Keywords

1 Introduction

Peatland is a wetland ecosystem, which is formed by the accumulation of organic matter in the basin under inundation conditions. Tropical peatlands are characterized by warm temperature, high precipitation, but low evaporation, which initiate persistent wet conditions on the soil surface. This situation inhibits microbial activities (Takada et al. 2015). The decomposition process in the anaerobic condition is usually slower than the accumulation rate. This process occurs in the peat-swamp forest, producing significant organic matter (Blackham et al. 2014; Noor and Masganti 2016). Based on water source and topography, peatlands in Indonesia is mostly categorized as ombrogenous peat (Takada et al. 2015; Noor and Masganti 2016), where the peatland is raised above the surrounding landscape and the water source is only from precipitation; hence it is nutrient-poor (Neuzil et al. 1993; Takada et al. 2015; Noor and Masganti 2016).

The peat ecosystem consists of three components: vegetation, water, and organic matter, which are arranged in a unit completely, and form balance, stability, and productivity. A peat ecosystem positioned in a basin between two rivers or between a river and the sea is called the peatland hydrological unit (PHU). The PHU as a landscape can be seen from the edge of a river perpendicular to the other river and one or more basins can be located in the core of the two rivers (Barus et al. 2009; BRG 2019). This is because the horizontal distance between the two large rivers is several tens of kilometers. At the edges is shallow peat, and moving towards the center of the dome, the surface of the peat soil gradually rises. The height of the peat dome varies; it can reach 3–8 m above river water level. On deep peat, the center of the peat dome can be 8–13 m thick; groundwater is stagnant and very nutrient-poor. Around the top of the peat dome or the edge is sloping peat, shallower and more mixed with minerals so that the fertility rate is higher (Noor and Masganti 2016). Peat soils in narrow basins are usually thin peat (0.5–1 m) to medium peat (1–2 m). The position of the first major river to the next major river will be found, respectively, a river embankment or levee, a backswamp, a basin containing peat soil. The highest topography has the thickest peat called peat dome, then a backswamp plain and a subsequent river embankment (see Fig. 16.1; Subagyo 2000).

Fig. 16.1
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Schematic cross section of a PHU between two rivers (Source: adapted from Subagyo 2000)

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Based on the Government Regulation of Indonesia (Government Regulation No. 71 of 2014 jo. Government Regulation No. 57 of 2016 on Protection and Management of Peatland Ecosystem; https://forestlife.id/workshop-on-peatland-and-climate-change/), there are two functions of the PHU based on the peat depth, and those are protection and cultivation functions. The peat dome or peat depth deeper than 3 m is categorized as a protection function, while peat depth less than 3 m is a cultivation function for sustainable agriculture. However, the sustainability of agricultural practices on peatlands is threatened by over-drainage and fires (Suryadiputra et al. 2005; Wibisono et al. 2005; Surahman et al. 2018). To minimize the risk, agricultural system on peatlands should be developed as wise farming practices by considering the limiting factors of the peat ecosystem. Najiyati et al. (2005) suggested ten steps of developing sustainable agriculture on peatlands, such as: (1) identify and understand the type and behavior of peatlands; (2) utilize and organize land according to its typology without drastically changing the environment; (3) implementing a water management system that can guarantee soil moisture or avoid drought in the dry season and prevent flooding in the rainy season; (4) zero burning practice; (5) mixed farming by combining seasonal and perennial crops, livestock, and fish; (6) selecting plant types and varieties in accordance with land conditions and market demand; (7) using ameliorant materials, such as compost and manure to improve soil quality; (8) conducting minimum tillage in watery or moist soil conditions and zero waste; (9) using micro-fertilizers for seasonal crop cultivation; and (10) planting perennial crops in peatland, preceded by compaction and planting annual crops to increase soil-bearing capacity.

Developing a peat-friendly agriculture on peatlands is a challenge. Here, we propose an integrated farming cultivation system in a PHU without burning or producing waste, which meets the four principles of technically applicable, socially acceptable to local farmers. It is economically profitable and environmentally friendly (Surahman et al. 2018; Uda et al. 2020). The objective of this chapter is to describe various agroforestry models in peatland landscape which are present in levee, backswamp, and peat dome of the PHU of Kahayan and Sebangau river, Central Kalimantan. This has been used as agricultural and agroforestry practices for years and an integrated agricultural model for PHU management.

2 Agroforestry Landscape Analysis

Agroforestry is defined as a land management system based on sustainability, which increases overall land yield, combines the production of agricultural crops (including tree crops), forest plants, and/or animals simultaneously or sequentially on the same land unit, and applies management methods. According to the culture of the local population (King and Chandler 1978), interpretation of agroforestry is complex, between natural resource management through a combination of tree species on land and agricultural landscape and policy change required to secure the economic, social, and environmental benefits that can provide to various segments of society (Van Noordwijk et al. 2019). The relationship between peat ecosystems and agroforestry is that the peat ecosystem is a habitat and landscape with resources while agroforestry is an input system to produce benefit in the landscape (Mulatu and Hunde 2019; Plieninger et al. 2020).

Agroforestry landscape is a science that studies agroforestry systems at a landscape scale, where spatial and temporal aspects are very influential (Arifin et al. 2010). Agroforestry landscape study is different from agroforestry study that is generally carried out at the site or plot scale (Pastur et al. 2012). At the landscape scale, the land-use system usually uses ecological boundaries, such as watershed boundaries, peat depth, saturation level, period of inundation, the presence of a tidal effect, and others. The function of land use is related to the structure and biophysical condition (Arifin et al. 2010). In a PHU, the function of peatland use is determined by peat depth. The PHU protection and cultivation functions are carried out in an integrated and segregated approach (Zglobicki and Zglobicka 2012). Agroforestry landscape analysis can be assessed through interactions between objects and elements in the landscape and its impact. In the agroforestry landscape, each agroforestry type can be repeated at spatial and temporal scales (Pastur et al. 2012).

The discussion of the agroforestry landscape in this chapter cannot be separated from the discussion of the ecology of peatland landscape because agroforestry lands lie on a PHU. Agroforestry landscape consists of four main principles: (1) there is the heterogeneity of development and spatial dynamics, (2) there is the heterogeneity of interaction and exchange in the landscape, (3) there are effects on spatial and in biotic and abiotic processes, and (4) management of spatial heterogeneity (Arifin et al. 2010). These indicate that the characteristics of agroforestry landscapes emphasize the relationships among types of agroforestry practice, processes, and scale. Agroforestry landscapes also consider ecological flows in the mosaic of agroforestry landscapes, land use and land cover change, scale, and other ecological processes. This includes the conservation landscape and preserving its ecosystem (Pastur et al. 2012; Plieninger et al. 2020).

Agroforestry landscapes look at how spatial planning affects the abundance of organisms at the landscape level, the behavior and functions of organisms from a landscape to the entire ecosystem. It is also emphasizing the anthropogenic impacts on the landscape’s structure and functions. Landscape functional units can be evaluated both qualitatively and quantitatively in the context of agroforestry (Arifin et al. 2010; Dewi et al. 2017).

3 Landscape Characteristic of the PHU of Kahayan–Sebangau River

The PHU of Kahayan–Sebangau river is located in two districts of Katingan and Pulang Pisau, Central Kalimantan. It covers 451,507 ha (MoEF 2017), while the total peatland area is about 67% of the total PHU area (BRG 2017). The peatlands in this area are predominantly located in the freshwater swamp zone and partly in the tidal swamp zone. A schematic cross-section illustration of the PHU is described in Fig. 16.1.

Based on soil nutrient or soil fertility level, most of the peat soil of the PHU of the Kahayan–Sebangau river is classified as oligotrophic peat. This type of peat is acidic and poor in nutrients and is generally found in the backswamp and peat domes of the PHU. Meanwhile, peat in the small and shallow basins is classified as eutrophic peat, which is relatively more fertile because it is enriched with nutrients and sediment from rivers brought in every time a seasonal flood occurs (Takada et al. 2015; Noor and Masganti 2016).

Agricultural development on the PHU of the Kahayan–Sebangau river depends on the characteristics of peatlands. Most peatland area is not suitable for agricultural development, because of some limiting factors, which consists of seasonal flooding or inundation, the thickness of peat, very acidic and very low nutrient content of peat soils (Ritung and Sukarman 2016).

Kalampangan is a transmigration village laid on peatland, at 20°16′00″–20°19′20″S and 113°58′20″–114°03′50″E. The village is located administratively in Sabangau subdistrict, Palangkaraya city, Central Kalimantan province (Fig. 16.2). Kalampangan covers an area of 5000 ha with a flat topography (slope of 0–3%) and an altitude of 14–18 m above sea level (asl). The soil type of Kalampangan consists of humic gley soil and Histosol. The wet season occurs from November to February and the dry season from June to September (Kalampangan 2018).

Fig. 16.2
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Kalampangan village in the PHU of Kahayan–Sebangau river

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The Kalampangan village’s peatlands state within the PHU of the Kahayan–Sebangau river is one of heavy settlement and agriculture. Since the transmigration program began years ago, the peatlands have been drained. The presence of a number of drainage canals in the form of one principal canal, which also serves as an area boundary with Kameloh village, as well as a number of minor and tertiary canals, demonstrates this (Fig. 16.3). Apart from those three canals, there is also a quaternary ditch locally known as “parit cacing” in farmers’ farm (Fig. 16.3d). It has narrower dimensions of 30–40 cm in width and depth.

Fig. 16.3
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Three types of canal types based on their dimension. (a) primary canal, (b) secondary canal, (c) tertiary canal, (d) quaternary ditch (parit cacing)

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3.1 Agroforestry Landscape of the PHU of Kahayan–Sebangau River

In the PHU of the Kahayan–Sebangau river, farmers applied various types of agroforestry depending on the physiographic unit of the peatland (river embankment, backswamp, and peat dome). The agroforestry system developed by farmers in Kalampangan village can be classified into six categories, namely: (1) agroforestry with four cropping patterns; (2) agrosilvofishery with three cropping patterns; (3) silvopasture with three cropping patterns); (4) agrofishery with one cultivation pattern; (5) apiculture with two cultivation patterns; and (6) agropasturesilvofishery. The composition of the components of each of these systems is described in Tables 16.1, 16.2, and 16.3.

Table 16.1 Agroforestry types on the levee in the Kalampangan village
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Table 16.2 Agroforestry types in the backswamp in the Kalampangan village
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Table 16.3 Characteristics of the agrisilviculture, agrosilvopastoral, silvopastoral, and apiculture systems in the peat dome of PHU Kahayan–Sebangau in the Kalampangan village
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3.1.1 Agroforestry in the Levee Area

Local farmers develop two agroforestry systems in the river embankments, namely, agrosilvofishery and agrofishery (beje pond). One of the typical agrosilvofishery systems in this area is a dike pond. The embankment pool technique is carried out to overcome the high tide water higher than 2 m. The pond embankment height is 4–5 m, with the width of the embankment 1.5–2 m. The size of the embankment pool is 10–15 m wide and 20–50 m long. The embankment is usually combined with a beje pond. Local farmers planted the embankments with several seasonal crops and tree species. The tree species used to strengthen the pond embankments are Shorea balangeran (kahui) and Nauclea orientalis (bengkel). Some vegetation is also planted on embankments, such as bananas, pineapples, rambutan, soursop, guava, and Mangifera odorata (kueni). Other than that, other seasonal plants such as red chilies, Sauropus androgynus, and cassava are also planted on the embankments. Some fish are cultivated in the pond (Table 16.1).

Another traditional agrofishery practiced by farmers is called beje. Beje is a rectangular pond, which is developed in a river embankment (levee) as shown in Fig. 16.4. The size of the beje varies from 10–30 m long, 5–10 m wide, and a water depth of 1.5–2 m. Each side of the beje pond is connected with a canal called “tatah” or “pelacar” in the local language. Tatah or pelacar aims to channel fish from the canal into the beje. A beje may contain 5–11 fish species, which is dominated by swamp fish (blackfish). The water plants that are kept in beje are water spinach, water hyacinth, and Azolla pinnata. Azolla pinnata and water hyacinth are used for fish feed and compost. Fish is harvested in the dry season when the water level in the beje is 20–30 cm lower than the surrounding land surface. One rectangular beje pond in size of 50–250 m2 produces fish between 128–1745 kg with an average of 879, 9 ± 83.60 kg fish/beje/year. Beje is a productive fishery business that can contribute to local farmers’ annual income around IDR 650,000 to 7,900,000 (or USD 46.4 to 564.3) per beje.

Fig. 16.4
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Profile of the agroforestry system in the embankment area. (a–b) Embankment pool, (c) beje pond

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The limiting factor for fish cultivation in the river embankments is waterlogging. Local farmers develop embankment pools to tackle this problem. They also make beje ponds and floating agriculture. Another obstacle to fisheries in Kalampangan is the high price of factory-made fish feed. The solution to this problem is to self-provide fish feed from local ingredients, such as water hyacinth leaves, Azolla pinnata leaves, taro leaves, snails, maggot, etc.

3.1.2 Agroforestry in the Backswamp

Agroforestry types in the backswamp in Kalampangan village differ from the levee. We found four types of agroforestry, which is summarized in Table 16.2. Some pictures of agroforestry in the backswamp are shown in Figs. 16.5 and 16.6.

Fig. 16.5
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Agroforestry in the backswamp. (a–b) Combination of rice field and P. falcataria trees, (c) alley cropping of D. polyphylla species with cassava

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Fig. 16.6
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Agroforestry system in the backswamp. (a) Timber trees around the land as a hedge. (b) Separate blocks of seasonal crops and timber trees

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First, the agro-silvicultural system (agroforestry) has four cropping types, namely: (a) the paddy fields on the edge of the land are planted with wood and banana trees. Vegetables are planted on the embankments of the paddy field, combined with Paraserianthes falcataria (sengon) trees. Vegetable crops and fruit trees are also planted. (b) Alley cropping with a split-plot technique. Woody trees are planted at a spacing of 6 × 7 m, 5 × 4 m, 5 × 3 m. In the alley that is formed between two tree lanes planted with seasonal plants (vegetables). Some timber trees are planted, such as P. falcataria, Aquilaria malaccensis (gaharu), Hevea brasiliensis (rubber tree), Dyera polyphylla and Elaeis guinensis (oil palm), and mixed with seasonal crops, such as corn, mustard greens, eggplant, kale, spinach, green onions, and chilies. (c) Timber trees (D. polyphylla) are planted around the land as a fence, and vegetable crops (corn, chilies, mustard greens, groundwater spinach and eggplant) are planted in the core area. (d) The farm is divided into two blocks. The first block is cultivated with the seasonal crop, while the second block is planted with timber trees, such as sengon, D. polyphylla. Other tree species, such as Combretocarpus rotundatus, Acacia mangium, are not planted, but they regenerate naturally. The farmers also plant seasonal crops (such as dragon fruit, corn, chilies, taro, and mustard greens) and fruit crops (Nephelium lappaceum and pineapple).

The second is agropasturesilvofishery. This system combines the cultivation of agricultural crops, cattle, fish farming in tarpaulin ponds, and tree crops (D. polyphylla) in one land unit. The cropping pattern and land arrangement were carried out using alley cropping techniques with the split-plot arrangement technique. The size of the trench around the land is 40–50 cm wide and 40–50 cm deep. There is a plastic pond for fish farming between two tree trails, 10 m long, 3 m wide, 1.5 m deep (Fig. 16.7). Species of cultivated fish are catfish and papuyu. D. polyphylla is mixed planted with vegetable crops, such as corn, chilies, and sweet vegetables (mustard greens). Also, farmers raise cattle on their farm. At the boundary of the land is planted with fodder grass.

Fig. 16.7
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(a) Agropasturesilvofishery system with (b) alley cropping

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Some farmers in Kalampangan currently practice apiculture or honey bee cultivation (Fig. 16.8). Apiculture is beneficial for farmers who do not have their own land as this forms a source of income. It is also beneficial for cultivated plants, as they help pollination and act as biocontrol of ants, flies, and other beetles that can damage flowers and fruits. Thus, it can increase plant productivity. The main obstacle to developing honey bee cultivation is the use of pesticides, which may kill bees. This obstacle can be overcome by planting ornamental plants, such as sunflowers, Antigonon leptopus, and calliandra plants, as the source for pollen and nectar.

Fig. 16.8
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Two types of apiculture system by Yoan farm in Kalampangan village

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Fourth, agrosilvopasture. In this system, the land is used to cultivate agricultural crops, tree crops and forage crops (Fig. 16.9). There are two types of agrosilvopastures developed by local farmers: (a) D. polyphylla is planted with a spacing of 5 × 5 m; between two lines of D. polyphylla, annual crops are planted. Fodder grass is planted on the edge of the land. Farmers raise cattle (cows and goats). (b) Jelutong species are planted mixed with seasonal plants. In the middle of the land, a house for swallow birds is built. Swallow’s manure can be used for biological fertilizers.

Fig. 16.9
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The agrosilvopastoral system in backswamp physiography. (a–b) Mixed vegetation. (c) A house for swallow bird on the farm

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3.1.3 Agroforestry in the Peat Dome

The five agroforestry systems in the peat dome of Kalampangan village are agrosilviculture, agrosilvopastoral, silvopastoral, apiculture and agrosilvofishery. The area of land used for agricultural cultivation with agroforestry systems is about 0.5–2 ha. The agroforestry characteristics are summarized in Tables 16.3 and 16.4.

Table 16.4 Characteristics of the agrosilvofishery system in peat dome in the Kalampangan village
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3.1.3.1 Agroforestry, where Woody Trees Are Cultivated with Vegetable Crops

D. polyphylla are overlaid with vegetable crops. The cropping patterns and land arrangement in this system can be grouped into three groups. (1) Seasonal plants are planted in an alley formed by two rows of D. polyphylla. On the inside, a “parit cacing” (small ditch) is made, which divides the land into plots of plant locations. The constituent components consist of (a) D. polyphylla, A. malaccensis (woody trees); (b) fruit crops: durian, rambutan, papaya, soursop, orange, pineapple; (c) seasonal crops: corn, cassava, chili, eggplant, mustard greens; (d) shade plants: Ceiba pentandra. (2) The land is divided into two blocks. The first block is for seasonal crop cultivation. The second block is for tree cultivation or is allowed to become forest from natural regeneration. Woody trees, like C. rotundatus and D. polyphylla, are planted with seasonal crops and fruit trees. (3) Woody trees (jelutong and aloe wood) are planted around the agricultural cultivation area (Fig. 16.10).

Fig. 16.10
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Agrisilvicultural systems in the peat dome. (a) Line tree planting with vegetable crops. (b) Tree and vegetable crops are in a separate block. (c) Fruit trees and timber trees

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3.1.3.2 Agrosilvopastoral

In this system, the land is used to cultivate vegetables, D. polyphylla trees and forage. Swamp Jelutung planted with a spacing of 5 × 5 m. Annual crops are planted in between two jelutong lines. On the edge of the land is planted with fodder grass. Fruit and tuber crops, such as taro, cassava and rambutan, are also planted. In addition, farmers raise livestock of cows and goats (Fig. 16.11).

Fig. 16.11
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Agrosilvopasture system in peat dome. (a) Trees and seasonal crops. (b) Trees and fodder grass. (c) Cattle shed

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3.1.3.3 Silvopasture

In this system, D. polyphylla trees are used for duck farming and goat grazing. The advantage of this model is that the D. polyphylla stands free from weeds and gets fertilizer from manure while they create a good environment for swallow. Swallow’s droppings can be used as organic fertilizer (ameliorant) after fermentation. The constituent components consist of tree species (such as D. polyphylla and A. malaccensis), fruit plants (rambutan and pineapple), seasonal crops (such as corn, cassava, chilies, eggplant, mustard greens), and livestock, such as chicken, ducks, swallows, cows, and goats (Fig. 16.12).

Fig. 16.12
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Silvopastoral system in the peat dome. (a) Weeds on the farm (without ducks), (b) the farm with ducks, no weeds, (c) goats in a cage

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3.1.3.4 Apiculture

Honey bee (Apis mellifera) colony boxes (hive) are placed in the yard, where a number of bee food sources were planted as a source of pollen and nectar, for example, ornamental plants, corn, spinach, dragon fruit (Fig. 16.13).

Fig. 16.13
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Crops as source of nectar and pollen for honey bees. (a) dragon fruit, (b) corn, (c) colony box of A. mellifera

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3.1.3.5 Agrosilvofishery

In this system, the land is used for vegetable cultivation, tree crops, and fish cultivation (Fig. 16.14). Pond wastewater can be used as liquid organic fertilizer, while agricultural waste can be used for fish feed. Based on the cropping pattern and land arrangement, this system can be grouped into two groups. (1) Woody plants (such as breadfruit, aloe wood, Pometia pinnata, Leucaena leucocephala, and hybrid coconut) are planted on the edge of the land. In the middle is a fish pond in size of 2–3 m wide, 10–15 m long, 1.5–2 m deep. Vegetables are planted on the edge of the fish pond (such as papuyu, lais, karper). (2) Perennials (such as agarwood, hybrid coconut, rambutan, and soursop) are planted on the edge of the land. A plastic pond is made for catfish farming in the middle, in size of 4 m wide, 10 m long, 1.5 m deep. Vegetables are planted on the edge of the fish pond. Table 16.4 describes the agrosilvofishery system in the physiography of the peat dome.

Fig. 16.14
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Agrosilvofishery system in peat dome. (a) Fish pond, (b) plastic fish pond, (c) vegetable cultivation

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3.1.4 Agroforestry System to Rehabilitate Degraded Peatland

Based on the agroforestry system that local farmers have developed, efforts to rehabilitate degraded peatlands can be carried out using the following techniques: (1) agroforestry, (2) silvofishery, (3) silvopastoral, (4) agrosilvopastoral (combination of annual crops, woody tree, and livestock), and (5) agrosilvofishery (combination of fish-tree-annual crops). Its application depends on the dominant resources available at the development site. The most common tree species cultivated in agroforestry systems is D. polyphylla. Swamp jelutung grows on the lowland (<100 m asl), plain landforms, shallow groundwater, and permanently or seasonally submerged land. It can be planted in combination with various trees and annual crops that have been described above (Sects. 16.3.1.2 and 16.3.1.3).

4 Integrated Agricultural Model (IAM) for PHU Management

The integrated agricultural model based on the agroforestry landscape that local farmers have developed in the Kalampangan village area has specific characteristics. This model can be used as a basis for further improvements and implemented in the similar characteristic condition in PHU Kahayan–Sebangau river.

4.1 Cultivation Practices on Shallow Peat

Important aspects of crop cultivation with agroforestry systems on shallow peatlands (peat thickness 50–100 cm) include land preparation, soil fertility management, water management, and type of mixed cropping. The following description explains this important aspect.

4.1.1 Land Preparation

This activity is carried out before planting, which includes cutting down weeds and ploughing the soil. The equipment used in this activity is the machete, hoe, and “sundak.” Local farmers in land preparation use machete for cutting down weeds and use as minimum tillage. Land preparation with minimal tillage is to minimize soil destruction so that the pyrite layer will not be exposed. The land preparation technique carried out by local farmers can be divided into two, namely, mounding (tongkongan) and “surjan” (Fig. 16.15). For farmers with large capital, the “surjan” technique was created. On the other hand, the use of the mounding (tongkongan) technique is mostly done by farmers who have small capital and then replace it with the “surjan” technique when conditions allow. Usually, “surjan” technique was applied in developing agroforestry systems on thin peatlands to minimize the tidal effect and optimize the land use. In the “surjan” technique, the land is divided into 80% of sunken beds (locally known as “tabukan”), which is the lower part of the land, and 20% of the raised beds or mounding, which is the higher part of the land. “Tabukan” is usually planted with rice or saturation-resistant plants, while the mounds are planted with rubber, jelutong, secondary crops, fruit crops, and/or forage.

Fig. 16.15
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(a–b) Preparation of mound engineering (c) “surjan” technique

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4.1.2 Management of Soil Fertility

This activity concerns ways to increase fertility and efforts to conserve land productivity. The source of nutrients for plants is obtained by processing the rice straw and weeds by means of scattering. This technique is a form of local wisdom of local farmers in obtaining nutrient sources for cultivated plants. This is done by twisting (rolling) the straw and weeds resulting from weeding at one of the stages of land preparation activities in rice cultivation. Spinning is done after the weeds wither, namely, by collecting weeds into one roll in the form of small mounds. The process of making organic fertilizers with the scatter ball system is as follows: (1) cleaning or weeding the weeds using a ploughing tool, (2) weeds that have been cut are left for 2–3 days to wilt, (3) spinning is carried out on weeds that have wilted, (4) evenly spreading the crushed (weathered) material (Maftu’ah et al. 2013).

Another wisdom practiced by local farmers in managing land fertility in rice cultivation is how to transfer seeds three times, which are called “taradak,” trace, and “ampak.” In addition to maintaining soil fertility, this method is also an effort to anticipate a lack of labor. Rice straw and weeds are used as organic materials to store nutrients that will be released slowly into groundwater and used by plants as a slow-release fertilizer. Also, the organic matter produced by the scattered ball in and above the soil surface protects and helps regulate soil temperature and humidity. This practice is often combined with other techniques with complementary functions, for example, soil cultivation and water collection with canal blocking (“tabat” system).

Farmers’ wisdom in utilising debris and weeds as organic material is specific for each individual farmer. In general, these can be grouped into four groups: (1) applying it directly to the soil, either as mulch on the soil surface or buried in the soil; (2) burning organic material (resulting in mineralization) and the ashes from the combustion function as a fast and inexpensive ameliorant; (3) composting organic material using scatter ball technique; and (4) making it as animal feed, then livestock manure can be used as manure.

4.1.3 Water Management

This activity is carried out by local farmers, which includes the construction of a canal and a canal blocking (tabat) system. Local farmers implement the canal blocking system to maintain water level during the planting season around March–April. “Tabat” is opened at the end of the dry season or before the rainy season to remove heavy metals in the soil (such as Al, Fe, H2S). Water systems that have been tested well in tidal areas are the one-way flow system and the block system, or called dam overflow.

4.1.4 Crops Planting System

Agroforestry systems on peatlands that local farmers have developed can serve as a basis for further development. The cropping patterns that local farmers have developed can be grouped into three groups: (1) agrosilvofishery, (2) mixed cropping, and (3) alley cropping. Table 16.5 describes the crops planting system.

Table 16.5 Agroforestry system that has developed on shallow peatlands
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4.2 Cultivation Practices on Moderate Thick Peatland

Important aspects of agricultural cultivation with agroforestry systems on thick peatlands (peat thickness around 200–300 cm) include land preparation, planting, soil fertility management, water management, and cropping patterns. The descriptions of the five important aspects are as follows.

4.2.1 Land Preparation

This is the most important aspect in the cultivation of agroforestry systems on thick peatlands. The land preparation is carried out by dividing the land into plots with trenches as a barrier between the plots (split-plot technique). The trenching has a dual function, namely, a water management system and a firebreak, especially for underground fires. The existence of a trench can maintain the groundwater level (soil moisture) between 30 and 40 cm from the soil surface so that it provides an opportunity for plant roots to grow well (soil drainage and aeration are good). The trench size used for 1 ha of land is 30–40 cm for the width and depth of the trench.

Pineapples are planted around the ditches to compact the soil around the trench so that it is not prone to landslides, as a green firebreak especially for surface fires, and to prevent weed growth on the cultivated land. According to Noor (2001), the constraints of planting trees on peatlands are the low soil bulk density and the small carrying capacity of the soil so that plants fall easily with increasing plant weight on the ground. Increasing the carrying capacity of the soil requires compaction, especially in the root zone or plant pathways. In general, the compaction techniques employed by local farmers can be grouped into two groups: using vegetation and compaction carried out in the planting hole. The vegetation that is commonly used for soil compaction activities is pineapple and cassava (Fig. 16.16). However, some farmers do not use pineapples for soil compaction because the roots of pineapples are difficult to rot. Cassava has high acidity resistance, and it accelerates the decomposition of the organic materials (Muslihat 2003).

Fig. 16.16
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(a) Pineapples are planted along a ditch, (b) cassava plants to accelerate decomposition of peat and soil compaction

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When preparing the land, especially for peatlands that are used for agricultural cultivation for the first time, it is necessary to clean the roots of ferns (Stenochlaena palustris and others) (Fig. 16.17). For smallholder farmers, this is usually done manually by using machete and hoe.

Fig. 16.17
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(a–b) Cleaning the roots of the ferns

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4.2.2 Planting

Two things that need to be considered in planting seedlings on peatlands are the making of planting holes and the condition of the seeds that are ready for planting. The steps for making planting holes commonly practiced in the field are as follows: (1) the location of the planting hole is cleared of vegetation growing on it; (2) remove fern roots at the planting point so that the seedling roots are in direct contact with the peat layer and chop the peat so that it becomes compact and no air cavity; (3) making a planting hole the size of the polybag; (4) tear the polybags only on the lower surface without removing them from the seedlings, with the aim that the soil moisture of the seed media does not break when there is fluctuation because it has not yet merged with the peat in the field; (5) inserting the polybag into the planting hole that has been made with the top end of the polybag parallel to the soil surface and the bottom of the polybag touching the peat layer instead of the fern roots; (6) compacting the peat around the polybags that have been planted to blend with the soil in the field. Seedlings that are ready to be planted in the field are those whose stems have undergone a hardening process, and the shoots are in a dormant state (resting), which forms as bud, not as a young leaf. This is important because seedlings that are still in young leaf buds will tend to wither when planted in the field quickly. This wilting condition often continues until the death of the seedlings in the field. The height of the seeds to be planted must be higher than the puddle (during the highest inundation) so that the seeds do not sink.

4.2.3 Management of Soil Fertility

The provision of ameliorant is important to improve soil condition. Some ameliorants commonly used by local farmers are lime, mineral soil, and ash from burning grass and litter. After harvesting agricultural crops, local farmers will do a fallow period to give a resting time for their land. In the subsequent land preparation, the grass is sprayed with herbicides. Ameliorant is given in the planting hole (Fig. 16.18).

Fig. 16.18
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(a) The process of managing soil fertility by making “baluran.” (b) Ameliorant application in each planting hole

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4.2.4 Water Management

Soil moisture regulation is made by making small ditch surrounding the land. The size of the outer drainage ditch (circumference) of the land is 30–40 cm in width and depth, while the inner ditch measures 15–30 cm for its width and depth (Fig. 16.19).

Fig. 16.19
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(a, b) Small ditch (parit cacing) profile for water management

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In addition to drainage ditches, farmers also make some rectangular wells (1 × 1 × 2 m3) as a source for watering the plants (Fig. 16.20). Farmers with large capital are also developing artesian well as a water source in the dry season. Table 16.6 describes agroforestry patterns developed on thick or deep peatlands.

Fig. 16.20
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(a) Well profile. (b) Watering from pump wells as a source of water in the dry season

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Table 16.6 Agroforestry patterns that have developed on thick/deep peatlands
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The development of sustainable agricultural cultivation on peatlands with an agroforestry system is prioritized on peatlands that have been converted but are not suitable for agricultural and plantation crops. The chosen agroforestry system (agroforestry, agrosilvofishery, agrosilvopasture, silvopasture) depends on dominant resources available at the development site. Sustainable agroforestry on peatlands is intended to diversify commodities, businesses, and farmers’ income. Hence, it must go through a diagnostic activity to see the needs of local farmers and design an agroforestry model through the active participation of the local farmers.

4.3 Development of Zero Burning and Zero Waste Agriculture on Peatlands

4.3.1 Ameliorant as Ash Substitute

Forest and land fires are major threats to the sustainability of agriculture and peat ecosystems. Burning peatlands is considered dangerous because it can trigger forest and peatland fires. Peatland fires will be difficult to distinguish if they are underground fires that are not visible from above but can spread to nearby places (Najiyati et al. 2005). The control burning on peatland affected productivity.

To reduce fire occurrence on forest and land is to practice cultivation without burning and without waste. Currently, local farmers are still using control burning in land preparation, locally known as “besik-bakar” (Fig. 16.21).This aims to clear the land and to obtain ash as an ameliorant material. Amelioration is used to improve soil fertility.

Fig. 16.21
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The practice of control burning (besik-bakar). (a) A pile of dry grass. (b) Burning the pile of grass. (c) The ashes

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The problems as the result of control burning are burned peat surface and subsidence (Fig. 16.22). The thickness of the peat that is carried out by the controlled burning ranges from 1.0 to 8.5 cm (Table 16.7). The decline of peatland surface due to control burning is 4.3 cm. If the land is planted three times a year, the peatland surface will decrease by 12.9 cm per year. The continued decline of peatlands causes flooding in the rainy season and even become permanent swamps.

Fig. 16.22
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(a, b) Surface subsidence of peat due to control burning (besik bakar) practice

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Table 16.7 Thickness of peat brought on by “besik-bakar” activity
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The choice of ameliorant considers the land classification and the evaluation results of land suitability on selected plant commodities (Basu et al. 2011; Hartatik 2012). Amelioration can be done by adding organic, inorganic, or a combination of both. Organic ameliorant materials include manure, compost, straw, and agricultural debris. Inorganic ameliorant materials are lime or dolomite, zeolite, volcanic ash, and river mud (Salampak 1999; Ervina et al. 2016). Peat ameliorant is a material used to increase the fertility of peatland, which will be used for crop cultivation activities through improving physical and chemical conditions. The criteria for a good ameliorant for peatlands have high base saturation (BS), increase pH significantly, improve soil structure, having complete nutrient content, and neutralizing toxic compounds (acids organic). Ameliorants can be in the form of organic, inorganic, or a mixture of both (Salsi 2011; Maftu’ah et al. 2013; Masganti et al. 2014). Ameliorant used by farmers to improve peatland fertility in PHU Kahayan–Sebangau in the Kalampangan village (Table 16.8).

Table 16.8 Chemical properties of some ameliorants used by farmers in the PHU Kahayan–Sebangau river, Kalampangan village
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It is known that the ameliorant material used by local farmers is proven to increase soil pH and soil alkalis (Table 16.8). The ameliorant material traditionally used by local farmers has met the requirements for good ameliorant, which has high alkaline base saturation (BS), is able to reduce the acidity of peatlands (increases pH significantly), and has complete nutrient content. The laboratory analysis of ameliorant nutrient content in the four study locations as listed in Table 16.11 shows that the ameliorant used by local farmers can be used to improve the peatland fertility. The ameliorant can increase the pH and contain nutrients according to the national standard (Standar Nasional Indonesia, SNI) of compost. This is very necessary considering that peatlands contain a low number of macro and micronutrients (Najiyati et al. 2005). The ameliorant material study provides optimal results. Chicken manure is a source of P and K elements, ash due to burning organic matter as an N binding, and as a source of P elements, lime, or dolomite as a source of Ca and Mg elements.

The content of ameliorant elements can be further explained as follows—first, the degree of acidity or pH (potential of hydrogen). One good indicator of ameliorants is to have a pH close to neutral. The ameliorant pH value commonly used by local farmers ranges from 5.99–7.8. Based on these results, the ameliorant commonly used by the farmers has met the requirements of a good ameliorant. The four ameliorants are categorized as slightly acidic- neutral.

Second, the element content of C, N, and C/N. Nitrogen is a key element in amino acids and nucleic acids. Therefore, nitrogen is essential for all life. Ameliorant N content commonly used by farmers ranges from 18.56–27.66%. The content of the N ameliorant element has met the SNI requirements. The C and N content of the four ameliorants is in the very high category (>0.75) (Harjowigeno 1996). The C/N ratio of ameliorant is 1. This means it is in a low category. The C/N ratio is an important parameter to determine the quality of ameliorants. This ratio is used to determine whether ameliorants are “ripe” enough or not (Wahyuningtyas et al. 2010).

Third, the element content of mineral cations (K, P, and Mg). Ameliorant content ranged from 0.55–295.63%. The elemental content of ameliorant ranges from 0.12% to 0.64%. Samekto (2006) states that good ameliorants contain macronutrients N > 1.5%, P2O5 (phosphate) > 1% and K2O (potassium) > 1.5%. Based on the criteria in Table 16.9, the P elements contained in type 1 and type 2 ameliorants are in the very high category (> 60). Meanwhile, the ameliorant of type 3 and type 4 is very low (<10). The ameliorant used by local farmers has a very low K content (<10). Ameliorant type 3 and type 2 contain very low elemental Na (<0.1). Ameliorant type 4 contains a moderate amount of Na element (0.4–07). Meanwhile, type 1 ameliorant contains low category Na elements (0.1–0.3). Ameliorant type 2 and type 3 contain elements of Ca, including the low category (2–5). Ameliorant type 1 has a high content of the element Ca (11–20). Ameliorant type 3 contains a moderate amount of Ca element (6–10). Ameliorant type 1 has a very high category of Mg content (> 8). Ameliorant type 3, type 2, and type 4 contain high-category Mg elements (2,1–8). Ameliorants of type 4 have a very high CEC (> 40). Meanwhile, ameliorants of type 2, type 3, and type 1 have high CEC categories (25–40).

Table 16.9 The chemical properties of ameliorants used by farmers in Kalampangan village
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The results of the identification of ameliorant materials used by farmers in KHG Kahayan–Sebangau, Kalampangan Urban Village, show that there are 11 kinds of ameliorant composition used (Table 16.9).

Also, there are 12 single ingredients used as ameliorants (Table 16.10). The single material used as an ameliorant is derived from manure and compost from organic matter decomposition. It is known that in the PHU Kahayan–Sebangau–Kalampangan village area, there are 12 raw ameliorant materials. This potential can be used to support agriculture without burning on peatlands. Farmers can mix their ameliorants according to the needs of the plants to be planted. For example, if you want to cultivate root crops such as taro, cassava, sweet potatoes, ameliorants made from wallet dung containing high P elements.

Table 16.10 Chemical properties of single ameliorant substance
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The peatland that is used for plant cultivation has better chemical properties than peatland that is not used for plant cultivation (Table 16.11), as they often receive ameliorant and fertilizer input during the plant cultivation process.

Table 16.11 Ameliorant amendment effect on soil chemical properties at different peatland uses
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4.3.2 Zero Burning on Land Preparation

The technique of preparing land without burning or zero burning is a method of clearing land by processing weeds and organic materials, which are usually burned, into economic value items in the form of compost blocks, seed media, feed pellets of livestock and fish, and energy pellets (wood pellets). Some weed species, such as Plantago major (sasendok or uyah-uyahan), Dianella ensifolia (delingu), Asplenum nidus (fern), Baccaurea bracteata (asem-aseman), Cratoxylum glaucum (Geronggang), Stenochlaena palustris (Kelakai), Clerodindrum sp. (lombok-lombokan), and Melastoma malabathrichum (karamunting), are available in abundance on peatlands. According to Nurjannah (2006), weed species contain protein and minerals that can meet livestock needs. Plantago major contains protein (9.1%), calcium (2.9%), phosphor (0.2%), magnesium (0.8%), and zinc (13.0%), while Stenochlaena palustris (kelakai ferns) contains protein (11.0%), calcium (1.1%), phosphor (0.1%), magnesium (1.1%), and zinc (11.1%).

Moreover, weeds can be processed into planting media and compost block. Compost block is used to support the successful rehabilitation and reclamation of ex-mining plants. Processing of weeds into products, such as feed pellets of livestock and fish, energy pellets, planting media and block compost, is economically beneficial for the communities (Fig. 16.23). It is also a preventive action on forest and land fires. By processing the weeds into energy pellet, farmers may provide energy for domestic uses. The combination of energy pellets and biomass compost can build energy independence for villagers. Farmers are also able to feed their livestock and fish independently. It is hoped that the application of planting media to agriculture on peatlands can increase the capability of farmers in meeting fertilizer needs independently.

Fig. 16.23
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Processing of weeds into beneficial products. (a–b) Feed pellet processing. (c) Energy pellet from weeds can be used for cooking. (d) Organic materials to be used as compost block

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5 Conclusion

Rehabilitation of degraded peatlands can be carried out using the following techniques: agroforestry (agrosilvic structure), silvofishery, silvopastoral, agrosilvopastoral (annual-tree-livestock crops), agrosilvofishery (fish-tree-annual crops), and apiculture (beekeeping). Its application depends on the dominant resources available at the development site. Ameliorant material in the four peatland typologies studied can increase soil pH and soil alkalis. The ameliorant material traditionally used by local farmers has met the requirements of good ameliorant, which has high base saturation (BS), is able to reduce the acidity of peatlands (increases pH significantly), and has complete nutrient contents. These can be adopted and applied in other places which have almost the same characteristics (similar). The development of the agroforestry system is carried out through a diagnostic activity to see the needs of local farmers and designed to model the cropping through active participation so that local farmers can practice it.