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Cranfield University (2005)

Reservoir tillage for semi-arid environments

Patrick, Cecil

Titre : Reservoir tillage for semi-arid environments

Auteur : Patrick, Cecil.

Université de soutenance : Cranfield University

Grade : Doctor of Philosophy (Ph.D.) : 2005

Résumé
This thesis presents the findings from a study to adapt reservoir tillage to semi-arid environments. This was done through modelling and experimentation under soil bin, rainfall simulator and glasshouse laboratory conditions. The aim was to investigate, understand and quantify water storage from this method of tillage and how it could be adapted to improve infiltration of harvested water for the benefit of field crops. A synthesis of information on infiltration characteristics, run-off and plant seed location from depressions is required in order to provide strategies and techniques for improving food production in semi-arid climates through reservoir tillage. The Aqueel (Simba International Ltd) is a commercially available, trailed tillage tool designed to form discrete depressions for water storage by compression of a soil surface under a normal load. Results showed that reservoir tillage is an effective method of collecting and string a significant proportion of rainfall. It reduces surface run-off by 54% when depressions are positioned with the long axis down-slope and by 91% if the long axis is across-slope and the depressions are staggered. Compared to depressions formed in shear (scoop), the internal soil dry bulk density of depressions formed in compression (Aqueel) was 36% more than outside thus causing significant compaction / consolidation to the soil. This compaction conserved sufficient water and did not cause any major mechanical impedance to both emergence and growth of wheat seedlings producing 5.8% more biomass accumulation than from shear formed depressions. Ballasting the Aqueel to increase penetration compromised depression wall structure, but increased depression volume by an average of 36%. Volume reduction averaged a significant 64% with increasing pre-formation soil bulk density. A theoretical exercise showed that it might be feasible to adapt a rotary tiller to form depressions in shear for semi-arid conditions at high soil strength conditions i.e. without the necessity of a previous soil loosening operation.

Présentation : EThOS (UK)

Accès au document : Proquest Dissertations & Theses

Page publiée le 6 juin 2009, mise à jour le 18 octobre 2018