Effects of foliar applied nitrogen fertilizer on cotton waterlogged in a cracking grey clay

1987 ◽  
Vol 38 (4) ◽  
pp. 681 ◽  
Author(s):  
AS Hodgson ◽  
DA MacLeod

Foliar-applied nitrogen (N) fertilizer was investigated as a means of ameliorating the damage to cotton of waterlogging associated with extended furrow irrigation of a cracking grey clay. Dissolved urea was applied at 0, 5, 10 and 20 kg N ha-1 to the cotton foliage one day before furrow irrigations lasting 4, 8, 16 and 32 h. Treatments were repeated at three crop irrigations. Storms following the first two irrigations delayed the recovery from waterlogging and reduced treatment differences. However, foliar-applied N significantly increased late square and green boll numbers after the third irrigation, and produced more open bolls and heavier lint yields than the control treatment at harvest. Lint yields increased by 2.8, 5.9, 8.4 and up to 10.5 kg ha-1 per kg of foliar N applied before irrigations lasting 4, 8, 16 and 32 h, respectively. From this interaction it was concluded that foliar-applied N ameliorated the effects of waterlogging. Nevertheless, in the most severe waterlogging treatment, yield response to foliar N reached a limit, indicating that some other factor had become limiting.

2020 ◽  
Vol 8 (2) ◽  
pp. 60-71
Author(s):  
Helizani C. Bazame ◽  
Francisco A.C. Pinto ◽  
Domingos S. Queiroz ◽  
Daniel M. de Queiroz ◽  
Daniel Althoff

The objective of the present work was to evaluate the use of spectral sensors to determine nitrogen fertilizer requirements for pastures of Urochloa brizantha cv. Xaraés in Brazil. The experimental design was a randomized block design with 4 replications of 4 treatments: a control treatment (TT) without application of N; a reference treatment (TR) with N applied at a standard predetermined fixed rate (150 kg urea/ha/cycle); a treatment using GreenSeekerTM (TG) to determine N requirement by the canopy normalized difference vegetation index (NDVI); and a treatment using SPAD 502 (TS) to determine N requirement by foliar chlorophyll assessment. For treatments involving spectral sensors, N fertilizer was applied at half the rate of that in the reference treatment at the beginning of each cycle and further N was applied only when the nitrogen sufficiency index dropped below 0.85. The sensors used in the work indicated that no additional N fertilizer was required by these pastures above the half rates applied. Applying N at the reduced rates to the pastures was more efficient than the pre-determined fixed rate, as both sensor treatments and the fixed rate treatment produced similar total forage yields, with similar crude protein concentrations. All fertilized pastures supported similar stocking rates, while the sensor treatments used less N fertilizer, i.e. 75 kg urea/ha/cycle less than the reference plot. Longer-term studies to verify these findings are warranted followed by promotion of the technology to farmers to possibly reduce fertilizer application rates, improve profitability and provide environmental benefits.


1968 ◽  
Vol 8 (31) ◽  
pp. 223 ◽  
Author(s):  
JS Russell

The response of Gabo wheat to nitrogen fertilizer at 52 sites in the wheat growing areas of South Australia during 1956-61 was examined in relation to climatic factors by a stepwise multiple regression analysis using a computer. The ten dependent variables were the linear and quadratic coefficients obtained by fitting orthogonal polynomials to response curves of various parameters (grain yield, grain + straw yield, harvest index, grain nitrogen percentage, and grain nitrogen yield) to applied nitrogen at each of the 52 sites. The 23 independent variables were the amounts of rainfall and evaporation during the growing period, maximum and minimum temperatures and estimates of high temperature stress during spring and amount of rainfall immediately after sowing at each site. The climatic variables examined explained 46.5, 64.3, and 64.3 per cent of the variation in the response to nitrogen fertilizer of grain yield, grain + straw yield, and grain nitrogen yield respectively. The positive effects of increasing amounts of winter rainfall on yield response to applied nitrogen were marked. On the other hand, the negative effects of high maximum temperatures in the latter part of the growing period, particularly during October, on yield response were also evident.


1988 ◽  
Vol 111 (1) ◽  
pp. 85-90 ◽  
Author(s):  
D. M. Firman ◽  
E. J. Allen

SummaryThree experiments are reported in which the photosynthetic rates of potatoes grown with various amounts of applied nitrogen (N) fertilizer were measured. Rates of photosynthesis in leaves of plants grown without applied N reached levels as high as those receiving N in all experiments. The rate of photosynthesis in the uppermost leaves of the variety Pentland Crown was found to increase during the season, whereas in Estima rates remained the same. Decline in the rate of photosynthesis with leaf age was more rapid in strongly shaded leaves than in less shaded leaves which were found to be photosynthetically active 8 weeks after expansion.


1968 ◽  
Vol 8 (35) ◽  
pp. 736 ◽  
Author(s):  
JS Russell

The difficulties in predicting grain yield response to applied nitrogen under conditions of low and variable rainfall are discussed. Three models of grain yield response to applied nitrogen fertilizer for each of two strategies are proposed, based on data from field experiments carried out in the wheat growing areas of South Australia. In the first strategy (nitrogen applied at sowing) the parameters are May-August rainfall, October mean maximum temperature and one of three alternative site criteria, initial soil nitrate content (0-6 inches sampled shortly before sowing), 15-atmospheres soil moisture percentage (0-6 inches), or estimated nitrogen status. In the second strategy (nitrogen applied in late winter) the parameters are similar, except that May-July rainfall replaced May-August rainfall and a statistical relationship between yield response due to late application as compared with application at sowing was used. The response surfaces were examined using a calculated most profitable rate of application with a range of grain : fertilizer price ratios from 2 to 8. These calculations emphasize the importance of economic factors in affecting fertilizer use in areas where responses are small and variable. The limitations of the models and problems associated with the use of predicted climatic criteria are discussed. There is a need for further studies to iteratively test and modify these empirical models and ultimately to develop mechanistic models. Further study is also suggested on field aspects of late application and the possible role of both plant analysis and the single ion nitrate electrode for site characterization.


1970 ◽  
Vol 10 (45) ◽  
pp. 450 ◽  
Author(s):  
VF McClelland

The effect of nitrogen fertilizer on the yield and grain protein content of several cultivars of wheat grown under wheat-fallow and wheat-pasture-pasture-fallow rotations was studied in the Victorian Mallee during 1962 to 1965. Nitrogen fertilizer increased whest yield on the wheat-fallow rotation, but had little effect on the wheat-pasture-pasture-fallow rotation. Changes in grain protein content due to nitrogen fertilizer were small compared with changes due to the type of cropping rotation. Climate had relatively little influence on grain protein content despite marked variability in rainfall. The significance of this result is discussed in relation to a correlation established between grain protein content of unfertilized plots and yield response to applied nitrogen. The performance of the wheat cultivars Insignia, Olympic, and Beacon with and without applied nitrogen was similar under both rotations.


2015 ◽  
Vol 181 ◽  
pp. 52-59 ◽  
Author(s):  
Hui Li ◽  
Rihuan Cong ◽  
Tao Ren ◽  
Xiaokun Li ◽  
Changbao Ma ◽  
...  

2021 ◽  
Vol 24 (1) ◽  
pp. 77-87
Author(s):  
SS Keya ◽  
MG Miah ◽  
MA Rahman ◽  
MT Islam

Excess use of agrochemicals for intensive cultivation affects crop quality and destroys agro-ecosystems, and eventually creates health hazards. The study aims to investigate the effect of Gliricidia sepium (GS) tree leaf as suitable green manures for supplementing nutrient supply along with nitrogen (N) fertilizer to produce quality tomato and soil fertility improvement. A field experiment was conducted at the Bangabandhu Sheikh Mujibur Rahman Agricultural University, Bangladesh, from November 2016 to March 2017. The experiment was laid out in a randomized complete block design (two factors) with three replications. There were nine treatment combinations with three levels of GS tree leaves (5, 10 and 15 t ha−1) and three doses of N (0, 50 and 100% of the recommended dose of fertilizer). The highest tomato yield was recorded in GS15×N100 treatment combination, which was 41.68% higher compared to the control treatment. Decreasing C: N ratio in increasing dose of GS and N treated plot indicated the quality of tree leaves that ensures faster decomposition and high nutrient release pattern of this species. Increasing rate of soil pH and cation exchange capacity (CEC) in different treatments as compared to initial soil showed soil fertility improvement. Overall, the results indicated that quality tomato could be grown successfully by the application of G. sepium tree leaves along with an appropriate amount of N fertilizer. Ann. Bangladesh Agric. (2020) 24(1) : 77-87


1989 ◽  
Vol 112 (1) ◽  
pp. 57-66 ◽  
Author(s):  
N. Moreira

SummaryExperiments were conducted on the seed rates of the components of oat-vetch mixtures combined with varying rates of nitrogen fertilizer in a rainfed area of north-east Portugal in 1982–3 and 1984–5.Forage oats grown alone showed a very high yield response to N and rainfall ranging from 30 to 18·2 t D.M./ha, but had a very low crude protein concentration (37–54 g/kg D.M.) and a poor mineral nutrient composition.The increased use of vetch in the seed mixture had a buffering effect on dry-matter (D.M.) yield but this depended very much on crop N nutrition. For N-deficient conditions vetch inclusion increased the D.M. yield and had a strong positive effect on total forage crude protein (CP) and mineral composition. When crop N nutrition was good, very high D.M. yields (> 12 t D.M./ha) were possible using a high proportion of oats, with vetch making a reduced contribution to the yield and nutritive value of total forage.Seed rates suggested in the literature for Mediterranean conditions are adequate for low N inputs and low available soil N, but not for high D.M. yields which can only be obtained by using a higher proportion of oats and adequate N fertilizer.


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