Living Land

and then incorporated into the soil or applied in furrows and

mixed with the sand in the furrows. However, furrow appli-

cation of POME or poultry manure was superior to broadcast

application for a number of vegetable crops in sand tailings

such as French bean, okra, cucumber and tomato.

In both methods, it is important that the organic source

is thoroughly mixed into the soil and then left for about

three to five days before sowing or transplanting, especially

if animal manure is used. This is to ensure that the seeds or

aerobic fermentation. Solid particles of the effluent settle

to the bottom of the pond and as the water evaporates the

POME is produced. POME is rich in nutrients and has a

low carbon-nitrogen ratio indicating that the material has

undergone extensive degradation during the fermentation

process. The nutrients present in POME are readily avail-

able to the growing plants. Studies have shown that POME

is a good nutrient source for vegetables and sweetcorn in

sand tailings.

Animal manures have also been reported to improve

yields and soil properties of sand tailings. Poultry, sheep,

goat and cattle manure are good sources of slow-release

nutrients for crops on sand tailings such as chilli.

In addition to using agrobiomass directly, plant and

animal materials can be composted and used as nutrient

sources. The nutrient content of compost can vary widely

depending on the nutrient content of the source materials

as well as the proportion of the different materials used.

Legume species, with their ability to fix atmospheric

nitrogen, can be used as a soil ameliorant on sandy soil.

These legumes can be ploughed in at flowering, as a means

to maintain or improve soil organic matter and fertility.

Legumes such as

Calopogonium mucunoides

Centrosema

pubescens

Indigofera tinctoria

Mucuna cochinchinensis

Vigna radiata

Glycine max

Arachis pintoi

and

Pueraria

javanica

have been found to establish well on sandy soils.

The legume species must be inoculated with appropri-

ate inoculants and mixed with a little phosphorus before

sowing to get effective nodulation and nitrogen fixation to

occur. Incorporation of the green manure must be done

three weeks before seed sowing.

For the rehabilitation of sand tailings, the organic sources

of biomass can either be broadcast on the surface of the plot

Sweet potatoes planted on sand tailings to produce a crop of VitAto (red) and gendut (white) varieties

Images: MARDI

Newly planted sweet potato on sand-tailing for the production of

cuttings with a sprinkler watering system

Image: MARDI

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