'Haying-off', the negative grain yield response of dryland wheat to nitrogen fertiliser. I. Biomass, grain yield, and water use

1998 ◽  
Vol 49 (7) ◽  
pp. 1067 ◽  
Author(s):  
A. F. van Herwaarden ◽  
G. D. Farquhar ◽  
J. F. Angus ◽  
R. A. Richards ◽  
G. N. Howe
Keyword(s):  
Grain Yield ◽  
Soil Water ◽  
Water Status ◽  
Kernel Weight ◽  
Yield Response ◽  
Daily Maximum ◽  
Evaporative Demand ◽  
Spike Density ◽  
High Rainfall ◽  
A Site

"Haying-off" was studied by comparing wheat responses to applied nitrogen (N) at 3 sites in southern New South Wales, which differed in the amount and timing of rainfall during crop growth. At a site where the crops encountered little water deficit, dry grain yield increased from 607 g/m2 for a low-N control crop to 798 g/m2 for a high-N crop. At a site with severe terminal drought, dry grain yield decreased 24% from 374 g/m2 for the control, to 284 g/m2 for the highest N crop. At the third site, yields increased with small applications of N, whereas greater applications resulted in a negative yield response. At the 2 latter sites, the crops that showed decreased yield with applied N had clearly hayed-off. At all sites, irrespective of water status, N application resulted in increases in biomass at anthesis, spike density, kernels per spike, and kernel number. Kernel weight decreased in response to additional N at all sites, but most markedly at the haying-off sites, where it decreased by up to 38%. Harvest index increased in response to N at the high-rainfall site, but decreased in crops that hayed-off. Grain protein increased in response to N at all sites, with a range from 9% to 18% at the haying-off sites. The apparent retranslocation of assimilates to grain contributed 37-39% of grain yield (depending on N supply) at the high-rainfall site, compared with 75-100% at the haying-off sites. In contrast, when apparent retranslocation was expressed in relation to biomass at anthesis, it remained relatively constant, amounting to 23-26% at the high-rainfall site and 24-28% when crops hayed-off. By anthesis, high-N crops extracted more soil water than the low-N crops. By maturity the most severely hayed-off crop had extracted 10 mm less soil water than a low-N crop, but at the high rainfall site the high-N crops extracted 20 mm more soil water than the control crops. The weather conditions between anthesis and physiological maturity were relatively mild, with no daily maximum temperatures above 30ºC and no sudden increases in evaporative demand. Thus, there appeared to be 3 processes leading to haying-off. Firstly, the results confirm previous studies showing that haying-off was associated with reduced post-anthesis assimilation in response to a lack of soil water. The water deffcit was due to vigorous vegetative growth stimulated by a high level of soil N and was not associated with heat shocks or sudden increases in evaporation. Secondly, the most severely hayed-off crop failed to extract soil water fully, leading to a further reduction in post-anthesis assimilation. Thirdly, there was inadequate apparent retranslocation of pre-anthesis reserves to compensate for the lack of post-anthesis assimilation.

Spring wheat (Triticum aestivum) yield and grain protein responses to N fertilizer in topographically defined landscape positions

2001 ◽  
Vol 81 (4) ◽  
pp. 505-514 ◽  
Author(s):  
F. Walley ◽  
D. Pennock ◽  
M. Solohub ◽  
G. Hnatowich
Keyword(s):  
Grain Yield ◽  
Protein Content ◽  
Soil Water ◽  
Water Status ◽  
Economic Feasibility ◽  
N Fertilizer ◽  
Yield Response ◽  
Grain Protein ◽  
Variable Rate ◽  
N Application

A 3-yr field study was initiated in 1996 to examine the different grain yield and grain protein responses of wheat to varied N fertilizer rates in a typical glacial till landscape in Saskatchewan, Canada. Our objective was to assess the agronomic and economic feasibility of variable rate fertilizer (VRF) N application for wheat. Results suggest that spring soil water status largely determined the yield and the protein content of wheat both within different years of the study and between different landscape positions within a given year. Although grain yield was strongly related to spring soil water and was predictable on that basis, the grain yield response of wheat to fertilizer N additions was highly variable due, in part, to the dual role that N played in determining both grain yield and grain protein content. As a consequence of the unpredictable nature of the varied response of wheat to N fertilizer additions, there was little economic rationale for using VRF strategies in the 3 yr of this study. However, in the long-term, we believe that VRF N application strategies can be employed to manage N inputs from the perspective of managing and replacing harvested N. Key words: Variable rate fertilizer application, precision farming, nitrogen application, N fertilizer, Saskatchewan

Post-anthesis sink size in a high-yielding dwarf wheat: yield response to grain number

1977 ◽  
Vol 28 (2) ◽  
pp. 165 ◽  
Author(s):  
RA Fischer ◽  
I Aguilar ◽  
DR Laing
Keyword(s):  
Grain Yield ◽  
Wheat Yield ◽  
Kernel Weight ◽  
Yield Response ◽  
High Fertility ◽  
Grain Number ◽  
Wide Range ◽  
Carbon Dioxide Fertilization ◽  
Sink Size ◽  
The One

Experiments to study the effect of grain number per sq metre on kernel weight and grain yield in a high-yielding dwarf spring wheat (Triticum aestivum cv. Yecora 70) were conducted in three seasons (1971–1973) under high-fertility irrigated conditions in north-western Mexico. Crop thinning, shading and carbon dioxide fertilization (reported elsewhere), and crowding treatments, all carried out at or before anthesis, led to a wide range in grain numbers (4000 to 34,000/m2). Results indicated the response of grain yield to changing sink size (grains per sq metre), with the post-anthesis environment identical for all crops each year, and with all but the thinner crops intercepting most of the post-anthesis solar radiation. Kernel weight fell linearly with increase in grain number over the whole range of grain numbers studied, but the rate of fall varied with the season. Grain yield, however, increased, reaching a maximum at grain numbers well above those of crops grown with optimal agronomic management but without manipulation. It was concluded that the grain yield in normal crops was limited by both sink and post-anthesis source. There was some doubt, however, as to the interpretation of results from crowded crops, because of likely artificial increases in crop respiration on the one hand, and on the other, in labile carbohydrate reserves in the crops at anthesis. Also deterioration in grain plumpness (hectolitre weight) complicates the simple inference that further gains in yield can come from increased grain numbers alone.

A Hydrological Study of a Subtropical Semiarid Forest of Acacia harpophylla F. Muell. Ex Benth. (Brigalow)

1981 ◽  
Vol 29 (3) ◽  
pp. 311 ◽  
Author(s):  
BR Tunstall ◽  
DJ Connor
Keyword(s):  
Soil Water ◽  
Water Status ◽  
Water Storage ◽  
Soil Water Storage ◽  
Severe Drought ◽  
Plant Water ◽  
Evaporative Demand ◽  
Water Potentials ◽  
Plant Water Potential ◽  
Stem Flow

Water input, soil water storage and plant water status were measured at monthly intervals over 2� years In a mature brigalow (Acacla harpophylla) forest. Redistribution of rainfall by the canopy was slight and stem flow averaged only 1.8%, but the direct loss of intercepted water accounted for 15% of the Annual ramfall In the wettest condltlon the soil stored 890 mm of water to a depth of 3 m The minimum sod water store measured under severe drought conditions was 840 mm when the dawn values of plant water potential were -6.8 MPa The soil water potentials below 1 m were consistently around -3.5 MPa due largely to high salt concentrations The tendency in a drying soil was towards a uniform profile of soil water potentlal, and soil water at depths below 1 m was extracted only when dawn plant water potentials were less than - 3.5 MPa Over monthly Intervals the maximum and minimum rates of evapotransplratlon were 3.3 and 0 .46 mm/d respectively, and the pattern of community water use was related to rainfall and not to potentlal evaporation. To survive in such an environment the plants develop and withstand extremely low water potentials associated wlth the low availability of water and the high evaporative demand.

Responsiveness of barley cultivars to nitrogen fertiliser

1997 ◽  
Vol 37 (2) ◽  
pp. 199 ◽  
Author(s):  
G. Fathi ◽  
G. K. McDonald ◽  
R. C. M. Lance
Keyword(s):  
Grain Size ◽  
Grain Yield ◽  
Initial Response ◽  
Kernel Weight ◽  
High Yield ◽  
Malting Quality ◽  
Yield Response ◽  
Genotypic Differences ◽  
Barley Cultivars ◽  
N Rates

Summary. Genotypic differences in responses to nitrogen (N) fertiliser of 6 cultivars of barley (Clipper, Stirling, Weeah, Schooner, Chebec, Skiff) grown at 8 different rates of N were examined in 2 seasons. Measurements of vegetative growth, N content, grain yield, grain protein concentration (GPC) and yield components were taken to identify traits that may contribute to high yield responsiveness. The optimum rates of N for dry matter production at ear emergence (DMee) were greater than 80 kg N/ha for all cultivars and often growth increased up to 105 kg N/ha. Optimum rates of N for grain yield (Nopt) were lower and ranged, on average, from 50 kg N/ha for Clipper to 96 kg N/ha for Chebec. The initial response to N varied from 13–14 kg/kg N in Chebec, Weeah and Schooner, to 36 kg/kg N in Skiff. The Nopt for the semi-dwarf cultivar Skiff was 71 kg N/ha and it tended to show the greatest yield response to N. It produced 19 kernels/g DMee, compared with 15–17 kernels/g DMee in the other cultivars. Unlike most other cultivars, Skiff’s yield was consistently and positively correlated with ears/m2; Stirling was the only other cultivar to show a similar relationship. However, the average kernel weight of Skiff was up to 5 mg lower than that of Clipper, Weeah and Schooner, and varied more than these cultivars between sites, suggesting that consistent grain size may be a problem in this cultivar. By comparison, Clipper and Schooner had lower Nopt (51 kg/ha) and a less variable kernel weight. There were no signs of differences in GPC of the 6 cultivars used here at 3 N-responsive sites. Adding N increased GPC up to the highest rate of N and the responses were generally linear, but GPC at Nopt exceeded the upper limit for malting quality of 11.8% in all cultivars. Average N rates of between 38 kg N/ha (Schooner) and 58 kg N/ha (Skiff) were sufficient to raise GPC above 11.8%. The experiments showed that the N rates for optimum yields varied considerably among cultivars, but applyi1ng rates to achieve maximum yields may cause GPC to exceed the maximum value for malting barley. The use of semi-dwarf cultivars, such as Skiff, which are very responsive to N, can provide some leeway in the choice of N, but there may be a trade-off in quality associated with reduced grain size.

scholarly journals Effect of Canopy Structure on Water Use of Wheat (Triticum Aestivum L.) During Post-Anthesis Stage

2018 ◽  
Vol 1 (1) ◽  
pp. 116-121
Author(s):  
Özgür Tatar ◽  
Uğur Çakaloğullari ◽  
Gülden Deniz Ateş Atasoy ◽  
Deniz Iştipliler
Keyword(s):  
Soil Moisture ◽  
Grain Yield ◽  
Soil Water ◽  
Water Status ◽  
Canopy Cover ◽  
Yield Potential ◽  
Grain Number ◽  
Soil Water Status ◽  
Grain Number Per Spike ◽  
Spike Number

AbstractWheat, being the main crop in Mediterranean type environments, is grown during winter under rainfed conditions and its yield potential is mostly affected by the amount and distribution of rain. This study is conducted at experimental fields of Ege University, Department of Field Crops in Izmir-Bornova which is characterized as Mediterranean type climate conditions during 2011/2012 and 2012/2013 growing season. Totally 9 canopy structures were generated by different row and line distances. Plant height, total dry weight, tiller number, harvest index, spike number, grain number per spike, thousand grain weight and grain yield were determined after harvest time while digital leaf area index and soil moisture contents were monitoring during specific growth periods to evaluate changes in soil water status by different canopy closer. Increasing in sowing density by different row and in-line distance reduced tiller and spike number per plant. On the other hand, grain number per spike and thousand grain weights were significantly affected by in-line distance instead of row distance. Higher grain yield were obtained from 20x1 cm treatments. Canopy cover speed determined using with digital imaging was not remarkable correlated (r=0.06) with soil moisture content during post-anthesis stage of wheat when higher rain amount is recorded in 2012. However, there was a significant negative correlation (r=0.51) between canopy cover speed and soil water status during post-anthesis stage when the rain amount is limited in 2013. We may suggest that rapid canopy cover lead to negative effect on soil water status via higher transpiration if the rain is limited during post-anthesis stage of wheat.

scholarly journals Diverse responses of old, modern and landraces of Syrian wheat genotypes to common root rot under field conditions

2019 ◽  
Vol 12 (2) ◽  
pp. 91-96
Author(s):  
M.I.E. Arabi ◽  
E. Al-Shehadah ◽  
M. Jawhar
Keyword(s):  
Grain Yield ◽  
Root Rot ◽  
Management Practices ◽  
Kernel Weight ◽  
Yield Response ◽  
Common Root ◽  
Experimental Conditions ◽  
Common Root Rot ◽  
Breeding Programmes ◽  
Favorable Conditions

Abstract The yield response of widely grown cultivars and landraces of Syrian wheat challenged with common root rot (CRR: Cochliobolus sativus) was measured by comparing plots with and without artificial inoculation under experimental conditions in two consecutive seasons. The results showed that response to CRR differed depending on the susceptibility levels of the wheat cultivars, and that the disease significantly (P<0.05) reduced grain yield, number of tillers and kernel weight. The diseased plants had fewer tillers which consequently reduced grain yield per plant. Yield losses of Triticum durum cultivars were higher than those of Triticum aestivum. In addition, the T. durum landrace Horani exhibited the best level of resistance to the disease, which indicates that this landrace might be a candidate donor for resistance in future breeding programmes. As CRR can dramatically reduce wheat grain yields under favorable conditions, management practices that reduce disease severity are highly recommended.

Effect of waterlogging on the grain yield response of wheat to sowing date in south-western Victoria

1987 ◽  
Vol 27 (5) ◽  
pp. 661 ◽  
Author(s):  
GK McDonald ◽  
WK Gardner
Keyword(s):  
Grain Yield ◽  
Stem Elongation ◽  
Sowing Date ◽  
Kernel Weight ◽  
Early Flowering ◽  
Yield Response ◽  
Nitrogen Concentrations ◽  
The Mean ◽  
Low Levels ◽  
Western Victoria

Two experiments were conducted in 1983 and 1984 in the Hamilton district in south-western Victoria, which examined, in 1983, the interaction of cultivars of different maturity with sowing date and, in 1984, the interaction of soil waterlogging with anthesis date. In the first experiment the grain yield of Isis and Condor were not significantly (P = 0.05) affected when sowing was delayed from 18 April to 13 May despite greater DM yield at anthesis of the April sown crops (44% with Isis and 8 1 % with Condor). Early sowing resulted in early flowering and in Condor 25% fewer grains per ear. When the effect of anthesis date on grain yield was examined in 1984 at a poorly drained site (Hamilton) and a nearby better drained site (Tabor), it was found that early flowering caused yield reductions of 46 and 25%, respectively. The reduced yield at Hamilton was caused by fewer grains per ear and a lower kernel weight. Grain yield was found to be associated with the severity of waterlogging during the 30 days before anthesis. For each 1% decline in the mean air-filled porosity of the surface soil at this time, yield was reduced by 0.29 t/ha (r2 = 0.83; P< 0.05). When the soils became waterlogged, nitrogen concentrations in the plant tops declined to low levels between stem elongation and anthesis. The need to avoid waterlogging damage during stem elongation in spring may necessitate anthesis being delayed beyond the time currently recommended for the district.

Accuracy of soil water budgets based on a range of relationships for the influence of soil water availability on actual water use

1975 ◽  
Vol 26 (5) ◽  
pp. 871 ◽  
Author(s):  
GG Johns ◽  
RCG Smith
Keyword(s):  
Soil Water ◽  
Water Use ◽  
Water Status ◽  
Surface Zone ◽  
Evaporative Demand ◽  
Water Budgets ◽  
Soil Water Status ◽  
Complex Functions ◽  
Simple Ratio ◽  
Water Values

The accuracy of six published functions for deriving dryland water use from evaporative demand and soil water status was assessed by incorporating them in water budgets which were used to estimate dryland soil water status from actual climatic records. Budget-derived estimates were compared with values actually measured under improved pastures in the field over an 842 day period. The root mean square (RMS) of the differences between computed and observed soil water values was used to evaluate the various functions. RMS values were found to vary from 8.1 to 29.5 mm for the various functions tested. Soil water estimations made by using a simple ratio function were generally as good as or better than those made by using more complex functions. The sensitivity of the various functions to changes in their input assumptions was tested. The results of these tests will facilitate the selection of the optimum functions for conditions other than those encountered in this study. Reduced accuracy of soil water prediction resulted from the use of functions to set water use equal to the potential rate, regardless of the overall dryness of the soil profile, whenever recent rainfall was calculated to have made water available in the surface zone.

scholarly journals Stomatal Conductance of Lysimeter-grown Asian Pear Trees before and during Soil Moisture Deficits

1994 ◽  
Vol 119 (6) ◽  
pp. 1261-1264 ◽  
Author(s):  
A. Richard Renquist ◽  
Horst W. Caspari ◽  
M. Hossein Behboudian ◽  
David J. Chalmers
Keyword(s):  
Soil Moisture ◽  
Stomatal Conductance ◽  
Soil Water ◽  
Water Deficit ◽  
Sap Flow ◽  
Water Status ◽  
Evaporative Demand ◽  
Pulse Technique ◽  
Asian Pear ◽  
Pear Trees

Stomatal conductance (gs) of `Hosui' Asian pear (Pyrus serotina Rehder) trees growing in lysimeters was characterized for trees in well-watered soil and after brief water deficit. The measures of water status used to interpret gs data were soil-water content, leaf water potential (ψl), and instantaneous water use (trunk sap flow by the compensation heat-pulse technique). The diurnal course and range of gs values of well-irrigated Asian pear trees were similar to those reported for other tree fruit crops. Soil moisture at the end of a midsummer deficit period was 60% of lysimeter pot capacity, and diurnal ψl reflected this deficit predawn and in the late afternoon compared to well-irrigated trees. The gs was sensitive to deficit irrigation during more of the day than ψl, with gs values <3 mm·s-1 for most of the day; these were less than half the conductances of well-irrigated trees. The reduction of gs in response to a given soil-water deficit was not as great on days with lower evaporative demand. After a water deficit, gs recovered to predeficit values only gradually over 2 to 3 days. The low gs of trees in dry soil was the apparent cause of reduced transpiration, measured by trunk sap flow, and reduced responsiveness of sap flow to fluctuations in net radiation.

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