**4. Conclusions**

fertilized while in the following two campaigns, wheat was again preceded by wheat and it was not fertilized. The extraction by the aerial part at the other treatments ranged between 134 and 188 kg N ha−1. Mineralization rate was between 93 and 123 kg N ha−1 at the three campaigns.

O em) 5 ± 4 4 ± 1 8 ± 3

Nmin after harvest (NminAH) 50 ± 4 37 ± 4 30 ± 3 40 ± 1 N TOTAL OUTPUTS 160 ± 135 ± 8 229 ± 21 224 ± 25 296 ± 22 N not computed 12 ± 16 58 ± 24 65 ± 28 86 ± 27 Fertilizer use efficiency (NUE) 0.76 ± 0.22 0.82 ± 0.21 0.72 ± 0.11 N harvest index (HI) 0.76 ± 0.77 0.77 ± 0.03 0.71 ± 0.08 0.65 ± 0.04

Dosage (kg N ha−1) 0 140 140 220 Splitting 0 40 + 100 40 + 60 + 40 80 + 140 Nmin initial (NminS) 25 ± 5 24 ± 1 25 ± 3 40 ± 10 N mineralized (MIN) 123 ± 12 123 ± 12 123 ± 12 123 ± 11 N fertilized (F) 0 140 140 220 N TOTAL INPUTS 147 ± 13 287 ± 12 288 ± 13 383 ± 15 N absorbed by the aerial part (Nab) 53 ± 6 139 ± 21 145 ± 25 180 ± 22 N absorbed by the roots (Nabr) 13 ± 1 35 ± 5 36 ± 6 45 ± 5 N leached (Nlix) 14 ± 3 14 ± 2 12 ± 2 23 ± 3

It can be observed that the non-accounted N augmented with the N fertilizer dose, as it hap-

also observed for balances performed in Navarra and Castilla-La Mancha [34]. As Estavillo et al. [15] reported, these facts suggest an N mineralization rate different to that of the nonfertilized treatment and dependent on the broadcast N fertilizer dose. In this sense, Kuzyakova and Stahr [27] observed there was an effect on the mineralization pattern after the fertilizer application and Webster et al. [44] imputed the increasing Nc to short periods of immobilization that increased with the increasing quantity of available Nmin. Another possibility is that the increase of Nc might be due to some other kind of undetermined losses in the study such as those derived from ammonia leaching, which is presumed not to be very large since the ammonia quantity regarding nitrate is around 10% of the Nmin (**Table 5**). The losses corresponding to ammonia volatilization were not accounted for, but in posterior studies in the zone, they

NUE (nitrogen use efficiency) ranged between 0.35 and 0.60 in the year 2002 and between 0.62 and 0.82 in the years 2003 and 2004 (**Tables 9–11**). This occurred due to the major extraction of the non-fertilized treatment at the first campaign as compared to the following two, since in the first campaign, the essay was preceded by a fertilized crop, while in the following two campaigns, the

O. In general, such an effect was

pened with the leached N quantities and the N emitted as N<sup>2</sup>

The average values ± standard error are indicated.

**Table 10.** N balance (kg N ha−1) during campaign 2003.

N gas (N2

92 Global Wheat Production

have proved to be dismissible (personal communication).


nitric N quantities leached until years 2003 and 2004 ranged between 4 and 6% of the N broadcast. If the sampling period after harvest in year 2004 was also considered, the losses ranged between 8 and 14% of the N broadcast.

**References**

Wallinford, UK: CAB International; 1991

Resources, Development and Management Service; 1998

logy. Clackomas, OR, Alpkem Corp; 1986. p. 1-10

Clackomas, OR, Alpkem Corp; 1987: p. 1-7

AOAC International; 1999. p. 24127

mental Geology. 1997;**30**:257-265

de Navarra; 2006

Amsterdam: Elsevier; 1985

Moisier. 2004. pp. 261-278

[1] Addiscot TM, Whtmore AP, Powlson DS. Farming, Fertilizers and the Nitrate Problem.

Nitrogen Losses: Gaseous and Leached Nitrogen Balance

http://dx.doi.org/10.5772/intechopen.75801

95

[2] Allen RG, Pereira LS, Raes D, Smith M. Crop Evapotranspiration—Guidelines for Computing Crop Water Requirements—FAO Irrigation and Drainage Paper 56. Water

[3] Alpkem, Nitrate + nitrite nitrogen (A353, S-170). In: Alpkem Corp editor. RFA Methodo-

[4] Alpkem. Ammonia nitrogen (A303, S-020). In: Alpkem Corp editor. RFA Methodology,

[5] Association of Official Analytical Chemists International (AOAC). Plants. In: Cunniff P, editor. Official Methods of AOAC International. 16th ed. Gaithersburg, Maryland, USA:

[6] Arrate I, Sanchez-Perez JM, Antigüedad I, Vallecillo MA, Iribar V, Ruiz M. Groundwater pollution in quaternary aquifer of Vitoria–Gasteiz (Basque Country, Spain). Environ-

[7] Arregui LM. Estrategiasparamejorar la eficienciadelnitrógeno en sistemascerealistas de secano en climamediterráneohúmedo [tesis doctoral]. Pamplona: Universidad Pública

[8] Aulakh MS, Doran JW, Moisier AR. Soil denitrification—Significance, measurement and

[9] Blake GR, Hartge KH. Bulk density. In: Klute A editor. Methods of Soil Analysis. Part 1. Physical and Mineralogical Methods. Madison WI: ASA-SSSA; 1986. p. 363-375

[11] Campbell GS. Soil Physics with BASIC: Transport Models for Soil-Plant Systems.

[12] Dobermann A, Casssman KG. Environmental Dimensions of Fertilizer Nitrogen: What Can Be Done to Increase Nitrogen Use Efficiency and Ensure Global Food Security? In:

[13] EEC. Council Directive 88/778/EEC of 15 July 1980 relating to the quality of water

[14] Gobierno Vasco-EuskoJaurlaritza (GV-EJ). Decreto 390/1998 por el que se dictannormaspara la declaración de ZonasVulnerables a la contaminación de lasaguaspor los nitratosprocedentes de la actividadagraria and se aprueba el Código de BuenasPrácticasAgrarias

de la ComunidadAutónoma del País Vasco. BOPV. 1999;**18**:1448-1474

effects of management. Advances in Soil Sciences. 1992;**18**:1-57

[10] Bouwman AF. Soils and the Greenhouse Effect. New York: Wiley; 1990

intended for human consumption. OJL. 1980;**229**:11

