The factors influencing the size and shape of exptl. field plots (area of exptl. lot, soil types, trial objective, no. of replicates, and degree of accuracy and homogeneity of the exptl. material) for the execution of field expt. are discussed. The basic principles of the following different methods to determine plot size are described: max. curve method, method of Koch and Rigney, Hatheway's method, and the max. curve method using the multiple linear regression model. Some considerations are presented on the border effect and on plot size in bush and climbing bean trials.

The results of a case study conducted in Betulia (Sucre, Colombia) in May-Dec. 1983 to evaluate the competition for land between cassava cultivation (monocropped or in association with maize or yam) and cattle raising are discussed. In general, profits from cassava either in association or in monoculture are much higher than for cattle raising. Regarding labor requirements, cassava cultivation and cattle raising are equally attractive from an economic viewpoint.

Discusses issues in the development of dairying in Africa & Asia, outlining main approaches employed in the organization of production, and the need to take into consideration five interrelated factors in dairy development strategies, viz, the supply of dairy stock, animal health, fodder systems, marketing arrangements and training of farmers; also points out the need for research, and institutional support in the form of advisory & extension services as well as credit provision to assist in dairy development.

The results of a survey conducted in 1983 among 416 farmers participating in the integrated rural development project (DRI, Colombia) in Atlantico (60), Bolivar (66), Cordoba (156), and Sucre (134), on land use and importance of cassava within the farming system, are presented. Except for Bolivar, where cassava and yam plantings decreased, increased land use attributable to increased credit availability was observed. In general, 1.7 ha cassava was planted per farm in 1982-83, mainly in association with yam, maize, and plantains; 55 percent of the land planted included cassava.

Discusses ways of studying economics of household level activities in pastoral production systems, with particular reference to the collection and analysis of data on household income and expenditure as well as resources inventory.

Reviews differences between crop production and pastoral production, considering their effects on research possibilities; and describes basic methods that may be used to collect household level data, esp. informal & formal surveys, enumeration and the use of questionnaires.

Reviews most recent applications of methodologies for resource surveys appropriate to pastoral & agro-pastoral regions in Africa, with particular reference to remote sensing methodologies, viz. satellite imagery, aerial photography, side-looking radar (SLR), spectral radiance and low-altitutde aerial survey. Discusses the integration of remote sensing techniques with ground truth within the context of rapid appraisal methods and early warning procedures within a livestock systems research approach.

Discusses how low level aerial survey can be used to diagnose constraints within pastoral systems and the relative cost effectiveness of such operations, with particular reference to flight & sample procedures and information collection and analysis; presents some results from low-altitutde aerial survey undertaken by ILCA in Nigeria, Mali, Niger and Ethiopia.

Selection of presentations made at the workshop on "Pastoral systems research in sub-Saharan Africa", describing the framework used by ILCA for pastoral systems research (PSR), examining methods used in the descriptive and diagnostic stage of PSR, and showing how the design and testing procedures are followed in practice; with particular reference to low-altitude aerial surveys, livestock surveys & household studies.

Presents a collection of conference papers defining pastoral systems research; the survey and diagnostic phase of pastoral systems research; ILCA's experience in remote sensing techniques and aerial surveys; survey of vegetation resources; livestock productivity and animal nutrition; pastoral production strategies, wealth effects, household studies, and labour data collection as well as livestock marketing studies.