Spatial variability of barley (Hordeum vulgare) and corn (Zea mays L.) yields, yield response to fertilizer N and soil N test levels

2004 ◽  
Vol 84 (3) ◽  
pp. 307-316 ◽  
Author(s):  
I. P. O’Halloran ◽  
A. P. von Bertoldi ◽  
S. Peterson
Keyword(s):  
Zea Mays ◽  
Hordeum Vulgare ◽  
Spatial Variability ◽  
Zea Mays L ◽  
Spring Barley ◽  
Yield Response ◽  
Soil N ◽  
Fertilizer N ◽  
Site Specific ◽  
Yield Responses

Identification of management units for the variable application of fertilizer N is a critical component for the implementation of a site-specific N management program. Field studies were conducted to examine the spatial variability of soil nitrate levels, spring barley (Hordeum vulgare) and corn (Zea mays L.) yields and yield responses to fertilizer N applications on two sites in southwestern Ontario, Canada. Soil sampling on a 3 × 10 m grid indicated that soil NO3-N test values had a log-normal distribution and varied considerably at both sites with CVs exceeding 57% on the untransformed data. Ranges of spatial correlation varied from 20 to 95 m with 30 to 80% of the total variance of the ln-transformed data existing as either random or unsampled variance, and these parameters were not temporally stable. Although NO3-N tended to increase at lower slope positions in two of the 3 site-years, considerable within-slope variability of soil NO3-N levels was also observed. Spatial variations in soil N test levels, crop yields and crop yield responses to applied fertilizer N were not strongly related to one another indicating that it would be unlikely that either soil N test level or yield would adequately delineate management zones for the variable application of N fertilizer at these sites. Key words: Variogram, topography, site-specific crop management

Effect of nitrogen fertilization and topography on soft red winter wheat yield and protein content in two Ontario landscapes

2006 ◽  
Vol 86 (4) ◽  
pp. 729-739 ◽  
Author(s):  
Christopher J Denys ◽  
Ivan P O’Halloran ◽  
John D Lauzon
Keyword(s):  
Protein Concentration ◽  
Slope Position ◽  
Yield Response ◽  
Soil N ◽  
Fertilizer N ◽  
Management Units ◽  
Site Specific ◽  
Soft Red Winter Wheat ◽  
N Management ◽  
Red Winter Wheat

Identification of suitable management units for the variable application of fertilizer N is an essential component of a site-specific N management program. Topography and/or soil N test results are examples of two parameters that could potentially delineate N management units for improved grain yield or protein concentration. Field studies were conducted on soft red winter wheat (Triticum aestivum L.) to examine the effects of mineral soil N, soil organic carbon (SOC), and N fertilization on grain yields and protein concentrations in two variable landscapes in southwestern Ontario, Canada. Six N rates (0 to 145 kg N ha-1) were applied to plots (3 × 400 m long), arranged in a randomized complete split block design with four replicates. Sampling on a 3 × 20 m grid indicated slope position affected soil nitrate (NO3-N) and SOC levels at site 1, but not at site 2. The range of spatial correlation for NO3-N was 11.5 m at both sites and for SOC was 16.0 m and 32.4 m at site 1 and 2, respectively. Yields decreased and protein concentrations increased while moving upslope at both sites. Yield response to applied fertilizer N was characterized using a quadratic model. The most economic rate of N (MERN) for site 1 was 105 kg ha-1, and did not vary with topography. At site 2, yield response to applied fertilizer N varied with topography and MERN increased while moving downslope (91, 104, 120 kg N ha-1 for upper, mid, and lower, respectively). Protein concentration responses to applied N were fitted to cubic models, and the nature of the response to applied N did not vary with slope position. Based simply on grain yield, the potential to use topography and/or mineral N in the soil to identify management units for variable application of N was limited at these two sites; however, variably applying N may reduce the risk of exceeding the protein limits for export markets on the upper slope positions without sacrificing yield. Key words: Site-specific crop management, nitrogen application, N fertilizer, variogram, topography

Morpho-physiological and yield responses to exogenous moringa leaf extract and salicylic acid in maize (Zea mays L.) under water stress

2017 ◽  
Vol 64 (7) ◽  
pp. 994-1010 ◽  
Author(s):  
Hanafey F. Maswada ◽  
Usama A. Abd El-Razek ◽  
Abdel-Nasser A. El-Sheshtawy ◽  
Abdelnaser A. Elzaawely
Keyword(s):  
Zea Mays ◽  
Salicylic Acid ◽  
Water Stress ◽  
Leaf Extract ◽  
Zea Mays L ◽  
Yield Responses ◽  
Moringa Leaf Extract

EFFECTS OF INOCULATION AND FERTILIZER N LEVELS ON N2 FIXATION AND YIELDS OF SOYBEANS IN ONTARIO

1979 ◽  
Vol 59 (4) ◽  
pp. 1129-1137 ◽  
Author(s):  
ERNEST SEMU ◽  
D. J. HUME
Keyword(s):  
Glycine Max ◽  
Rhizobium Japonicum ◽  
Soil N ◽  
Fertilizer N ◽  
Fertilizer Nitrogen ◽  
Nodule Number ◽  
Glycine Max L ◽  
Yield Responses ◽  
Seed Yields ◽  
Nodule Efficiency

Soybeans (Glycine max (L.) Merrill) often do not give yield responses to added fertilizer nitrogen (N) because high soil N levels inhibit fixation of atmospheric N2. Yield responses to N fertilizer applied at planting usually indicate that N2 fixation is less than optimal. The effects of inoculation with Rhizobium japonicum, and fertilizer N levels, on soybean N2(C2H2) fixation and seed yields in Ontario were investigated in ’ 1976 and 1977. Three locations were used each year, representing areas where soybeans had been grown for many years (Ridgetown), for only a few years (Elora), or not at all (Woodstock). Treatments were (a) Uninoculated + 0 N, (b–e) Inoculated + 0, 50, 100 or 200 kg N/ha. Results indicated that inoculation increased seed yields only when soybeans were introduced into new areas. Fertilizer N applications at planting time did not increase yields in areas where soybeans had been grown several times previously, indicating that N2 fixation could support maximum yields. Nodule number and mass, and N2(C2H2) fixation rates were all decreased by fertilizer N. An increase in nodule efficiency, later in the season, in high N treatments was most marked at Ridgetown.

Relationship of the Illinois soil nitrogen test to spring wheat yield and response to fertilizer nitrogen

2008 ◽  
Vol 88 (5) ◽  
pp. 837-848 ◽  
Author(s):  
S J Steckler ◽  
D J Pennock ◽  
F L Walley
Keyword(s):  
Soil Nitrogen ◽  
Crop Yields ◽  
Wheat Yield ◽  
N Fertilizer ◽  
Yield Response ◽  
Regression Equations ◽  
Soil N ◽  
Fertilizer N ◽  
Available N ◽  
Nitrate N

The Illinois soil N test (ISNT) has been used to distinguish between soils that are responsive and non-responsive to fertilizer N in Illinois. We examined the suitability of this test, together with more traditional measures of soil fertility, including spring nitrate-N and soil organic carbon (SOC), for predicting yield and N fertilizer response of wheat (Triticum aestivum) on hummocky landscapes in Saskatchewan. The relationship between ISNT-N and wheat yield and fertilizer N response was assessed using data and soils previously collected for a variable-rate fertilizer study. Soils were re-analyzed for ISNT-N. Our goal was to determine if ISNT-N could be used to improve the prediction of crop yields. Although ISNT-N was correlated with both unfertilized wheat yield (r = 0.467, P = 0.01) and fertilizer N response (r = -0.671, P = 0.01) when data from all study sites were combined, correlations varied according to landscape position and site. Stronger correlations between nitrate-N and both unfertilized wheat yield (r = 0.721, P = 0.01) and fertilizer N response (r = -0.690, P = 0.01) indicated that ISNT-N offered no advantage over nitrate-N. Although both tests broadly discriminated between sites with high or low N fertility, few relationships were detected on a point-by-point basis within a field. Stepwise regression equations predicting yield and yield response did not include ISNT-N, due in part to the high degree of collinearity between ISNT-N and other variables such as SOC, suggesting that ISNT-N alone was not a key indicator of soil N supply. Key words: Illinois soil nitrogen test, potentially available N, soil N, fertilizer N recommendations

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