THE INFLUENCE OF WATER AVAILABILITY ON WINTER WHEAT YIELDS

1982 ◽  
Vol 62 (4) ◽  
pp. 831-838 ◽  
Author(s):  
R. C. JOHNSON ◽  
E. T. KANEMASU

Field experiments were conducted comparing yield and yield components of winter wheat (Triticum aestivum L.) grown under different soil water conditions. Soil water was controlled by excluding precipitation from a 150-m2 plot area with an automatic rain shelter. Treatment regimes were described according to their relative preanthesis/postanthesis soil water content as high/high (H/H), high/low (H/L), and low/high (L/H) in 1978–1979; an additional treatment, low/low (L/L) was added in 1979–1980. A neutron probe was used to periodically monitor soil water to the 150-cm depth in each regime. Plot yields ranged from 559 g/m2 in regime H/H (1978–1979) to 267 g/m2 in L/L (1979–1980) and were positively correlated with head number per square metre (r = 0.70) and kernel number per head (r = 0.79). Low preanthesis soil water reduced head number per square metre in both years. Regimes L/H and L/L in 1979–1980, which averaged the lowest preanthesis soil water of all regimes both years, had reduced kernels per spikelet compared to regimes with high preanthesis soil water. Increased kernel weight. associated with postanthesis irrigations, generally was not enough to compensate fully for fewer kernels per square metre associated with low preanthesis soil water. The results indicate that, if drought develops before grain filling in the spring, improved tiller survival and/or floret fertility could increase yields, even if some stress continued through grain filling. Under nonstress conditions, yield appears limited most by the amount of assimilate required to fill a high number of kernels per square metre.

1990 ◽  
Vol 70 (3) ◽  
pp. 605-609 ◽  
Author(s):  
J. A. IVANY ◽  
H. G. NASS ◽  
J. B. SANDERSON

In field experiments at Charlottetown, Prince Edward Island, herbicides were applied in the fall or spring on winter wheat (Triticum aestivum L.) to determine effect on yield. Application of 2,4-D or the mixture 2,4-D/mecoprop/dicamba in the fall gave significantly lower yields than when spring-applied on the cultivar Lennox. The herbicides MCPA, bromoxynil, dicamba, mecoprop, chlorsulfuron, MCPA/dicamba, and MCPA/bromoxynil had no adverse effect on yield of Lennox at either time of application. A further study on the cultivars Lennox, F29-76, and Borden using the herbicides MCPA, bromoxynil, MCPA/dicamba, chlorsulfuron, and dicamba showed no detrimental effects on 1000 kernel weight, or percent winter survival from fall or spring application. Yield losses were noted for spring application of dicamba but not for MCPA/dicamba and all cultivars responded similarly to all herbicide treatments.Key words: Wheat (winter) cultivars, fall versus spring application, 2,4-D, MCPA, dicamba, bromoxynil, chlorsulfuron


2011 ◽  
Vol 38 (5) ◽  
pp. 347 ◽  
Author(s):  
Jairo A. Palta ◽  
Xing Chen ◽  
Stephen P. Milroy ◽  
Greg J. Rebetzke ◽  
M. Fernanda Dreccer ◽  
...  

There is little consensus on whether having a large root system is the best strategy in adapting wheat (Triticum aestivum L.) to water-limited environments. We explore the reasons for the lack of consensus and aim to answer the question of whether a large root system is useful in adapting wheat to dry environments. We used unpublished data from glasshouse and field experiments examining the relationship between root system size and their functional implication for water capture. Individual root traits for water uptake do not describe a root system as being large or small. However, the recent invigoration of the root system in wheat by indirect selection for increased leaf vigour has enlarged the root system through increases in root biomass and length and root length density. This large root system contributes to increasing the capture of water and nitrogen early in the season, and facilitates the capture of additional water for grain filling. The usefulness of a vigorous root system in increasing wheat yields under water-limited conditions maybe greater in environments where crops rely largely on seasonal rainfall, such as the Mediterranean-type environments. In environments where crops are reliant on stored soil water, a vigorous root system increases the risk of depleting soil water before completion of grain filling.


2011 ◽  
Vol 50 (No. 7) ◽  
pp. 309-314 ◽  
Author(s):  
L. Ducsay ◽  
O. Ložek

Small-plot field experiments were established in the first decade of October at the Plant Breeding Station of Sl&aacute;dkovičovo-Nov&yacute; dvor with winter wheat (Triticum aestivum L.), variety Astella. There was investigated an effect of topdressing with nitrogen on the yield of winter wheat grain and its quality characteristics in the experiment. Nitrogenous fertilizers were applied at the growth phase of the 6<sup>th</sup> leaf (Zadoks = 29). Soil of the experimental stand was analysed for inorganic nitrogen content (N<sub>an</sub>) down to the depth of 0.6 m of soil profile. Productive nitrogen fertilizing rate was computed to ensure N<sub>an</sub> content in soil on the level of 120 and140 kg N/ha, respectively. Three various forms of fertilizers were examined, urea solution, ammonium nitrate with dolomite, and DAM-390. Different weather conditions statistically highly, significantly influenced grain yield in respective experimental years. Topdressing with nitrogen caused a statistically highly significant increase of grain yield in all fertilized variants ranging from +0.35 to +0.82 t/ha according to respective treatments. Average grain yield in unfertilised control variant represented 7.23 t/ha. Nitrogen nutrition showed a positive effect on the main macroelements offtake (N, P, K, Ca, Mg, S) by winter wheat grain in all fertilized variants. Nitrogen fertilizing to the level of 140 kg/ha N in soil positively influenced formation of wet gluten and crude protein with highest increment in variant 5 (solution of urea) representing +12.8 and +10.7%, respectively in comparison to control unfertilised variant as well as to variant 2 (solution of urea and fertilizing on the level of120&nbsp;kg N/ha) where increments represented +8.8 and 9.7%, respectively. Thousand-kernel weight, volume weight and portion of the first class grain were not markedly influenced by nitrogen fertilizing.


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7738
Author(s):  
Zhaoan Sun ◽  
Shuxia Wu ◽  
Biao Zhu ◽  
Yiwen Zhang ◽  
Roland Bol ◽  
...  

Information on the homogeneity and distribution of 13carbon (13C) and nitrogen (15N) labeling in winter wheat (Triticum aestivum L.) is limited. We conducted a dual labeling experiment to evaluate the variability of 13C and 15N enrichment in aboveground parts of labeled winter wheat plants. Labeling with 13C and 15N was performed on non-nitrogen fertilized (−N) and nitrogen fertilized (+N, 250 kg N ha−1) plants at the elongation and grain filling stages. Aboveground parts of wheat were destructively sampled at 28 days after labeling. As winter wheat growth progressed, δ13C values of wheat ears increased significantly, whereas those of leaves and stems decreased significantly. At the elongation stage, N addition tended to reduce the aboveground δ13C values through dilution of C uptake. At the two stages, upper (newly developed) leaves were more highly enriched with 13C compared with that of lower (aged) leaves. Variability between individual wheat plants and among pots at the grain filling stage was smaller than that at the elongation stage, especially for the −N treatment. Compared with those of 13C labeling, differences in 15N excess between aboveground components (leaves and stems) under 15N labeling conditions were much smaller. We conclude that non-N fertilization and labeling at the grain filling stage may produce more uniformly 13C-labeled wheat materials, whereas the materials were more highly 13C-enriched at the elongation stage, although the δ13C values were more variable. The 15N-enriched straw tissues via urea fertilization were more uniformly labeled at the grain filling stage compared with that at the elongation stage.


2013 ◽  
pp. 101-105
Author(s):  
Enikő Vári

The experiments were carried out at the Látókép experimental station of the University of Debrecen on chernozem soil in a long term winter wheat experiment in the season of 2011 and 2012 in triculture (pea-wheat-maize) and biculture (wheat-maize) at three fertilisation levels (control, N50+P35K40, N150+P105K120). Two different cropyears were compared (2011 and 2012). The research focused on the effects of forecrop and fertilisation on the Leaf Area Index, SPAD values and the amount of yield in two different cropyears. We wanted to find out how the examined parameters were affected by the cropyear and what the relationship was between these two parameters and the changes of the amount of yield. Examining the effects of growing doses of fertilizers applied, results showed that yields increased significantly in both rotations until the N150+PK level in 2011 and 2012. By comparing the two years, results show that in 2011 there was a greater difference in yields between the rotations (7742 kg ha-1 at N150+PK in the biculture and 9830 kg ha-1 at N150+PK in the triculture). Though wheat yields following peas were greater in 2012, results equalized later on at N150+PK levels (8109–8203 kg ha-1). Due to the favorable agrotechnical factors, the leaf and the effects of the treatments grown to a great extent in 2011, while in 2012 the differences between treatments were moderate. Until the N150+PK level, nitrogen fertilisation had a notable effect on the maximum amount of SPAD values (59.1 in the case of the biculture and 54.0 in the triculture). The highest SPAD values were measured at the end of May (during the time of flowering and grain filling) in the biculture. In the triculture, showed high SPAD values from the beginning. The same tendency could be observed in the 2012 cropyear, although increasing doses of fertilizers resulted in higher SPAD values until N150+PK level only from the second measurement. Maximum SPAD values were reached at the end of May in both crop rotation system


2011 ◽  
Vol 52 (No. 8) ◽  
pp. 377-384 ◽  
Author(s):  
J. Haberle ◽  
P. Svoboda ◽  
J. Krejčová

The apparent uptake of mineral nitrogen (N<sub>min</sub>) from top- and subsoil layers during the growth of winter wheat (Triticum aestivum L.) was studied in Prague-Ruzyne on clay loam Chernozem soil in years 1996&ndash;2003. Two (N0,&nbsp;N1) and three treatments, unfertilized (N0), fertilized with 100 kg (N1) and 200 kg (N2) nitrogen per hectare were observed in years 1996&ndash;2000 and 2001&ndash;2003, respectively. The apparent uptake of nitrogen from soil layers was calculated from the changes of N<sub>min</sub> content between sampling terms. Most of available mineral N in the soil down to 90 cm was almost fully depleted between tillering and anthesis in treatment N0. The uptake from subsoil layers was delayed and it continued during the period of grain filling in fertilized treatments. Nitrogen fertilization reduced utilization of N from subsoil. The apparent uptake of N from the zone 50&ndash;120 cm ranged from 21 to 62&nbsp;kg&nbsp;N/ha in&nbsp;N0 and from 15 to 60 kg N/ha in N1 in years 1996&ndash;2000. In years 2001&ndash;2003 the corresponding values (50&ndash;130&nbsp;cm) were 24&ndash;104 kg, 43&ndash;130 kg and 29&ndash;94 kg N/ha in treatments N0, N1 and N2, respectively. The uptake from 120&nbsp;(130)&ndash;150 cm was around zero in a half of experimental years, and it reached at maximum 12 kg/ha in N0 in 1997. There was a strong linear relation between the amount of N<sub>min</sub> in spring and the depletion of nitrogen from the zone 50&ndash;120 (130) cm, R<sup>2 </sup>= 0.94, 0.91 and 0.99 in N0, N1 and N2, respectively.


1973 ◽  
Vol 81 (2) ◽  
pp. 327-337 ◽  
Author(s):  
P. K. R. Nair ◽  
O. Talibudeen

SummaryProcedures for measuring K+ and NO-3 activities in the root zones of field crops, using specific-ion electrodes, were standardized. For K, a 1·0 M-NaCl salt bridge and KC1 standards in water, for NO3, a saturated KC1 salt bridge and KN03 standards in water, and for both electrodes, a 1:0·5, soil: water ratio, and 30 sec equilibration time were found satisfactory.Recovery of added K in soil pastes by the K electrode and chemical analysis of the soil water extract compared well, but the recovery was about 8% only. The corresponding recovery of added N was about 87 and 95% respectively.Relative changes in the rates and magnitudes of NO3 and K concentrations were measured with these electrodes, laterally and vertically, in the root zone, during active crop growth, from the N2 ½(PKNaMg), N2 PKNaMg, and N4PKNaMg treatments of the Broadbalk Winter Wheat Experiment.In all fertilizer treatments, at all times, the nutrient concentrations were most at 45 cm from the crop (in the uncropped area) and least within the cropped area. The differences between these extremes represent nutrient depletion by the crop, the ‘45 cm’ measurementsindicating changes in uncropped, but fertilized, areas.Soil nitrate depletion by the crop was much more at 12·5 cm and 20 cm depths than at 5 cm. Maximum NO3 depletion was observed during the later stages of crop growth, at ‘pre-panicle emergence’ and at ‘grain filling’. Depletion decreased and the soil NO3 level recovered partially as the crop reached maturity.Periodic changes in the K concentration at each site and the corresponding K depletions were much less. Periods of IC stress on the soil were few and less clearly demarcated. Soil K concentration started to recover at the ‘grain filling’ stage about a month earlier than with NO3.Changes in NO3 and K concentrations seem to relate more to the amounts given of each nutrient, than to the N:K ratio in each fertilizer treatment. However, changes in NO3 and K concentrations, and also NO3 and K depletion, occurred consecutively. This indicates an alternating periodicity in the demands of the crop for NO3 and K respectively throughout growth.


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