Showing papers on "Sowing published in 1976"

Effect of waterlogging on the growth, grain and straw yield of wheat, barley and oats

Abstract: Wheat, barley and oats were grown in undrained plastic buckets containing soil collected from upper, mid and lower slopes of a valley that was subject to winter waterlogging. Two weeks after planting, the water content for each soil was either maintained at 80 per cent of full water holding capacity or subjected to intermittent or continuous waterlogging for six weeks. In a second experiment, using lowerslope soil only, the same three cereals were subjected to similar waterlogging treatments commencing at two or six weeks after planting or at ear emergence. In this experiment the plants received either no nitrogen fertilizer or 100 kg nitrogen ha-1. Both soil composition and waterlogging had a significant effect on plant yield but the effect of waterlogging was much greater. Waterlogging reduced root growth and penetration, the production of tillers and fertile heads, and delayed ear emergence and plant maturation. Reduction in plant growth rate was measurable within three days from the onset of waterlogging. In the first experiment intermittent and continuous waterlogging reduced vegetative growth yield (mean of three cereals in three soils) by 37 per cent and 55 per cent respectively; and wheat grain yields by 40 per cent and 53 per cent respectively. However, there was no differential effect of the two waterlogging treatments on the grain yield of barley and oats, the mean reduction being 39 per cent for barley and 48 per cent for oats. In the second experiment waterlogging at the earliest growth stage resulted in the greatest reduction in root, herbage and grain yield. Waterlogging at ear emergence killed some tillers and roots and reduced the plants stability at maturity. Grain size was reduced in some treatments. Application of nitrogen fertilizer compensated, either partially or fully, for reduction in grain yield due to waterlogging treatments on all three cereals. Some reasons for yield reduction in the three species and the practical implications of the results are discussed.

Effect of various covers on soil fertility under Hevea brasiliensis muell. arg. and on growth of the tree

Abstract: A survey was made of the relationship between ground covers, soil fertility, and the growth of Hevea brasiliensis. Four different cover management systems were widely tested in Malaysia, namely a mixture of creeping legumes (Calopogonium muconoides, Centrosema pubescens and Pueraria phaseoloides), grasses (mostly Axonopus compressus with Paspalum conjugatum), a pure crop of Mikania cordata, and a naturally regenerating system representing the normal colonisation process on cleared land. Of the four systems, legumes initially had the fastest rate of growth, and generally contained more nutrients than the other covers tested. The greater nutrient return to the soil from growing a leguminous cover was reflected in higher levels of these nutrients in rubber leaves. This, coupled with improved soil physical properties, led to an increased rate of growth of the rubber tree. Nitrogen fixation under legumes grown in association with rubber averaged 150 kg per ha per year over a 5-year period, with maximum rates of nitrogen fixation being about 200 kg per ha per year. Competition effects from both the shade and roots of Hevea caused a gradual diminution in vigour of all the covers such that they virtually died out by about the 6th year after planting. Dry rubber yield benefits in ex-leguminous plots extended for about 20 years, and amounted to approximately 4 metric tonnes more than the yields achieved with any of the other cover systems. In simple economic terms this means that only 4% of the monetary benefit of a legume cover policy derives from nitrogen fixation while the remaining 96% stems from post-legume effects. Two hypotheses have been invoked to explain these effects: first, that legumes re-cycle nutrients at or near the soil surface until such a stage that they can be efficiently utilised by Hevea; and second, that legumes, by processes not fully understood, cause increased Hevea root proliferation which facilitates nutrient uptake.

Effect of Calcium and Irrigation Treatments on Peanut Yield, Grade and Seed Quality1

Abstract: The effect of irrigation and/or Ca (calcium) application on yield, grade and seed quality was studied using Florigiant peanuts planted on three dates. Calcium application resulted in a small, but consistent, yield increase at all planting dates. Irrigation resulted in a large yield response on early planted peanuts and no response on late planted ones. Grade, specifically sound mature kernel percentage, was improved by both Ca and irrigation treatments but the effects were only slightly additive. Similar interaction effects were noted as these treatments increased the germination percentage of the seed produced and decreased the percentage of kernels with the form of damage termed dark plumule. Both treatments also decreased the amount of watery hypocotyl damage and increased the Ca concentration in the seed. Germination was 89 to 94% when the seed Ca level was greater than 420 ppm, but fell linearly to 52% when the seed Ca decreased from 420 to 200 ppm.

Effects of seed bed conditions on the germination of four Stylosanthes species in the Northern Territory

Abstract: Absf rac t Since the proposed use of low input management practices in the Northern Territory will require the establishment of Stylosanthes species in the native grasslands with the least possible disturbance, the effects of soil surface, soil type and seed treatments on the germination of four Stylosanthes species were studied. The species were the annual S. humilis, the facultative perennial S. hamara cv. Verano, and two obligate perennials, S. scabra ~~140289 and S. viscosa ~~134904. The study was carried out on microplots in burnt and unburnt pasture near Katherine in the Northern Territory. Although all species germinated in both burnt and unburnt grassland, germination was much better under the grass sward. The two perennial species germinated much more slowly than either S. humilis or S. hamata, and the removal of grass cover caused low germination of these species, especially under the poor moisture conditions existing on the surface of sandy soils. Under the existing method of establishment with burning late in the dry season followed by sowing in the early wet season, the germination of the perennials S. scabra and S, viscosa will not attain the same levels as that of S, hamata and S. humilis. Our results suggest that field germination of the perennials could be enhanced by either pretreating the seed to improve its potential rate of germination, or by sowing later in the wet season to take advantage of the greater probability of prolonged moisture conditions.

The effect of time to emergence on head weight and variation in head weight at maturity in lettuce (Lactuca sativa)

Abstract: SUMMARY In lettuce, results of three experiments showed that between 60 and 90 % of the variation in mature head weight and the date of head maturity could be accounted for by variation in the date of seedling emergence. Sowing pre-germinated seeds using a fluid drill considerably reduced the time spread of both emergence and maturity compared with size-graded natural seed sown conventionally.

Plant Population Effects on the Seed Yield of Phaseolus vulgaris L. 1

Abstract: Seed yields of Phaseolus vulgaris L. have not increased under the current production systems even with more precise management inputs. Recent studies of snap beans grown for processing suggested that yields could be increased by high density planting. Our study was made to evaluate the effects of plant populations on the seed yields of four representative field and snap bean cultivars grown under sprinkler irrigation on a Portneuf silt loam (Xerollic Calciorthid). Two cultivars each of bush snap beans and semivining field beans were grown in plant populations of 107,600 to 968,700 plants/ha in nearly equidistant plant arrangements. The optimum plant population or seed yield for the bush cultivars was approximately 400,000 plants/ ha and less than 300,000 plants/ha for the semivining cultivars. At smaller plant populations, seed yields decreased for the bush cultivars and remained constant for the semivining cultivars. The harvest index (seed weight/ total plant weight) increased slightly for the bush cultivars as their plant population decreased, but remained constant for the semivining cultivars up to 300,000 plants/ ha, then increased rapidly. The production index (seed yield/amount seeded) increased curvilinearly as plant population decreased for all cultivars. Plant maturity was advanced 7 to 10 days at the highest plant populations for all cultivars. Pods were located at upper nodes on the plants as the populations increased. These results suggest that greater seed yields could be expected with the equidistant plant arrangements as compared with conventional row plantings for the bush cultivars, but not for the semivining cultivars, primarily because of the ability of the semivining cultivars to compensate for the increased area/plant at smaller plant populations.

Temperature/light interactions and the effect of seed source on germination of annual ryegrass (Lolium rigidum Gaud.) seeds

Abstract: Germination of Lolium rigidum seeds, in the light (12 hr day length) and in the dark, was studied at constant and alternating (12/12 hr) temperatures in the range 8–35°C. Seeds had after-ripened for 22 weeks. Different constant temperature optima for germinability were found: 27° in light and 11° in dark. Germinability at alternating temperatures in darkness was determined solely by the minimum temperature of the alternation, and there was no response to thermoperiodicity per se. In contrast, light and alternating temperature appeared to interact to increase germinability, although the highest germinability occurred only when the maximum temperature was close to the optimum constant temperature, i.e. about 27°. Germination in both light and dark was most rapid where either the constant or the average temperature of an alternating regime was between 18 and 29°. Below 18° germination rates decreased markedly, and at 8°, rates were one-third of those at 18°. Seeds germinated more slowly in light than in darkness at all temperatures, but the differences were small relative to the effects of low temperatures. In another study, seeds collected from plants naturalized in eight different localities in the cereal belt of Western Australia and subsequently planted together in two contrasting environments were examined for germinability at 24/12°C in light and dark 18 weeks after harvest. Dark germinability differed between seed sources but not between planting sites, and ranged between 78 and 93%. Exposure of germinating seeds to light substantially alleviated dormancy in seeds from all sources.

Downy Brome Control in Dryland Winter Wheat with Stubble-mulch Fallow and Seeding Management1

Abstract: Differences in downy brome (Bromus tectorum L.) control had been observed under field conditions of eastern Idaho when dates of stubble-mulch tillage, final rod weeding, and winter wheat (Triticum aestivum L.) planting were varied. This field-plot experiment on Tetonia silt loam (Pachic Cryoboroll-coarse, silty, mixed) tested the degree of downy brome control obtained with three initial stubble-mulch tillage dates, two final rod weeding dates, and three winter wheat planting dates. Downy brome was best controlled with a combination of initial tilling early in the spring and a final rod weeding just before the late (15 September) wheat planting date. The early tillage killed downy brome before they produced seed. This also resulted in sufficient soil moisture retention in the seed zone for fall germination of other downy brome seeds, which were then killed by the final rod weeding just before the late wheat planting. A reduction in natural downy brome emergence was observed at later fall dates. This was confirmed in a separate field.plot experiment (Portneuf silt loam, Xerollic Calciorthid, coarse, silty, mixed) where downy brome seed was planted at several dates, and helped explain some of the benefits of the mentioned late rod weeding and planting treatment. These procedures incorporating stubble-mulch fallow are recommended, as normally practiced moldboard plowing creates an erosion hazard.

Field Establishment of Some Vegetable Crops: Response to a Range of Soil Conditions

Abstract: SummaryCalabrese, carrot, onion and red beet seeds were sown at approximately weekly intervals throughout the spring and early summer of 1972–4. In a situation where soil tilth and seed placement in the soil were apparently non-limiting, regression analysis showed that in eight of the twelve crop × year combinations there were no significant relationships between seedling emergence and soil moisture or temperature at sowing. In 1972 emergence levels of beet and calabrese were depressed by either excess or lack of soil moisture at sowing, and calabrese emergence was positively related to temperature; in 1973 and 1974 onion emergence was negatively related to temperature at sowing. Rainfall occurring shortly after sowing was identified as a major factor causing emergence problems, apparently through the formation of a soil cap, but its effect varied with crop type, seed vigour and soil moisture content at the time of seedling emergence. The results suggest that low plant stands often found in agricultural p...

Physiological Aspects of Time of Application of Copper to Wheat Plants

Abstract: Time of application of Cu as soil dressing or foliar spray had large effects on grain yield of wheat plants grown in Cu-deficient soil in the glasshouse. Times of application of Cu (4 mg per pot in one dose) ranged from sowing to maturity in weekly intervals. The soil dressing of Cu produced excellent grain yield if applied any time from sowing to early boot stage. Little or no grain formed on any tillers which had passed this critical early boot stage at the time of appli cation; the pollen produced by these tillers was non-viable, anthers were not exserted, and maturation was delayed. These results suggest that microsporogenesis was interrupted by Cu deficiency at or near meiosis. Tillering was the optimum time for foliar application of Cu (CuS04 + Ca(OH)2 in suspension) ; early or late applications failed to produce grain. However, this form of Cu proved unsatisfactory for foliar application under glasshouse conditions, possibly owing to the absence of rain or dew.

The effect of planting date on the yield and some fibre properties of cotton in the Namoi Valley

Abstract: The effect of planting dates between September 30 and November 30 on the yield and some fibre properties of two cotton cultivars has been studied over three seasons. The yield of the commercial cultivar (Deltapine Smoothleaf) fell by an average of 20 kg ha-1 day-1 delay in planting after October 20, earlier planting dates having equal yields, producing a plateau effect. The yield of an early maturing cultivar (Short Sympodial) fell linearly by 11 kg ha-1 day-1 delay in planting. Planting dates after mid-October had an adverse effect on micronaire in the commercial cultivar, but lint length and strength were not affected. Thus maximum yield and micronaire for plantings after mid-October came from the early cultivar. Tolerance to low temperature is an important factor in cultivar earliness, and accounts for the performance of Short Sympodial in these experiments. The number of days from first flower to first frost was as reliable as growing degree days in explaining yield variation within a cultivar

Extraction of Teak Seeds from Fruits, their Storage and Germination

Abstract: A technique to extract teak seed from the fruits has been described. The extracted seeds germinate and give germination as high as 50% to 79% during favourable months. Periods immediately after the break of monsoon (June or July), October, February and March have been found to be the best months for germination in Chanda region. Success of germination depends upon the relative absence of the fungal attack during different months. Seeds germinates over a wide range or temperature (25°C to 40°C) but 30°C has been found to yield good results. The germination completes in about 10-12 days. Mercury fungicide (dust formulation) has been used for preventing fungal attack on the extracted seeds during storage. The extracted seeds can be stored in air-tight containers under the cover or fungicide-dust. Seeds stored upto 2 months have so far seed tried and gave germination upto 54%. Too wet conditions cause decay of seeds soaking or seeds in water before sowing was found to be harmful.

Native grass seed drill

Abstract: A grass seed drill particularly adapted for the planting of native grass type seeds which are characterized by a low density, irregular length and shape, and having a propensity to stick together The drill has a pair of seed boxes, at least one of which is adapted to handle the aforementioned type of seeds The seed box has a plurality of bins with downwardly converging side walls terminating at a horizontal bottom wall provided with an elongate seed discharge opening An agitator in each bin has a plurality of rotatable blades shaped and sized to rotate about a path substantially conforming to the shape of the interior of the bin and agitate the seeds located therein A picker wheel associated with the discharge opening discharges seeds into a transition or seed funnel located substantially directly above a drill shoe which discharges the seed into the soil A press wheel follows the shoe to compact the soil around the seed

Time of planting effects on development, yield and oil quality of irrigated sunflower

Abstract: The effects of time of planting on irrigated sunflower were tested at Emerald during the 1969-70 and 1970-71 summer seasons. Plantings ranged from September to March. A growing degree day summation from a base of 0¦C (GDDo) was the most reliable index of commencement of flowering (cv. 5.7 per cent). Sunfola commenced flowering at 1331 ¦ 76 GDDo. In both seasons significantly higher seed and oil yields were obtained from a December planting (Seed yields 2628 kg ha-1 1969-70, 1808 kg ha-1 1970-71, oil yields 1025 kg ha-1 1969-70, 61 5 kg ha-1 1970-71). Lower yields at all times of planting in the second season were attributed to rust infection (Puccinia helianthi Schw) . A good correlation was obtained between oil quality (proportions of oleic and linoleic acids) and temperatures during the post flowering period. Oleic acid levels ranged from 12 to 48 per cent. Linoleic acid levels ranged from 39 to 73 per cent. Oil quality (per cent linoleic acid) improved with late sowing in association with lowered temperatures

The effect of sowing date and season on the development and yield of Navy beans ( Phaseolus vulgaris ) in south-east England

Abstract: The results of experiments in which Navy beans (cv. Purley King) were precision drilled at the beginning, middle and end of May in 1972, 1973 and 1974 suggest that the optimum time to sow is mid-May when soil temperatures at 10 cm depth have reached 12–13 °C. Earlier sowing usually led to a reduced plant stand and low yields whilst in 1972 and 1974, two exceptionally cool years, later sowing resulted in lower yields following a reduction in 1000-seed weight.Despite contrasting weather conditions acceptable yields of seed were obtained in all 3 years from mid-May sowings although cool wet conditions in the autumn of 1974 curtailed drying of the seeds below 30% moisture content. Accumulated temperatures (Ontario units) were successfully used to predict stages in crop development and the data used to demarcate the areas in England most suitable for Navy-bean production.

Use of a soil moisture model and risk analysis to predict the optimum time for the aerial sowing of pastures on the Northern Tablelands of New South Wales

Abstract: The objective of this study was to determine the time of year that maximized establishment and . minimized the risk of failure in aerial sowing of pasture seed on the Northern Tablelands of New South Wales. This was achieved by relating a set of monthly measurements of establishment spanning two years to mean soil moisture, predicted by a water balance model for the six-week period following sowing. From this relationship, establishment was simulated for 61 years using historical rainfall data to estimate probability density functions of establishment for each week of the year. From these functions it was concluded that maximum establishment with minimum risk can be expected from sowing in the June-July period. For perennial species plant survival over the first summer is of more practical importance than per cent establishment. Our data on plant survival, although not presented, indicated a close relationship existed between establishment and survival and supported the conclusion that the optimal time for oversowing is June-July.

Relationships and Uses of Yield Components in Safflower Breeding1

Abstract: An understanding of the interrelationships of growth characters is needed to improve breeding of safflower, Carthamus tinctorius L. The objectives of the study were to evaluate five plant characters and four seed characters as units of selection and to determine the optimum combination of years, locations, and dates of planting for testing cultivar performance. Indirect yield components (plant height∕plot, canopy depth∕plant, canopy width∕plant, and head diam∕plant) were intercorrelated. They were also correlated to seed yield and to seeds∕head but with the exception of head diam∕plant they were not correlated to seed weight. The direct yield components (heads∕area, seeds∕head, and seed weight) were not intercorrelated but they were all correlated to seed yield. In several tests involving seven cultivars, variance components were usually significant for plant height, heads∕section, and seed weight and usually nonsignificant for canopy depth, head diameter, and seeds∕head. Cultivar × date of planting and cultivar × location interactions were generally nonsignificant. However heads∕section, seeds∕head, and seed weight showed significant interactions of cultivars with location and date of planting and made it evident that a single year's testing did not adequately evaluate these effects. Cultivar × year interactions were not significant when the data from only one location, Mesa, were analyzed. However when all three locations were considered, some significant interactions appeared. Expected variances of varietal means for heads∕section, seed yield∕section, and seed yield∕plot were calculated for all combinations of environments and also extrapolated to six replications. Expected variances were virtually identical for the second and third years and second and third planting dates. Satisfactory precision for these characters was obtained for the cultivars tested using the combination of 2 years, two locations, two dates of planting, and four replications.

Hybrid Wheat seed Production Methods for North Dakota 1

Abstract: In trials at several sites in 1972-4, average yield of hybrid seed when a male fertility restorer and several male-sterile wheat lines were sown in male:female ratios of 1:1, 2:1 or 3:1 in strips 3.1-11 m wide were 1.37, 1.0 and 0.84 t/ha, respectively, or 0.69, 0.67 and 0.64 t/ha when adjusted for the area occupied by the restorer. Decreasing the width of strips to reduce pollen travel distances did not increase yields. Higher yields were obtained by sowing the earlier restorer line 44 growing degree days (growing degree day = average of maximum and minimum temperature - growth threshold temperature in this case 4.4 deg C) before sowing the later male sterile lines than with 0, 22 or 66 growing degree day differences. Hybrid seed yields were highly correlated with restorer yields indicating that hybrid seed production was much more likely to succeed at high than at low yielding sites.

Predictions of likely theft by ants of oversown seed for the Northern Tablelands of New South Wales

Abstract: At Armidale, New South Wales, ant theft rates of pasture seeds at sites that had been topdressed with 10 kg ha-1 seed immediately before a four day observation period averaged 27 per cent less than on areas where no such application was made. Strong regression relationships were established between theft rates of the various seed types and both air and soil temperatures, but no relationship was found between either relative humidity or soil water availability and theft rate. High theft rates recorded in the first 24 hours after seed placement were not sustained over longer periods of time. A relationship between the decline in theft rate and the quantity of seed available was established. A series of predictions have been made of the proportion of seed likely to remain during fine weather following oversowing in the Armidale environment. These predictions incorporate seed type, time since sowing and prevailing air temperatures. It is predicted that during winter 70 to 80 per cent of bare seed and 90 to 97 per cent of coated seed could remain 30 days after oversowing. During summer the comparable figures are 7 to 30 per cent and 22 to 36 per cent respectively.

Effect of sward age on nitrate accumulation in ryegrass.

Abstract: Two indoor trials were done with Italian ryegrass (Lolium multiflorum) and perennial ryegrass (Lolium perenne) to obtain more information about the nitrate-accumulating process of a new-sown grass sward. With an abundant NO3 supply for Italian ryegrass, NO3 accumulation in herbage decreased during 5 successive cuts after sowing, because of increasing NO3 conversion. In the same way the NO3 content in DM in perennial ryegrass was more in the first cut after sowing than in old plants from a pasture 5 years old. After sowing, a considerable part of the assimilate produced was used for stubble and root growth. With older swards these assimilates were increasingly retained in herbage, which is rich in organic N and to a lesser extent in stubble and roots, which are poor in organic N. Because of this, NO3 conversion is restricted in a new-sown grass sward and reaches a maximum in old sward of a permanent pasture, which almost exclusively produces herbage. Consequently nitrate is more apt to accumulate in new-sown grass than in old pasture. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Some factors affecting the establishment and early production of oversown grasses

Abstract: The effects of rate of sowing, herbicide, and superphosphate on seedling establishment of two oversown improved grass species, their sward performance, and the resultant soil phosphate levels were studied in two experiments at Glen Innes, New South Wales in 1973. The experimental area had received 1250 kg ha-1 superphosphate prior to sowing and was carrying native grasses and white clover (Trifolium repens). In the first experiment, treatments applied were combinations of: four sowing rates (5.5, 11, 22, 44 kg ha-1) ; three herbicide rates (0 + 0, 8.3 + 0.55, 49.5 + 3.3 kg a.i. ha-1 2,2-DPA 4- amitrole) and two superphosphate rates (0, 250 kg ha-1). In the second experiment, three rates each of herbicide (0 + 0, 8.3 + 0.55, 16.6 + 1.1 kg a.i. ha-1 2,2-DPA + amitrole) and superphosphate (0, 125, 250 kg ha-1) were applied in a factorial design. Both experiments were sown with Phalaris aquatica and Festuca arundinacea. For both species, seedling numbers increased as herbicide and sowing rates increased but declined with superphosphate application. These main effects were more pronounced during the earlier samplings. Seedling numbers of both species, particularly phalaris declined with time. As herbicide rates increased, total dry matter production was progressively reduced, but production of fescue increased from 19 to 232 and phalaris from 0.5 to 60 kg dry matter ha-1. The addition of superphosphate eliminated the adverse effect of herbicide on the legume component. Superphosphate increased fescue dry matter production but decreased that of phalaris. Prior application of herbicide at the heaviest rate and superphosphate applied at 125 kg ha-1, both increased soil phosphate by approximately the same amount (7.5 and 8.2 p.p.m. respectively).

Insect Pests of Soyabean in Japan and their Control

Abstract: From thirty species of economic importance, the biology, damage caused and control measures for three pod borers, one pod gallmidge and four stink bugs are reviewed. Some high correlations have been recognised between the percentage of injured seed at harvest time and the mean temperatures of January, July or August, and some equations have been obtained for forecasting the percentage of the damage to soyabean seeds. The late podding varieties are generally less damaged by major pests. Even in one variety, damage decreased when sowing was delayed. Hence consideration should be given to the choice of variety and sowing date in order to avoid the coincidence of the peak of pest occurrence with the podding period of the soyabean plants. In the central southern region of the Tohoku district where all species of economic importance occur, insecticidal applications should be carried out when indicated by the forecast, two or three times at intervals of one to two weeks, during early pod-setting and on ...

Seasonal variation in establishment of oversown seed in relation to tussock proximity

Abstract: Seed was sown in small quadrats adjacent to Festuca novae-zelandiae tussocks in a dry hygrous soil. Monthly measurements of seedling establishment were made at each of 3 tussock densities, 3–7 sampling positions, 5 seed species, 4 sowing dates, and in each of 2 years. Proximity to tussocks had little effect on spring germination, but during summer there was lower mortality on the shaded and cooler south side of tussocks. Fewer grass than legume seeds established during the spring phase. Establishment from different sowings increased with increasing rainfall in the week before and 5 weeks after sowing.

Effect of timing of glyphosate and 2,2-DPA application on establishment of surface-sown pasture species

Abstract: In two experiments on unploughed hill country near Turondale, New South Wales, the effects were examined of applying glyphosate and 2,2-DPA before and after the autumn break and at various intervals before sowing on the establishment of surface-sown Medicago sativa, Trifolium subterraneum, Dactylis glomerata and Phalaris tuberosa. Good control of resident species was obtained by applying herbicides from 10 to 30 days after autumn rain had promoted germination of winter annuals; poor control resulted if herbicides were applied before the autumn break. Glyphosate was more efficient in controlling resident species than 2,2-DPA. The establishment of all species except subterranean clover depended on good control of the resident plants. It was also necessary to have an adequate period between spraying and sowing to allow the residual herbicide to dissipate; 10 days was sufficient for the grasses, 20 days for lucerne and longer for subterranean clover. A 4.5 kg a.e. ha-1 rate of glyphosata had a more serious residual effect than a 1.5 kg a.e. ha-1 rate or the 2,2-DPA treatment. Results showed that good establishment of surface-sown legumes and grasses can be obtained by applying 0.5 to 1.5 kg a.e. ha-1 of glyphosate, or 8.7 kg a.e. ha-1 of 2,2-DPA, 10 to 30 days after autumn rain and then sowing 10 to 20 days later.

The influence of date of sowing and seed rate on the production of pure-sown red clover

Abstract: Hungaropoly tetraploid broad red clover was sown at seed rates of 6, 12 or 18 kg ha-1 on six dates from April to September 1971. Three crops were harvested in 1972 and one in June 1973. In 1972, total herbage dry matter yields ranged from 5.22 to 12.22 t ha-1 and red clover dry matter yields from 3.61 to 11.92 t ha-1 when meaned over all seed rates. April to July sowing dates gave significantly higher yields than later sowings. In general, August and September sowings gave the lowest red clover contents in a range from 63.2 to 96.5%, the highest digestibilities within a range 61.9 to 65.0% and the lowest crude protein contents in a range 15.5 to 17.3%. The influence of seed rate was less marked than sowing date. Mean annual yields of total herbage dry matter increased from 9.88 to 10.85 t ha−1 as seed rate was increased from 6 to 18 kg ha−1. Red clover dry matter yields and contents of red clover and crude protein in the total herbage also followed this trend. The sowing date effects on total herbage yield and content of red clover did not persist into the second harvest year but the seed rate effects were still noticeable. Plant numbers in spring the first harvest year and hence percentage survival from sowing were depressed by late sowing; plant numbers rose but percentage survival declined as seed rate was increased. The seed rate effects on plant population persisted until spring of the second harvest year but sowing date effects did not. Better stands of red clover were obtained from sowings made between April and June, when a seed rate of 12 kg ha−1 was adequate. The adverse effects of late sowing cannot be fully compensated by raising seed rates of clover. There was a significant interaction between seed rate and date of sowing. For April-May sowings, seed rate was not critical. Thereafter, a linear effect of seed rate on yield was discernible.

Effect of sowing rate and sowing date on lupin seed yield

Abstract: Trials were carried out with Lupinus angustifolius cv. ‘Uniharvest’ sown in autumn and spring at five sowing rates. The spring-sown trial included L. luteus cv. ‘Weiko III’ at four sowing rates. Autumn sowing produced the highest yields, and ‘Weiko III’ yielded substantially less than spring-sown ‘Uniharvest’. The optimum sowing rates demonstrated by the results were higher than the rates currently being recommended. Yield component analysis showed that numbers of seeds per pod and 100-seed weight were not generally affected by sowing rate or sowing date. Autumn sowing greatly increased the numbers of lateral branches.