Efficient use of water in the southern region of Portugal: agronomic aspects

The present paper analyses several aspects of agricultural production techn iques and their relationship with an efficient water use paying special att ention to the conditions prevailing in the Mediterranean environment. The a gronomic aspects discussed are the following: crop rotation, seeding date a nd nitrogen fertilisation. With regard to the crop rotation in the effect o f the preceding crop on the yield of the following wheat crop is analysed f or different precipitation regimes as they frequently occur under Mediterra nean conditions. What the concerned seeding date is and its effect on the w ater availability is studied for both the autumn and spring sown annual cro ps. Finally the importance of the quantity and distribution of the nitrogen fertilisation for reasonable crop yields in wet years is discussed. (C) 19 99 Elsevier Science B.V. All rights reserved.