A network of field studies determined that the traditional method for predicting soil N availability …a pre-plant nitrate test … can be combined with an indicator of soil N mineralization capacity to significantly improve the diagnosis for soil N availability for both wheat and corn.Fil: Reussi Calvo, Nahuel Ignacio. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Laboratiorio de Suelos. Fertilab; ArgentinaFil: Echeverría, Hector E.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Sainz Rozas, Hernan Rene. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Berardo, Angel. Laboratiorio de Suelos. Fertilab; ArgentinaFil: Diovisalvi, Natalia. Laboratiorio de Suelos. Fertilab; Argentin

Berardo, Angel

Diovisalvi, Natalia

Echeverría, Hector E.

Reussi Calvo, Nahuel Ignacio

Sainz Rozas, Hernan Rene

English

CONICET Digital

12Better Crops/Vol. 98 (2014, No. 2) Abbreviations and notes: N = nitrogen; NH4+ = ammonium; NO3- = nitrate; OM = organic matter; ppm = parts per million; RY = relative yield.ARGENTINAThe process of mineralization is a major source of available N for crops, particularly in soils with high OM content. Mineralization usually satisfi es 30% and 60% of the N demand of wheat and corn grown in the southern region of Buenos Aires Province. However, soil N mineralization poten-tial is site-specifi c. A simple and reliable way to estimate this potential in the region is the laboratory soil test known as Nan, which stands for anaerobically incubated N. This technique consists of measuring NH4+-N released during a 7 day, 40°C anaerobic incubation of surface soil (0 to 20 cm sample depth). The Nan test is closely correlated to potentially mineralizable N determined by long-term aerobic incubations (Soon et al., 2007), and it is sensitive to changes in management practices and tillage systems (Genovese et al., 2009). Moreover, the short period of time required to perform the Nan test repre-sents an advantage over other methodologies that estimate N mineralization, which makes it useful as a routine method in soil testing laboratories.In a soil survey in the Buenos Aires Province, Reussi Calvo et al. (2011) determined values of Nan ranging from 25 to 115 mg/kg. These values varied with location and tended to decrease from east to west (Figure 1). This change in Nan is evidence of different soil N mineralization potential within the area that should be considered when adjusting the rate of N application (Sainz Rozas et al., 2008; Reussi Calvo et al., 2013a). This particular pattern of N mineralization potential may refl ect agricultural history, management practices, and climatic conditions (Genovese et al., 2009).Today, the most widely used N diagnostic method for wheat and corn in Argentina is a NO3--N soil test of top 60 cm of the soil profi le taken at planting time (Sainz Rozas et al, 2008; Barbieri et al, 2009).  Different thresholds for N availability (soil + fertilizer) have been proposed, which vary by region, tillage system, and yield goal (Barbieri et al., 2009). However, this simplifi ed model does not consider the direct contribution of soil N mineralization. Only 38 to 54% of the variation in crop yield is explained by NO3--N (0 to 60 cm) availability at planting time (Sainz Rozas et al, 2008; Barbieri et al., 2009). Nan Experiments in WheatThe contribution of Nan to N fertilization diagnose in wheat (Figure 2) was evaluated in southern Buenos Aires (Balcarce region) for a 5 year period at 28 sites. Soil OM content varied from 4.4 to 6.8 %, while Nan varied from 34 to 94 mg/kg and the availability of NO3--N varied between 39 and 130 kg N/ha. These values are strong indicators of a signifi cant difference in soil N mineralization potential (Reussi Calvo et al., 2013a).Only 24% of the yield variability in the control plots (CY) was explained by the soil NO3--N test (Table 1), which high-By Nahuel Reussi Calvo, Hector E. Echeverría, Hernan Sainz Rozas, Angel Berardo, and Natalia Diovisalvi A network of field studies determined that the traditional method for predicting soil N availability …a pre-plant nitrate test … can be combined with an indicator of soil N mineralization capacity to significantly improve the diagnosis for soil N availability for both wheat and corn.Can a Soil Mineralization TestImprove Wheat and Corn Nitrogen Diagnosis?Figure 1. Average levels of anaerobically incubated N (Nan) in the surface layer (0 to 20 cm) of soil (3,240 samples) in the Buenos Aires Province, Argentina. Anaerobically incubated nitrogen25-35 ppm26-50 ppm51-65 ppm66-80 ppm81-115 ppmKilometers50.000 100.000 200.0000Response to N (on left) in an environment with low soil N mineralization as determined by the Nan diagnostic test.Better Crops/Vol. 98 (2014, No. 2)13lights the limitations of using this single variable for soil N diagnosis in wheat. Nan concentration had a greater impact on the CY than did NO3--N content, as it explained 41% of yield variability (Table 1). When NO3--N availability and Nan were combined the estimation of CY was improved signifi cantly (Table 1 and Figure 3a).Pre-plant NO3--N content was not a good predictor of N exported in grain. However, when Nan was incorporated into the model, the estimation was improved from 11 to 58% (Table 1 and Figure 3b). Nan Experiments in CornNan’s contribution to the N diagnosis in corn was evalu-ated for six years at 14 sites within the provinces of Santa Fe and Buenos Aires (Figure 2). In these respective regions, the Figure 2. Location of experiments for wheat and corn in Santa Fe and Buenos Airies, Argentina.   Table 1.   Models to estimate the yield (kg/ha) in control plots and the N exported in wheat grain, and the relative yield (%) of corn at planting and six-leaf (V6). Sources: Reussi Calvo et al., 2013a; Sainz Rozas et al. (2008).Models for wheat (n = 28) Adjusted r2 Control yield = 3,609+ 18.810 x NO3--N 0.24Control yield = -1,555+ 80.732 x NO3--N- 0.38 x (NO3--N )2 + 47.423 x Nan 0.66Grain N = 57.8+ 0.172 x NO3--N 0.11Grain N = 19.1+ 0.134 x NO3--N + 0.662 x Nan 0.58Models for corn (n = 26) Adjusted r2 Relative yield at planting = 61.7+ NO3--N x 0.234 0.37Relative yield at planting = 53.8+ NO3--N x 0.182 + 0.213 x Nan 0.57Relative yield at V6 = 41.9 + NO3--N x 0.653 0.56Relative yield at V6 = 41.5 + NO3--N x 0.492 + 0.193 x Nan 0.73Nan = anaerobic N (mg/kg, 0 to 20 cm). For wheat and corn, NO3--N at planting is kg/ha, at 0 to 60 cm. For corn, NO3--N at V6 is kg/ha, at 0 to 30 cm.South AmericaArgentinaSanta Fe ProvinceBuenos AiresProvinceSoutheasternBuenos AiresWHEATCORNFigure 3. Contribution of Nan and preplant NO3--N to the yield (a) and N exported in wheat grain (b). Adapted from Reussi Calvo et al. (2013a).409,0008,0007,0006,0005,0004,0003,0002,0001,000060801001204070100130Control yield, kg/ha8,000-9,0006,000-7,0005,000-6,0004,000-5,0003,000-4,000a) Nan, mg/kg NO 3- -N, kg/ha7,000-8,000120-140100-12080-10060-8040-604070100130020406080100120140406080100120N in grain, kg/hab)Nan, mg/kg NO 3- -N, kg/ha14Better Crops/Vol. 98 (2014, No. 2)soil NO3--N test already explained 53% and 45% of the crop yield variability (Reussi Calvo et al., 2013b). When Nan was included in the model the predictor improved by 5% in Santa Fe and 16% in Balcarce. The larger contribution of Nan to corn yield estimation in Balcarce is explained by the region’s lower temperatures and higher OM contents, which would limit the overall predictive capability of the soil NO3--N test that is performed at planting.A network of 26 experiments conducted in the southern Pampas (Sainz Rozas et al., 2008) determined that the com-bined measurement of soil NO3--N content with Nan improved the estimation of N availability at planting and V6 (Table 1). Furthermore, Nan has a greater partial contribution to the RY sampling at V6 than at planting (Table 1; Figure 4a and 4b). The use of NO3--N at planting or V6 may be a relatively reliable methodology for predicting corn response to N fertilization in the Pampas. However, the predictive value is increased when Nan is incorporated for N diagnosis. BCDr. Reussi Calvo is with FERTILAB Soil Testing and Unidad Integrada INTA-FCA Balcarce (e-mail: nreussicalvo@laboratoriofertilab.com.ar). Mr. Echeverria and Dr. Sainz Rozas are with Unidad Integrada INTA-FCA Balcarce, Mr. Berardo and Mrs. Diovisalvi are with FERTILAB Soil Testing.    ReferencesBarbieri, P.A., H.E. Echeverría, and H.R. Sainz Rozas. 2009. Cien. Suelo 27:115-125.Genovese, F., H.E. Echeverría, G.A. Studdert, and H. Sainz Rozas. 2009. Cien. Suelo 27:225-236.Reussi Calvo, N.I., H. Sainz Rozas, H.E. Echeverría, and A. Berardo. 2013a. Agron. J. 105:321-328.Reussi Calvo, N., H. Saiz Rozas, A. Berardo, H.E. Echeverría, and N. Dio-visalvi. 2013b. Simposio de Fertilidad. 22 y 23 de Mayo, Rosario, Santa Fé, Argentina. 269-272.Sainz Rozas, H., P. Calviño, H.E. Echeverría, M. Redolatti, and P. Barbieri. 2008. Agron. J. 100:1020-1025.Soon, Y.K., A. Haq, and M.A. Arshad. 2007. Com. Soil Sci. Plant Anal. 38:2029-2043.2030405060708090100406080100Relative yield, %90-10080-9070-8060-70a) at planting Nan, mg/kg NO 3- -N, kg/ha305070901102030405060708090100406080100Relative yield, %90-10080-9070-8060-70b) at six-leaf (V6)Nan, mg/kg NO 3- -N, kg/ha304050806070Figure 4. Contribution of Nan and NO3--N content to the relative performance of corn sampled at planting (a) and at six-leaf (V6) stage (b). Adapted from Sainz Rozas et al. (2008).–Nitrogen response in an environment with low Nan. From left to right 0, 100, 200, and 300 kg N/ha.

Can a Soil Mineralization Test Improve Wheat and Corn Nitrogen Diagnosis?

LAReferencia - Red Federada de Repositorios Institucionales de Publicaciones Científicas Latinoamericanas

http://ri.conicet.gov.ar/bitstream/11336/25886/5/CONICET_Digital_Nro.27df9a9c-8046-4524-b6fd-fb0ef89afd56_B.pdf

Can a Soil Mineralization Test Improve Wheat and Corn Nitrogen Diagnosis?

Abstract

Similar works

Full text

Available Versions

CONICET Digital

LAReferencia - Red Federada de Repositorios Institucionales de Publicaciones Científicas Latinoamericanas