Summary This paper describes the application of stochastic search techniques to the production scheduling of a group of linked oil and gas fields. The goal was to maximize the total net present value (NPV). A genetic algorithm with problem-specific crossover operators was particularly successful in this respect.

The Integrated Management of Major Irrigation Schemes (INMAS) programme in Sri Lanka is an attempt by the Sri Lankan Government to provide an integrated management system for irrigated, smallholder settlement schemes. The purpose of the programme is to provide a framework both for co-ordinating the activities of the various government agencies concerned and for facilitating the participation of farmers in scheme management. This paper discusses the operation of the INMAS programme, identifies the elements which are critical to programme success and describes the ways in which the Sri Lankan Government has attempted to incorporate these elements in a system of matrix management.

The results of a research investigation into water management practices during the commissioning of a paddy irrigation project are described. Investigations centred on the water issues and areas irrigated by the project's Right Bank main canal during commissioning. The water use observed during this period was compared with that forecast for the project at full development. From the limited data available, feasible targets for the phasing-in of land during commissioning are suggested, for use both by planners and managers. The effect of adopting these targets on project viability is also briefly discussed.

This paper considers the role of farm management in ensuring compatibility of extension content with the motives and constraints of individual peasant farmers. It emphasises the need for a modicum of farm management expertise in the communication of innovation from extension agent to farmer but questions the suitability of advanced farm management techniques for this purpose. It is argued that, if the potential contribution of farm management is to be realised, there is a need for an intermediate and appropriate farm management technology.

New residual-resistivity data are presented for all solutes which show an appreciable solubility in zinc (Cu, Ag, Au, Cd, Hg, Al). In contrast with some previous work for zinc, the residual resistivity per atomic percent impurity is found to be a well-defined experimental quantity. The results are discussed within the framework of Blatt's lattice-distortion model for impurity resistivity, and clear evidence is obtained for significant lattice-distortion screening effects. Some systematic departures from the model predictions are correlated with solute position in the Periodic Table.