scholarly journals Transplanting as a means to enhance crop security of fodder beet

2016 ◽  
Author(s):  
EN Khaembah ◽  
WR Nelson
Keyword(s):  
Canopy Cover ◽  
Significant Loss ◽  
Plant Population ◽  
Weed Competition ◽  
Crop Failure ◽  
Plant Populations ◽  
Fodder Beet ◽  
Crop Establishment ◽  
Target Plant ◽  
Early Establishment

AbstractFodder beet has become a popular winter feed for all stock classes in New Zealand. However, poor crop establishment frequently leads to either significant loss in yield, through below-target plant populations, weed competition, or crop failure. This study demonstrates that establishing the crop from transplants, common in the vegetable industry, is one way to achieve a uniform plant population and reduce weed competition through early establishment of canopy cover. The most significant effect of transplant establishment is that the target plant population is readily achieved.

Optimising maize plant population and irrigation strategies on the Darling Downs using the APSIM crop simulation model

2008 ◽  
Vol 48 (3) ◽  
pp. 313 ◽  
Author(s):  
A. S. Peake ◽  
M. J. Robertson ◽  
R. J. Bidstrup
Keyword(s):  
Simulation Model ◽  
Plant Population ◽  
Soil Types ◽  
Crop Failure ◽  
Higher Plant ◽  
Plant Populations ◽  
Crop Simulation ◽  
Gross Margins ◽  
Irrigation Volume

Optimum plant population and irrigation strategies for maize grown in the Dalby district of the Darling Downs in Queensland, Australia, were investigated using the APSIM crop simulation model. After testing the model against three seasons of experimental data, simulation experiments using different irrigation strategies were conducted across a range of plant populations ranging from 20 000 to 80 000 plants/ha, on two soil types with plant available water capacities (PAWC) of 146 mm and 220 mm. All soil type × plant population × irrigation strategy scenarios were simulated using the historical climate record for Dalby from 1889 to 2004, in order to obtain long-term average yield and gross margins (LGM) for each scenario. Soil water was reset to two-thirds of PAWC at sowing in each year. Plant populations required to achieve maximum LGMs ranged from 50 000 to 80 000 plants/ha across the range of scenarios, and were higher than currently recommended by district agronomists for partially irrigated maize. The use of higher plant populations increased season-to-season variability in grain yield and gross margins and may not be a suitable strategy for growers who do not want to increase their risk of crop failure. Partially irrigated maize achieved substantially higher gross margins in years where a positive Southern Oscillation Index phase was recorded in August, and the use of higher plant populations in such years also increased long-term profitability, but also increased the risk of crop failure. Economic gains were achieved by varying the timing and amount of irrigation within a limited available irrigation volume, with a single 100 mm irrigation giving greater LGMs than two 50 mm irrigation events on both soil types, when the irrigation events were scheduled to fill a soil water deficit equal to the effective irrigation volume. However, under full irrigation the use of smaller irrigation volumes increased LGMs on the 146 mm PAWC soil, demonstrating the importance of timely irrigation scheduling on low PAWC soils.

Effects of Plant Population on Sole-crop Cassava in Sierra Leone

1978 ◽  
Vol 14 (3) ◽  
pp. 239-244 ◽  
Author(s):  
W. Godfrey-Sam-Aggrey
Keyword(s):  
Sierra Leone ◽  
Yield Components ◽  
Dry Matter ◽  
Weight Ratio ◽  
Land Plant ◽  
Plant Population ◽  
Root Weight ◽  
Plant Populations ◽  
Sole Crop ◽  
Yield And Yield Components

SUMMARYEffects of plant population on mean yield and yield components of 2-year sole cassava crops were studied on Njala upland soils of Sierra Leone in two experiments. Increasing plant population of multi-shoot Cocoa cassava over 7000/ha decreased all the parameters studied except top/root weight ratio, which increased. The observed effects were attributed to competition for environmental resources, since area of land/plant unit decreased as plant population increased. The relations between plant populations and yields of fresh root and cortex dry matter were asymptotic, indicating that the respective yields were products of the vegetative phase of cropping.

scholarly journals Plant population and soil origin effects on rhizosphere nematode community composition of a range-expanding plant species and a native congener

Oecologia ◽  
2020 ◽  
Vol 194 (1-2) ◽  
pp. 237-250
Author(s):  
Rutger A. Wilschut ◽  
Kim J. H. Magnée ◽  
S. Geisen ◽  
W. H. van der Putten ◽  
O. Kostenko
Keyword(s):  
Plant Species ◽  
Plant Population ◽  
Enemy Release ◽  
Native Range ◽  
Centaurea Stoebe ◽  
Plant Populations ◽  
Range Theory ◽  
Dispersal Abilities ◽  
Population Effects ◽  
Root Feeding

Abstract Climate change causes species range expansions to higher latitudes and altitudes. It is expected that, due to differences in dispersal abilities between plants and soil biota, range-expanding plant species will become associated with a partly new belowground community in their expanded range. Theory on biological invasions predicts that outside their native range, range-expanding plant species may be released from specialist natural enemies, leading to the evolution of enhanced defence against generalist enemies. Here we tested the hypothesis that expanded range populations of the range-expanding plant species Centaurea stoebe accumulate fewer root-feeding nematodes than populations from the original range. Moreover, we examined whether Centaurea stoebe accumulates fewer root-feeding nematodes in expanded range soil than in original range soil. We grew plants from three expanded range and three original range populations of C. stoebe in soil from the original and from the new range. We compared nematode communities of C. stoebe with those of C. jacea, a congeneric species native to both ranges. Our results show that expanded range populations of C. stoebe did not accumulate fewer root-feeding nematodes than populations from the original range, but that C. stoebe, unlike C. jacea, accumulated fewest root-feeding nematodes in expanded range soil. Moreover, when we examined other nematode feeding groups, we found intra-specific plant population effects on all these groups. We conclude that range-expanding plant populations from the expanded range were not better defended against root-feeding nematodes than populations from the original range, but that C. stoebe might experience partial belowground enemy release.

The influence of inter-row spacing and plant population on the yield of peanuts at Katherine, N.T

1962 ◽  
Vol 2 (4) ◽  
pp. 54 ◽  
Author(s):  
LJ Phillips ◽  
MJT Norman
Keyword(s):  
Plant Population ◽  
Row Spacing ◽  
Clay Loam ◽  
Plant Populations ◽  
Kernel Yield ◽  
Multifactorial Experiment

In 1957-58 and 1958-59, Virginia Bunch and Natal Common peanuts were sown on Tippers clay loam at Katherine, N.T., in a multifactorial experiment at two inter-row spacings (2 ft and 3 ft), four plant populations (10, 20, 40 and 80 thousand per acre) and two dates. In 1960-61, Natal Common only was sown at the same inter-row spacings, at two dates, and at populations of 10, 20, 30 and 40 thousand per acre. Over two seasons, the yield of Virginia Bunch kernels was not significantly influenced by variation in population, though the yield of hay was 42 per cent higher at 80,000 plants per acre than at 10,000 plants per acre. Kernel yields from 2 f t rows were 14 per cent higher than from 3 f t rows. In the first two seasons, the yield of Natal Common kernels was lower at 80,000 plants per acre than at 40,000 plants per acre. Over three seasons, maximum kernel and h g yields were achieved at 40,000 plants per acre ; the kernel yield at this population was 35 per cent greater than at 10,000 plants per acre. With early-planted Natal Common, 2.ft rows gave an 11 per cent higher yield of kernels than 3 f t rows, but with later planting there was no significant effect of inter-row spacing. The optimum economic seeding rates were estimated approximately as 30 lb an acre for Virginia Bunch and 45 lb an acre for Natal Common.

Effects of Sheep Grazing Astrebla Grasslands in Central Western Queensland. Iii. Dynamics of Astrebla Spp. Under Grazing and Exclosure Between 1975 and 1986.

1991 ◽  
Vol 13 (1) ◽  
pp. 36 ◽  
Author(s):  
DM Orr ◽  
CJ Evenson
Keyword(s):  
Population Dynamics ◽  
Seed Production ◽  
Basal Area ◽  
Summer Rainfall ◽  
High Variability ◽  
Plant Population ◽  
Sheep Grazing ◽  
Plant Population Dynamics ◽  
Winter Rainfall ◽  
Plant Populations

The basal area, yield and plant populations of Astrebla spp. were monitored under grazing and exclosure in Astrebla grasslands between 1975 and 1986. This study was undertaken to develop an understanding of how Astrebla spp. respond to grazing, particularly in relation to the high variability of rainfall. Basal area and yield of Astrebla spp. varied widely between years in response to summer rainfall, with few differences between exclosure and grazing. The failure of summer rainfall resulted in increased utilization of Astrebla spp. but this effect was partially offset in some years by the growth of forb species following winter rainfall. Grazing stimulated the recruitment of Astrebla spp. seedlings by increasing the density of inflorescences which, in turn, increased seed production. Survival of seedling cohorts depended on adequate summer rainfall and grazing tended to enhance cohort survival. There was a greater plant flux under grazing than under exclosure. It was concluded that rainfall is the major factor influencing the biomass and plant population dynamics of Astrebla spp. and that grazing up to about 30% utilization is not detrimental to Astrebla spp.

scholarly journals Plant Population Affects Yield and Fruit Size of Pumpkin

HortScience ◽  
1999 ◽  
Vol 34 (6) ◽  
pp. 1076-1078 ◽  
Author(s):  
Stephen Reiners ◽  
Dale I.M. Riggs
Keyword(s):  
Growth Habit ◽  
Plant Competition ◽  
Fruit Size ◽  
Field Studies ◽  
Plant Population ◽  
Lower Yield ◽  
Marketable Yield ◽  
Plant Populations ◽  
Fruit Number ◽  
Row Width

Field studies were conducted in 1996 on two pumpkin (Cucurbita pepo L.) cultivars, `Howden' (vining-type growth habit) and `Wizard' (semi-bush growth habit), at two locations to determine the effect of plant population and row width on marketable yield. Increasing plant populations from 2990 to 8960 plants per hectare resulted in significantly greater fruit number and yield at both locations and for both varieties. Average fruit size declined at the highest populations. Increasing row width from 1.8 to 3.6 m resulted in a slight but significant decrease in number of fruit per hectare with no effect on other yield parameters. At one location, the effect of row width on yield and number of fruit per hectare depended on the population. At low populations, row width did not influence yield or fruit number; at high populations, wide rows produced lower yield and fewer fruit than narrow rows. The results demonstrate that growers may increase pumpkin yield by increasing plant populations but should use narrower row widths and wider in-row spacing. Growers who choose higher populations should ensure that all inputs are optimized to reduce potential plant-to-plant competition and use regionally adapted cultivars.

Do wheat breeders have suitable genetic variation to overcome short coleoptiles and poor establishment in the warmer soils of future climates?

2016 ◽  
Vol 43 (10) ◽  
pp. 961 ◽  
Author(s):  
Greg J. Rebetzke ◽  
Bangyou Zheng ◽  
Scott C. Chapman
Keyword(s):  
Soil Temperature ◽  
Crop Yields ◽  
Triticum Aestivum L ◽  
Wheat Breeding ◽  
Crop Failure ◽  
Coleoptile Length ◽  
Crop Establishment ◽  
Air Temperatures ◽  
Reduced Height ◽  
Soil Temperatures

Increases in air and soil temperatures will impact cereal growth and reduce crop yields. Little is known about how increasing temperatures will impact seedling growth and crop establishment. Climate forecast models predict that by 2060, mean and maximum air temperatures in the Australian wheatbelt will increase by 2−4°C during the March–June sowing period, and particularly at lower latitudes. Concomitant increases in soil temperature will shorten coleoptile length to reduce crop establishment, particularly where deep sowing to access sub-surface moisture. Mean coleoptile length was reduced in commercial wheat (Triticum aestivum L.) germplasm with increasing soil temperature (106 mm and 51 mm at 15°C and 31°C, respectively). Coleoptile lengths of modern semidwarf varieties were significantly (P < 0.01) shorter than those of older tall wheats at 15°C (95 mm and 135 mm) and 31°C (46 mm and 70 mm). A 12-parent diallel indicated large additive and small non-maternal genetic effects for coleoptile length at 15°C and 27°C. Large genotype rank changes for coleoptile length across temperatures (rs = 0.37, P < 0.05) contributed to smaller entry-mean heritabilities (0.41–0.67) to reduce confidence in selection for long-coleoptile genotypes across contrasting temperatures. General combining ability effects were strongly correlated across temperatures (rp = 0.81, P < 0.01), indicating the potential of some donors in identification of progeny with consistently longer coleoptiles. Warmer soils in future will contribute to poor establishment and crop failure, particularly with deep-sown semidwarf wheat. Breeding long-coleoptile genotypes with improved performance will require targeted selection at warmer temperatures in populations incorporating novel sources of reduced height and greater coleoptile length.

Holocene palynology: I principles, population and community ecology, palaeoclimatology

1991 ◽  
Vol 15 (3) ◽  
pp. 261-289 ◽  
Author(s):  
Glen M. MacDonald ◽  
Kevin J. Edwards
Keyword(s):  
Population Biology ◽  
Plant Population ◽  
Fossil Pollen ◽  
Pollen Data ◽  
Plant Populations ◽  
Climate Reconstructions ◽  
Large Databases ◽  
Temporal And Spatial ◽  
The Relationship ◽  
Important Progress

The latter half of the past decade witnessed important progress in elucidating the principles of fossil pollen analysis and in the application of palynology to the study of palaeoecology and palaeoclimatology. Areas with particularly notable efforts include: 1) the theoretical consideration of the spatial representation of fossil pollen records and the relationships of pollen proportions to the abundance of contributing plant populations; 2) the quest for palynological data with increasingly fine temporal and spatial resolution; 3) the development of large databases of modern and fossil pollen data for macroscale palaeoecological and palaeoclimatic studies; 4) the application of palynology to questions of plant population biology, most notably the study of plant invasion and implications for invading and pre-existing plant populations; 5) the demonstration of the relatively ephemeral nature of major vegetation types; 6) the refinement and development of techniques for providing quantitative estimates of past climate and testing climate reconstructions. Despite this progress important uncertainties remain regarding the relationship between plant abundance and pollen representation and the nature of climate-vegetation relationships, particularly at the meso- and microscales. Resolution of these questions is particularly important for plant population and climatic studies based on fossil pollen data.

The influence of row spacing and plant population on the effect of weed competition in soybeans

1976 ◽  
Vol 16 (83) ◽  
pp. 926 ◽  
Author(s):  
WL Felton
Keyword(s):  
Plant Population ◽  
Grain Weight ◽  
Stem Diameter ◽  
Weed Competition ◽  
Row Spacing ◽  
Pod Yield ◽  
Cent Decrease

An experiment was done to determine the reduction in yield attributable to weed competition when soybeans were grown in 25,50,75 and 100 cm rows and within-row densities of 10, 20 and 40 plants m-1. There was no effect of weeds on yield when soybeans were grown in 25 cm rows but a 20 per cent decrease with 50 cm rows, 26 per cent with 75 cm rows and 37 per cent with 100 cm rows. Within-row density had no effect but there was a trend towards an interaction between within-row density and the presence or absence of weeds. Narrow rows and higher within-row densities increased the height of the bottom pod, lodging and the number of pods m-2 but decreased stem diameter, number of pods per plant and the yield per plant. Narrow rows decreased yield per pod and seeds per pod. There was a trend, which was not significant (P < 0.05), towards reduced yield per pod and seeds per pod with higher within-row densities. Weed competition reduced stem diameter, pods per plant, pods m-2 and yield per plant. Weeds had no effect on the height of the bottom pod, yield per pod and seeds per pod. Soybean grain weight was not changed by row spacing, row density or weed competition.

Yield-density relationships and optimum plant populations in two cultivars of solid-seeded dry bean (Phaseolus vulgaris L.) grown in Saskatchewan

2002 ◽  
Vol 82 (3) ◽  
pp. 521-529 ◽  
Author(s):  
Steven J. Shirtliffe ◽  
Adrian M. Johnston
Keyword(s):  
Seed Weight ◽  
Plant Density ◽  
Maximum Yield ◽  
Plant Population ◽  
Seeding Density ◽  
Seeding Rate ◽  
Higher Plant ◽  
Plant Populations ◽  
Dry Bean ◽  
Density Relationship

There is relatively little agronomic information on solid-seeded production of dry bean in western Canada. Recommended seeding density for dry bean can depend on the growth habit of the plant, the yield–density relationship, percent emergence, seed cost and environment. The objective of this study was to determine the yield–density relationships in two determinate bush type cultivars of dry bean and the optimum plant population under solid-seeded production in Saskatchewan. CDC Camino, a late-season pinto bean and CDC Expresso, a medium-season-length black bean were the cultivars evaluated. In most sites, the yield-density relationship of the cultivars was asymptotic and an optimum plant density for maximum yield could not be determined. Camino generally required a lower plant population to reach a given yield than Expresso. Increasing plant population did not affect 1000-seed weight. Higher seeding rate did result in a greater number of seeds produced m-2, with Expresso having a greater increase in seed produced m-2 compared with Camino. Expresso was required to be at higher plant densities than Camino to maximize economic returns. This reflects the differences between cultivars in yield-density relationship and seed cost, as Camino has a heavier 1000-seed weight than Expresso. Saskatchewan bean growers wishing to maximize profit should target plant populations for Expresso and Camino of approximately 50 and 25 plants m-2, respectively. Key words: Saskatchewan, yield components, non-linear regression, seeding rate, narrow rows, solid-seeded

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