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.
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Showing items 1 through 9 of 31.-
Library ResourceJournal Articles & BooksDecember, 1985Colombia, Central America, South America
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Library ResourceJournal Articles & BooksDecember, 1979Colombia, Central America, South America
Some cultural control measures of weeds in cassava are discussed: quality of the material, planting system and density, density x plant type interaction and use of mulching. In order to study the interaction plant type x planting density, var. M Mex 59 (vigorous) and M Col 22 (nonvigorous) were planted in plots of 7500 and 15,000 plants/ha; and 3 levels of weed control were established: complete, intermediate and no control. The vigorous var.
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Library ResourceJournal Articles & BooksDecember, 1980Colombia, Central America, South America
Efforts to develop cassava technology for the vast areas of acid infertile soils were continued Large-scale germplasm screening in the field was begun in Carimagua for tolerance to low levels of P and acidity and in Quilichao, for tolerance to low levels of P. Various fertilizer trials were used to determine: (a) nutrient absorption and distribution within the plant during a 12-mo.
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Library ResourceJournal Articles & BooksDecember, 1980Colombia, Central America, South America
Research of the physiology section was centered on identifying the characters associated with high root yields and quality in cassava under stress conditions. Plant reaction to water stress was studied, specifically regarding growth and yields of var. M Mex 59 and M Col 22 with a period of artificial rain exclusion. Observations were made throughout the stress period and subsequent recovery. Water stress reduced LAI notably although M Mex 59 maintained a LAI approx. twice that of M Col 22 during the stress period. LAI for both var.
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Library ResourceJournal Articles & BooksDecember, 1980Colombia, Central America, South America
Research of the physiology section was centered on identifying the characters associated with high root yields and quality in cassava under stress conditions. Plant reaction to water stress was studied, specifically regarding growth and yields of var. M Mex 59 and M Col 22 with a period of artificial rain exclusion. Observations were made throughout the stress period and subsequent recovery. Water stress reduced LAI notably although M Mex 59 maintained a LAI approx. twice that of M Col 22 during the stress period. LAI for both var.
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Library ResourceJournal Articles & BooksDecember, 1980Colombia, Central America, South America
Efforts to develop cassava technology for the vast areas of acid infertile soils were continued Large-scale germplasm screening in the field was begun in Carimagua for tolerance to low levels of P and acidity and in Quilichao, for tolerance to low levels of P. Various fertilizer trials were used to determine: (a) nutrient absorption and distribution within the plant during a 12-mo.
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Library ResourceJournal Articles & BooksDecember, 1983Colombia, Central America, South America
A guideline for carrying out regional trials in cassava is given, including necessary steps (identification of collaborators, selection of sites, identification of person in charge, planting and harvesting season, exptl. design, plot size, and border rows); the technology used (selection and treatment of cuttings, plant density, land preparation, planting position, application of herbicides and fertilizers, pest and disease control); necessary visits (a min. of 7); and final agronomic trials to determine optimum density and age of var. at harvest.
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Library ResourceJournal Articles & BooksDecember, 1983Colombia, Central America, South America
In May 1980 the soil section of CIAT's cassava program established a fertilization trial with 3 cassava var. [Barranquena (regional), M Col 113, and CMC 921 to measure its effect on yield and establish optimum levels from an economical point of view. The trial took place in Mondomito and Agua Blanca, municipality of Santander de Quilichao, Cauca (Colombia). Twelve levels of NPK (0-0- 0; 0-100-100; 50-100-100; 100-100-100; 200-100-100; 100-0-100; 100- 50-100; 100-200-100; 100-100-0; 100-100-50; 100-100-200; 200-200- 200) were applied.
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Library ResourceConference Papers & ReportsBolivia, Brazil, Colombia, Ecuador, Peru, Central America, South America
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Library ResourceJournal Articles & BooksDecember, 1984Colombia, South America
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.
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