Agricultural technologies and tropical deforestation - Center for ...

142 Peter Roebeling and Ruerd Ruben
zero soil nutrient loss restriction. We generated different technology levels by
combining levels of fertilizer use, crop protection and substitution between
manual weeding and herbicide use. For pastures, we defined seven separate
levels of nutrient mining, ranging from 0 to 60 kg ha −1 year −1 . Weeding, fertilization
levels and stocking rate determine pasture technology. We defined four
beef-cattle production systems based on target animal grsowth rates.
Technical coefficients include labour requirements, inputs, yields and
sustainability indicators and are expressed on a ‘per hectare’ basis. Our
sustainability indicators were the depletion of nitrogen (N), phosphorus (P)
and potassium (K) stocks in the soil and the amount of pesticides and herbicides
used.
Technological options for improving arable cropping systems can be
divided into pure yield-increasing and input-saving practices. Farmers can
improve their yields by using better crop phenotypes that make more efficient
use of available water and nutrients (maize, beans) or by producing higherquality
products (pineapple). Capital-saving technologies improve input
efficiency by controlling nutrient losses and reducing pesticide use through
crop-residue management strategies, erosion control measures and integrated
pest management practices. Labour-saving technologies involve better timing
of operations and the mechanization of soil preparation, sowing and fertilizer
applications. Better fertilization or weeding of pastures, the use of feed supplements,
adjustment of stocking rates and improved herd management are some
of the options for technological progress in pasture asnd livestock systems.
4. Model Results
4.1. Base run
Table 8.2 presents base-run results for each farm type. In the small farm
type, forest represents more than half of the total farm area and is mostly teak
forest. The farmers’ main cash crops are pineapple and plantain. Food crops
(maize and cassava) as well as beef and milk are important for household
consumption. Small farms are the most labour-intensive. The medium-sized
type focuses on beef production and the exploitation of natural forests, which
take up 50% and 32% of the farm area, respectively. The only cash crop they
produce is pineapple. Medium-sized farms have a lower labour intensity than
small farms, due to the restricted availability of family labour. Their greater
capital resources and better access to credit allow their production systems to
be more capital-intensive. The hacienda type specializes in beef production
using natural pastures, with an average stocking rate of about 1.6 animal
units per hectare. As a result, their cattle-raising activities use little labour and
capital.
We aggregated the partial model results for each farm type, weighted by
the number of farms of that type, to obtain base-run results at the regional