Biochar is widely used as a soil amendment to increase crop yields. However, the details of its impact on soil properties have not been fully understood. A pot experiment was conducted using soybean (Glycine max (L.) Merr. cv. Toyoharuka) and sorghum (Sorghum bicolor (L.) Moench cv. Hybrid Sorgo) under four soil treatment combinations (cattle farmyard manure with or without biochar and rapeseed cake with or without biochar) to elucidate the mechanisms of its beneficial effects on plant growth in terms of the microbial community structure and mineral availability in soils with different types of organic manure application. The application of biochar significantly increased the growth of both species, particularly sorghum with rapeseed cake application by 1.48 times higher than that without biochar. Microbial activity in soil was also enhanced by biochar application in both species with rapeseed cake application, particularly in sorghum. Principal component analysis using Biolog EcoPlate (TM) data indicated that biochar application changed the microbial community structure in soil, particularly sorghum-grown soil. The changes in microbial community structure in sorghum were considered to be at least partly affected by changes in soil pH due to interaction between plant and biochar under organic manure application. Biochar application had little effect on the profile of ammonium-acetate-extractable mineral elements in soil including calcium, potassium, magnesium, sodium and sulfur with both types of manure application under soybean. Under sorghum, however, biochar with rapeseed cake manure application altered the profile. This alteration is attributable to an increase in the extractable concentration of certain metals in the soil including aluminum, cadmium and zinc, possibly caused by enhanced organic matter decomposition producing metal-chelating organic compounds. These different changes in the soil properties by biochar application may be directly or indirectly related to the different growth responses of different plant species to biochar application under organic manure application

Water management is a key factor in the development of swampland for agriculture, especially rice. Naturally, swampland is affected by water tide from the sea or river during spring and neap tide. Micro water management greatly influences the success of farming in swampland. The functions of micro water management: improvement of land quality, leaching out of ions and toxic compounds, controlling of certain weeds and pests, plant growth and yield, and mitigating of climate change and greenhouse gas emissions. There are many factors influence the increasing rice production in swampland through improved water management. For example, the implementation of a one-way water flow system or a dam overflow system is restricted by tide strength, canal dimensions, and construction and operational of water gate. Support of water supply network infrastructure is important and influences land productivity and cropping intensity. In poor swamp irrigation areas (SIA), most farmers can only plant once a year (Cropping Index, CI=100) with productivity 2-3 t ha-1. But in a good SIA, the yield reaches 6-7 t ha-1 and 2-3 planting times a year (CI 180-200). The implementation of water management in agriculture in swampland also requires the participation of farmers and solid institutional of water administrator. This paper is a review of several research results on the implementation of water management in tidal swampland that have been carried out by Indonesian Swampland Agricultural Research Institute (ISARI). This paper will address the constraints, limitations and opportunities of water management including an effort to mitigate and adapt to climate change through water management in tidal swampland of Kalimantan, Indonesia.

Peatland describes the typology of tidal and freshwater swamplands. Peatlands are affected by tidal activity; the water level fluctuation causes the peat to dry out and then get wet, which affects the soil’s water content and carbon emissions. Additionally, mineral enrichment from river overflows affects soil fertility and peat stability. Peat stability is importantly related to the peatland management for agriculture. Functional groups in the peat, such as carboxyl and hydroxyl, are volatile and easily transform, decomposing from CHO bonds into CO₂ under aerobic conditions. The characteristics of functional groups can be changed from polar to non-polar at the organic colloid surface, leading to hydrophobicity. This study evaluated carbon dioxide emissions and peat hydrophobicity. The research was conducted by survey and field sampling on two differently managed plots of peatlands: a rubber-and-pineapple intercrop plot and a traditionally-managed rubber plot. Parameters measured were CO₂ flux, groundwater levels, water content, and peat hydrophobicity. Peat hydrophobicity was assessed by analyzing certain functional groups using a Fourier-Transform Infrared (FTIR) spectrophotometer. The results showed that CO₂ emissions were 21.78 ± 5.44 (mg ha^-1yr^-1) for the rubber-and-pineapple intercrop and 19.15 ± 5.18 (mg ha^-1 yr^-1) for the traditionally-managed rubber plot. Peat hydrophobicity for both plots decreased with increasing soil depth, indicating that peat on the surface layer (0–50 cm) is more vulnerable to drought and fires, especially if there is no water management.

<p>Masa depan pangan Indonesia ada di lahan rawa. Pembukaan rawa untuk produksi pangan oleh pemerintah melalui Proyek Pembukaan Persawahan Pasang Surut (P4S) tahun 1969-1984 yang disebut sistem reklamasi garpu dan sisir membawa Indonesia swasembada tahun 1985, sekalipun pasokan utama produksi dari lahan irigasi. Disusul Proyek Pengembangan Lahan Gambut (PLG) di Kalimantan Tengah tahun 1995-1999 bersamaan saat impor beras 2-3 juta ton per tahun, namun kemudian, di tengah kecaman, Proyek PLG dihentikan pada tahun 1999. Pandemik Covid 19 membuat pemerintah menginisiasi pengembangan <em>Food Estate</em> lahan rawa di Kalimantan Tengah tahun 2021-2023.  Luas lahan rawa sekitar 32,64-33,39  juta hektar, diantaranya 14-19 juta hektar sesuai untuk pertanian. Hanya saja baru 6,90 juta hektar yang dimanfaatkan diantaranya 2,90 juta hektar untuk padi dan masih tersedia seluas 27,60 juta hektar yang belum direklamasi dari  luas total rawa dan 0,84 juta hektar yang belum dimanfaatkan dari 2,90 juta hektar yang telah direklamasi. Produktivitas padi di lahan rawa yang dicapai petani masih rendah (2-3 t/ha)sementara dari hasil penelitian mencapai 4,5-7,5 t/ha. Kendala budidaya padi di lahan rawa antara lain kemasaman tanah yang tinggi, kualitas air jelek, unsur dan senyawa toksik, kahat hara makro dan mikro, serangan hama dan penyakit tanaman. Pendekatan pengembangan rawa memerlukan penanganan yang terpadu dan spesifik lokasi. Implementasi program yang dilaksanakan pemerintah memberikan pelajaran bahwa pengembangan pertanian, khususnya padi memerlukan dukungan infrastruktur tata air, perencanaan sistem produksi, kelembagaan manajemen, dan langkah implementasi yang cepat dan tepat. Beberapa catatan menunjukkan pendekatan pengelolaan masih bersifat parsial, tidak terintegrasi, tanpa <em>road map</em> dan target yang jelas, manajemen dan kelembagaan petani masih lemah, sehingga dampak terhadap kesejahteraan petani masih belum tercapai. Tulisan ini mengemukakan tentang perjalanan penelitian dan pengembangan lahan rawa selama 53 tahun meliputi dinamika kegiatan pengembangan, peluang, kendala dan pembelajaran dari petani pada pengembangan kawasan <em>food estate</em> di Kalimantan Tengah.  </p>

Water management is the most important component in developing peatlands for agriculture. Utilization of peatlands for food crops and research on its physical, chemical and biological characteristics have been carried out previously since a long time. However, the implementation of peatland management technology is not much well known. Peatland agricultural commodities are developing. In 1970-1990, mostly for food crops and horticulture. Since 2000 plantation crops had been developed rapidly. About 0.5-0.8 million ha of peatlands are planted by food crops, including horticulture and 2.5-3.0 million ha for oil palm. The use of peatlands is still being debated along with threats to the environment, especially greenhouse gas (CO2) emissions. The use of peatlands for agriculture by local communities aimed at sustaining life and has an interesting long history. Farmers who live in peatlands have special abilities and expertise in peatland management. Based on this experience and local wisdom, the government then planned to open peatlands, especially in supporting transmigration programs from Java, Nusa Tenggara, and Bali. However, the use of peatlands for agriculture has changed the fertility of peatlands and reported to be a trigger for land degradation so that improvement efforts are needed. The government has also issued several policies in improving the management and conservation of peatlands. This paper is a review of the results of research and experience on water management on peatlands for food crop and horticulture production.