Tidal swamp lands in Indonesia, despite their low productivity, hold significant potential for improving maize (Zea mays L.) cultivation and food security. Biostimulants derived from plants, animals, and plant growthpromoting rhizobacteria (PGPR) can enhance productivity and maize yields. Notably, rice husk ash (RHA), rich in silica, and golden apple snail (GAS; Pomacea canaliculata, Lamarck, 1822), containing amino acids, offer growth-promoting benefits. This study examines the impact of liquid RHA, GAS, and microbial inoculant (PGPR) on maize yield in acid sulphate soils from Barambai District, South Kalimantan, Indonesia. A randomized complete block design was used to test nine treatments, including a control (no NPK or biostimulants), full NPK, 75% NPK, and six biostimulant formulations (B1 to B6) combining RHA, GAS, and PGPR with 75% NPK. Biostimulants with more than 50% GAS extract significantly improved maize growth and yield while reducing NPK fertilizer use by 25%. Specifically, biostimulant formulations B1 (10% RHA, 80% GAS, 10% PGPR), B2 (20% RHA, 70% GAS, 10% PGPR), and B3 (30% RHA, 60% GAS, 10% PGPR), combined with 75% NPK, produced 126.0, 125.0, and 111.0 g plant(-1), respectively, compared to 97.67 g plant-1 with full NPK. This suggests that biostimulants can reduce fertilizer use without sacrificing yield. The results highlight the role of amino acids in GAS extract for enhancing maize productivity. Biostimulants, particularly those rich in GAS extract, show promise in increasing maize grain yield and reducing reliance on inorganic fertilizers. Further field testing in real-world tidal swamps is needed to validate these findings.

Corn is the second most important food commodity in Indonesia. However, its production is lower than the demand. This problem can be overcome using suboptimal land, such as tidal swampland, with its naturally low productivity. The soil quality in such areas can be improved by applying biostimulant. Therefore, this study aims to examine various biostimulant formulas supplemented with microbes and their application frequency on corn productivity in tidal swamplands. It was conducted on a pot experiment using a completely randomized block design with three replications. The treatments were six formulas of biostimulant, each with three application frequencies. The biostimulant materials included rice husk ash, golden apple snail extract, and microbes serving as P-solubilizers, N2-fixers, and IAA phytohormone. The results revealed that biostimulant formulas can increase the production of corn. The B3 formula, followed by the B4 and B5 formula, led to superior grain yields compared to the other treatments. In comparison, the most effective application frequency was observed with four times application (D2) followed by five times application (D3) as the next best option. These biostimulant formulas need to be tested in the field to know their effectiveness in tidal swamplands. Keywords: corn productivity, biostimulant formulas, tidal swamplands, microbial supplements

The rice yield gap (YG) is a global concern, requiring more detailed studies spatially and temporally. As a staple food in Indonesia, rice was produced from 7.4 Mha paddy fields in 2019. Better insight into the YG helps assess measures to boost rice production. However, the information on YG variation among regions scale is limited. This study aimed to identify the rice YG based on 295 historical trial datasets from 23 provinces in Indonesia. We surveyed published trial results from 2012 to 2022 and analyzed YGs, expressed as the percentage of farmer yield (FY). The potential yield (PY) was estimated from field trial results using introduced rice cultivation technology package, whereas FY from results using existing farmer practices. Our study showed that the average YG was 62% in rainfed, 54% in tidal, and 32% in irrigated paddy fields. The YG was significantly high in the paddy fields of Kalimantan (74%) and Maluku-Papua (49%), while the lowest was in Sulawesi (27%) and Java (31%). The YG varied significantly with geo-regions, rice varieties, and cultivation technology packages. Closing the YG and ensuring sustainable rice production requires the implementation of sustainable intensification through applying site-specific technology packages, reallocation of agricultural interventions to a higher YG region, and rice variety improvement to increase PY.

The Indonesian government is continuously developing swampy land through Ministry of Agriculture to support the rice production increase program. Known as a low-cost and environmentally friendly, biofertilizer can be applied to increase the nutrient availability, reduce inorganic fertilizer use, improve the soil health and increase the rice production in a sustainable ways. The experimental aim is to test the dose of liquid biofertilizer, P-solubilizer, and N-fixer to increase rice productivity in tidal swamp lands. The experiment was conducted on November 2020 – Maret 2021 in Karang Buah, Belawang District, Barito Kuala Regency, South Kalimantan. The experiment design was RCBD with four replicates. The treatments were A. 300 kg/ha NPK + 150 kg/ha Urea (recommended dose); B. 75 % of the recommended dose + Biofertilizer 2L/ha; C. 75 % of the recommended dose + Biofertilizer 4L/ha; D. 75 % of the recommended dose + Biofertilizer 6L/ha; and E. 75 % of the recommended dose + Biofertilizer 8L/ha. The research results showed that the use of liquid biofertilizer of up to 6L/ha in combination with 225 kg/ha NPK+ 112.5 kg/ha. Urea gave the highest grain yield (6.88 t/ha for tiles or 5.77 t/ha for plots) brought a yield increase of 0.57 t/ha (9.03%) for tiles or 0.45 t/ha (8.46%) for plots compared to the recommended dose treatment (300 kg/ha NPK + 150 kg/ha Urea). Liquid biofertilizer application 6L/ha could reduce the application of inorganic fertilizer by up to 25% of the recommended dose and can be used to eco-friendly yield boost up with low input costs reducing the continuous use of inorganic chemical fertilizer.

Coastal acid-sulfate soils are crucial for producing crops and thus, for food security. However, over time, these soil resources experience degradation, leading to higher agro-input, lower yields, and environmental hazards that finally threaten food security. The optimal use of this fragile resource is only attained by implementing vigorous integrated water–soil–crop management technologies amid the climate change impact. This study aimed to review the distribution, properties, use, and management of acid-sulfate soils in Kalimantan, Indonesia. Acid-sulfate soils cover about 3.5 Mha of the coastal area in Kalimantan and have high acidity, high-risk iron and aluminum toxicity, and low fertility, requiring precise water management, amelioration and fertilizer application, crop variety selection, and rice cultivation technologies. Lime, biochar, organic fertilizer, compost, ash, and fly ash are ameliorants that raise pH, reduce iron and aluminum toxicity, and improve crop yield. Rice cultivation has developed from traditional to modern but needs re-designing to fit local conditions. Depending on the soil nutrient status, rice cultivation requires 80–200 kg ha−1 of urea, 50–150 kg ha−1 of SP36, 50–150 kg ha−1 of KCl, and 125–400 kg ha−1 of NPK compound fertilizer, but is affected by CH4 and CO2 emissions. Good water management impacts the effective implementation of amelioration and fertilizer application technologies. The remaining challenges and future directions for water management, amelioration, fertilizer application, crop varieties, cultivation techniques, land use optimization, climate change adaptation and mitigation, technology adoption and implementation, and resource conservation are outlined. Acid-sulfate soils remain a resource capital that supports food security regionally and nationally in Indonesia.

CO2 emissions are agriculture-related problems in peatlands, requiring mitigation. Irrigation and mulching are needed to reduce CO2 emissions in peatlands. This research aimed to study the effect of irrigation system and type of mulch for soil properties and CO2 emissions at shallot cultivation in peatlands. This research was carried out on degraded peatland in the Kalampangan village, Sebangau District, Palangkaraya, from April to December 2017. A split-plot design repeated at 4 times was employed. The main plot was type of rewetting, including manual watering (P) and sprinkler methods (S), the subplot was type of mulches, comprising TM = without mulch, G = weed in situ (Stenochlaena palustris ) mulch, J = straw mulch (O ryza sativa ). Observed variables included soil pH, Eh, EC, organic C, water contents, and CO2 emissions, performed twice within two months. The results showed that the sprinkler irrigation system and mulch did not affect significantly on pH, Eh and soil moisture content, but significantly influence EC and organic C. The sprinkler irrigation system reduced CO emissions up to 10% (2916 kg/ha/season) compared to conventional 2 methods (3250 kg/ha/season). Compared to no mulch (6175 kg/ha/season), Kalakai mulch ( Stenochlaena palutris ) reduced CO2 emissions up to 33% (4119 kg/ha/season) and rice straw increased CO2 emissions up to 32% (8207 kg/ha/season).

Peatlands are potential for cultivating horticultural plants including shallot. This research aims to study the effect of shelter and fertilization on shallots and CO 2 emissions in peatlands. This study was conducted on peatlands in Landasan Ulin village, North Banjarbaru District, Banjarbaru, South Kalimantan. We used a split-plot design with main plot was shelter (R1) and without shelter (farmer’s practice) (R2), and subplot was fertilization consist of 100% recommended dosage (P0), 50% recommended dose + Liquid organic fertilizer (P1), 75% recommended dose + Liquid organic fertilizer (P2), 100% recommended dose + Liquid organic fertilizer (P3), and 125% recommended dose + Liquid organic fertilizer (P4). Observations included soil periodic of pH, available P, available K, CO 2 emissions, growth and yield of shallot. The results showed that shelter application increased the availability of P and K in peatlands. A combination of shelter and 75% recommended dose+Liquid organic fertilizer could increase the shallot yield in peatlands up to 25.7% compared to P0. The highest cumulative flux CO 2 were shown by the treatment without rain shelter (treatment R2PO) reaching 6.2 t CO 2 /ha/year and the lowest was in the rain shelter application plot (treatment) R1P4 (i.e., 4.5 t CO 2 /ha/year) which was not significantly different from treatment R1P2 (4.7 t CO 2 /ha/year).

This study aims to assess the effect of rice husk biochar, raised beds, and chicken manure on the CO2 flux and shallot production on peatland. This study adopted a factorial randomized block design with three factors and three replications. The P1 treatment was recommended by the Swamp Land Agricultural Research Institute by adding chicken manure (5 ton ha−1) and rice husk biochar (5 ton ha−1) while the P2 treatment was recommended by the Vegetable Research Institute by adding chicken manure (10 ton ha−1). The raised beds heights were 20 cm (A) and 30 cm (B). Variance analyses were applied to each observation variable and followed by Duncan's Multiple Range Test at a 5% level. The P1A treatment was the best in improving the shallot production up to 10.88 tons and producing the lowest CO2 cumulative flux up to 0.158 ton ha-1 season-1.

The utilization of agricultural waste as biochar is one way to manage agricultural waste to encourage swamps optimization. There is quite a lot of agricultural waste in Indonesia estimated to reach 10.7 t y −1 , including rice-husks, cocoa pods, coconut-shells, oil palm shells, and corncobs. One of the management of agricultural waste is to make biochar from various sources of raw materials. This paper is intended to provide information about agricultural waste as biochar in agriculture to optimize swampland in Indonesia. The quality of biochar depends on raw materials, incinerator, combustion temperature, and the length of combustion. The application of biochar on agricultural land serves as a soil enhancer that can improve its chemical properties and soil physical properties. Improvements in the quality of the soil chemical and physical properties impact the availability of nutrients and water through the ability of biochar to retain nutrients and water. In the end, the addition of biochar has implications for increasing the productivity of food crops. In the future, it is expected that with the application of biochar, swamplands can increase productivity.

Biochar has pores suitable for microbial habitat, and it contains carbon which can be used as an energy source by microbes. The research aims to determine the potential of some biochar as a carrier of biological fertilizer for swamplands. The treatment given was the type of biochar (rice husk, coconut shell, and palm empty fruit bunches) and the microbial type ie decomposer, Phosphate Solubilizing Bacteria (PSB), N Fixing Bacteria, and a consortium microbial. The design used was a Factorial Complete Randomized Design, 3 replications. Biochar analysis included organic C, total N, pH, CEC, SiO2, ash content and water content. Calculation of microbial populations was done at 2, 6 and 10 weeks after inoculation. Biochar rice husks, oil palm empty fruit bunches and coconut shells were very effective as decomposer carrier material. The highest of population of N-fixing bacteria and PSB at 6 weeks after inoculation was in the biochar rice husk reached 0.33 x 106 cfu/g for N-fixing bacteria and 54.8 x 106 cfu/g for P solvent bacterial. Rice husk biochar can be used as a carrier material both for a single biofertilizer, as well as a consortium biofertilizer that consists of decomposer fungi, P solubilizing bacteria and N-fixing bacteria.

Slash and burn are commonly practiced in opening new field in tropical peatland. This method, if uncontrolled, may cause peat fires and increase CO2 emissions. Therefore, alternative method of peatland preparation for agriculture is needed. The study aimed to obtain peatland preparation technologies to prevent peat fires and reduce CO2 emissions. The study was conducted at degraded peatland in Kalampangan, Central Kalimantan from June to October 2017. Split plot design with three replications was used. The main plot was the type of land arrangement, i.e. without and with raised beds. The subplot was the type of land preparation, i.e. slash and burn, slash followed by composting the weeds, slash and make the weeds as mulches, and slash followed by composting the weeds and accompanied by plastic mulch. Soil characteristics, fires vulnerability, and CO2 emissions were measured before and after land preparation. Results showed that slash and composting reduced CO2 emission from cultivated peatland. Slash and burn resulted 4.98 t CO2 ha-1 emissions per season, which is four times higher than slash followed by composting that produced 1.20 t CO2 ha-1 per season. Groundwater level, redox potential (Eh), soil pH, and soil water content affected CO2 emissions. Groundwater level and water content negatively correlated with CO2 emissions. The shallow water level and the high water content, the lower is CO2 emissions. The Eh and soil pH positively correlated with CO2 emissions. The high positive value of Eh indicates that the soil was in high oxidative conditions, resulting in high CO2 emissions.

Lahan gambut berpotensi untuk dijadikan areal pengembangan tanaman cabai, namun diperlukan teknologi pengelolaan lahan yang tepat. Salah satu teknologi yang diperlukan adalah teknologi persiapan lahan tanpa bakar dan penataan lahan. Penelitian bertujuan untuk mempelajari pengaruh persiapan dan penataan lahan terhadap kesuburan, pertumbuhan dan hasil tanaman cabai merah. Penelitian dilaksanakan di lahan gambut di desa Kalampangan, Kecamatan Sebangau, Kodya Palangkaraya, pada bulan Juni sampai Oktober 2017. Rancangan percobaan menggunakan Split Plot yang diulang 3 kali. Petak utama adalah jenis penataan lahan (U1= tanpa bedengan dan U2 = bedengan tinggi 30 cm). Anak Petak adalah jenis persiapan lahan (A1= semprot, tebas, bakar, A2 = tebas, kompos, A3 = tebas, mulsa, A4 = tebas, kompos, mulsa plastik). Pengamatan meliputi tinggi tanaman dan hasil tanaman cabai, pH tanah dan kadar P tersedia di tanah. Perlakuan yang memberikan hasil cabai tertinggi adalah perlakuan penataan lahan sistem guludan yang dikombinasikan dengan sistem persiapan lahan tebas, kemudian bahan dikomposkan+mulsa plastik, sedangkan hasil paling rendah pada perlakuan penataan lahan tanpa guludan pada sistem persiapan lahan tebas dan gulma digunakan untuk mulsa. Hasil tanaman cabai di tanah gambut berhubungan dengan pH tanah dan konsentrasi P tersedia di tanah. Kata kunci: mulsa plastik, sistem bedengan, tebas-bakar, tebas-kompos, tebas-mulsa

Lahan gambut berpotensi untuk dijadikan areal pengembangan tanaman cabai, namundiperlukan teknologi pengelolaan lahan yang tepat. Salah satu teknologi yang diperlukan adalahteknologi persiapan lahan tanpa bakar dan penataan lahan. Penelitian bertujuan untuk mempelajaripengaruh persiapan dan penataan lahan terhadap kesuburan, pertumbuhan dan hasil tanaman cabaimerah. Penelitian dilaksanakan di lahan gambut di desa Kalampangan, Kecamatan Sebangau, KodyaPalangkaraya, pada bulan Juni sampai Oktober 2017. Rancangan percobaan menggunakan Split Plotyang diulang 3 kali. Petak utama adalah jenis penataan lahan (U1= tanpa bedengan dan U2 = bedengantinggi 30 cm). Anak Petak adalah jenis persiapan lahan (A1= semprot, tebas, bakar, A2 = tebas,kompos, A3 = tebas, mulsa, A4 = tebas, kompos, mulsa plastik). Pengamatan meliputi tinggi tanamandan hasil tanaman cabai, pH tanah dan kadar P tersedia di tanah. Perlakuan yang memberikan hasilcabai tertinggi adalah perlakuan penataan lahan sistem guludan yang dikombinasikan dengan sistempersiapan lahan tebas, kemudian bahan dikomposkan+mulsa plastik, sedangkan hasil paling rendahpada perlakuan penataan lahan tanpa guludan pada sistem persiapan lahan tebas dan gulma digunakanuntuk mulsa. Hasil tanaman cabai di tanah gambut berhubungan dengan pH tanah dan konsentrasi Ptersedia di tanah.Kata kunci: mulsa plastik, sistem bedengan, tebas-bakar, tebas-kompos, tebas-mulsa

Peat swamp forest is a unique and fragile ecosystem, with specific flora and fauna that play important roles in maintaining healthy natural conditions with high economic values. This habitat also has important role for equilibrium and maintenance of living environment such as water reservoir, carbon storage, climate change, and biodiversity. Utilization of peatland for agriculture, plantations, and other activities often lead not only to controversy, but also cause land and ecosystem degradation, including water resources availability. The objective of this research was to study comprehensive ecohydrology aspects in ex-mega rice project in Central Kalimantan in order to support sustainable agricultural practices and water resources management in peatland areas. The results of the study showed that the sustainability of agricultural systems in peatland was strongly influenced by ecological aspect. This aspect can be carried out from the condition of water management system, water color condition, and possible incidence of fires. The level of suitability for crops plantation was low (S3), with the limiting factors of pH, nutrient availability, and the risk of inundation. In this case, water gates should be installed to improve water management system. Water quality in this area was typical of peat water and do not meet the requirement for daily use for the local people.

Amelioration is very important in supporting plant growth in peat land. The use of low emission ameliorant will support the sustainability of agricultural system in peat land. The research is intended to study the effectiveness of some ameliorants in reducing CO₂ and N₂O emission in corn planting in peat land. The research was conducted in April to October 2013, in Kalampangan Village Palangkaraya Municipality Central Kalimantan. Ameliorant materials used were chicken manure fertilizer, domolite, mineral soil, paddy husk biochar, coconut shell biochar. Ameliorant treatments applied were the type of ameliorant compositions, those were (A1) 80% chicken manure fertilizer + 20% dolomite, (A2) 20% chicken manure fertilizer + 20% agricultural weeds + 20% spodosol mineral soil + 20% “purun tikus” (<em>eleocharis dulcis</em>) compost + 20% dolomite, (A3) 19% chicken manure fertilizer + 9% dolomite + 72% mineral soil, (A4) 100% coconut shell biochar, (A5) paddy husk biochar, (A6) farmer’s way (20% ash + 40% spodosol mineral soil + 40% chicken manure fertilizer) and control. Experiment design used a Randomized Factorial Block Design, with 3 repetitions. Ameliorant dosage used was 7.5 t/ha. The crop used was hybrid corn. Parameters which were observed periodically were emission of CO₂ and N₂O, ground water level height, soil pH and Eh, once a month for 5 periods. The research result showed that ameliorant was capable of reducing emission of both CO₂ and N₂O in corn planting in peat land. Coconut shell biochar could reduce emission of CO₂ up to 26% as compared with control, whereas paddy husk biochar could reduce emission of N₂O up to 52% as compared with control.