Perspectives on Soil Management for
Sustainable Agriculture in Asia and Pacific
by
Pisoot Vijarnsorn*
Due to increasing of crop production and cropping intensities, the region of Asia and
Pacific as a whole has been looking forward with appropriate technologies to overcome its food
security constraints. Although agricultural production in many countries, at present has
exceeded the rate of population growth, yet in some countries the crop productions could not
match their population growth. At the same time, the natural environment in many countries has
been subjected to increasing of degradation especially in term of land and water resources,
which in turn bringing about various problem on agricultural production, food security, living
hoods of the people as well as the long-term sustainable development.
In context with land area and population in Asia and Pacific region, it was recently
recorded that the whole region covers land area of about 2,173 million ha with a population of
about 2,946 million or about 55 percent of the world’s total population. At the same time, the
agricultural land on land capable of sustainable agriculture comprises only 1,008 million ha
while the agricultural population is about 1,800 million. Thus, these statistics indicate land
scarcity and all land capable of sustainable agricultural uses are already being farmed. Yet, due
to population pressure and to keep pace with population growth, millions ha of the marginal
land have to be cleaned for crop production of various kinds, causing problem on deforestation
in many countries. Thailand, as an example was recorded that all of the arable lands comprising
about 27 million ha or about 52 percent of the total area have been utilized for crop production.
In addition, at least 5 million ha of the marginal land and mountainous area have been used for
growing various kinds of crops. Totally, it can be stated that at present about 32 million ha (62
present of the total land) of the land area in Thailand have exclusively used for crop production
by an agricultural population of about 40 million. Ratio of land to agricultural population is
appropriately 0.8 ha/capita, indicating a small scale of farm unit. This has brought about number
of difficulties for agricultural development to increase soil productivity as a whole in comparison
to developed countries in America or Europe. These problems should be solved practically in
* Senior specialist on land development, Chai Pattana Foundation, Bangkok, THAILAND
order to accelerate growth in the agricultural sector for both national-wide consumption and for
exporting.
Although the relative share of agricultural in GDP of many countries in Asia and Pacific
has declined during the past 2-3 decade, mainly due to rapid growth in the service and
industrial sectors, the agriculture-based economics with agricultural sector in the whole region
are still deeply rooted in the socio-economic, political and cultural situation of each countries.
Therefore, to overcome its food security for the region, introduction of agricultural technology in
appropriate way needs to receive close attention by the concerned personal. Of it is so, as an
essential part of the agricultural technology, soil management has to be recognized, otherwise
the present welfare of rural people and the sustainability of farming systems can not be reached
the target.
Role of Soils for Crop Production
Soils, water, air and solar energy are the four important natural resources which
exclusively support the living system on this planet. Amongst them, soils are basic to civilization
and with water constitute most important resources to our society. Soils provide food, fiber and
alternative medicines, support buildings and roads help transferring sunlight to usable forms of
energy and other resources. Soils have very close association with geological materials
beneath, vegetative and microbial activities within and above and ground water percolating
through the soils. Thus, it can be defined that soils are discrete bodies forming by the
interaction of climate, vegetation, and surficial geologic materials on the earth’s surface.
Moreover, they are often called “the great integrator” because soils so enormous affect every
other part of the ecosystem
Soils are very essential to food production because they support plant growth and
contain nutrients and water for every kind of plants growing on them. Since soils vary from place
to place in landscapes, often within even short distances and the soil requirement of crops are
also vary from crop to crop. Therefore, to establish appropriate soil management for each crop,
ones must understand soil characteristics on its behavior to manage in accordance with crop
requirement and other relevant factors like water supply, agro-climate and farmer’s socioeconomic. Furthermore, the cultivators should be well aware that soil has its own inherent
tendencies to deteriorate owing to improperly management and misuses. Therefore, the
maintenance of permanent crop lands to some extent, depends upon the understanding of soil
behaviors or soil characteristics when those soils are cultivated to various kinds of crops.
Soil Constraints for Sustainable Agriculture
Until now, when the supply and demand sides of food security equation have been met,
land or soil has been considered bountiful although with limitations for food and fiber
production. Traditional societies that have been practiced a rational that has increased the
exploitation of land to the extent that it became barren. For example, shifting cultivation on area
of steep slopes in many countries of Asia and Pacific is a response to this motion and
surprisingly, crop yields on those marginal lands are relatively low. At the same time, the
environment has always damaged to great extent, for instances landslides, soil erosion, flood
damage in the valley and water pollution in the nearby streams or rivers.
In broad sense, when the land or soils have been used without proper and appropriate
management, it can bring about land degradation that always result in productivity declining
and in the long term, this issue could impact to food security of the nation. However, most
countries in Asia and Pacific like Thailand, has never made a national assessment in detail nor
has a program of long-term monitoring land degradation been conducted. In facts, the inherent
quality of the land is a major factor that determines rate and degree of land degradation. For
agricultural use, the quality is related to the major land resource or soil stresses. Identifying the
stresses is a first step in assessing land quality and eventual task of monitoring degradation
The following are an example of major soil stresses that prevent the use of land for most
agricultural purposes:
Soil erosion, extended periods of moisture stress, steep lands, shallow soils,
salinity/alkalinity, high organic matter, low water holding capacity, low moisture and
nutrient status, acid sulfate condition, low nutrient holding capacity, excessive nutrient
leaching, calcareous and gypseous condition, high aluminum, seasonal moisture stress,
impeded drainage, root restriction layer, seasonally excess water, low organic matter
and high shrink/swell potential.
It should be noted here that some of the stresses afore-mentioned cannot be corrected,
e.g. shallowness of the soils. Other may be corrected, e.g. irrigation for areas with moisture
stress. Moreover, correcting the major stress may or may not ensure sustainable use of the soil.
Other stresses may be present or correcting one stress may result in creating another one. An
example is irrigation in dry land where consisting of some salt affected soils and without
adequate drainage. The result is rapid salinization, which reduces the quality of the soil.
General Soil Managements
Soil management is the general term used for all tillage operations, cropping practices,
fertilizer, lime and other treatments applied to the soils for the production of various crops. In
fact, it is believe that large portion of the farmers in Asia and Pacific still use tradition method in
soil management like application of farm manure, chemical fertilizer and liming, but with
changes in economic development, price structure and with new technology, those farmers like
to make necessary changes. However, needs to study the possible alternative treatment in
relation to various land uses seem most likely to be accomplished in order to select the most
suitable practices and apply them carefully. Nevertheless, kinds of soil management practices
that can be used always depend on the level of economic, social and technological
development.
To make more understanding, the following are important soil management practices for
various crop productions
 Proper land preparation including tillage and cultural practices.
 Adequate fertilizer application both chemical fertilizer and organic fertilizer.
 Use of green manure.
 Rotations of cropping systems that include soil improving plants, mostly legumes.
 Soil and water management: irrigation, drainage, flood control and water conservation.
 Changes of land use, where the soil is not suitable for cultivated crops and it may be
used for pasture, fast growing trees or forest.
Practices needed for soil conservation which are commonly introduced for controlling
soil degradation caused by erosion are as follows
Contour planting, construction of field terraces, use of alley cropping and/or grass
strips, use of cover crops and mulching, and reforestation.
Potential and Alternatives Uses of Marginal Land for Agriculture and Agro forestry
In accordance with soil forming factors, soils in Asia and Pacific, by themselves, have
some properties with severe constraints for agronomic production. The lands containing those
soils are so called the marginal land, which consist of the following soil types
 Mangrove soils (saline soils with permanent sea or brackish water logging)
 Inland sail-affected soils (saline soils, sodic soils and saline-sodic soils)
 Acid sulfate soils
 Sandy soils
 Sandy soils with hard pans (spodic horizon)
 Black clayey soils
 Skeletal soils (shallow soils)
 Organic soils
 Soils of hills and mountains
 Man-made lands like mine-tailings
Depending on severity, one or more constraints may either limit the number of possible
plants to be grown or increase the inputs required. The cost of correction in many cases
however, may not be economically justifiable. Some development costs may involve substantial
government funding or long-term credit. Since there has been a downward trend in the ratio of
agricultural population in Asia and Pacific, more people are being forced to use marginal lands
for food production; this is based mostly on the temporary cultivation of dry land annual crops or
the planting of commercial timber species. With low production factors, the result is that these
marginal farmlands have deteriorated rapidly and are left idle after a few years of continuous
cultivation. As a consequence, expansion into new lands under primary forest threatens to
aggravate the situation.
It is worth mentioning that any attempt to introduce a permanent cropping system on
those marginal lands without the provision of essential management inputs often results in crop
failure and serious physical and chemical land degradation, therefore their use should restrict to
pasture, woodland, wildlife food and cover, water supply and recreation. However, if it is really
need to use those soils for certain specific social reasons, the following options offer the most
rational development strategy
 Reclamation of marginal lands should be a carefully coordinated government activity
and not done in a sporadic manner by individual farmers or settlers.
 Technologies for increasing production must be developed and the farmers must be
able to apply them.
 Low cost production technology is preferable, i.e. giving high priority for the selection of
an adapted crop.
 Farmers’ participation in planning and execution of the program should be encouraged
and strengthened.
 The marketing infrastructure to secure suitable farm-gate prices should be improved by
the agencies concerned.
Conclusion and Recommendation
Soils are a limited resource in Asia and Pacific. With time, the situation will worsen due to
soil degradation which reduces the performance of the soil, thereby having negative impact to
crop production. Moreover, exponential growth of urbanization often consumes large areas of
prime land as the centers originally developed on lands that had potential to feed the
community. In additions, the countries which established large-scale programs to increase their
food producing capacity are generally at risk due to salinization or alkalization which slowly but
surely accompanies irrigation in low-rain full areas or in semi-arid regions. Under rain fed
agriculture, farmers always face problem on drought, resulting in soil moisture stress which
become a limiting factor for crop production.
Another important factor that often prevents efficient land use in many countries
included in Asia and Pacific is the purchasing power of the land users, which is a result of
poverty. Appropriate technological inputs can double production. However, farmers have no
capital to invest in the land or no incentives, when they do not own the land. Further, they have
fewer facilities and an inadequate knowledge base to implement land management
technologies and thus there can be few expectations of managing land degradation.
Sustainability and the efficient use of the land can only result from the appropriate application of
modern knowledge. Reincarnating past technologies is not a solution to the challenges of today;
it is an excuse for a lack of national will and ineptitude.
The analysis of constraints in the use of land resources clearly indicates that sustainable
agriculture is a major challenge that decision-makers and land users face. It is only through an
understanding of the location of such constraints that mitigating technology can be
implemented effectively. Finally, in the absence of a monitoring program little progress to attain
sustainability can be attained. This analysis provides new information for re-evaluation of the
country’s land use policy and can be used for targeting areas for new initiatives.
It is worth mentioning that they are some international agencies conducting various
activities directly or indirectly on proper soil management on land management to minimize
processes leading to land degradation. For example, FAO has executed a project as so called
Land Degradation Assessment in Dry lands (LADA) and the United nation Convention to
Combat Desertification (UNCCD) has also made remarkable progress to flight against
desertification However, the available data on the extent of land degradation are still limited
(FAO Regional office fur Asia and the Pacific, 2009) although there are two studies namely
Global Assessment of Human Induced Soil Degradation (GLASOD) and Soil Degradation in
South and Southeast Asia (ASSOD) have been made. Moreover, climate change seems to be
an additional stress to treat our fragile ecosystem that can affect to the present soil productivity.
In a solution-oriented approval, the followings are some recommendation on policy
adjustment and actions to be taken on soil management to increase soil productivity. Hopefully,
they may be applicable for the countries in Asia and Pacific.
1. Until recently, there has been no place to collect and disseminate information upon
soil constraints or land degradation within the countries in Asia and Pacific Therefore, at the
international level, an international organization concerning various aspects on soil management
in Asia and Pacific should be established. Such organization will help to promote and assists
government in Asia and Pacific to mitigate various problems on soil managements and land
degradation.
2. Attention on soil management for the members in the countries should focus on the
adoption and use of new cost-saving technologies and integrated planning of the land
resources to increase food production, while at the same time minimizing environment damage.
3. The capacities developed and the knowledge bases contributed by the proposed
international institute or organization should constitute the basic data-base for policy-making at
the national and international levels within Asia and Pacific.
4. Soil management researches although time consuming and relatively expensive,
carefully formulated and planned researches are still needed to ensure sufficient crop
production. However, Those researches should include the following guideline:
 the research should clearly address the major problems of soil constraints and
land degradation
 the research should be in the line with the priority of the governments and the
communities.
 the research should be aimed for increasing soil productivity by means of
sustainable agricultural development.
 the research should be a cost-effective technology appropriate to the
condition of small holders which occupy most farms in Asia and Pacific
 The research should be multidisciplinary and with the cooperation of a soil
scientist, an agronomist, an agricultural economist, a sociologist and
agricultural engineer
References
Asian Productivity Organization. 1995. Agricultural Land use Management in Asia,
Report of an APO Seminar. Tokyo. Japan.
FAO Regional office for Asia and the Pacific. 2009 Proc. of the Regional Land Degradation
Assessment in Dry lands (LADA) Workshop for Southeast Asia Bangkok, Thailand.
IBRAM 1986 Proc. of the Seminar on Soil Management Under Humid Conditions in Asia
ASIALAND International Broad for soil Research and Management, Bangkok, Thailand.
Vijarnsorn P and H. Eswaran. 2002. The Soil Resources of Thailand. Department of Land
Development, Bangkok, Thailand.