EFFETS DES TEMPERATURES DU SOL, DES DATES DE SEMIS ET DES MAUVAISES HERBES SUR LES COMPOSANTES DU RENDEMENT DE L’AVOINE

1980 ◽  
Vol 60 (1) ◽  
pp. 61-68 ◽  
Author(s):  
J. M. DESCHENES ◽  
C. A. ST-PIERRE

On a St-André sandy loam and on a Kamouraska clay, the effect of soil temperature on oats (Avena sativa L.) was measured in the greenhouse using a system described by Deschênes et al. in 1974 and in the field, using two dates of seeding. The effect of weeds was measured by using un weeded and hand-weeded treatments. In the greenhouse, cool soil temperatures have delayed maturity and decreased straw and grain yields as well as total phytomass of oats on the two soil types. The dry weight of weeds in un weeded pots increased slightly. The effect of hand-weeding on oats was especially noticeable on the St-André sandy loam where three times as many weeds were observed. The straw yield and the total phytomass of oats were higher in the field experiment following an early seeding of oats on both soil types. On the other hand, grain yield was lower on plots seeded early and located on St-André sandy loam while the opposite was true on Kamouraska clay. The dry weight of weeds was lower on unweeded plots seeded early. The weeds reduced straw and grain yields on the St-André sandy loam but had no effect on Kamouraska clay because of the low weed infestation on the latter. The greenhouse and field experiments suggest that soil temperature is not the main factor in explaining the increase in grain yield observed with early-seeded cereals.

1979 ◽  
Vol 59 (4) ◽  
pp. 981-989
Author(s):  
J. M. DESCHENES ◽  
J. P. DUBUC

The effect of four rates (9–36 t/ha) of sheep manure applied in the fall was compared to conventional inorganic fertilization (49 kg of N, 60 kg of P2O5 and 60 kg of K2O/ha) applied at seeding on three species of cereals. Weed populations, lodging and grain yields were recorded on oats (Avena sativa L.), barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) from 1976 to 1978 on the St-André sandy loam and in 1977 and 1978 on the Kamouraska clay. The manure applied came from sheep fed entirely with hay silage. The various rates of sheep manure had no effect on weed population since no significant difference has been observed between the organic and inorganic fertilization. Lodging did not occur in any of the plots, irrespective of the soil type, during the 3 yr of the experiment. For the two soil types, the grain yields of oats, barley and wheat were usually higher on plots that received 27–36 t/ha of sheep manure than on plots that received inorganic fertilizer. The rates of 9 and 18 t/ha of manure resulted in grain yields significantly lower. An application on all plots of 15 kg/ha of inorganic nitrogen in the spring of 1978 has sensibly increased the grain yield. These results suggest that the fall spreading and the incorporation into the soil of 36 t/ha of sheep manure followed by an application of about 15 kg/ha of inorganic nitrogen in the spring provide a very satisfactory grain yield and do not increase the incidence of lodging and weed infestation.


2018 ◽  
Vol 5 (2) ◽  
pp. 117-122
Author(s):  
Mebrate Tamrat Woldeselassie ◽  
Daniel Admasu

Field experiments were carried out to study the response of two lentil varieties to varying sowing dates in a split plot design with three replications, in which varieties were assigned to main plots and sowing dates to sub plots. The study was conducted at Enewari research site of Debre Birhan agricultural research center for three consecutive years (2007 - 2009) on two soil types. The results showed that no significant difference between varieties for grain yield. However, variety Alemaya produced highest grain yields of 1.3 t/ha and 1.22 t/ha from fifth (30-July) sowing date on heavy and relatively light Vertisols respectively. On the other hand, the local variety produced highest grain yields of 1.4 t/ha and 1.06 t/ha on the fifth and six sowing dates on heavy and relatively light Vertisols respectively. Grain yield proportionally increased with increasing biological yield in different sowing dates on both soil types. On heavy Vertisol varieties responded differently to the changes of sowing dates. Variety Alemaya had responded to a wider sowing dates. Early August to mid-August sowing found to be optimum for local variety. On light Vertisol, the functional relationship was unexplained for both varieties. In general, heavy Vertisol gave higher responses than relatively light vertisol throughout most parameters and levels tested.  


1988 ◽  
Vol 110 (1) ◽  
pp. 119-140 ◽  
Author(s):  
G. N. Thorne ◽  
P. J. Welbank ◽  
F. V. Widdowson ◽  
A. Penny ◽  
A. D. Todd ◽  
...  

SummaryWinter wheat grown following potatoes on a sandy loam at Woburn in 1978–9, 1980–1 and 1981–2 was compared with that on a clay loam at Rothamsted in 1978–9 and 1980–1, and on a silty clay (alluvium) at Woburn in 1981–2. The cultivar was Hustler in the harvest years 1979 and 1981 and Avalon in 1982. On each soil in each year multifactorial experiments tested effects of combinations of six factors, each at two levels.The best 4-plot mean grain yield ranged from 89 to 11·1 t/ha during the 3 years; it was smaller on the sandy soil than on the clay soil in 1979, but larger on sand than on the clay in 1981 and 1982. Until anthesis the number of shoots, dry weight and N content of the wheat giving these best yields were less on sand than on clay. Unlike grain weight, straw weight was always less on sand.Sowing in mid-September instead of mid-October increased grain yield on clay in each year (by 0·4·0·7 t/ha) and increased yield on sand only in 1981 (by 1·6 t/ha). Early sowing always increased dry weight, leaf area, number of shoots and N uptake until May. The benefits were always greater on clay than on sand immediately before N fertilizer was applied in the spring and usually lessened later on both soils.Aldicarb as an autumn pesticide increased grain yield of early-sown wheat on both soils in 1981 by lessening infection with barley yellow dwarf virus. Aldicarb increased yield on clay in 1982; it also decreased the number of plant parasitic nematodes.Wheat on sand was more responsive to nitrogen in division, timing and amount than was wheat on clay. In 1979 yield of wheat on sand was increased by dividing spring N between March, April and May, instead of giving it all in April, and in 1982 by giving winter N early in February. In 1981 division and timing on sand interacted with sowing date. Yield of early-sown wheat given N late, i.e. in March, April and May, exceeded that given N early, i.e. in February, March and May, by 1·4 t/ha; single dressings given all in March or all in April also yielded less than the late divided dressing. Yield of later-sown wheat given all the N in April was at least 1·2 t/ha less than with all N given in March or with divided N. In all years treatments that increased yield usually also increased N uptake. Grain yield on clay was never affected by division or timing of spring N or by application of winter N. This was despite the fact that all treatments that involved a delay in the application of N depressed growth and N uptake in spring on both sand and clay. The mean advantage in N uptake following early application of spring N eventually reversed on both soils, so that uptake at maturity was greater from late than from early application. Increasing the amount of N given in spring from the estimated requirement for 9 t/ha grain yield to that for 12 t/ha increased yield in 1982, especially on sand. The larger amount of N always increased the number of ears but often decreased the number of grains per ear and the size of individual grains.Irrigation increased grain yield only on the sandy soil, by 1·1 t/ha in 1979 and by 07 t/ha in 1981 and 1982. The component responsible was dry weight per grain in 1979 and 1982, when soil moisture deficits reaching maximum values of 136 and 110 mm respectively in the 2 years developed after anthesis; the component responsible was number of ears/m2 in 1982 when the maximum deficit of 76 mm occurred earlier, in late May.


2004 ◽  
Vol 52 (2) ◽  
pp. 199-203 ◽  
Author(s):  
G. Singh ◽  
R. S. Jolly

Two field experiments were conducted during the kharif (rainy) season of 1999 and 2000 on a loamy sand soil to study the effect of various pre- and post-emergence herbicides on the weed infestation and grain yield of soybean. The presence of weeds in the weedy control plots resulted in 58.8 and 58.1% reduction in the grain yield in the two years compared to two hand weedings (HW) at 30 and 45 days after sowing (DAS), which gave grain yields of 1326 and 2029 kg ha-1. None of the herbicides was significantly superior to the two hand weedings treatment in influencing the grain yield. However, the pre-emergence application of 0.75 kg ha-1 S-metolachlor, and 0.5 kg ha-1 pendimethalin (pre-emergence) + HW 30 DAS were at par or numerically superior to this treatment. There was a good negative correlation between the weed dry matter at harvest and the grain yield of soybean, which showed that effective weed control is necessary for obtaining higher yields of soybean.


2017 ◽  
Vol 155 (9) ◽  
pp. 1394-1406 ◽  
Author(s):  
X. M. MAO ◽  
W. W. ZHONG ◽  
X. Y. WANG ◽  
X. B. ZHOU

SUMMARYThe production of winter wheat (Triticum aestivum L.) is affected by crop population structures and field microclimates. This 3-year study assessed the effect of different precision planting patterns and irrigation conditions on relative humidity (RH), air and soil temperature within the canopy, intercepted photosynthetically active radiation (iPAR), evapotranspiration (ET), water productivity (WP) and grain yields. Field experiments were conducted from 2011 to 2014 on a two-factor split-plot design with three replicates. The experiments involved three precision planting patterns (single row, alternating single and twin rows [hereafter ‘single–twin’] and twin row) and three irrigation treatments (0 mm (I0), 90 mm (I90) and 180 mm (I180)). Planting patterns and irrigation treatments exerted a significant effect on RH, air and soil temperature, iPAR, ET, WP and grain yield. The lowest RH and iPAR levels were detected in the single row pattern. When the irrigation treatment was identical, the highest soil and air temperatures were detected in the single row pattern, followed by the single–twin row and twin row patterns. Compared with the single row, the single–twin and twin row patterns increased ET by 0·3 and 1·4, WP by 4·7 and 5·7% and yields by 6·0 and 7·9%, respectively. Compared with I0, the I90 and I180 irrigation treatments increased ET by 0·3 and 1·4%, and WP by 4·7 and 5·7%, respectively. The grain yields of the twin row pattern were 5·8 and 1·7% higher than those of the single row and single–twin row patterns, respectively. Compared with I0, I90 increased yield by 19·3%. The twin row pattern improved crop structure and farmland microclimate by increasing RH and iPAR, and reducing soil and air temperatures, thus increasing grain yield. These results indicated that a twin row pattern effectively improved grain yield at I0. On the basis of iPAR, WP and grain yield, it was concluded that a twin row pattern combined with an I90 irrigation treatment provided optimal cropping conditions for the North China plain.


2014 ◽  
Vol 6 (4) ◽  
pp. 188 ◽  
Author(s):  
Joseph Adigun ◽  
A. O. Osipitan ◽  
Segun Toyosi Lagoke ◽  
Raphael Olusegun Adeyemi ◽  
Stephen Olaoluwa Afolami

Weed problem appears to be the most deleterious factor causing between 25 and 60% reduction in potential yield of cowpea. Field trials were therefore conducted to study the effect of inter-row spacing and period of weed interference on growth and yield of cowpea (Vigna unguiculata (L) Walp) at the Teaching and Research Farm of the Federal University of Agriculture, Abeokuta (07° 15'; 03° 25' E) in South Western Nigeria during the early and late wet seasons of 2009. The experiment consisted of eight main plots of weed interference which included initial weed removal for 3, 6, 9, and 12 weeks after sowing (WAS) and subsequently weed –infested until harvest as well as initial weed infestation for corresponding periods and thereafter kept weed free until harvest. There were also sub-plot treatments of three inter-row spacing of 60, 75, and 90 cm. All treatments in different combinations were laid out in a split-plot design with three replications. In both trials, the use of inter-row spacing of 60 cm resulted in significant reduction in weed growth as evident in lower weed dry matter production and subsequent higher cowpea pod and grain yields than those of 75 and 90 cm inter-row spacing. Initial weed infestation of up to 3 WAS did not have any adverse effect on crop growth and cowpea grain yields provided the weeds were subsequently removed. On the other hand, cowpea grain yield loss was not significantly averted by keeping the crop weed free for only 3 WAS without subsequent weed removal. In this study, initial weed-infestation for 6 WAS and beyond significantly depressed various crop growth parameter and cowpea grain yield compared with the crop kept weed free throughout its life cycle. In order to obtain optimum yields similar to that of the weed free cowpea field, it was required to keep the crop weed free for 6 WAS and beyond. However, frequent weeding beyond 9 weeks after sowing did not improve cowpea yield significantly and as a matter of fact it may even result in reduction of cowpea grain yield due to mechanical damage of hoe weeding. The practical implication of this finding is that early weeding starting from 3 WAS is very crucial for cowpea production while the critical period of weed removal for optimum yield in cowpea is between 3 and 9 WAS in the forest-savannah transitional zone of south Western Nigeria.


2016 ◽  
Vol 8 (1) ◽  
pp. 59
Author(s):  
Valentín A. Esqueda ◽  
Arturo Durán ◽  
Ernesto López

Three experiments were carried out in the central area of the state of Veracruz, Mexico, during the Fall-Winter seasons of 1989-90, 1991-92 and 1992-93. The main objective was to determine the effect of the time and type of weeding on the yield of residual moisture growing beans. Twelve treatments, arranged in a CRBD with four replications were evaluated. Treatments consisted in hoeing at different times. In some treatments, hoeing was complemented with hand-weeding. The highest grain yields were obtained when the weeds were eliminated at least in two ocations during the early stages of development of the crop. The yield of these treatments was significantly higher than that obtained with the traditional weeding practice (hoeing at 25 days after emergence).Handweeding after hoeing increased grain yields at high weed densities,but when the weed density was not very high, handweeding after hoeing made no difference. The increase in grain yield obtained when two weeding operations were performed instead of one, was sufficient to cover for the expenses of this additional practice and to generate economic profits.


1996 ◽  
Vol 21 (1) ◽  
pp. 339-339
Author(s):  
P. R. Heller ◽  
R. Walker

Abstract The turfgrass area consisted primarily of annual bluegrass (40%), Kentucky bluegrass (40%), and perennial ryegrass (20%). Treatment plots were 9 X 6 ft, arranged in a RCB design and replicated 3 times. Granular formulations were applied with a hand-held shaker and mixed with a fine grade top-dressing sand to facilitate product distribution. At treatment time (22 Aug) the following soil and environmental conditions existed: air temperature, 74°F; soil temperature at 1 inch depth, 82°F; soil temperature at 2 inch, 80°F; RH, 54%; amount of thatch, 0.375-0.5 inches; soil textural class, loamy sand to sandy loam; soil particle size analysis: 74.8% sand, 20.5% silt, 4.7% clay; organic matter, 23.8%; soil moisture (oven dry weight), 40.2; water pH, 7; soil pH, 6.2; application time, mid-morning; and clear skies. Immediately after treatment the experimental area was irrigated with 0.3 inch of water. Posttreatment counts were completed on 3 Oct. Three ft2 sod samples were taken from each replicate, and the total number of viable Japanese beetle grubs/ft2 was recorded.


1991 ◽  
Vol 31 (3) ◽  
pp. 357 ◽  
Author(s):  
RJ Jarvis ◽  
MDA Bolland

Five field experiments with lupins (Lupinus angustifolius) measured the effectiveness, for production, of 4 superphosphate placements either: (i) drilled with the seed to a depth of 4 or 5 cm; (ii) applied to the soil surface (topdressed) before sowing; or (iii) banded 2.5-5 cm and 7.5-8 cm below the seed while sowing. Levels of applied phosphate (P) from 0 to 36 kg P/ha were tested. In all experiments lupin grain yield responded to the highest level of superphosphate applied. At this P level, the average grain yield from all trials was 1.16 t/ha for the deepest banded treatment. This was 0.38 t/ha (49%) better than P drilled with the seed, and 0.62 t/ha (115%) better than P topdressed. Relative to superphosphate drilled with the seed and regardless of the lupin cultivar or the phosphate status of the soil, the effectiveness of superphosphate was increased by 10-90% by banding below the seed, and decreased by 30-60% by topdressing. Increasing the levels of superphosphate drilled with the seed generally reduced the density of seedlings and reduced early vegetative growth, probably due to salt or P toxicity. However, during the growing season, the plants treated with high levels of superphosphate recovered, so that eventually yields of dried tops and grain responded to increasing superphosphate drilled with the seed. In each experiment there was a common relationship between yield and P content in lupin tissue, regardless of how the superphosphate was applied, suggesting that lupins responded solely to P, and other factors did not alter yield. We recommend that farmers band superphosphate 5-8 cm below the seed while sowing, rather than continue the present practices of either drilling the fertiliser with the seed, or topdressing it before sowing.


2006 ◽  
Vol 46 (8) ◽  
pp. 1005 ◽  
Author(s):  
S. M. Robertson

The GrassGro decision support tool was designed to quantify sheep and pasture production in response to management and climate variability in temperate Australia, and has been tested in temperate but not low-rainfall Australian conditions. Data from field experiments and from on-farm monitoring was used to test GrassGro predictions of annual and perennial pasture production, and sheep production at 4 locations throughout the Victorian Mallee, which is a low-rainfall area (275–375 mm annually). Predictions of long-term pasture production were then made. Predictions of the herbage biomass of annual pastures closely matched observed data for both a sandy loam (1991–2002 data) and a whole paddock (combining sandy loam and loam and sand) (2001–2002 data) soil type, at several locations across the Victorian Mallee. Linear regression between observed and simulated (April to September) data produced coefficients, significance and root mean square error of r2 = 0.81, P<0.001, 217 kg DM/ha, respectively, for sandy loam soil types and r2 = 0.94, P<0.001, 72 kg DM/ha, respectively, for whole paddock soil types. A series of simulations for individual years from 1970 to 2002 quantified the large impact of climate variability and demonstrated that seedbank and location, but not soil fertility, had a large influence on annual pasture production. However, GrassGro underestimated the production of the perennial pasture, lucerne (r2 = 0.2). GrassGro was also unable to adequately predict sheep production because it failed to take into account the sparse, clumpy structure of the low biomass pastures typical of this region. Methods to improve GrassGro were identified and included: (i) the need to adjust sheep intake from low biomass, sparse pastures, (ii) the ability to predict summer growing and autumn growing plant species, (iii) the ability to graze crop stubbles and (iv) refinements to the coefficients of equations used to model lucerne growth.


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