FRANCISCO MARROQUÍN AGREDA1, JÜRGEN POHLAN2, MARC J.J. JANSSENS1
1University of Bonn, Institute of Horticulture, Germany
2El Colegio de la Frontera Sur (ECOSUR), Manejo Integrado de Plagas, Mexico
The abuse of chemical products in the production systems in the Central American tropical region has caused a series of drastical effects on natural resources. The deterioration of such destroy sustainable production possibilities and depends on high external inputs, mainly fertilisers and pesticides. The objective of this research was to analyse bases for the implementation of sustainable agriculture practices and to enhance the sustainability of agricultural maize production systems in Chiapas. The investigation was carried out during cropping cycle 2002-2003 in the region of the Soconusco, Chiapas, Mexico. Four treatments with experimental areas of one hectare each were selected: (i) a production system with maize (roza-tumba-quema) with 2 years cropping; (ii) a production system with 6 years monoculture maize; (iii) a production system with 12 years monoculture maize; (iv) an area with tropical rain-forest.
In each experimental unit were determined the physical and chemical soil properties, the dynamic of weed populations and the system's productivity. An one way experimental design was used, with seven levels, and four repetitions. The collected data indicates that the content of organic C, N total, and interchangeable K, Ca and Mg, strongly declined with the duration of maize cultivation. The lowest values presented the maize treatment with 12 years of monoculture, whereas the treatment with 2 years maize cropping had soil values very similar to the tropical rain-forest. Opposite, the P increased in the systems with maize. The weed biomass decrease with maize cropping duration, showing the highest biomass production in the treatment with 2 years of maize cropping. The diversity of weeds also decreased by maize cropping duration. The treatment with 2 years maize cropping had 20 weed species followed by the 6 years maize monoculture with 17 weed species and the treatment 12 years monoculture present only 12 weed species. Maize yield ranged between 4353 kg ha-1 with 2 years maize cropping and 1785 kg ha-1 with 12 years of maize monoculture.
Keywords: Maize, production systems, soil fertility, weed biomass, weed diversity