Agronomic - Economic Benefits of Intercropping Bean with Banana

1995 Annual Report for LS95-072

Project Type: Research and Education
Funds awarded in 1995: $99,845.00
Projected End Date: 12/31/1998
Matching Non-Federal Funds: $50,239.00
Region: Southern
State: Puerto Rico
Principal Investigator:
Lii-chyuan Liu
University of Puerto Rico, College of Agricultural Sciences

Agronomic - Economic Benefits of Intercropping Bean with Banana

Summary

Objectives

1. Determine the effects of planting time and frequency of bean on yield and quality of banana

2. Determine additional benefits of intercropping as contribution to nitrogen fertility, weed control, and soil conservation provided by intercropped bean.

3. Determine the economic feasibility of the best planting time and frequency of bean/banana intercropping on a semi-commercial scale.

The project was aimed at determining the agronomic and economic benefits of intercropping bean with banana in Puerto Rico. For achieving the first objective, we intercropped two bean cultivars, either once or twice with a banana cultivar, in the first field experiment to determine the best timing and frequency of this intercropping.

The November planting of banana, together with two consecutive cycles of bean intercroppings proved to be the best timing and frequency of the intercropping. Banana yields were not significantly affected by either one cycle or two cycles of bean intercropping.

For achieving the second objective, we collected soil and banana leaf tissue samples from the first field experiment and analyzed for nitrogen content under laboratory conditions to determine the contribution of bean plants to nitrogen fertility of the soil and to the intercropped banana plants.

Soil analysis data indicated that the contribution of bean plants to total nitrogen, ammonium nitrogen and nitrate nitrogen contents in soil was minimal. Plant tissue analysis data indicated that there was no significant difference in total nitrogen content between the intercropped banana plants and the banana monoculture plants.

The contribution of bean plants to weed control was also determined from the same field experiment. The weed count in the bean-intercropped plots was significantly lower in bean-intercropped plots than in non-bean intercropped plots during the November and January plantings, but in March and May plantings there was no such difference. The plant cover factors of bean and banana plants were collected from the first field experiment for calculating the soil loss under bean-intercropped and banana monoculture conditions. There was a greater amount of soil loss detected in the bean-intercropped plots than in the banana monoculture plots.

To achieve objective 3 on the economic benefits of adopting bean/banana intercropping practice, we conducted a second field experiment next to the first field experiment. Eonomic analysis data indicated that two cycles of bean intercropping produced a combined net income of $4,319.12/ha. This sum is $3,008.17/ha more than the net income of $ 1,310.95/ha from banana monoculture.

Impact and Contribution
The result of our first banana-bean intercropping experiment indicated that the most productive intercropping treatment was the November planting of banana together with two consecutive intercroppings of bean cultivar Arroyo Loro. By adopting this November planting of banana with two intercroppings of bean, banana farmers living in the mountain region of Puertto Ricco would be earning an additional income of $ 3,008.17/ha as obtained from our second field experiment. In addition, banana yields were not significantly affected by intercropping of bean, irrespective of different dates of their planting.

All these favorable results should promote the practice of bean-banana intercropping in Puerto Rico. The inclusion of soil conservation practices (no tillage and contour planting) in our field experiments will serve as a model for banana farmers to achieve sustainable production of this commodity.

Furthermore, during the course of conducting our field experiments, we observed that a number of banana plants with heavy fruit bunches were toppled. In order to prevent the fruit bunches from falling to the soil, we have developed a fruit supporting device made of PVC pipe (1.5 m long x 5.1 cm in diameter) coupled with a piece of y-shaped tree branch. This practice proved to be highly effective and cheap, and should be adopted by the banana farmers in the mountain regions of Puerto Rico.

We are disappointed in the finding that a positive contribution of the intercropped bean to nitrogen fertility in soil or to the banana plants did not materialize. The bean seeds we used were treated with nitragin inoculum and developed normal nodulation on roots. However, the probability of reducing the use of chemical fertilizer through the aid of nitrogen fixation of the bean plants did not succeed in the present research.

December 1998.