An introduction to sustainable agriculture practice on suboptimal land
Feeding the world in 2050 may be possible, but only if food is produced at a sustainable rate in the next three decades. Among others, major constraints come from agricultural land conversion. In Indonesia, about 150,000 hectares per year are lost due to residential and industrial purposes. Climate change impact will also surely negatively impact agricultural production. The changing pattern of rainfall and mean temperature due to climate change also affect food crop yields.
There are approaches to adapt and address the challenges, yet all have limitations. Intensification, if it surpasses the limit of maximum yield, could degrade the land. Urban farming could only produce a minimal amount of food. The need to expand into new farmland is inevitable – but with the ambition of avoiding deforestation. There are abandoned and degraded land areas that can potentially be converted for farming, this is known as suboptimal land. The present article will introduce the characteristics of this suboptimal landscape and explore the ways to convert it into arable land, using the example of Indonesia.
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This introduction on suboptimal land is the first in a series of Tay Juhana Foundation (TJF) Briefs on Suboptimal Lands, aimed at proffering the notion of producing food in this type of land. In Part 1 of the series, we summarize the initial information necessary to have a basic understanding of suboptimal land. Thorough desk research is used to compile information obtained from scattered case studies about suboptimal land, especially in Indonesia. In writing the series, field observation was conducted in Indragiri Hilir Regency, in the Riau Province, during which we visited a farming practice in a suboptimal area. While some information from the field cases can be found in this article, more findings will be disclosed in the rest of the series.
Suboptimal Land Definition
The simplest way to define suboptimal land is as land producing less than optimal crop yields. The “sub” term is a prefix indicating the land inhibits the growth of crops since the amount of water, light, or nutrients are below optimum. The “suboptimal land” term has started to be widely used to describe the typical character of land with low productivity, reduced economic return, and/or severe limitations for agricultural use.
Different names are connected and used to describe the suboptimal land – infertile, marginal, low potential, resource-poor, fragile, vulnerable, or degraded. This type of land is naturally difficult to transition into productive agricultural land. It has several limitations that are caused by human activities or natural environmental characteristics such as (1) lack of water availability, (2) acidic soil condition (low pH), (3) unpredicted tidal inundation, (4) seawater intrusion, (5) pyrite poisoning, (6) poor soil nutrients, and (7) thin layer of soil (rocky ground).
Types of Suboptimal Land
Based on its dominant characteristics, there are only two broad types of suboptimal land: dryland and wetland. In Indonesia, there are five divisions of suboptimal lands, namely (1) acidic dryland, (2) dryland in a dry climate, (3) tidal swampland, (4) lowland swamp, and (5) peatland. The determination of suboptimal land types is based on soil types, rainfall, and landform.
Dryland, both acidic and under a dry climate, is never inundated by freshwater. Low water levels in dryland is due to low rainfall and high evaporation. Acidic dryland is characterized by high acidity on the soil which appears from the rapid mineral corrosion process. This type of land formed by a combination of low precipitation, drought, and heatwave. Unsustainable farming practices also can create dryland conditions through land burning, livestock grazing, forest utilizing, and intensive soil cultivation.
Tidal swampland is found along the coastline and is characterized by all year water inundation. Some swamplands contain saline water, others are brackish, and the rest are freshwater. Lowland swamp is formed by rainfall that was trapped on land depressions. Similarly, peatland is an accumulation of organic matter formed in an anaerobic condition over many years which drives long-process yet partial decomposition. Because of its unique characteristic, peatland is differentiated from lowland swamp. Many challenges to cultivate these suboptimal wetlands are pertinent to water management, pyrite soil existence, thick peat soil layer, and saltwater intrusion.
Strategies for Practicing Agriculture in Suboptimal Land
Suboptimal lands provide essential ecosystem services and support local communities. The communities have benefited from the lands for timber to build houses, wild food, and medicinal plants, and to access clean water. In circumstances where the local community decided it is necessary to add staple food provision to their ecosystem services, the challenge in managing the suboptimal land starts starting with addressing the unique features of the land. The utilization for agriculture cannot be achieved without overcoming the unique limitations whilst maintaining their ecosystem value to local communities. The practice requires additional investment in land preparation which is determined by three following factors:
- Land management to handle the acidic condition of the soil, the poor nutrient content, the shallow depth of soil, and soil pyrite poisoning.
- Water management – which is crucial in both dryland and wetland. In drylands, management aims to provide water for irrigation, while on wetland it serves to regulate water.
- Cultivar selection, to make crops adaptive in suboptimal conditions.
The chart above (Fig. 1)indicates that engineering measures application such as ameliorants, fertilizer, and proper water management can bring a significant change in the production yield of suboptimal land.
To increase soil pH, ameliorants such as lime, ash, salt, and rice husk are commonly applied. Furthermore, fertilizer application is essential for optimum yield.
The development of the irrigation system in dryland areas will boost the yield since it enables cultivation all year-round. In the areas without irrigation systems, crop production relies on cultivars that adapt to low water availability. Meanwhile, in wetland, it is more about regulating excess water on soil and maintaining moist soil conditions. A well-regulated water management system is necessary to control the quantity and quality of water throughout the phases of agriculture production while avoiding harm to the local ecosystem.
Even when water and soil are well-managed, sometimes the cultivar does grow well as it is not well adapted to the conditions. The use of adaptive cultivars becomes necessary. Particularly, local genetic sources are vital to the development of new varieties. For example, there are rice varieties with high tolerance of iron and aluminium (high acidity) which can be present in suboptimal land, such as IR64.
From Suboptimal to Arable Land
Enhancing agricultural productivity on suboptimal land can contribute to the improvement of food security globally, and avoids solely relying on land intensification. Crop yield produced by the formerly suboptimal lands will increase the availability and accessibility of food, especially for surrounding areas. In the case of Indonesia, suboptimal land actually constitutes two-third of the total land area. Leveraging the potential of these lands will reduce the dependence on current food production centers in the most populous island, Java.
Knowing the varied characteristics of suboptimal land, there are three aspects that should be employed simultaneously. First, the state of the soil needs to be improved in all aspects including physical, chemical, and (micro) biological. Second, the water resource should be regulated by implementing water management both in dryland or wetland. And finally the expansion of adaptive agricultural crop cultivars that are necessary to yield the optimum harvest.
These planned measures will only succeed through the inclusive engagement of all relevant stakeholders in the various processes of the measure. Intense cooperation between the involved stakeholders where they can exchange information and form complex social networks will affect the decision-making to institutionalize the whole process.
Food Production as Ecosystem Service
Often lands become suboptimal due to unsustainable land management practices that degrade them. While it would be ideal to restore them to their natural states, it is very challenging and takes a long time to achieve. Nowadays, food production efforts are included in the restoration measures, especially to support people who depend on land for food and livelihood.The first step of sustainable agriculture practice on suboptimal land is to identify if the land belongs to a protected or production zone. Converting suboptimal land to arable land should not mean compromising other ecosystem services. Further analysis is needed to identify what practice will be most sustainable by considering both people and the environment. Elaboration of challenges to ensure sustainable agriculture in suboptimal lands and specific case studies for each land type will be delivered on upcoming issues.
Rahmasary AN, Fawzi NI, Qurani IZ. 2020. Suboptimal Land Series: An introduction to sustainable agriculture practice on suboptimal land. TJF Brief. Available from https://tayjuhanafoundation.org/resources/
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