Resumo

FIGUEROA VIRAMONTES, Uriel; NUNEZ HERNANDEZ, Gregorio; RETA SANCHEZ, David Guadalupe  e  FLORES LOPEZ, Hugo Ernesto. Regional nitrogen balance in the milk-forage production system in the Comarca Lagunera, Mexico. Rev. mex. de cienc. pecuarias [online]. 2015, vol.6, n.4, pp.377-392. ISSN 2448-6698.

The intensive system of milk production in the Laguna Region is characterized by large farms with more than 1,000 milking cows and irrigated areas for forage production. The objective of this study was to estimate the balance between manure nitrogen (N) added to the soil and the requirement of N for forage crops. SAGARPA statistics were reviewed about dairy cows inventory and forage production during 1999-2011. Manure production and N excretion were estimated using daily milk production, while the crop N requirement was estimated based on crop yield and crop N removal. Forages occupied 69 % of the irrigated area, with 89,500 ha. Forage production was 1.2 million t yr-1 dry matter (DM), while the N requirement was 15,070 t yr-1. The dairy cow inventory was 423,000, with 53 % lactating. Manure production in DM was 842,000 t yr-1, while the N excreted was 44,154 t yr-1. The regional balance expressed as [N incorporated - crop N requirement] was 187 kg ha-1, which represents an excess. Previous studies showed that a balance <150 kg ha-1 allows a sustainable milk production. According to the results of this study, municipalities with a cow density greater than 2.87 cows ha-1 will have a balance >150 kg ha-1.

Palavras-chave : Manure; Cow density; N efficiency; N excretion; Crop N extraction.

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