scholarly journals A sensitivity analysis of the prediction of the nitrogen fertilizer requirement of cauliflower crops using the HRI WELL_N computer model

2001 ◽  
Vol 137 (1) ◽  
pp. 55-69 ◽  
Author(s):  
C. RAHN ◽  
A. MEAD ◽  
A. DRAYCOTT ◽  
R. LILLYWHITE ◽  
T. SALO
Keyword(s):  
Sensitivity Analysis ◽  
Computer Model ◽  
N Fertilizer ◽  
Yield Potential ◽  
Yield Response ◽  
Soil Mineral N ◽  
Soil Mineral ◽  
Mineral N ◽  
Wide Range ◽  
Fertilizer Requirement

HRI WELL_N is an easy to use computer model, which has been used by farmers and growers since 1994 to predict crop nitrogen (N) requirements for a wide range of agricultural and horticultural crops.A sensitivity analysis was carried out to investigate the model predictions of the N fertilizer requirement of cauliflower crops, and, at that rate, the yield achieved, yield response to the fertilizer applied, N uptake, NO3-N leaching below 30 and 90 cm and mineral N at harvest. The sensitivity to four input factors – soil mineral N before planting, mineralization rate of soil organic matter, expected yield and duration of growth – was assessed. Values of these were chosen to cover ranges between 40% and 160% of values typical for field crops of cauliflowers grown in East Anglia. The assessments were made for three soils – sand, sandy loam and silt – and three rainfall scenarios – an average year and years with 144% or 56% of average rainfall during the growing season. The sensitivity of each output variable to each of the input factors (and interactions between them) was assessed using a unique ‘sequential' analysis of variance approach developed as part of this research project.The most significant factors affecting N fertilizer requirement across all soil types/rainfall amounts were soil mineral N before planting and expected yield. N requirement increased with increasing yield expectation, and decreased with increasing amounts of soil mineral N before planting. The responses to soil mineral N were much greater when higher yields were expected. Retention of N in the rooting zone was predicted to be poor on light soils in the wettest conditions suggesting that to maximize N use, plants needed to grow rapidly and have reasonable yield potential.Assessment of the potential impacts of errors in the values of the input factors indicated that poor estimation of, in particular, yield expectation and soil mineral N before planting could lead to either yield loss or an increased level of potentially leachable soil mineral N at harvest.The research demonstrates the benefits of using computer simulation models to quantify the main factors for which information is needed in order to provide robust N fertilizer recommendations.

Dependence of soil mineral N on N-fertilizer application

1986 ◽  
Vol 91 (3) ◽  
pp. 417-420 ◽  
Author(s):  
J. J. Neeteson ◽  
D. J. Greenwood ◽  
E. J. M. H. Habets
Keyword(s):  
Fertilizer Application ◽  
N Fertilizer ◽  
Soil Mineral N ◽  
Soil Mineral ◽  
Mineral N

Measurement and simulation of the effects of N-fertilizer on growth, plant composition and distribution of soil mineral-N in nationwide onion experiments

1992 ◽  
Vol 31 (3) ◽  
pp. 305-318 ◽  
Author(s):  
D. J. Greenwood ◽  
J. J. Neeteson ◽  
A. Draycott ◽  
G. Wijnen ◽  
D. A. Stone
Keyword(s):  
N Fertilizer ◽  
Soil Mineral N ◽  
Soil Mineral ◽  
Plant Composition ◽  
Mineral N

Nutrient management in a Pinusradiata plantation after thinning: the effect of nitrogen fertilizer on soil nitrogen fluxes and tree growth

1995 ◽  
Vol 25 (10) ◽  
pp. 1673-1683 ◽  
Author(s):  
J.C. Carlyle
Keyword(s):  
N Uptake ◽  
Fertilizer Application ◽  
N Fertilizer ◽  
Soil Mineral N ◽  
Fertilizer N ◽  
Soil Mineral ◽  
Mineral N ◽  
N Fluxes ◽  
Highly Correlated ◽  
The Relationship

The influence of N fertilizer on soil mineral N fluxes, canopy development, and tree growth was studied in a thinned 11-year-old Pinusradiata D. Don plantation. Ammonium sulphate and single superphosphate were applied in an incomplete factorial design, but only the main effects of N application at 0 (control) or 200 kg N•ha−1 are considered here. Spring application of fertilizer increased the quantity of mineral N in the forest floor plus surface soil (0–0.30 m) from 1.2 to 194 kg•ha−1. Within 51 weeks this had fallen to 8.3 kg•ha−1, and after 89 weeks had returned to prefertilizer levels. In the unfertilized soil, rates of net mineralization were low with little seasonal variation. Nitrogen fertilizer increased N mineralization; over the 2 years of measurement fertilized and unfertilized soils mineralized 155 and 77 kg N•ha−1, respectively. There was no net immobilization of fertilizer N. There was no leaching of mineral N from the unfertilized soil whereas 149 kg N•ha−1 was leached below 0.30 m during the 2 years after fertilizer application. Nitrogen uptake increased from 71 kg•ha−1 in the control to 203 kg•ha−1 in the fertilized treatment. Fifty-one percent (103 kg•ha−1) of N uptake by trees in the fertilized treatment occurred within 20 weeks of fertilizer application. Fertilized trees took up 58% of the available N (N added as fertilizer plus N mineralized), while 42% was leached. Ammonium dominated the soil mineral N pool and mineral N fluxes, with nitrate generally accounting for less than 10% of mineral N in both fertilized and unfertilized soils. Leaching of mineral N from the fertilized soil (Nleach, kg•ha−1•week−1) was highly correlated (r2 = 0.92) with soil mineral N content (Nstart, kg•ha−1) and effective rainfall (rainfall minus evaporation, Reff, mm•week−1) according to the relationship Nleach = aNstart + bReff, while N uptake (kg•ha−1•week−1) was highly correlated (r2 = 0.91) with soil mineral N content and N mineralization (Nmin, kg•ha−1•week−1) according to the relationship Nuptake = aNstart + bNmin. Fertilizer increased needle N concentrations and content by 52 and 87%, respectively, after 58 weeks, and resulted in a 17% increase in leaf area index after 71 weeks. These differences were reflected by an increase in basal area increment of 23% during the 2 years since fertilizer application. The rapid uptake of N fertilizer was associated with storage in existing biomass. Uptake of fertilizer N should, therefore, increase with plantation biomass. Consequently, it should be possible to increase the uptake of N fertilizer, and minimize leaching, by applying fertilizer before, rather than after, thinning. Such a strategy may be particularly appropriate for soils that have a low capacity to retain applied N.

scholarly journals Limits to nitrogen fertilizer on grassland.

1984 ◽  
Vol 32 (4) ◽  
pp. 319-321 ◽  
Author(s):  
W.H. Prins
Keyword(s):  
Lolium Perenne ◽  
Nitrogen Fertilizer ◽  
N Fertilizer ◽  
Clay Soils ◽  
Nitrate Content ◽  
Soil Mineral N ◽  
Soil Mineral ◽  
Mineral N ◽  
N Application ◽  
N Rates

The effect of N fertilizer on seasonal response of predominantly Lolium perenne grassland, sward quality and productivity, herbage nitrate content and soil mineral N was studied in cutting trials lasting 1-6 years. At an assumed marginal profitability of 7.5 kg DM/kg N applied, the av. opt. annual N application on sand and clay soils was 420 kg/ha. At this rate, herbage nitrate content did not exceed 0.75% NO3 and accumulation of soil mineral N was minimal. At annual N rates exceeding 500 kg/ha sward quality deteriorated and productivity decreased the following year. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals DETERMINING FERTILIZER NITROGEN NEEDS FOR FRESH MARKET TOMATO IN KENTUCKY

HortScience ◽  
1996 ◽  
Vol 31 (5) ◽  
pp. 759f-760
Author(s):  
R. Terry Jones ◽  
David C. Ditsch
Keyword(s):  
Fruit Size ◽  
Yield Response ◽  
Residual Soil ◽  
Soil Mineral N ◽  
Soil Mineral ◽  
Fresh Market ◽  
Available Nitrogen ◽  
Mineral N ◽  
Significant Difference ◽  
Petiole Sap

Tomato fertility trials (1992–94) showed no yield response to fertigation N rates between 101–393 kg·ha–1. In 1995, soil Cardy NO3-N readings taken just prior to fertigation showed 53 kg NO3-N/ha in the top 30 cm. Laboratory test on the same sample showed 72.4 kg/ha (NO3 + NH4-N). Forty percent of the available nitrogen was NH4-N, which is not detected by Cardy meters. Soil mineral N levels were measured at fourth injection, second harvest, and 9 days after last harvest. On these dates the 0 kg N/ha treatment had 28, 24, and 8 mg N/kg available in the top 15 cm of soil, similar to the N fertigation treatments. As the growing season progressed, soil mineral N levels decreased, and 9 days after the last harvest residual soil N levels were close to those seen initially. Tomato petiole sap Cardy NO3-N readingsshowed a significant difference between the 0 kg·ha–1 treatment and those (84, 168, and 252 kg·ha–1) receiving N (512 ppm vs. 915, 1028, and 955 ppm NO3-N, respectively). Treatments receiving fertigation N gave petiole sap NO3-N readings higher than those listed by Hochmuth as sufficient for tomatoes. While the data showed a clear separation between the three N treatments and 0 N rate, no significant difference in yield of US #1 or US #2 large fruit occurred. This suggests that adequate N fertility was provided from O.M. mineralization. The highest N rate also had significantly more US #1 small and cull tomatoes than the other treatments. Some Kentucky soils have adequate residual N capable of producing commercial fresh-market tomato crops with little or no additional N. In addition to potential ground water pollution, overfertilization of tomatoes may decrease fruit size and reduce fruit quality by causing NH4-K + ion competition, as well as increase the risk of certain fungal and bacterial diseases.

Can split or delayed application of N fertiliser to grain sorghum reduce soil N2O emissions from sub-tropical Vertosols and maintain grain yields?

Soil Research ◽  
2019 ◽  
Vol 57 (8) ◽  
pp. 859 ◽  
Author(s):  
G. D. Schwenke ◽  
B. M. Haigh
Keyword(s):  
Grain Yield ◽  
N Uptake ◽  
Grain Sorghum ◽  
Yield Response ◽  
N2o Emissions ◽  
Residual Soil ◽  
Soil Mineral N ◽  
Soil Mineral ◽  
Mineral N ◽  
Crop N Uptake

Most soil nitrous oxide (N2O) emissions from rain-fed grain sorghum grown on sub-tropical Vertosols in north-west New South Wales, Australia, occur between fertiliser nitrogen (N) application at sowing and booting growth stage. At three experiments, we investigated the potential for deferring some (split-N) or all (delayed) fertiliser N until booting to mitigate N2O produced without compromising optimum crop yields. N products included urea, 3,4-dimethyl pyrazole phosphate (DMPP)-urea, polymer-coated urea (PCU) and N-(n-butyl)thiophosphoric triamide (NBPT)-urea. For a fourth experiment, the N fertiliser rate was varied according to pre-sowing soil mineral N stocks left by different previous crops. All experiments incorporated 15N mini-plots to determine whether delayed or split-N affected crop N uptake or residual soil N. Compared to urea applied at-sowing, delayed applications of urea, DMPP-urea or NBPT-urea at booting reduced the N2O emission factor (EF, percentage of applied N emitted) by 67–81%. Crop N uptake, grain yield and protein tended to be lower with delayed N than N at-sowing due to dry mid-season conditions. Much of the unused N remained in the soil at harvest. Split-N (33% sowing:67% booting) using urea, reduced EF by 59% compared to at-sowing urea, but maintained crop N uptake, grain yield and protein. Using DMPP-urea or PCU for the at-sowing portion of the split reduced EF by 84–86%. Grain yield was maintained using PCU, but was lower with DMPP-urea, which had more N in vegetative biomass. Using NBPT-urea for the in-crop portion of the split did not affect N2O emissions or crop productivity. Nitrogen budgeting to account for high pre-sowing soil mineral N nullified urea-induced N2O emissions. An N-budgeted, split-N strategy using urea offers the best balance between N2O mitigation, grain productivity and provision of a soil mineral N buffer against dry mid-season conditions. Split-N using DMPP-urea or PCU further enhanced N2O mitigation but there was no yield response to justify the extra expense.

scholarly journals DOUBLE-CROP FALL CABBAGE AS A SCAVENGER OF RESIDUAL FERTILIZER NITROGEN

HortScience ◽  
1996 ◽  
Vol 31 (5) ◽  
pp. 758c-758
Author(s):  
David C. Ditsch ◽  
Richard T. Jones
Keyword(s):  
Cover Crops ◽  
Sweet Corn ◽  
N Fertilization ◽  
Yield Response ◽  
Winter Rye ◽  
Soil Mineral N ◽  
Fertilizer N ◽  
Soil Mineral ◽  
Mineral N ◽  
Residual Fertilizer N

High-value crops (tobacco and sweet corn) often receive high levels of N fertilizer during the growing season rather than risk yield and/or quality reductions. Following harvest, small-grain winter cover crops are sown to reduce soil erosion and recover residual fertilizer N. Fall cole crops, such as cabbage, grow rapidly in early fall, respond well to N fertilization, and have the potential to be sold for supplemental income. The objectives of this study were to 1) compare fall cabbage and winter rye as scavengers of residual fertilizer N and 2) determine if a relationship between fall soil mineral-N (NO–3 +) levels and fall cabbage yield response to N fertilization exists. Soil mineral N levels following sweet corn and tobacco ranged from 22 to 53 mg·kg–1 in the surface 30-cm and declined with depth. Fall cabbage appeared to be as effective as rye at reducing soil mineral N levels. No fall cabbage dry matter yield response to applied N was measured in 1993 and 1995. However, following sweet corn in 1994, a small cabbage yield response to N at 56 kg·ha–1 was measured when the soil mineral level, prior to fall fertilization, was 22 mg·kg–1.

scholarly journals Growth and Yield of Broccoli as Affected by the Nitrogen Content of Transplants and the Timing of Nitrogen Fertilization

HortScience ◽  
2005 ◽  
Vol 40 (5) ◽  
pp. 1320-1323 ◽  
Author(s):  
Carmen Feller ◽  
Matthias Fink
Keyword(s):  
Field Experiments ◽  
N Fertilizer ◽  
Growth And Yield ◽  
Growth Stages ◽  
Soil Mineral N ◽  
Soil Mineral ◽  
Mineral N ◽  
N Content ◽  
Available N ◽  
N Supply

The nitrogen requirement of broccoli (Brassica oleracea var. italica) ranges from 300 to 465 kg·ha–1. Recommendations for N fertilization are accordingly high. High fertilizer rates applied at planting result in a high soil mineral N content that remains high for weeks because the N requirement of the crop is low at early growth stages. Therefore, the risk of leaching is high for several weeks until the available N is finally taken up by the crop. Our study had two objectives: 1) to quantify yield responses to preplant fertilization, and 2) to test our hypothesis that the preplant fertilization rate could be reduced without yield losses by increasing the N content in the transplants and improving crop establishment. Field experiments were carried out on transplants with four levels of N content in dry matter (0.018 to 0.038 g·g–1 dry weight), which were tested in all combinations with four fertilization timings. All treatments received the same amount of N fertilizer (270 and 272 kg·ha–1 in 2001 and 2002, respectively), but with different rates of supply at the time of planting (0 to 90 kg·ha–1 N fertilizer plus 30 and 28 kg·ha–1 soil mineral N in 2001 and 2002, respectively). Total and marketable yields increased significantly with an increasing N supply at time of planting. In our experiments, in which topdressing was applied 25 days after planting, an N supply at planting of 80 to 118 kg·ha–1 was required to obtain maximum marketable yields. The N content in transplants had little effect on growth and yield, and there were no significant interactions between the N content in the transplant and fertilizer timing.

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