Risk in production, pest control and productivity of pesticides in irrigated lowland rice, Philippines
1989
Huelgas, Z.M.
Log-linear yield regression estimates for all variable, were found positive and significant at 1 to 10% level for all sites [Koronadal, South Cotabato; Zaragosa and Guimba, Nueva Ecija, Philippines] and for the two seasons. Output elasticities ranged from 0.8 to 3.6 for insecticides and 10.8 to 24.4 for nitrogen. Intercept dummy coefficients for resistant variety ranged from 0.360 to 1.774, and for synchronous planting 0.119. Results of log-linear error regression failed to strongly confirm the direction of the effects of pest management and nitrogen on risks. Only the results obtained from the Guimba data set were founed useable. Risk coefficient for insecticides (-0.065) was significant in the wet season only. Estimates for resistant variety (-0.622) and nitrogen (0.832) were significant but only in the dry season. Results of the preserved output regressions for all sites and the two seasons were more interesting coefficients for insecticides were positive, ranging from 0.098 to 0.539, whereas, those for the squared term were negative, ranging from -0.133 to -0.001. Insecticides consistently exhibited diminishing marginal product. Results also showed that insecticides were more productive in rice areas of high yield potential and were more efficient (as a pest control method) in the dry season. Positive farm benefits to pest control were evident even at rates below the prophylactic recommendation. In addition, foregoing protection in any stage of crop growth resulted in considerable yield loss. Per hectare benefits to control at the flowering stage amounted to P216 to P516 for the wet and dry season, respectively.
Afficher plus [+] Moins [-]Mots clés AGROVOC
Informations bibliographiques
Cette notice bibliographique a été fournie par University of the Philippines at Los Baños
Découvrez la collection de ce fournisseur de données dans AGRIS