Abstract
The root systems of one years-four years' pepper plants were observed in Belém, Amazonia region, in 1966-'67, and some problems in the cultivation under existing method on the stand point of this root system were considered:
Feature of root system.
1. The root system is derived from adventious roots which sprouted on the nodes of stem cutting.
2. The root system is divided into two groups in function on the bases of morphological appearance and position of rhizosphere namely;
a. nutrient absorbing root system.
b. water absorbing root system.
The former, consists of many roots, looks as slender in general, has many branches and finer roots, shallow rooted and spreads the longer horizontally and the more in the upper part of soil, e.g. 2years' and 4years' plants occupy 90% and 85% of total roots upto 30 cm depth, 98% and 90% up to 40cm depth respectively. The latter, consists of several roots, comparatively thick, elastic, waving sometimes twist, deep rooted, e.g. 4 years' plant reaches to 4m depth.
3. Develops well in aerial condition especially in the planting and fertilizing holes.
4. New roots of the nutrient absorbing root system are observed to develop in the end of the dry season already that is shortly after harvest.
5. Distribution of nutrient absorbing root system is uneven in radial and vertical directions.
6. Top-root ratio increases as the plant age increases.
Problems in the cultivation under existing method.
1. Drainage; drain off surplus water and to keep safe from water standing in the planting and fertilizing holes.
2. Mulching; recommend overall mulching with straw, haulm or other grasses.
3. Fertilizing; a) apply fertilizer by ring belt ditch method spreading out as the plant grows, in place of the existing single cubic hole. b) straw, haulm and compost are effective.
4. Fertilizing time is recommendable in the end of dry season and in the end of rainy season.
5. 30-40cm depth of digging to make planting and fertilizing holes under existing method is sufficient for root development.
6. The cultivating method, depending on mulching as a main point, combining with top dressing of fertilizer, disregarding hole making for fertilizer application is considered to be effective and is now under experiment.
