The book centres around an analysis of the options for the agronomic development of semiarid regions with winter rains (i.e. Mediterranean regions). Data obtained in the northern Negev desert in Israel served as a starting point. On the basis of these data crop and sheep husbandry systems were designed and integrated into agro-pastoral systems in which small-grain crops act as a buffer for feed production. These systems serves as a basis for rational planning of regional agricultural development under alternative development objectives. In analyzing the possibilities a three-step approach was developed: first the feasibility and robustness of selected innovative techniques at the farm level were investigated in relation to variability in weather and prices, then a matrix of production techniques for a region was formulated in terms of their physical imputs and outputs, and finally this matrix was embedded into a dynamic multiple-goal linear programming model. In comparing results for different goals, the consequencess for goal achievement and desired production techniques can be made explicit, and in this way the book can be a guide for actual development planning in semiarid regions.

In the early seventies, scientists in Israel and The Netherlands started a cooperative project on actual and potential production under semi-arid conditions. In Israel research concentrated on primary production of natural pastures and small grain crops, and on the associated secondary production of small ruminants. Most of the experimental work was carried out at the Migda Experimental Farm in the semi-desert of the northern Negev where the long term average annual rainfall is 250 mm. In The Netherlands existing facilities in Wageningen were used for measuring growth, photosynthesis and transpiration of Negev pasture plants and small grains under controlled conditions, both as individual plants and as simulated swards and crops. The joint research program was initiated by the late N.H. Tadmor and A. Dovrat from Israel and by C.T. de Wit and Th. Alberda from The Netherlands and conducted by various scientists from both countries, some of whom are among the authors of this book. The experimental results first served as a basis for the development, calibration and validation of simulation models of the growth and water use of pasture and crops. Subsequently, additional models were developed, allowing incorporation of socio-economic considerations, both at the farm and regional level, so harnessing the research results for analysis of regional development possibilities."

The study of soils has taken on increased importance because a rapidly expanding population is placing demands on the soil never before experi enced. This has led to an increase in land degradation. Land degradation is one of the most severe problems facing mankind. Volume 11 of Advances in Soil Science was devoted entirely to this critical area of soil science. The editors of that volume, R. Lal and B.A. Stewart, defined soil degradation as the decline in soil quality caused by its misuse by humans. They further stated that soil degradation is a major concern for at least two reasons. First, it undermines the productive capacity of an ecosystem. Second, it affects global climate through alterations in water and energy balances and disruptions in cycles of carbon, nitrogen, sulfur, and other elements. Through its impact on agricultural productivity and environment, soil deg radation leads to political and social instability, enhanced rate of deforesta tion, intensive use of marginal and fragile lands, accelerated runoff and soil erosion, pollution of natural waters, and emission of greenhouse gases into the atmosphere. In fact, soil degradation affects the very fabric of mankind."