INVESTIGADORES
RUBIO Gerardo
artículos
Título:
Potential nitrate losses under different agrictural practices in the pampean region, Argentina
Autor/es:
RIMSKI-KORSAKOV H., G. RUBIO, R.S. LAVADO
Revista:
AGRICULTURAL WATER MANAGEMENT
Referencias:
Año: 2004 vol. 65 p. 83 - 94
ISSN:
0378-3774
Resumen:
 In agricultural soils, fertilization is an important cause of groundwater contamination with nitrates. The objectives of the present work were i) to quantify the nitrate leaching in two fertilized and irrigated soils of the Pampas Region, Argentina; ii) to test the ability of the NLEAP model to predict residual and leached nitrate in those soils. The soils were a Typic Hapludoll and a Typic Argiudoll. The treatments were: natural grassland never ploughed or fertilized; maize with a short history of fertilization; maize with a long history of fertilization; irrigated maize with a long history of fertilization. Both soils were sampled after harvest in two consecutive years to a 3 m depth. Residual nitrates and potential losses below 150 cm were estimated by NLEAP model. The average amount of nitrates (NO3-N) in the upper layer (0-1.5 m) was 128 kg NO3-N ha-1 in the first sampling date and  was consistently lower in the second sampling date (38 kg NO3-N).  In the deeper layer (1.5-3 m) these values were 80 and 28 kg NO3-N ha-1 for the first and second sampling date respectively. Differences between the non-fertilized and the fertilized treatments were significantly smaller in the second sampling date. Obtained results suggests that the rainfall previous to the first sampling was not enough to displace nitrates below 3 m depth. The afterwards heavy rainfall leached nitrates previously accumulated in the soil . Simulated residual and leached nitrates showed a high correlation with observed values. Although both soils have different characteristics, their nitrate leaching is related to the rainfall regime and to crop yields. Simulated residual and leached nitrates showed a high correlation with measured values in both soils, which suggests that NLEAP was appropriate to predict soil nitrate leaching under the studied conditions.