Productivity & plant genetic diversity in upland agroecosystems of bondoc peninsula, the Philippines

Issue Date

12-2006

Abstract

A total of 60 belt transects (BTs) representing sampling units were established to determine the productivity and plant diversity in the various cropping systems at Batabat Sur, Buenavista, Bondoc Peninsula, Quezon Province, the Philippines. Indices of plant diversity (H) and evenness (J) were computed. Productivity indices included biomass, gross income and net income. Factors affecting diversity and productivity were determined using Stepwise Multiple Regression Analysis. Plant productivity indicators (biomass (tons/ha/year) and gross monetary value of crops varied significantly across the 60 belt transects (BTs). Highest biomass was obtained in BTs with coconuts + corn intercrop (34 tons/ha) and lowest was in BTs with corn monocrop (12 tons/ha). Number of coconut trees was the only variable found to significantly contribute to biomass yield which was attributed to the natural heavy biomass of a coconut tree. The number of nuts, number of trees, and the weight of corn ears significantly affected the gross monetary value. The equation derived was: Gross Monetary Value = -1373.25 + 17366 Number of nuts + 3357.76 Number of trees + 89.13 Weight of corn ears + 5436.63 (R² = 0.914). The index of diversity was highest in coconut monocropping ay H = 1.62, although this was not statistically significantly different from H = 1.57 in coconut + corn intercropping. The lowest index of diversity was obtained in corn monocropping at H = 1.57, but it provided the highest gross monetary value at ₽ 27,560 ha/year and net income of ₽ 6,619 ha/year. Shrubs and weed species comprise the bulk of species diversity in upland agroecosystems but they do not have directs monetary value, which explains the lack of correlation between gross monetary value and species diversity. Also, biomass was not correlated with species diversity H or species evenness J across belt transects, since coconut trees provided the bulk of biomass in the 3 agroecosystems. Intercropping corn with coconut, while it yielded the highest biomass (15.0 tons/ha), had a lower index of diversity than coconut alone. Plant diversity could not be used as an indicator of agroecosystems biomass yield and farm productivity measured as gross monetary value.

Source or Periodical Title

Philippine Journal of Crop Science

ISSN

0115-463x

Volume

31

Issue

3

Page

35-47

Document Type

Article

Frequency

tri-quarterly

Physical Description

tables, picture

Language

English

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