Showing papers on "Sowing published in 1970"

Entomology of the cocoa farm.

Abstract: planting before the first crop can be harvested. This review is therefore largely of entomo logical problems encountere d in Africa where the facts "are well-documented, thanks mainly to the outstanding work of scientist s associated with the West African Cocoa Research Institute" (19). In Cameroun and Cote d'Ivoire, cocoa is often a plantation crop but in

Nodulation and growth of Medicago truncatula on acid soils. II. Colonization of acid soils by Rhizobium meliloti.

Abstract: Six strains of Rhizobium meliloti varied greatly in their ability to colonize two moderately acid sandy soils (pH 5.0-5.1 in 115 suspension of soil in 0.01M calcium chloride) in the year of sowing inoculated lime-coated seeds of Medicago truncatula. The strains also varied in their ability to nodulate M. truncatula in the year after sowing. With all rhizobial strains and on both soils, calcium carbonate applied in the year of sowing strongly promoted colonization in the year of sowing. It also greatly increased nodulation and growth of M. truncatula in the year after sowing. Apparently calcium carbonate increased second year nodulation by promoting the colonization of the acid soils by R. meliloti in the year of sowing. Differences among strains in second year nodulation appeared to be related to differences in the ability of the strains to colonize the soils in the year of sowing. Strains isolated from moderately acid sandy soils were markedly superior in both properties, and on both soils, to strain SU47 from commercial inoculum, but were generally no better than strain U45 from commercial inoculum. Even the most acid-tolerant strains colonized the acid soils relatively slowly. It is suggested that R. meliloti strains in general have a poor ability to colonize acid soils and that this property is a major factor limiting the growth and persistence of annual Medicago species on acid soils in the field.

Effects of fertilizer-nitrogen and water supply on distribution of dry matter and nitrogen between the different parts of wheat

Abstract: Wheat in pots and in the field was subjected to different watering regimes and fertilizer-N, either as ammonium-N with a nitrification inhibitor or as nitrate-N, was applied at sowing or during growth. More weight of leaves and stems was produced during early growth with ammonium-N than with nitrate-N, but the two forms gave similar yields of grain. The grain:straw ratio with ammonium-N was smaller than with nitrate-N, and more N was retained in the straw. Both forms of N increased the weight per spike but not the number of spikes per unit area (tillering). Applied at the boot stage of growth, N increased dry matter much less than when applied at sowing, but increased the percent N in the grain. Divided dressings, half at sowing and half during growth, increased yield and N uptake by the same amount as applying all the N at sowing. Drought during spike formation or floret development led to smaller spikes and yields of grain, and also to a smaller grain:straw ratio; up to three-quarters of the extra N tak...

Seeding Rate and First-Year Stand Relationships for Six Native Grasses

Abstract: treatment. These rates agree with those reported by Ames ( 1966), but are higher than those reported by Fisher et al. (1959). However, the cost stated by Fisher did not include labor at $2.00 per man hour. Based on the number of trees killed, basal spray is an economical method to kill small and medium size trees (Table 4). Costs ranged from 11 to 18 cents per dead tree, depending on the size and density of the mesquite. Stump application was more costly and less effective than the basal treatment. For trees greater than 5 inches in diameter, chaining was the most economical method. The cost for uprooting

Relationships between initial seed weight and mature plant characters in spring wheat

Abstract: For each of the three spring wheat cultivars, Pembina, Thatcher, and Manitou, the weight of approximately 900 seeds from 30 randomly selected heads was recorded. These seeds were grown to maturity in the field and mature plant characters associated with yield were recorded. Simple and partial correlation coefficients as well as multiple regression formulae were calculated for all traits. The size of the individual seeds planted was shown to account for 2.5 to 4.5% of the observed variations in yield and other mature plant characters, including the number of heads produced per plant. Head number was the most important component of yield.

Wheat Seed Protein: Chemical Influence on and Relationship to Subsequent Growth and Yield in Michigan and Mexico1

Abstract: Simazine [2-chloro-4,6-bis (ethylamino)-s-triazine] and terbacil [3-tert.butyl-5-chloro-6.methyluracil] were applied at subherbicidal rates as protein and growth regulatrs to wheat at two Michigan locations in 1968 and 1969 and at Ciudad Obregon, Mexico in 1969. Different N levels were used at all locations. Winter wheat from Michigan and spring wheat from Mexico were planted at two Michigan locations to determine the effect of herbicide and N treatments on the growth, yield, and protein content of the second generation.Neither supplemental N nor herbicides increased the yield and protein content in all experiments. Nitrogen increased both the yield and protein content in three out of the four tests. Subherbicidal applications increased the protein content in all tests and also the yield in two tests.Increases in seed protein due to both herbicide and N applications were reflected in higher yields the next generation in all three Michigan field experiments. Yield was directly correlated with seed protein content, but not with seed size. In one test in Mexico the effect of protein in the seed on the next generation was eliminated by 120 kg N/ha applied at time of planting.

Small mammals and regeneration of White Spruce forests in western Alberta.

Abstract: The fate of 7,800 pesticide—treated and radiotagged white spruce seeds (Picea glauca (Moench) Voss var. albertiana (S. Brown) Sarg.) was studied under field conditions near Hinton, Alberta, Canada, from 1962 to 1967. Approximately 50% of spring—placed seeds were destroyed by small mammals within 4 months, whereas only 19% or less of winter—placed seeds were lost within a year. From five to six times more seeds germinated following the winter seeding operations than after the first spring seeding test. Calcualted ground seed—eating small—mammal populations varied from 2.0 to 7.4 (average 4.5) animals per acre in spring and from 4.9 to 12.2 (average 8.1) in the fall. Percentages of seeds destroyed were more directly related to time of seeding than to the number of animals present.

Nodulation and growth Of Medicago truncatula on acid soils. II. Colonization of acid soils by Rhizobium meliloti.

Abstract: Six strains of Rhizobium meliloti varied greatly in their ability to colonize two moderately acid sandy soils (pH 5.0-5.1 in 115 suspension of soil in 0.01M calcium chloride) in the year of sowing inoculated lime-coated seeds of Medicago truncatula. The strains also varied in their ability to nodulate M. truncatula in the year after sowing. With all rhizobial strains and on both soils, calcium carbonate applied in the year of sowing strongly promoted colonization in the year of sowing. It also greatly increased nodulation and growth of M. truncatula in the year after sowing. Apparently calcium carbonate increased second year nodulation by promoting the colonization of the acid soils by R. meliloti in the year of sowing. Differences among strains in second year nodulation appeared to be related to differences in the ability of the strains to colonize the soils in the year of sowing. Strains isolated from moderately acid sandy soils were markedly superior in both properties, and on both soils, to strain SU47 from commercial inoculum, but were generally no better than strain U45 from commercial inoculum. Even the most acid-tolerant strains colonized the acid soils relatively slowly. It is suggested that R. meliloti strains in general have a poor ability to colonize acid soils and that this property is a major factor limiting the growth and persistence of annual Medicago species on acid soils in the field.

The growth of vining peas:II. The effect of density of planting

Abstract: Yield and growth analysis has been carried out on vining peas (variety Dark Skinned Perfection) sown at 43, 97 and 172 seeds/m2 at a rectangularity of 1:1. No difference wasobtained in the yield of green peas (at tenderometer reading 110) over this fourfolddifferencein sowing density.At a high seed rate (172/m2) a high peak leaf area (8·3) was attained 1 week afterthe start of flowering but declined rapidly. The peak number of flowers and pods reached 1002/m2 at this density, but there was a greater wastage (34 %) by abscission than inthe lower seed rates which resulted in a similar number of pods/unit area being present at the time of vining for all densities.In contrast, peas sown at low density (43/m2) resulted in a lower peak leaf area (4·3) but this occurred during the stage of pod fill; net-assimilation rate was somewhat higher also. Thus the yield of green peas may depend less on the ability of the plant stand to provide reproductive nodes than on its ability to produce photosynthate during the post-flowering period.

Sunflower date of planting and chemical composition at various growth stages.

Abstract: Six sunflower (L.) varieties were planted at seven dates ranging from April 24 to June 28,1967 through 1969. Early May plantings produced highest seed yields, hectoliter weights, oil percentages, and large seed percentages. Days from planting to emergence and emergence to flowering decreased from early to late planting dates. Date of planting was the variable which most consistently affected seed yield. It overshadowed both varieties variation and the interaction of dates ✕ varieties.Whole plant samples for N, S, P, K, Ca, Mg, Fe, Na, Sr, Zn, Cu, Mo, Mn, and B analyses were taken at 13 different growth stages and separated into root, stem-leaves-receptacle, and seed. Comparative data for seedling, heaaing, flowering, and maturing periods of growth showed concentrations of most elements declined with age in stems- leaves-receptacle.Variation in composition of stem-leaves-receptacle among growth stages was greater than among varieties, but this relationship was reversed in seed. Seed; stemleaves-receptacle, and root differed in composition and in relative rank of the elements

Studies on the productivity of tropical pasture plants. II. Growth analysis, photosynthesis, and respiration of 20 species of grasses and legumes in a controlled environment

Abstract: A previous study of one grass and one legume at early vegetative stages has been extended to include a further nine species of each. It confirms the superior relative growth rates (RW) of grasses, arising from very high net assimilation rates (EA), in turn dependent on high photosynthetic rates (P). Leaf area ratios (FA) varied over a similar range in both groups. RW values of grasses in the second week after sowing varied from 0.41 to 0.55 gg-1 day-1; for legumes, they were 0.31-0.36. Corresponding EA values were 1.5-1.9 g dm-2 wk-1 in grasses, and 1.1-1.8 in legumes. Within both grasses and legumes, comparisons between species can be made with less certainty. In grasses, variation in FA combined with generally uniform EA values resulted in variable RW values. Both FA and EA varied in the legumes but were usually compensatory, leading to uniformity in RW. Watson and Hayashi's method of separating EA into photosynthetic and respiratory components was used. Differences both between and within grasses and legumes were shown, but there are probably important errors in this technique, particularly where there are discrepancies between light and dark respiration.

Studies on seed pelleting as an aid to legume seed inoculation. 2. Survival of Rhizobium meliloti applied to medic seed sown into dry soil

Abstract: Seed of Medicago truncatula and Medicago littoralis, with and without lime pelleting and inoculation, was sown dry into medic-free, Rhizobim meliloti-free soils at 12 sites in the Western Division of New South Wales. At the different sites, periods between 1 and 88 days elapsed before germinating rain fell. Seedling nodulation was used as the index of inoculant survival. Nodulation was variable, but the variation was independent of the time between sowing and germination. Best nodulation occurred in treatments in which peat inoculant was incorporated within a lime pellet around the seed. These treatments were superior to others where broth inoculant was incorporated in the pellet or where peat inoculant was applied externally to pelleted or unpelleted seed. Nodulation was improved by incorporating an increased level of peat inoculant in the pellet. In storage, a very low survival rate was recorded in all treatments except those incorporating peat inoculant within the pellet. The results are discussed in relation to the practicalities of pre-inoculation techniques and of sowing inoculated medic seed into dry seed beds.

Competition for nodule sites between two inoculum strains of Rhizobium japonicum as affected by delayed inoculation.

Abstract: Competition for nodule sites between two strains of Rhizobium japonicum applied at sowing, or at intervals thereafter, was studied. The number of root-nodules formed by the strain applied later and competing with the strain applied at sowing, decreased rapidly with time from sowing to inoculation. The strain D 216 was confirmed to be superior competitively to the strain D 344. The frequency of the root-nodules occupied by both inoculum strains and giving non-specific immune precipitations, was highest when both were applied at sowing.

Influence of soybean seed size on response to atrazine.

Abstract: In the greenhouse, we examined approximately 2,700 strains of soybeans [Glycine max (L.) Merr.] for response to 2chloro-4-(ethylamino)-6-(isopropylamino)-s-t ri a z in e (a t r a z in e), a herbicide which inhibits photosynthesis. Duration of survival when grown in soil containing 0.84 kg/ha was the initial selection criterion. Strains thus selected as most tolerant and most susceptible were grown then for 3 to 31/2 weeks in soil containing 0.45 kg/ha of atrazine. The dry weight of shoots expressed as a percentage of each strain's own untreated check was used to measure the strains' tolerance of atrazine. Tolerance, thus measured, generally increased as seed size increased. Regression analysis inlicated that 80% of the variation in response was attributable to variation in seed size. We suggest the possibility of minimizing soybean injury from atrazine (and perhaps other herbicides) by planting large seed.

DNA synthesis in the seedlings of Sinapis alba L

Abstract: Seedlings of Sinapis alba were grown under standard conditions. In the hypocotyls and cotyledons DNA synthesis still takes place 36 h after sowing. This synthesis decreases in the following 24 h, but an incorporation of 3H-thymidine was found 108 h after sowing.

Coated seeds and process for coating seeds

Abstract: A NEW PROCESS FOR COATING SEEDS FOR PLANTING IS DESCRIBED. SEEDS ARE INITIALLY COATED WITH FINELY-GROUND, POROUS PARTICLES, E.G., HEAT EXPANDED VERMICULITE, DAMPENING THEM ONLY ENOUGH TO CAUSE THE VERMICULITE PARTICLES TO ADHERE TO THE NATURAL SEED COAT AND TO EACH OTHER. WHEN THE SEED IS COMPLETELY COATED AN OVERCOAT IS APPLIED. THE OVRCOAT COMPRISES FINELY-GROUND POROUS PARTICLES APPLIED WITH A BONDING AGENT COMPRISING ABOUT EQUAL PARTS POLYVINYL ACETATE AND POLYVINYL ALCOHOL WITH ENOUGH WATER TO MAKE THE AGENT SPRAYABLE. SMALL SEEDS TO COATED GERMINATE SUBSTANTIALLY AS QUICKLY AS UNCOATED SEEDS AND TOTAL GERMINATION IS COMPARABLE. SMALL SEEDED VEGETABLE CROPS CAN BE PLANTED TO A STANT WITH AVAILABLE PRECISION PLANTERS.

Effect of Plant Spacing and Time of Sowing of Sugar Beet on Aphid Infestation and Spread of Virus Yellows

Abstract: SUMMARY Aphid infestation and incidence of plants with virus yellows in sugar-beet crops at Broom's Barn Experimental Station from 1964 to 1968 differed greatly with changes in densities of stand ranging from 8,000 to 68,000 plants per acre (0.4047 ha), and with changes in sowing date. The numbers of Myzus persicae (Sulz.) and of Aphis fabae Scop, infesting beet during June and July, the numbers of virus-itifected plants per unit area, and the percentages of plants with yellows, usually decreased as the plant population increased but usually increased with delay in sowing from mid-March to early May.

Velvetleaf Control as Influenced by Herbicide Placement and Seed Depth

Abstract: In a 3-year field study, from 51 to 1% of seed of velvetleaf (Abutilon theophrasti Medic) planted at 1 and 6-inch depths, respectively, produced established plants. Utilizing a microplot technique, 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) and the ammonium salt of 3-amino-2,5-dichlorobenzoic acid (amiben) were applied at 2 and 3 lb/A, respectively, at soil depths of 0, 2, and 4 inches. Velvetleaf seed were planted at depths of 1, 2, and 3 inches. Compared with the number of plants establishing in untreated plots, surface-applied amiben reduced the number of established plants 39, 23, and 29% from seed planted at depths of 1, 2, and 3 inches, respectively. Amiben at or below seed depth gave over 95% control, and when applied below the soil surface but above the seed, 86% control. Atrazine, surface-applied, reduced weed establishment 33, 62, and 85% from seed planted at depths of 1, 2, and 3 inches, respectively. When atrazine was at, below, or above the seed but below the soil surface, control was 96% or higher.

Effect of stratification and gibberellin on seed germination in Ginkgo biloba.

Abstract: WEST, W. CHARLES, FRANCESCA J. FRATTARELLI, ancd KAREN J. RusSIN (The City College, New York, N.Y. 10031). Effect of stratification ancd gibberellin on seed germinationi in Ginkgo biloba. Bull. Toirey Bot. Club 97: 380-384. 1970.-The effects of stratification ancd exogenous gibberellic acid on seed germination in Ginkgo biloba were followed for a 12-week period. Most nonstratified seeds either remain dormant or decompose during this period, while nearly 100% of stratified seeds germinate within 7-10 weeks. Reilloval of the hard portion of the seed coat produces oiily a slight enhancement in germination of noiistratified seeds. Exogenous application of gibberellic acid to nonstratified seeds enhaniees ger mination to a level that approaches that of stratified seeds. Barley endosperm bioassay data of ethyl acetate extractable gibberellins froim Ginkgo embryos indicate that stratified embryos contain approximately 100 times more GA, equivalents thani nionstratified embryos. It is coneluded that stratificationi anid gibberellin metabolism are related in the germination of Ginkgo seeds, anid that exogenious GA3 will largely substitute for stratification in lionstratified seeds to promote germ-iinationi.

Corn Yields, Soil Temperature, and Water Use with Four Tillage Methods in the Western Corn Belt

Abstract: Corn grown with four systems of tillage (conventional, wheeltrack planting, till planting, and listing) was compared for yield and several growth characteristics. Yields from the three reduced-tillage systems in 1965, 1966, 1967, and 1968 were at least as good as those from the conventional system. The four tillage methods created a wide range of soil conditions, so that differences in growth and yield indicate the range of response that can be expected from tillage for the seasons experienced. Because of below normal rainfall, corn was under stress during flowering and ear formation in each of the four years. Soil temperature at seed depth was lowest in the listed plots where corn was planted in the bottom of the furrow. Although this resulted in slower plant growth, the delayed maturity was not correlated with final yield of dry grain or total dry matter. No significant difference among tillage systems in either total water use or in the pattern of water use was detected.