Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Factors influencing the productivity of irrigated crops in Southern Peru, in relation to prediction by simulation models

Auteur : Versteeg, M.N.

Université de soutenance : Wageningen Universiteit

Grade : PhD thesis 1985

Résumé partiel
The objective of the study was to determine the growth potential of alfalfa, potato, Rhodes grass and maize in the irrigated desert of S. Peru, as at that production level the highest utilization efficiency of irrigation water is usually obtained. Important growth- influencing factors were identified for each crop. In addition, measured results were compared to results from simulation models developed in Wageningen. Maximum annual alfalfa production was 27 t/ha dry forage. Experimental evidence suggested that assimilate partitioning favouring the root system, was a significant reason why yields were not higher. Other factors analysed were N 2 fixation, NPK fertilization, plant density decline, cultivar differences and weed infestation. Photosynthetis measurements on artificial swards are also presented.

Potato yields of 80 t/ha were recorded. Very high growth rates of 270 kg/ha.d were obtained with the local andigena cultivar, but growth duration was shorter and harvest index lower than those obtained in temperate regions. Results of a line source sprinkler irrigation experiment indicated low transpiration coefficients, but also large irrigation losses due to a low uptake capacity of the roots. Further data are given on leaf area development, light interception, cultivar differences, split fertilizer application, NPK uptake and NO 3 -N concentration in the petioles.

Mots clés : agronomy / computer simulation / irrigated farming / peru / simulation / simulation models / yield increases / yield losses / yields

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