Effects of Seed Treatments and a Soil-applied Nematicide on Corn Yields and Nematode Population Densities

Plant-parasitic nematodes are microscopic worms that feed on plants. Almost every nematode that feeds on corn is capable of feeding on many other plants. These nematode parasites are thought to be native to most Iowa soils and to have fed upon native plants before corn was grown as a cultivated crop. Population densities (numbers) of most species of plant-parasitic nematodes that feed on corn have to increase to damaging levels (called damage thresholds) before yield loss occurs.

Effects of Seed Treatments and a Soil-applied Nematicide on Corn Yields and Nematode Population Densities

Plant-parasitic nematodes are microscopic worms that feed on plants. Almost every nematode that feeds on corn is capable of feeding on many other plants. These nematode parasites are thought to be native to most Iowa soils and to have fed upon native plants before corn was grown as a cultivated crop. Population densities (numbers) of most species of plant-parasitic nematodes that feed on corn have to increase to damaging levels (called damage thresholds) before yield loss occurs. Products that are currently available to manage plant-parasitic nematodes on corn in the state include the soil-applied insecticide/nematicide Counter® and two relatively new protectant seed treatments, Avicta® and Votivo®. Counter® is a contact and systematic nematicide with the active ingredient terbufos. Avicta® is a contact nematicide (active ingredient abamectin) that moves on the surface of the root, and Votivo® is a special strain of the natural soil bacterium Bacillus firmus that grows on the root. Counter® is available from AMVAC, Avicta® from Syngenta Seedcare, and Votivo® from Bayer CropScience. The objective of this experiment was to assess and compare the nematode population densities and yields of corn growing in plots with and without the seed-treatment nematode protectants and the soil-applied nematicide Counter®.

Effects of Seed Treatments and a Soil-applied Nematicide on Corn Yields and Nematode Population Densities

Plant-parasitic nematodes are microscopic worms that feed on plants. Almost every nematode that feeds on corn is capable of feeding on many other plants. These nematode parasites are thought to be native to most Iowa soils and to have fed on native plants before corn was grown as a cultivated crop. Population densities (numbers) of most species of plant-parasitic nematodes that feed on corn have to increase to damaging levels (called damage thresholds) before yield loss occurs.

Effects of different soil management practices on soil mechanic resistance and seed depth placement in a maize crop in Alentejo, Portugal Mediterranean region.

No tillage, minimum tillage and conventional tillage practices are commonly used in maize crops in Alentejo, affecting soil physic conditions and determining seeders performance. Seeders distribution can be evaluated in the longitudinal and vertical planes. Vertical plane is specified by seeding depth (Karayel et al., 2008). If, in one hand seeding depth uniformity is a goal for all crop establishment , in the other hand, seeders furrow openers depth control is never constant depending on soil conditions. Seed depth uniformity affects crop emergence, Liu et al. (2004) showed an higher correlation between crop productivity and emergence uniformity than with longitudinal plants distribution. Neto et al. (2007) evaluating seed depth placement by measuring maize mesocotyl length under no tillage conditions in 38 farms concluded that 20% of coefficient of variation suggests the need of improvement seeders depth control mechanisms. The objective of this study was to evaluate casual relationships and create spatial variability maps between soil mechanic resistance and vertical distribution under three different soil practices to improve seed depth uniformity.

Art and life and Seed, soil, tillage and crop,

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Soil management, seed treatment and soil compaction on the sowing furrows affect grain yields of upland rice genotypes.

The water availability for flood irrigated rice (Oryza sativa L.) is decreasing worldwide. Therefore, developing technologies to allow growing rice in aerobic condition, such as a no-tillage system (NTS) can contribute to produce upland rice grains without yield losses and also in saving more water. The objective of this study was to determine the effect of soil management, seed treatment and compaction on the sowing furrow on grain yield of upland rice genotypes. We made two trials, one in an NTS and another using conventional tillage, CT (one plowing and two diskings). The field experiments were performed in the Central Region of Brazil in Cerrado soils. For each trial, the experimental design was a randomized block design in a factorial scheme, with three replications. The treatments consisted of a combination of 10 genotypes with 2 compaction pressures on the sowing furrow (25 kPa and 126kPa) and 2 types of seed treatment (with and without pesticide). Under CT, the seed treatment did not contribute to increase upland rice grain yields. However, under NTS the grain yield of some genotypes [BRS Esmeralda (from 723 to 1,766 kg ha-1), BRS Pepita (from 930 to 1,874 kg ha-1), AB072044 (from 523 to 1,579 kg ha-1), and AB072085 (from 632 to 1,636 kg ha-1) at 25 kPA soil compaction pressure, and Sertaneja (from 994 to 2,167 kg ha-1), BRS Pepita (from 1,161 to 2,100 kg ha-1), and AB072085 (from 958 to 2,213 kg ha-1), at 126 kPA soil compaction pressure] increased with the use of this practice. At CT the higher soil compaction pressure on the sowing furrow (from 25 kPa to 126 kPa) increased rice grain yield only when it was used seed treatment and the genotypes Serra Dourada (from 1,239 to 2,178 kg ha-1), Sertaneja (from 1,510 to 2,379 kg ha-1), and Cambará (from 1,877 to 2,831 kg ha-1). On the other hand, under NTS, increasing soil compaction pressure on the sowing furrow allowed for an increased rice grain yield of Serra Dourada (from 1,553 to 2,347 kg ha-1), Esmeralda (from 723 to 1,643 kg ha-1), AB072044 (from 523 to 2,040 kg ha-1), and Cambará (from 1,243 to 2,032 kg ha-1) without seed treatment and Sertaneja (from 1,385 to 2,167 kg ha-1) and AB072044 (from 1,579 to 2,356 kg ha-1) with seed treatment. In CT the most productive genotypes were AB062008 (2,714 kg ha-1) and BRSMG Caravera (2,479 kg ha-1), while at NTS were the genotypes: BRSGO Serra Dourada (2,118 kg ha-1), AB072047 (1,888 kg ha-1), AB062008 (1,823 kg ha-1), BRSMG Caravera (1,737 kg ha-1), Cambará (1,716 kg ha-1), AB072044 (1,625 kg ha-1), BRS Esmeralda (1,604 kg ha-1), and BRS Pepita (1,516 kg ha-1).

Rice affected by seed treatment, soil compaction and nitrogen at no-tillage and conventional tillage.

The objective of this study was to determine the best combination of management options for upland rice production: seed treatment, N management and soil compaction in zero and conventional tillage methods.

Seed phytate and protein content in beans depending on the application of basalt powder

Seed phytate and protein content in beans depending on the application of basalt powder. The content of phytate in the grains is correlated with the supply of phosphorus to the plant, but there is a lack of knowledge as to possible effect of slower availability of nutrients in the soil. The objectives of this study were to assess the effect of rock powder, alone or combined with cattle manure, on the productivity, levels of phosphorus, protein and phytate content in beans. The experiment was carried out in a randomized blocks design, with four replications. The treatments were control (limestone, granite and natural phosphate); conventional fertilization; powder basalt (2.5, 5.0, 10.0 and 20.0 ton. ha(-1)); cattle manure, and doses of powder basalt with cattle manure. In the treatment with conventional fertilizer, the total phosphorus content in grain was higher than the control, but the application of powder of basalt did not show a difference significant. Increase in the doses of basalt powder increased the phosphorus content, but phytate content remained constant. Basalt powder proved to be an alternative to maintain low levels of phosphorus in the form of phytate in the grains.

Use of growth regulators to overcome seed dormancy in Xylopia aromatica (Annonaceae)

Xylopia aromatica is a species of the Annonaceae family, native to the Brazilian ""Cerrado"". Seeds of this species usually possess morphophysiological dormancy which makes propagation more difficult. The objective of the present study was to evaluate the efficiency of removing the aril and sarcotesta and applying plant growth regulators to overcome dormancy in X. aromatica seeds. Seeds were separated into two groups: one consisting of seeds with aril and sarcotesta and another without these two seed coat appendices. Seeds with and without these appendices were soaked for 48 hours in distilled water or Promalin (R) (gibberellin 4 [GA(4)] + gibberellin 7 [GA(7)] and cytokinin [6-Benziladenine]) solutions of 250, 500 and 1,000 mg.L(-1), and sown in ""Cerrado"" soil. Later, seeds without the aril and sarcotesta were soaked for 48 hours in distilled water. Promalin (R) or GA(4) + GA(7) solutions at same concentrations and sown in sand or ""Cerrado"" soil. The removal of the aril and sarcotesta had a positive effect on the seed germination. Application of plant growth regulators helped to overcome dormancy in X. aromatica, with the greatest percentage of seedling emergence being observed in seeds treated with Promalin at 250 and 500 mg.L(-1) then sown in sand.

Salinity tolerance in Schinopsis quebracho colorado: Seed germination, growth, ion relations and metabolic responses

Soil salinity is a major abiotic stress influencing plant productivity worldwide. Schinopsis quebracho colorado is one of the most important woody species in the Gran Chaco, an and and salt-prone subtropical biome of South America. To gain a better understanding of the physiological mechanisms that allow plant establishment under salt conditions, germination and seedling growth of S. quebracho colorado were examined under treatment with a range of NaCl solutions (germination: 0-300 mmol l(-1) NaCl; seedling growth: 0-200 mmol l(-1) NaCl). The aim was to test the hypothesis that S. quebracho colorado is a glycophite that shows different salt tolerance responses with development stage. Proline content, total soluble carbohydrates and Na+, K+ and Cl- concentrations in leaves and roots of seedlings, and the chlorophyll concentration and relative water content of leaves were measured. Germination was not affected by 100 mmol l(-1) NaCl, but decreased at a concentration of 200 mmol l(-1). At 300 mmol l(-1) NaCl, germination did not occur. Seedling growth decreased drastically with increasing salinity. An increase in NaCl from 0 to 100 mmol l(-1) also significantly reduced the leaf relative water content by 22% and increased the proline concentration by 60% in roots. In contrast, total soluble carbohydrates were not significantly affected by salinity. Seedlings showed a sodium exclusion capacity, and there was an inverse correlation between Cl- concentration and the total chlorophyll concentration. S. quebracho colorado was more tolerant to salinity during germination than in the seedling phase. The results suggest that this increased tolerance during germination might, in part, be the result of lower sensitivity to high tissue Na+ concentrations. The significant increment of proline in the roots suggests the positive role of this amino acid as a compatible solute in balancing the accumulation of Na+ and Cl- as a result of salinity. These results help clarify the physiological mechanisms that allow establishment of S. quebracho colorado on salt-affected soils in arid and semi-arid Gran Chaco. (c) 2008 Elsevier Ltd. All rights reserved.

Seed dormancy and germination responses of nine Australian fire ephemerals

Fire ephemerals are short-lived plants with seeds that persist in the soil and germinate after a fire or physical soil disturbance. Ex situ germination of many Australian fire ephemerals has previously been difficult. Dormancy was present in most of the nine fire ephemerals examined. Alyogyne hakeifolia (Giord.) Alef. and Alyogyne huegelii (Endl.) Fryxell (Malvaceae) seeds had physical and possibly also physiological dormancy, Actinotus leucocephalus Benth. (Apiaceae) seeds had morphophysiological dormancy, Austrostipa compressa (R.Br.) S.W.L. Jacobs & J. Everett and Austrostipa macalpinei (Reader) S.W.L. Jacobs & J. Everett (Poaceae) seeds were either non-dormant or possessed physiological dormancy, and seeds of all remaining species possessed physiological dormancy. A proportion of the Alyogyne hakeifolia, Alyogyne huegelii, Austrostipa compressa and Austrostipa macalpinei seed populations were non-dormant because some seeds could germinate at the various incubation temperatures without further treatment. At 20 degrees C, artificial methods of inducing germination such as manual or acid scarification were among the optimal treatments for Austrostipa compressa, Austrostipa macalpinei, Alyogyne huegelii, Actinotus leucocephalus and Grevillea scapigera A.S. George (Proteaceae), and gibberellic acid induced maximum germination of Tersonia cyathiflora (Fenzl) J.W. Green (Gyrostemonaceae) seeds. Heat (70 degrees C for 1 h) and smoke water was one of the most effective treatments for germinating Actinotus leucocephalus and Codonocarpus cotinifolius (Desf.) F. Muell. (Gyrostemonaceae) seeds. Germination of Grevillea scapigera, Codonocarpus cotinifolius, Gyrostemon racemiger H. Walter (Gyrostemonaceae) and Tersonia cyathiflora did not exceed 40% and may require other treatments to overcome dormancy. Although the nine fire ephemerals examined require fire to germinate under natural conditions, a range of germination responses and dormancy types was observed.

Effects of foliar fertilization of common bean (Phaseolus vulgaris, L.) during the seed-filling stage

An experiment was carried out with common bean (Phaseolus vulgaris, L.) in a Red Yellow Latossol, sandy phase, in order to study the influence of foliar spraying of the Hanway nutrient solution (NPKS) at grain filling stage on: 1) grain yield; 2) the uptake of fertilizer and soil nitrogen by this crop through the root system and 3) the efficiency of utilization of the nitrogen in the foliar spray solution by the grain. The results of this experiment showed that the foliar application of the Hanway solution with ammonium nitrate at the pod filling period caused severe leaf burn and grain yield was inferior to that of the plants which received a soil application of this fertilizer at the same stage. These facts can be attributed to the presence of ammonium nitrate in the concentration used. The composition of final spray was: 114,28 Kg NH4NO3 + 43,11 Kg potassium poliphosphate + 12,44 Kg potassium sulphate per 500 litres. The uptake of nitrogen fertilizer through the root system and the efficiency of its utilization was greater than that through the leaves.