percent skips, multiples, singulation, coefficient of variation (CV), and crop emergence from the field data. Statistical analysis on field data suggested that the percent skips, singulation, CV, and crop emergence were significantly (p<0.05) affected by the seeding rate, and the ground speed did not have any significant (p>0.05) effect on these variables. The percent multiples and CV values also differed significantly (p<0.05) between the John Deere Standard and Precision Planting eSet meter at different ground speed and seeding rate treatments. The percent skips (0.5-3.8%) observed in the field data were, on average, higher than the percent multiples (0.0-1.8%) for both seed meters. The percent skips in general decreased with an increase in the seeding rate whereas no particular trend was observed in the percent multiples. The singulation values varied between 96.0% and 99.4%, and they were not statistically different between the seed meters. The percent CV values increased with an increase in the seeding rate indicating higher variability in plant spacing with increases in the seeding rate. The mean percent emergence for both seed meters ranged from 92.8% to 99.3%, and it was influenced by the seeding rate for the JD Standard meter. A weak association (R2 values between 0.2028 and 0.6587) between the meter performance parameters (percent skips, singulation, and CV) and the meter speed was determined for both seed meters. Results from the study suggested that meter performance was significantly affected by the seeding rate, and the type of seed meter had a significant impact on percent multiples and CV (plant spacing) values attained during planting. Keywords: Field performance, Ground speed, Meter speed, Seed meter, Seeding rate.

Impact of Different Seed Rates and Knocking Down Days of Sesbania on Weed Density and Yield of Dry Direct Seeded Rice

The weed is a major constraint of dry-direct seeded rice (DDSR) due to change in establishment methods and shifting weed flora towards competitive grasses and sedges. To minimize the weed density, its species and dry weight with brown manuring and for optimizing the yield of DDSR, the experiment was conducted during monsoon season of 2014 at Chitwan, Nepal. The experiment was done using a strip plot design to find the optimum seed rate and killing date of Sesbania under rice-Sesbania co-culture. Among different seed rates (60, 80, 100 kg ha-1) and knocking down days (21, 28, 35 & 42 DAS) of Sesbania, the optimum seed rate of Sesbania was 102 kg ha-1 and killing date was 32 days. The individual plot size was 5 x 4 m2. The growing of Sesbania with 100 kg seeds ha-1 along with its knocked down at 28 DAS was seen best to minimize the weeds having better performance of rice. The experiment clearly demonstrated the importance of brown manuring on effective control of weeds and on grain yield of rice under dry direct seeded rice.
 Int. J. Appl. Sci. Biotechnol. Vol 6(4): 359-365

Effect of Plant Density on the Water Use Efficiency and Quality of Potato (Solanum tuberosum L. Cv. Spunta) in the Jordan Valley

Plant density affected yield, quality and water use efficiency. Little information describing plant density to optimize yield and quality of potato production is available in the Jordan Valley. This study was aimed to investigate the effects of plant density on the yield and yield components of the potato (Solanum tuberosum L.) cultivar “Spunta” grown in the middle of the Jordan Valley. Five different densities of plants (41,600 plants ha-1 (D1), 56,000 plants ha-1 (D2), 83,200 plants ha-1 (D3), 28,000 plants ha-1 (D4), and 41,600 plants ha-1 (D5) were randomly distributed over five replicate sites during the growing season from November 2013 to March 2014. Plant height, number of branches, fresh and dry weight of potato plants, tuber number, tuber weight, total yield, specific gravity and water use efficiency of potato plant grown under different plant density were measured. It was found that the productivity of potato increased with increasing plant density, with the highest total, marketable, and non-marketable yields being obtained at densities of 83,200 seeds ha-1, and the lowest occurring at 41,600 seeds ha-1, which equated to total fresh yields of 45.1 and 25.3 tons ha-1, respectively. The highest water use efficiency for marketable yield (11.9 kg m-3) was obtained at a density of 83,200 seeds ha-1, whereas the lowest water use efficiency (7.5 kg m-3) was obtained at a density of 41,600 seeds ha-1. The specific gravity ranged from 1.04 to 1.08 and the average tuber weight ranged from 77.02 g at a density of 83,200 seeds ha-1 to 115.84 g at a density of 28,000 seeds ha-1.

Soybean agronomic performance in response to seeding rate and phosphate and potassium fertilization

ABSTRACT Most studies that found soybean high phenotypic plasticity under different seeding rates adopted the same fertilization levels used for the recommended seeding rates. Therefore, the interaction between these factors is little known. This study aims to assess the interaction between seeding rate and levels of phosphorus and potassium fertilization on soybean growth, grain yield and contents of protein and oil in the grains. The experiment was carried out under a randomized complete block design, in a split-plot scheme, with six replicates. Four seeding rates (150, 300, 440 and 560 thousand viable seeds ha-1) were used in the plots, and two levels of phosphorus and potassium fertilizer were applied in the subplots to meet the export of 3 and 6 t ha-1 of grains (level 1 = 30 kg ha-1 of P2O5 + 60 kg ha-1 of K2O; and level 2 = 60 kg ha-1 of P2O5 + 120 kg ha-1 of K2O). There was no interaction between the experimental factors. Increase in fertilizer doses did not alter the evaluated characteristics, regardless of the seeding rate. Seeding rate did not change grain yield or protein and oil contents, but at low densities there was an increase in the number of pods per plant, apparent harvest index and SPAD index.

Control of soil weediness and sugar beets by after crop green manure and different tillages

The research program envisaged the studying of the variation of weediness of sugar beet crops under the influence of after crop sideration and the application of soil protection cultivation. The application of oil radish green manure provided a significant decrease in the amount of seed weeds in the entire 0-30cm layer of soil in comparison with the non-seeded background on 2.8-3.4 mln. seeds ha-1 and a significant decrease in the weed density of all biological groups weeds on 0.5-6.5 weeds m-2 and their weight on 5.6-77.4g m-2 for the period of growing sugar beets. Comparing to plowing the methods of mouldboard-free cultivation provided a significant increase in the quantity of weed seeds in the layer of soil 0-10cm to 18.3-22.9×106 seeds ha-1 and their significant decrease deeper than 10cm on 19.0-23.3 mln. seeds ha-1. Among the variants of mouldboard-free cultivation the lowest amount of weed seeds in the soil layer of 0-5cm was discounted at the deepest cultivation – 24.5 and 23.5×106 seeds ha-1. The decrease of the depth of the mouldboard-free cultivation led to a significant increase in the weed density (by 4.8-68.2 weeds m-2) and their weight (82.5-1193.5g m-2) in sugar beet crops and a substantial shortfall in yields of root crops – 2.9-5.8t ha-1. It follows from the research results that the application of after crop siderate of radish oil and basic mouldboard-free cultivation reduce the potential amount of weed seeds of root layer 0-30 сm; the deep soil cultivation on 28-30cm at the siderate background provides the greatest decrease in real weediness of sugar beet crops and allows to receive high yields of crops – 34.3 t ha-1.

Fertilización nitrogenada y mezcla de Trachypogon plumosus con Stylosanthes capitata cv. Lavradeiro bajo diferentes densidades de siembra

The effect of nitrogen levels (0, 40, 80, 120, 160, and 200 kg of N ha-1) on pure pastures of Trachypogon plumosus and the sowing densities of Stylosanthes capitata cv. Lavradeiro (1.0; 2.0; 3.0 and 4.0 kg of seeds ha-1) on forage yield, botanical composition and apparent fixation and transfer of nitrogen (N) was evaluated under field conditions. Nitrogen fertilization quadratically affected grass forage yields and its nitrogen content, and the maximum values were estimated by the application of 154.6 and 155.7 kg N ha-1, respectively. The legume forage yield was directly proportional to the densities of its sowing, occurring the opposite for the grass forage yield. The forage yields of the grass-legume mixture, independently of legume sowing density, were higher than those showed by the grass grown alone and for all doses of N evaluated. The use of legume sowing densities between 2.0 and 3.0 kg ha-1 allows the establishment, the productive stability and the persistence of the grass-legume mixture. The apparent N fixation by the legume and its transfer to the grass were directly proportional to the legume sowing densities.

Size, chlorophyll retention and protein and oil contents of grains from soybean plants grown in different spatial arrangements

The spatial arrangement of soybean plants, determined by row spacing and seeding rate, affects the intraspecific competition for water, light, and nutrients, as well as plant architecture and grain development, quality, and chemical composition. The aims of this study were to evaluate the effect of row spacing and seeding rate on the grain size produced, and the influence of these three factors on chlorophyll retention and protein and oil content in grain. Two experiments were conducted in the 2013/14 and 2014/15 growing seasons, using a 4 × 3 factorial randomized block design with three replications. Four different row spacings [20 cm (narrow row), 50 cm (conventional), 20/80 cm (twin rows) and crossed lines (50 cm)] and three seeding rates (150, 300, and 450 thousand viable seeds ha-1) were evaluated. The grains were classified by size using oblong sieves and then the effects of spatial arrangements and size of grain on the percentage of green grains and protein and oil contents were evaluated. Higher plant densities were associated with larger grain size, whereas the effects of spacing between the rows on the grain size varied between growing seasons. The arrangement in cross-rows and high plant density produced a higher percentage of green grains under weather conditions favorable to the development of this attribute. The effects of plant spatial arrangements on the contents of protein and oil in grains were variable, and it was not possible to determine whether the spatial arrangement of plants had an effect on the levels of protein and oil in grains. Larger grains had higher protein content, but oil contents were not affected by grain size.