NITROGEN TRANSFORMATIONS IN SOIL-PLANT SYSTEMS IN THREE YEARS OF FIELD EXPERIMENTS USING TRACER AND NON-TRACER METHODS ON AN AMMONIUM-FIXING SOIL

1978 ◽  
Vol 58 (2) ◽  
pp. 195-208 ◽  
Author(s):  
C. G. KOWALENKO ◽  
D. R. CAMERON
Keyword(s):  
Plant Uptake ◽  
N Mineralization ◽  
Maximum Rate ◽  
Field Experiments ◽  
N Uptake ◽  
Growing Season ◽  
N Fertilization ◽  
Mineralization Rate ◽  
Fertilizer N ◽  
Inorganic N

Three years of field experiments showed the interplay of plant uptake of N, N movement, denitrification, fixation of fertilizer NH4+ and its release, and N mineralization in soil–plant systems. The N uptake by barley (Hordeum vulgare L.), averaged over the growing season, ranged between 0.97 and 2.02 kg N/ha/day and the rate depended on initial extractable inorganic N in the soil, and form and timing of N fertilization. The net mineralization rate of this soil, averaged over the growing season, ranged between 0.16 and 1.80 kg N/ha/day and varied with year and N fertilization practices. However, detailed monitoring of plant uptake showed that a maximum rate of uptake occurred early in its growth, decreasing to a negligible rate later in the season. The N mineralization rate was more uniform over the growing season. A pool of inorganic N in the soil at seeding or within the first half of the growing season overcame the seasonal deficit in N supply and resulted in increased crop growth and/or N uptake. Fertilizer N movement was small and never beyond the maximum (75-cm) sampling depth. This supported the assumption that unrecovered fertilizer N in this study was largely due to denitrification. Denitrification was shown to be greatly influenced by the season, with a maximum rate occurring in the spring or early summer, and concurred with the period of maximum rate of plant uptake of N. Denitrifiers were capable of competing with high rates of plant uptake since the rate of denitrification was similar in fallow and cropped systems. The form of N application (NO3−, NH4+, NH4+ plus N-serve) did not significantly affect the denitrification rate. The soil used in this study fixed 34–60% of the 150 kg NH4+/ha fertilizer immediately upon application. The fixed fertilizer N was available to barley, with 71–96% of the recently fixed NH4+ being released over the growth period. The presence of N-serve resulted in less fixed fertilizer NH4+ being released during crop growth.

The effect of stubble management and N-fertilization practices on the nitrogen economy under intensive rice cropping

Soil Research ◽  
1989 ◽  
Vol 27 (4) ◽  
pp. 685 ◽  
Author(s):  
PE Bacon ◽  
LG Lewin ◽  
JW McGarity ◽  
EH Hoult ◽  
D Alter
Keyword(s):  
Field Experiments ◽  
Oryza Sativa L ◽  
N Uptake ◽  
Application Rate ◽  
N Fertilization ◽  
Rice Crop ◽  
Soil N ◽  
Fertilizer N ◽  
N Application ◽  
Total N

The fate of 15N-labelled fertilizer applied to rice (Oryza sativa L) was studied in microplots established within two field experiments comprising a range of stubble levels, stubble management techniques, N application rates and times. The first experiment investigated uptake of soil and fertilizer N in plots where application of 0 or 100 kg N ha-1 to the previous rice crop had produced 11.5 and 16.1 t ha-1 of stubble respectively. The stubble was then treated in one of four ways-burn (no till); burn then cultivated; incorporated in autumn or incorporated at sawing. Microplots within these large plots received 60 kg ha-1 of 5% 15N enriched urea at sowing, just prior to permanent flood (PF), or just after panicle initiation (PI) of the second crop. The second experiment was undertaken within a field in which half of the plots had stubble from the previous three rice crops burned, while the other plots had all stubble incorporated. In the fourth successive rice crop, the two stubble management systems were factorially combined with three N rates (0, 70 or 140 kg N ha-1) and three application times (PF, PI or a 50 : 50 split between PF and PI). Nitrogen uptake and retention in the soil were studied within 15N-labelled microplots established within each of these large plots. Only 4% of the 15N applied at sowing in the first experiment was recovered in the rice crop, while delaying N application to PF or PI increased this to an average of 20% and 44% respectively over the two experiments. The doubling of N application rate doubled fertilizer N uptake and also increased uptake of soil N at maturity by 12 kgN ha-1. Three years of stubble incorporation increased average uptake of fertilizer and soil N in the second experiment by 5 and 12 kg N ha-1 respectively. In both experiments, the soil was the major source of N, contributing 66-96% of total N uptake. On average, in the fourth crop, 20% of fertilizer N was in the grain, 12% in the straw and 3% in the roots, while 23% was located in the top 300 mm of soil. A further 3% was in the soil below 300 mm. The remaining 39% was lost, presumably by denitrification.

Fate of urea nitrogen applied in solution in furrows to sunflowers growing on a red-brown earth: transformations, losses and plant uptake

1988 ◽  
Vol 39 (5) ◽  
pp. 793 ◽  
Author(s):  
CJ Smith ◽  
JR Freney ◽  
PM Chalk ◽  
IE Galbally ◽  
DJ McKenney ◽  
...  
Keyword(s):  
Plant Uptake ◽  
N Uptake ◽  
Fertilizer Application ◽  
Urea Solution ◽  
15N Balance ◽  
Nitrogen Transformations ◽  
Fertilizer N ◽  
Inorganic N ◽  
N Loss ◽  
Soil N Uptake

Nitrogen transformations and transfers were investigated after applying a urea solution to a crop of sunflowers by ponding in furrows. The fertilizer was applied 24 days after sowing. Distribution of the applied nitrogen (N) in the soil, N uptake by plants, and losses by ammonia (NH3) volatilization and denitrification were measured. This method of fertilizer application resulted in concentration of the applied N in the furrow and shoulder zone of the soil beds; little of the applied N moved across to the centre of the beds. Inorganic N was not leached into the clay B horizon, but was retained by the surface 0-200 mm layer. A 15N mass balance showed that 28 kg of the 80 kg N ha-1 applied (35%) was lost during the experiment. Less than 5 kg N ha-1 (6% of the applied N) was lost as NH3 and the remainder (22 kg N ha-1 or 29% of the applied N) appeared to be lost by denitrification. The 15N balance data suggest that c. 4.6 kg ha-1 fertilizer N were lost after each irrigation up to 44 days after fertilizer application. The study indicates that N loss could be markedly reduced by delaying the bulk of the application to coincide with the period of rapid uptake.

Nitrogen Fertilization of Guinea and Napier Grass (Panicum maximum and Pennisetum purpureum) in Malaysian Oligotrophic Peat

1982 ◽  
Vol 18 (1) ◽  
pp. 73-78
Author(s):  
W. Y. Chew ◽  
K. Ramli ◽  
A. B. A. Majid
Keyword(s):  
Nitrogen Fertilization ◽  
Field Experiments ◽  
Positive Response ◽  
N Uptake ◽  
N Fertilization ◽  
Napier Grass ◽  
Pennisetum Purpureum ◽  
N Recovery ◽  
Panicum Maximum ◽  
Fertilizer N

SUMMARYTwo field experiments studied the nitrogen fertilizer requirements of guinea and napier grass on peat. Plants in the control plots, though optimally limed and fertilized with other nutrients, absorbed only 1.7 and 2.4% of total peat N in a year and N fertilization improved DM yield, with an optimum at 900 kg/ha/yr. Further positive response was not observed, probably because of a reduced ratio of N to other nutrients. Optimum N uptake, and N concentration in the DM, were achieved at 600 kg/ha/yr N but N recovery decreased linearly with increasing fertilizer N at the rate of about 2–4% per 100 kg/ha/yr N.

Tillage, crop residue and crop sequence effects on nitrogen availability in a legume-based cropping system

2004 ◽  
Vol 84 (4) ◽  
pp. 421-430 ◽  
Author(s):  
Y. K. Soon ◽  
M. A. Arshad
Keyword(s):  
Crop Yield ◽  
Crop Residue ◽  
N Uptake ◽  
Microbial Biomass N ◽  
Fertilizer N ◽  
Inorganic N ◽  
Soil Inorganic N ◽  
Crop Sequence ◽  
Extractable Soil ◽  
Soil Inorganic

A field study was conducted to determine the effects and interactions of crop sequence, tillage and residue management on labile N pools and their availability because such information is sparse. Experimental treatments were no-till (NT) vs. conventional tillage (CT), and removal vs. retention of straw, imposed on a barley (Hordeum vulgare L.)-canola (Brassica rapa L.)-field pea (Pisum sativum L.) rotation. 15N-labelling was used to quantify N uptake from straw, below-ground N (BGN), and fertilizer N. Straw retention increased soil microbial biomass N (MBN) in 2 of 3 yr at the four-leaf growth stage of barley, consistent with observed decreases in extractable soil inorganic N at seeding. However, crop yield and N uptake at maturity were not different between straw treatments. No tillage increased soil MBN, crop yield and N uptake compared to CT, but had no effect on extractable soil inorganic N. The greater availability of N under NT was probably related to soil moisture conservation. Tillage effects on soil and plant N were mostly independent of straw treatment. Straw and tillage treatments did not influence the uptake of N from its various sources. However, barley following pea (legume/non-legume sequence) derived a greater proportion of its N from BGN (13 to 23% or 9 to 23 kg N ha-1) than canola following barley (nonlegumes) (6 to 16% or 3 to 9 kg N ha-1). Fertilizer N constituted 8 to 11% of barley N uptake and 23 to 32% of canola N uptake. Straw N contributed only 1 to 3% of plant N uptake. This study showed the dominant influence of tillage on N availability, and of the preceding crop or cropping sequence on N uptake partitioning among available N sources. Key words: Crop residue, crop sequence, labile nitrogen, nitrogen uptake, pea, tillage

Use of hot KCl-NH4-N to estimate fertilizer N requirements

1997 ◽  
Vol 77 (2) ◽  
pp. 161-166 ◽  
Author(s):  
C. A. Campbell ◽  
Y. W. Jamel ◽  
A. Jalil ◽  
J. Schoenau
Keyword(s):  
N Mineralization ◽  
Growth Models ◽  
Growing Season ◽  
Order Rate Constant ◽  
Weather Data ◽  
N Availability ◽  
Fertilizer N ◽  
Available N ◽  
Mineralizable N ◽  
Potentially Mineralizable N

We need an easy-to-use chemical index for estimating the amount of N that becomes available during the growing season, to improve N use efficiency. This paper discusses how producers may, in future, use crop growth models that incorporate indices of soil N availability, to make more accurate, risk-sensitive estimates of fertilizer N requirements. In a previous study, we developed an equation, using 42 diverse Saskatchewan soils, that related potentially mineralizable N (N0) to NH4N extracted with hot 2 M KCl (X), (i.e., N0 = 37.7 + 7.7X, r2 = 0.78). We also established that the first order rate constant (k) for N mineralization at 35°C is indeed a constant for arable prairie soils (k = 0.067 wk−1). We modified the N submodel of CERES-wheat to include k and N0 (values of N0 were derived from the hot KCl test). With long-term weather data (precipitation and temperature) as input, this model was used to estimate probable N mineralization during a growing season and yield of wheat (grown on fallow or stubble), in response to fertilizer N rates at Swift Current. The model output indicated that the amount of N mineralized in a growing season for wheat on fallow was similar to that for wheat on stubble, as we hypothesized. Further the model indicated that rate of fertilizer N had only minimal effect on N mineralized. We concluded that, despite the importance of knowing the Nmin capability of a soil, it is available water, initial levels of available N and rate of fertilizer N that are the main determinants of yield in this semiarid environment. The theoretical approach we have proposed must be validated under field conditions before it can be adopted for use. Key words: N mineralization, Hot KCl-NH4-N, potentially mineralizable N, CERES-wheat model

The short-term fate of urea applied to barley in a humid climate. II. A simple model

Soil Research ◽  
1984 ◽  
Vol 22 (2) ◽  
pp. 181 ◽  
Author(s):  
DR Scotter ◽  
IH Mohammed ◽  
PEH Gregg
Keyword(s):  
Simple Model ◽  
Plant Uptake ◽  
Field Experiments ◽  
Root Zone ◽  
Companion Paper ◽  
Fertilizer Application ◽  
Fertilizer N ◽  
Humid Climate ◽  
Data Set ◽  
Programmable Calculator

A simple model describing the transformations, leaching and plant uptake of the nitrogen (N) in urea fertilizer applied to a barley crop is presented. The model considers the root zone as a single compartment and uses daily time steps, and so can be run on a small programmable calculator. It consists of separate submodels for water, fertilizer N and native soil N. Data from a field experiment described in a companion paper were used for parameterization, and the model was then tested on another data set from that experiment. The model successfully predicted the effect, on the leaching and plant uptake of fertilizer N, of a large increase in rainfall plus irrigation from 103 mm to 186 mm in the 35 days following sowing and urea application. As an example of the model's utility, it is used to predict that if 30 mm of drainage occurred within 24 h of fertilizer application, about 33% of the fertilizer N would be leached from the root zone in the silt loam soil studied. However, the same amount of drainage occurring a week after fertilizer application would result only in about 8% of the fertilizer N being leached. The complementary roles that process-oriented field experiments and simple mechanistic models can play in soil fertility research are discussed.

Soybean nitrogen contribution to corn and residual nitrate under conventional tillage and no-till

1997 ◽  
Vol 77 (4) ◽  
pp. 543-551 ◽  
Author(s):  
F. S. Rembon ◽  
A. F. MacKenzie
Keyword(s):  
Glycine Max ◽  
Field Experiments ◽  
N Uptake ◽  
Conventional Tillage ◽  
Winter Precipitation ◽  
Silty Clay ◽  
Fertilizer N ◽  
Growing Seasons ◽  
Glycine Max L ◽  
Tillage Method

Soybean (Glycine max L. Merill) can produce high-N residues that may benefit subsequent corn (Zea mays L.) production, but the degree of benefit is often unpredictable and may be related to tillage methods. This study investigated the effects of conventional-tillage (CT) and no-tillage (NT) on fertilizer replacement values for corn in a corn-soybean rotation. Field experiments were conducted for two growing seasons on two soils, a Ste. Rosalie clay (Humic Gleysol), and an Ormstown silty clay (Humic Gleysol). Continuous corn, corn following soybean, soybean following corn, continuous soybean, and three levels of fertilizer N (0, 90, 180 and 0, 20, and 40 kg N ha−1 for corn and soybean, respectively) were compared. Tillage did not effect yield or N uptake consistently. Corn grain yields and N uptake were greater following soybean than following corn. Soybean provided N fertilizer credits ranging from 40 to 150 kg N ha−1, which was greater than the residual NO3 in the soil prior to planting. Credits were greater in the year with higher corn yields and lower previous winter precipitation resulting in greater NO3 carryover. Tillage effects on N credits from soybean differed between the sites. Consequently, N contributions of soybean to corn could not be related to tillage method or soil type. Key words:Zea mays L., Glycine max L. Merill, rotations, grain yield, N uptake, tillage, fertilizer N

scholarly journals The Nitrogen Use Efficiency: Meaning and Sources of Variation—Case Studies on Three Vegetable Crops in Central Italy

2011 ◽  
Vol 21 (3) ◽  
pp. 266-273 ◽  
Author(s):  
Paolo Benincasa ◽  
Marcello Guiducci ◽  
Francesco Tei
Keyword(s):  
Field Experiments ◽  
N Uptake ◽  
Irrigation Management ◽  
Central Italy ◽  
Utilization Efficiency ◽  
Fertilizer N ◽  
Application Method ◽  
N Concentration ◽  
Sources Of Variation ◽  
Use Efficiency

Nitrogen (N) use efficiency (NUE) of crops is examined by taking into account both plant N uptake efficiency, focusing on the recovery of fertilizer-N, and the utilization efficiency of the absorbed N. The latter is further analyzed as the overall effect of the absorbed N on crop leaf area, light absorption, photosynthesis, crop growth, biomass partitioning, and yield. The main sources of variation for the NUE of crops are considered, and several of them are discussed based on results from field experiments carried out at the University of Perugia (central Italy) between 1991 and 2008 on sweet pepper (Capsicum annuum), lettuce (Lactuca sativa), and processing tomato (Solanum lycopersicum). More specifically, the effects of species, cultivar, fertilizer-N rate, form and application method (mineral and organic fertilization, green manuring, fertigation frequency), and sink limitation are reported. Implications for residual N in the soil and leaching risks are also discussed. The fertilizer-N rate is the main factor affecting crop NUE for a given irrigation management and rainfall regime. Indeed, avoiding over fertilization is the first and primary means to match a high use efficiency and economic return of fertilizer-N with limited environmental risks from nitrate leaching. The form and application method of fertilizer-N also may affect the NUE, especially in the case of limiting or overabundant N supply. Particularly, high fertigation frequency increased the recovery of fertilizer-N by the crop. It is suggested that species-specific curves for critical N concentration (i.e., the minimum N concentration that allows the maximum growth) can be the reference to calibrate the quick tests used to guide dynamic fertilization management, which is essential to achieve both the optimal crop N nutritional status and the maximum NUE.

scholarly journals Yield, Nitrogen Dynamics, and Fertilizer Use Efficiency in Machine-harvested Cucumber

HortScience ◽  
2009 ◽  
Vol 44 (6) ◽  
pp. 1712-1718 ◽  
Author(s):  
Laura L. Van Eerd ◽  
Kelsey A. O'Reilly
Keyword(s):  
N Uptake ◽  
Growing Season ◽  
Control Treatment ◽  
Yield Response ◽  
N Recovery ◽  
Fertilizer N ◽  
N Budget ◽  
Available N ◽  
N Removal ◽  
Use Efficiency

The increase in fertilizer costs as well as environmental concerns has stimulated growers to re-evaluate their fertilizer applications to optimize nitrogen use efficiency (NUE) while maintaining crop yields and minimizing N losses. With these objectives, field trials were conducted at seven sites with five N rates (0 to 220 kg N/ha) of ammonium-nitrate applied preplant broadcast and incorporated as well as a split application treatment of 65 + 45 kg N/ha. In three contrasting years (i.e., cool/wet versus warm/dry versus average), N treatment had no observable effect on grade size distribution or brine quality. Based on the zero N control treatment, the limited yield response to fertilizer N was the result of sufficient plant-available N over the growing season. In the N budget, there was no difference between N treatments in crop N removal, but there was a positive linear relationship between N applied and the quantity of N in crop residue as well as in the soil after harvest. As expected, apparent fertilizer N recovery and N uptake efficiency were lower at 220 versus 110 kg N/ha applied preplant or split. The preplant and split applications of 110 kg N/ha were not different in yield, overall N budget, or NUE. Considering the short growing season, planting into warm soils, and the generally productive, nonresponsive soils in the region, growers should consider reducing or eliminating fertilizer N applications in machine-harvested cucumber.

scholarly journals Fresh Market Tomato Yield and Soil Nitrogen as Affected by Tillage, Cover Cropping, and Nitrogen Fertilization

HortScience ◽  
2000 ◽  
Vol 35 (7) ◽  
pp. 1258-1262 ◽  
Author(s):  
Sidat Yaffa ◽  
Bharat P. Singh ◽  
Upendra M. Sainju ◽  
K.C. Reddy
Keyword(s):  
Soil Erosion ◽  
N Uptake ◽  
N Fertilization ◽  
N Leaching ◽  
Hairy Vetch ◽  
Inorganic N ◽  
Cover Cropping ◽  
Tomato Yield ◽  
Soil Inorganic N ◽  
Soil Inorganic

Sustainable practices are needed in vegetable production to maintain yield and to reduce the potential for soil erosion and N leaching. We examined the effects of tillage [no-till (NT), chisel plowing (CP), and moldboard plowing (MP)], cover cropping [hairy vetch (Vicia villosa Roth) vs. winter weeds], N fertilization (0, 90, and 180 kg·ha-1 N), and date of sampling on tomato (Lycopersicon esculentum Mill.) yield, N uptake, and soil inorganic N in a Norfolk sandy loam in Fort Valley, Ga. for 2 years. Yield was greater with CP and MP than with NT in 1996 and was greater with 90 and 180 than with 0 kg·ha-1 N in 1996 and 1997. Similarly, aboveground tomato biomass (dry weight of stems + leaves + fruits) and N uptake were greater with CP and MP than with NT from 40 to 118 days after transplanting (DAT) in 1996; greater with hairy vetch than with winter weeds at 82 DAT in 1997; and greater with 90 or 180 than with 0 kg·ha-1 N at 97 DAT in 1996 and at 82 DAT in 1997. Soil inorganic N was greater with NT or CP than with MP at 0- to 10-cm depth at 0 and 30 DAT in 1996; greater with hairy vetch than with winter weeds at 0- to 10-cm and at 10- to 30-cm at 0 DAT in 1996 and 1997, respectively; and greater with 90 or 180 than with 0 kg·ha-1 N from 30 to 116 DAT in 1996 and 1997. Levels of soil inorganic N and tomato N uptake indicated that N release from cover crop residues was synchronized with N need by tomato, and that N fertilization should be done within 8 weeks of transplanting. Similar tomato yield, biomass, and N uptake with CP vs. MP and with 90 vs. 180 kg·ha-1 N suggests that minimum tillage, such as CP, and 90 kg·ha-1 N can better sustain tomato yield and reduce potentials for soil erosion and N leaching than can conventional tillage, such as MP, and 180 kg·ha-1 N, respectively. Because of increased vegetative cover in the winter, followed by increased mulch and soil N in the summer, hairy vetch can reduce the potential for soil erosion and the amount of N fertilization required for tomato better than can winter weeds.

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