The effects of soil type and seasonal rainfall on the optimum seed rate for wheat in Western Australia

2004 ◽  
Vol 44 (6) ◽  
pp. 585 ◽  
Author(s):  
R. Del Cima ◽  
M. F. D'Antuono ◽  
W. K. Anderson

Seventeen experiments were conducted in 1996, 1997 and 1998 in the central and northern wheatbelt of Western Australia, covering a range of soil types, seasonal rainfall, cultivars and sowing times. The objective of the experiments was to investigate how these factors affect the range of optimum seed rates derived from seeding rate experiments and, thus, to improve advice to farmers. Our results suggest that soil type and seasonal rainfall were the major factors influencing the differences in optimum seed rate. Regression tree methods were used to show that experiments in clay loam soils had higher optimum seed rates (52–76 kg/ha, depending on the cultivars used). In sandier soils, the optimum seed rate was lower (35–60 kg/ha, depending on cultivar and sowing time) but higher (67�kg/ha) at higher seasonal rainfall (>450 mm). We found some cultivars were grouped into consistent response patterns. Sowing time also influenced optimum seed rate; later sowing required higher seed rates, to maximise grain yield. A positive correlation was not observed between grain yield and optimum seed rate, possibly due to the narrow range of yields recorded in the experiments. Our data showed that the percentage of establishment fell off rapidly at higher seed rates. This implies that lower establishment percentages should be used when calculating the seed rates required to produce high plant populations in the field.

2008 ◽  
Vol 59 (10) ◽  
pp. 958 ◽  
Author(s):  
D. L. Sharma ◽  
M. F. D'Antuono ◽  
W. K. Anderson ◽  
B. J. Shackley ◽  
C. M. Zaicou-Kunesch ◽  
...  

Sowing wheat (Triticum aestivum L.) at the right time is one of the most important means of maximising grain yield in dryland agriculture. Objectives of this study were to understand the variation in estimates of optimum sowing time as influenced by cultivar and environmental characteristics, and to assess the relative importance of location, season, sowing time, and cultivar factors in maximising grain yield in Western Australia. Twenty-seven cultivar × time of sowing experiments were conducted over three seasons (2003–05) at a range of locations (annual rainfall 300–450 mm, lat. 28–35°S). There were four types of cultivar × sowing time responses, namely, quadratic, linear declining, flat, and linear increasing, associated with opening rains before mid-May, opening rains after mid-May, low-yielding sites, and good spring rains, respectively. Regression-tree analysis revealed that differences among cultivars in Tmax (sowing time when maximum grain yield was achieved) were much less in the eastern sites (mostly drier seasons). A biplot differentiated cultivars for Tmax across the range of environments used, while the subset regression analysis specifically indicated an association of average temperature and growing-season rainfall with variation for Tmax of individual cultivars. The yield penalty for sowing before the optimum time in quadratic-type responses was clearly greater for shorter season cultivars but no clear relationship was apparent between maturity class of cultivars and the penalty for late sowing, possibly due to differential plasticity of cultivars for grain weight under harsh finishing conditions. The duration of the optimum sowing window at a given location was inversely proportional to the yield potential, implying that it is critical to sow at or close to the optimum time when the yield potential is high, most common when the season breaks early. Yield component analysis showed that the relative change in grain yield over sowing dates was significantly correlated with relative changes in grain numbers/m2 in the late May sowings but other yield components were also important in the early May experiments. Sowing time accounted for 10% of grain yield variation compared with cultivar (1%), while the rest was due to uncontrollable factors of location and season.


1997 ◽  
Vol 37 (2) ◽  
pp. 173 ◽  
Author(s):  
W. K. Anderson ◽  
D. Sawkins

Summary. The aim of our experiments was to determine whether the soft-grained, club-head wheats used for the Australian Soft grade (cvv. Tincurrin and Corrigin), required different management to maximise grain yield and quality than the standard-head wheats used for other grades. Two series of field experiments were conducted in the 300–500 mm rainfall zone in the southern wheatbelt of Western Australia between latitudes 32 and 34°S from 1989 to 1993. Agronomic variables examined in the experiments included sowing time, nitrogen (N) fertiliser and seed rate. Grain yield, grain protein concentration, hectolitre weight and small grain sievings (below a 2 mm slotted screen) were measured on the grain samples. It was concluded that the optimum time for sowing the soft wheats, both of which are of mid-season maturity, was May. Small grain sievings and grain proteins of the soft wheats exceeded the receival standards for the grade when sown outside this period and were more sensitive to earlier or later sowings in this regard than the other wheats. The soft wheats had smaller kernels and were more likely than other cultivars to produce grain samples with high levels of sievings associated with sowing at inappropriate times and the use of N fertiliser. They had consistently 1–1.5% lower grain protein concentrations than the other cultivars used in the experiments. Hectolitre weights seldom fell below the receival standard of 74 kg/hL for any of the grain samples. Increasing seed rate did not increase the level of sievings at all sites. Although sievings were affected by sowing time, N fertiliser and cultivar, there were large influences associated with site factors that also caused excessive sievings. Fertile sites where the crop did not respond to N fertiliser and sites where the crop was infected by leaf rust were associated with high levels of sievings. Standard-head wheats were less susceptible to dockages, but lower yielding than the club-head, soft wheats. Seed rates for the soft wheats should be chosen to maximise yield rather than to attempt to avoid price dockages at receival.


1993 ◽  
Vol 33 (6) ◽  
pp. 751 ◽  
Author(s):  
DR Coventry ◽  
TG Reeves ◽  
HD Brooke ◽  
DK Cann

A 3-year study was conducted to measure the effect of sowing time and seeding rate on the development and yield of wheat (Triticum aestivum L.) grown under high-yielding conditions in north-eastern Victoria. A range of wheat cultivars with different development responses, including 'winter' types, was used in 2 experiments in each season. High grain yields for dryland wheat were measured in the first 2 seasons (1985-86), and in 1985, near-optimal water use efficiencies (>18 kg/ha. mm effective rainfall) were obtained. In the third season (1987) grain yield was limited by adverse climatic conditions-in the me- and post-anthesis period. In each season, grain yield declined with delay in sowing time. In 1985 there was a loss of 200-250 kg grain/ha for each week's delay in sowing time. In 1987, yield loss with delayed sowing was 50-110 kg grain/ha. In each season, cultivars with late or midseason maturity development gave the highest mean yields, and the use of these maturity types allowed earlier sowing, in mid April. However, with late sowing of wheat there was a trend for early maturity types to give higher yields, and so the use of 2 wheat cultivars with distinct maturity development responses to climate is recommended. If only 1 wheat cultivar is to be used, then a late maturity type is recommended. Higher wheat yields were also obtained as spike density increased, as a result of higher seeding rates. Our data suggest that in the higher rainfall region of north-eastern Victoria, a spike density of about 500 spikes/m2 is required to optimise wheat yields.


2018 ◽  
Vol 15 (2) ◽  
pp. 81-91
Author(s):  
MR Gondal ◽  
A Hussain ◽  
S Yasin ◽  
M Musa ◽  
HS Rehman

An experiment to investigate the effect of seed rate (5, 7.5, 10, 12.5 and 15 kg ha-1) and row spacing (30, 45 and 60cm) on agronomic characteristics of plants including stem densitym-2, plant height, stem diameter, number of heads m-2, number of heads per plant, number of grains per head, 1000-grain weight and grain yield was conducted using the cultivar “Sorghum 2011” for two years 2016 and 2017. Seed rates and row spacing had significant effect on plant height, plant density m-2, number of heads m-2, number of grains per head and grain yield. Row spacing had non-significant effect on stem diameter, number of heads per plant and 1000-grain weight. Row spacing at 30 cm produced the highest number of plants m-2 and plant height. Plant height increased with increase in seed rate in all the row spacing. Stem diameter decreased with increase in the seed rate and row spacing. Narrow row spacing (30 cm) and low seeding rate (5 kg ha-1) produced the maximum grain yield consistently during both years. Lower yields were recorded in the treatments having greater row spacing (60 cm) and higher seed rates (7.5, 10, 12.5 & 15 kg ha-1). Higher seed rates and wider row spacing induced morphological changes rendering plants to lodging.SAARC J. Agri., 15(2): 81-91 (2017)


2020 ◽  
Vol 15 (2) ◽  
pp. 53-58
Author(s):  
Irina Fadeeva ◽  
Marsel Tagirov ◽  
Ilyas Gazizov ◽  
Fail' Kurmakaev

In 2018-2019 in the Republic of Tatarstan the studies were carried out to study the effect of sowing dates and seeding rates on productuvuty of new varieties of winter wheat to identify the optimal elements of cultivation technology. The experiment scheme provided for the study of the following options: variety (factor A) - Darina, Universiada, Sultan; sowing time (factor B) - September 1 ... 2 (first, optimal), September 15 ... 17 (second); seeding rate (factor C) - 5.0; 5.5; 6.0; 6.5 million viable seeds per hectare. The predecessor is pure steam. Plot area 25 m2. The formation of the grain yield was mainly influenced by the sowing period (28.6%), the choice of the variety (21.2%) and the interaction of the three factors studied (15.8%). Universiada variety formed a yield of 4.91 t/ha during the first sowing period with a pure fallow and a seeding rate of 5.5 million pcs/ha. Sowing after September 15 resulted in a 33.78% decrease in the productivity of this variety. Darina variety formed the highest stand density among all the studied genotypes, both at the first (551.5 pieces/m2) and at the second (476.0 pieces/ m2) sowing dates. The highest grain yield of this variety was noted with the optimal (first) sowing period for pure fallow and the seeding rate of 6.0 million pcs/ha - 4.70 t/ha. A shift in sowing to a later date reduced its yield by 26.48%. Sultan variety formed the highest grain yield when sowing on September 1 ... 2 on a clean fallow with a seeding rate of 6.0 million pcs/ha. With a delay in sowing, like other varieties, the value of this indicator decreased by 24.65%. The analysis of correlations showed the dependence of the yield at the optimal sowing time in a medium degree on the grain size (r = 0.66), with a late one - on the number of productive stems for harvesting (r = 0.56). Key words: winter wheat (Triticum aestivum L.), variety, productivity, yield, grain weight, correlation


2004 ◽  
Vol 55 (9) ◽  
pp. 921 ◽  
Author(s):  
W. K. Anderson ◽  
D. L. Sharma ◽  
B. J. Shackley ◽  
M. F. D'Antuono

In this paper we analyse existing experimental data (grain yield and yield components) from seed rate experiments on wheat in Western Australia, with the aims of determining which factors most influence the optimum plant population, and advancing some practical guidelines for improving the choice of seed rate under rain-fed conditions. Experiments (32) were conducted in the rain-fed cropping zone of Western Australia between 1996 and 2001, using factorial combinations of wheat cultivars (3–25) and target plant populations (4 or 5). Some of them also contained treatments of nitrogen fertiliser (0 or 40 kg/ha of N) or sowing times (2). Each cultivar × plant population dataset (248) was considered to be a record for the sake of the subsequent analyses. Actual plant numbers were counted in each experiment and the optimum plant population was estimated when the slope of an inverse polynomial curve (choosing the most appropriate of the LDL and QDL models in GenStat) fitted to each record was 2.5 kg/ha of grain yield for each extra plant/m2. The optimum populations were initially grouped using a regression tree technique into groups with similar characteristics using pre-sowing rainfall, rainfall in the growing season, sowing date, and soil type. The variables cultivar and nitrogen fertiliser rate were later added to the regression tree analysis. Yield components available for most experiments were used as an aid to interpretation of the results. The optimum plant population varied from 35 to 175 plants/m2 and average grain yields varied from 0.42 to 3.91 t/ha. Rainfall in the growing season (sowing date to harvest date) provided the first split in the regression tree, but pre-sowing rainfall (January to sowing date), sowing date, and soil type further modified the optimum population. The addition of N fertiliser rate as a variable in the regression tree did not induce any different groupings of the optimum population sets, but cultivars were grouped into 4 response types according to pre- and post-sowing rainfall amounts. Where rainfall in the growing season was <205 mm, improved growing conditions due to more pre-sowing rainfall, earlier sowing, and more seasonal rainfall, were associated with higher optimum plant populations. Where rainfall in the growing season exceeded 205 mm, higher pre-sowing rainfall was associated with lower optimum populations. The optimum population was greater on sands than on clay loams. However, on sandy loam soils the optimum was less where rainfall in the growing season was <291 mm, or more for crops sown after 27 May at rainfall >291 mm. Increases in yield components in response to improved growing conditions above about 400 culms/m2, 300 ears/m2, 10 000 kernels/m2, and 600 g/m2 of dry matter at anthesis were not associated with higher optimum plant populations. In general, the optimum plant population increased at about 40 plants/m2 for each tonne of grain yield up to about 3.0 t/ha. The effect of cultivar on the optimum population appeared at yield levels above 2.5 t/ha, but was only detectable when the rainfall in the growing season exceeded 205 mm. Growing conditions and cultivars associated with lower weight per ear (due to fewer kernels and/or lower kernel weight) were associated with higher optimum plant population when the rainfall in the growing season exceeded 205 mm. It is suggested that farmers can make better estimates of the appropriate plant population (and hence can calculate seed rate) on the basis of pre-sowing rainfall (likely stored water), rainfall zone (probability of rainfall in the growing season), sowing date, soil type, and characteristics of individual cultivars where known.


Weed Science ◽  
2020 ◽  
pp. 1-10
Author(s):  
Muhammad Javaid Akhter ◽  
Per Kudsk ◽  
Solvejg Kopp Mathiassen ◽  
Bo Melander

Abstract Field experiments were conducted in the growing seasons of 2017 to 2018 and 2018 to 2019 to evaluate the competitive effects of rattail fescue [Vulpia myuros (L.) C.C. Gmel.] in winter wheat (Triticum aestivum L.) and to assess whether delayed crop sowing and increased crop density influence the emergence, competitiveness, and fecundity of V. myuros. Cumulative emergence showed the potential of V. myuros to emerge rapidly and under a wide range of climatic conditions with no effect of crop density and variable effects of sowing time between the two experiments. Grain yield and yield components were negatively affected by increasing V. myuros density. The relationship between grain yield and V. myuros density was not influenced by sowing time or by crop density, but crop–weed competition was strongly influenced by growing conditions. Due to very different weather conditions, grain yield reductions were lower in the growing season of 2017 to 2018 than in 2018 to 2019, with maximum grain yield losses of 22% and 50% in the two growing seasons, respectively. The yield components, number of crop ears per square meter, and 1,000-kernel weight were affected almost equally, reflecting that V. myuros’s competition with winter wheat occurred both early and late in the growing season. Seed production of V. myuros was suppressed by delaying sowing and increasing crop density. The impacts of delayed sowing and increasing crop density on seed production of V. myuros highlight the potential of these cultural weed control tactics in the long-term management programs of this species.


2009 ◽  
Vol 89 (4) ◽  
pp. 763-773 ◽  
Author(s):  
W E May ◽  
S J Shirtliffe ◽  
D W McAndrew ◽  
C B Holzapfel ◽  
G P Lafond

Traditionally, farmers have delayed seeding to manage wild oat (Avena fatua L.) in tame oat (Avena sativa L.) crops, but this practice can adversely affect grain yield and quality. The objectives of this study were: (1) to evaluate the effectiveness of using high seeding rates with early-seeded oat to maintain grain yield and quality, and (2) to determine an optimum seeding rate to manage wild oat and maximize grain yield and quality. The factors of interest were wild oat density (low and high density), seeding date (early May, mid May, early June and mid June), and tame oat seeding rate (150, 250, 350 and 450 viable seeds m-2). The study was conducted at Indian Head and Saskatoon, SK, in 2002, 2003 and 2004, at Winnipeg, MB, in 2002, and at Morden, MB, in 2003 and 2004. Wild oat biomass, wild oat panicle density and wild oat seed in the harvested sample decreased as seeding rate increased, while tame oat biomass and grain yield increased. Wild oat density ranged between 0 and 100 plants m-2 with averages of 10 plants m-2 in the low density treatment and 27 plants m-2 in the high density treatment. At low seeding rates, grain yield decreased with increasing wild oat density. The difference in grain yield between the two wild oat densities decreased as the seeding rate increased. There was a curvilinear decrease in grain yield as seeding was delayed. A seeding date × seeding rate interaction was noted for test weight, plump seed, thin seed and groat yield. Seed quality improved as seeding rate increased for only the mid-June seeding date. Even though the mid-June test weight increased as the seeding rate increased it was always lower than the early May test weight at any seeding rate. The results from this study established that in the presence of wild oats, early seeding of tame oat is possible providing high seeding rates, 350 plants m-2 are used.Key words: Wild oat competition, wild oat density, wild oat biomass, grain yield, grain quality


2002 ◽  
Vol 42 (6) ◽  
pp. 717 ◽  
Author(s):  
R. A. Sudmeyer ◽  
P. R. Scott

This paper, which is the second in a series of three, describes dryland crop growth and yields in a windbreak bay in south-western Australia and relates changes to microclimate modification by the windbreaks. Over the 4 years of this trial, above ground biomass and the development rate of crops 3–20 times the tree height from the windbreak (H) were similar to crops growing in unsheltered conditions (more than 20 H from the windbreaks). Grain yield was 16–30% higher between 3 H and 20 H than at more than 20 H in 1994, the driest year on record for the district, in other years yield was largely unchanged. In contrast, above ground biomass growth was consistently less within 3 H than further from the windbreaks and grain yield within 3 H was 19–27% less than unsheltered yield. Water use by the trees is the most likely cause of reduced yield within 3 H. Over the 4 years, mean grain yield between 0.5 H and 20 H was 3.8% greater than yield at more than 20 H. This increase was largely due to the yield increase in 1994. As 5.4% of the paddock was directly occupied by, or uncropped next to, the windbreaks, there was a net yield decrease of 2.8% over 4 years compared to estimated production from a similar area with no windbreaks. The principle benefits of the windbreaks were reducing evaporative demand in extremely dry years and protection against extreme wind events. These benefits must be weighed against the costs of establishing and maintaining windbreak systems.


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