Shinya Funakawa

• Kyoto University

The rice-wheat cropping system (RWCS) provides the world’s population with staple foods, and it is crucial to maintain global food demand and security. Food systems are a complex ecosystem and sustain many feedback mechanisms. Crop residue management is one of those feedback mechanisms that was assessed under conservation agriculture, and a decompo...

Vietnam is situated along the eastern coast of the Indochina Peninsula in Southeast Asia. It appears as an S-shaped strip of land on the map, extending for 1,650 km from the north to south. Its population was 97.6 million people in 2020, with a population density of 295 people/km2. Its diverse topography includes hills, mountains, plains, coastline...

This chapter focuses on livelihood and the surrounding environment in Central Vietnam. Based on detailed field surveys, valuable insights are provided, alongside proposals to improve the current conditions. The main topics are (1) transitions of fishery aquaculture practices toward the natural environment challenges of brackish ecosystems. (2) Spat...

Vietnam has been rapidly developing since the 1980s, with the start of the Doi Moi (Đổi Mới) innovation policy to urbanize many cities and grow many economic activities. The rampant urbanization and enormous economic growth in recent times have impacted the quality of life of people in cities as well as in rural villages negatively rather than posi...

This study evaluates the impact of conservation agriculture (CA) on soil carbon sequestration and crop productivity in the Indo-Gangetic Plains, focusing on short-term effects over 3 and 5 years. Conducted at two distinct sites, Karnal and Samastipur, the research compares zero tillage, permanent raised beds, and conventional tillage systems across...

Despite the heightened contribution of soil erosion to soil degradation in the Sahel, its impact, particularly topsoil loss, on crop productivity remains unclear. To address this issue, we investigated the effects of simulated erosion by removing topsoil on the grain yield of pearl millet in the Sahel. Three-year field experiments conducted on an A...

Soil bacteria and fungi are key drivers of biogeochemical cycling, yet their distribution and primary controlling factors are obscure in tropical volcanic regions. Moreover, bacteria and fungi exhibit varying sensitivities to environmental factors with poorly understood interactions among climate and edaphic factors. To address these gaps, we colle...

Soil erosion by wind is a major cause of nutrient loss in the Sahel. The amount of nitrogen lost from the field by the wind is up to three times higher than the amount absorbed by the crop. The fallow band system (FBS) was designed to capture the windblown sediments. In the system, 5-m-wide fallow strips (fallow bands) are made in a north-south dir...

Pyrolysis-GC/MS Clay and silt Topsoil and subsoil A B S T R A C T Factors controlling organic carbon stabilization are elusive in neutral-to-alkaline soils, thereby hindering the assessment of carbon sequestration potential across vast agricultural regions like the Indo-Gangetic Plain (IGP). This study investigated controls over mineralization and...

Sustainable land management of smallholder farms is crucial for ensuring food security in sub-Saharan Africa. However, little is known about the nutrient dynamics of smallholder farming systems at the farm level based on primary data. In this study, carbon (C) and nutrient budgets of the home garden system in the Kilimanjaro highlands, where Andoso...

Phosphorus (P) addition is thought to have a minimal effect on the priming of preexisting soil organic carbon (C) mineralization after C addition. We hypothesized and tested that positive priming effects are driven by microbial P-mining under P-limitation when a relatively small amount of glucose is added to N-rich and P-poor tropical forest soils...

Active Al, Fe and Si (i.e., oxalate extractable fraction: Alo, Feo, Sio) strongly affect soil physical, chemical and biological properties. This study examined the pedogenic factors affecting Alo, Feo and Sio contents across a soil weathering sequence in the Cameroon volcanic line. We investigated the B horizon (∼50-cm depth) from 26 soils formed i...

• Some O horizons showed higher nitrification rate than mineral horizons.• Both total N and pH were positively correlated with nitrification rate in O horizon.• Nutrient richness in litters supported active nitrification in O horizon.• Nitrification rate in O horizon increased along with a pH threshold of 5.5–6.0.High nitrate leaching has been obse...

Sub-Saharan Africa (SSA) must undertake proper cropland intensification for higher crop yields while minimizing climate impacts. Unfortunately, no studies have simultaneously quantified greenhouse gas (GHG; CO2 , CH4 , and N2 O) emissions and soil organic carbon (SOC) change in SSA croplands, leaving it a blind spot in the accounting of global warm...

Climate and parent material are considered the primary factors determining the distributions of soil clay (secondary) minerals, but their influence has not been rigorously elucidated for tropical volcanic soils. Herein, we investigated soil secondary mineral distributions in volcanic regions of Java and Sumatra islands representing large variations...

Forest management practices such as clearcutting risk increasing the leaching loss of cations and soil acidification by increasing nitrification and reducing plant uptake. To evaluate the effect of two forest management practices, clearcutting and stem girdling, on soil acidification, we quantified proton budgets by measuring ion fluxes associated...

Understanding the farmer's perspective has traditionally been critical to influencing the adoption and out-scaling of CA-based climate-resilient practices. The objective of this study was to investigate the biophysical, socio-economic, and technical constraints in the adoption of CA by farmers in the Western- and Eastern-IGP, i.e., Karnal, Haryana,...

The increase of world population needs more food, feed, fuel, and fiber. Meanwhile, agricultural land supply is somewhat stationary or even decreasing. Ensuring food provision requires both intensification and expansion strategies. Considering internal circumstances, options may vary across countries. Indonesia, for instance, by population growth r...

Abstract Water erosion has created severe degradation problems in Vietnam and its Thua Thien Hue Province because it lies on the tropical typhoon belt and frequently experiences typhoons and floods. To clarify which environmental factors affect runoff generation and soil loss under specific climatic and soil conditions in the study area, we analyze...

Natural broadleaved forests have been widely converted to plantations with economically valuable trees mainly belonging to the family Pinaceae in temperate regions. Furthermore, mixed natural forests dominated by Pinaceae have been converted into pure cedar plantations involving members of the Cupressaceae in many areas. The objective of this study...

Impacts of forest management practices on soil carbon (C) and nitrogen (N) dynamics remain under debate due to complex interactions between belowground biogeochemical processes. To optimize practices that minimize soil C and N losses, we investigated the effects of management practices on soil C and N fluxes, including the leaching of dissolved org...

Deforestation of native tropical forests has occurred extensively over several decades. The plantation of fast-growing trees, such as Acacia spp., is expanding rapidly in tropical regions, which can contribute to conserve the remaining native tropical forests. To better understand belowground biogeochemical cycles and the sustainable productivity o...

We investigated soil organic carbon (SOC) storage and the quantitative relationship between SOC and geochemical properties in tropical surface and subsurface soils, where information on various soil geochemical properties remains limited. We used soil samples from 178 sites in Indonesia, Thailand, Cameroon, and Tanzania as tropical soils and 34 sit...

A field experiment was conducted during the rainy season of 2014, in the steeply sloping agricultural land of northern Laos to determine the factors that cause the generation of surface runoff water and sediment (i.e., soil erosion). Four treatments (upland rice cropping, maize cropping, maize cropping with mulch treatment, and bare land) were inst...

Soil organic carbon (SOC) in the subsoil may not be so resistant to decomposition as previously assumed, while the mechanisms controlling C dynamics in subsoils are not yet known. This study aimed to (1) identify the factors that control SOC pools in subsoil and (2) compare the differences in SOC pools and controlling factors between the subsoil an...

Understanding the factors that control the storage of soil organic carbon (SOC) is an urgent priority for mitigating global climate problems. The objective of this study was to determine the factors controlling SOC pools with differing stabilities. Surface soil samples were collected along an elevation gradient from four volcanic regions of Tanzani...

The soil cation exchange capacity (CEC), which is contributed by constant and variable charges, is a vital indicator of soil fertility and affects elemental cycling. Climate is expected to affect soil CEC by controlling soil secondary minerals and organic matter distributions. The objective of this study was to clarify the effects of climate on the...

PurposeSoil organic carbon (SOC) priming affects C sequestration in soils, the intensity of which differs depending on residue quality. N fertilization could also alter SOC priming. However, the interaction of crop residue quality and N fertilization on the SOC priming is still not clear. To address this gap in knowledge, we conducted this study.Ma...

Based on spatial variation and time, climate change has various levels of impacts on different communities and sometime with the state of development as well. The rural mountainous households that depend on natural resources for subsistence livelihoods and agriculture are particularly vulnerable with changing climate. Livelihood vulnerability asses...

Crop residue management strategies must be adapted for improving carbon (C) balance and soil C stock in agroecosystems in sub‐Saharan Africa with consideration of the crop residue availability and site‐specific soil characteristics. We conducted field experiments to determine the effects of crop residue application method (incorporation/mulching) a...

Combined applications of plant residues and nitrogen (N) fertilizer in agroecosystems may increase N immobilization and reduce N loss through microbial propagation using fresh organic matter (FOM). However, the effects of different carbon (C) availabilities in FOM to microbes on the immobilization of two forms of fertilizer-N (NH4 ⁺-N and NO3 ⁻-N)...

Soil nitrogen (N) mineralization is generally limited by amino acid production by proteases (depolymerization). Protease activities can be stimulated under N limitation, but it cannot directly increase microbial N release (ammonification) in temperate forest soils. To analyze factors determining rate-limiting steps of soil N mineralization, we comp...

There are limited studies on the mineralogy of tidal flats in Japan even though the composition would affect the functions of water purification and organic matter preservation. This study investigated the mineralogy of major Japanese tidal flats and clarified factors affecting the mineralogy. Sediment samples were collected at 46 sites from 21 tid...

Most peatlands in Indonesia border mineral upland, yet research reporting the effects of the presence of mineral upland on the distribution of mineral nutrients are limited. We collected multiple samples in surface layers from a peatland located between the Siak River and a mineral upland in Riau Province, Indonesia and measured electrical conducti...

On the slopes of Mt. Kilimanjaro, homegardens with banana-coffee cultivation have been managed using livestock dung for more than 100 years. However, there are few studies which quantitatively evaluated the effect of farmers’ practice such as the application of livestock dung on soil fertility of homegardens. The objective of this study was to eval...

Soil organic carbon (SOC) dynamics after slash-burn agriculture are poorly understood in African tropical forest, though recent studies have revealed C4 grass invasion as a forest understory influences SOC dynamics after deforestation. This study aimed to quantify the relative SOC contribution of C4 and C3 plants separately through the sequential f...

Nitrate (NO3−) leaching from agriculture is a growing environmental concern, but little attention has been given to the cropping systems in sub-Saharan Africa, where efforts are underway to increase fertilizer (especially nitrogen, N) use to secure food production. During 2015–2017, we monitored NO3− leaching from the critical root zone of maize in...

Cropland intensification is needed to meet the demand for food in sub-Saharan Africa (SSA). This process requires a dramatic increase in resource inputs, including fertilizer-nitrogen (N) and organic residues (e.g., stover), which alter the soil-atmosphere exchange of nitrous oxide (N2O). The dearth of N2O emission data for SSA croplands, however,...

The arginine mineralization assay has been used to estimate microbial potentials of soil ammonification, but the validity of saturating arginine dose must be assessed before applying the assay to forest soils as well as cropland soils. We studied the Michaelis–Menten kinetics of ¹⁴C-radiolabeled arginine mineralization (¹⁴CO2 production) at wide ra...

In humid regions, soil acidification is a natural process accelerated by acidic deposition and intensive agriculture. Proton budget analysis has revealed that excess cation uptake by plants is the dominant proton source in most forest ecosystems. However, translocation of temporary acids (e.g., organic acids) and distribution of root biomass contri...

Expansion of oil palm (Elaeis guineensis Jacq.) plantations in tropical peatlands is always followed by a lowering groundwater level, which exposes peat to oxidic condition and releases large amounts of carbon dioxide (CO2) to atmosphere. This study is concerned with decomposition of organic matter in the soil profile of tropical peatland under oil...

Enhancing crop production by maintaining a proper synchrony between soil nitrogen (N) and crop N demand remains a challenge, especially in under-studied tropical soils of Sub-Saharan Africa (SSA). For two consecutive cropping seasons (2013–2015), we monitored the fluctuation of soil inorganic N and its availability to maize in the Tanzanian highlan...

Many surface soils in Japan may experience more frequent and intense drying–rewetting (DRW) events due to future climate changes. Such DRW events negatively and positively affect microbial biomass carbon (MBC) through microbial stress and substrate supply mechanisms, respectively. To assess the MBC immediately after DRW and during the incubation wi...

The forest–savanna transition zone is widely distributed on nutrient-poor Oxisols in Central Africa, and a population explosion has led to the rapid cultivation of these vegetation types in this zone. To reveal and compare the effects of short-term (3 years) cultivation on the soil nutrient status of the forest and savanna vegetation in this area,...

Nutrient deficiency, high rate of evapotranspiration, and insufficient and erratic rainfall are the critical challenges for crop production in the dryland areas (DLAs) of Sub-Saharan Africa, including Tanzania, where 61% of arable land is prone to drought. In addressing these challenges, field trials were conducted in central Tanzania to evaluate t...

Black saxaul (Haloxylon aphyllum) is a native tree species tolerant of aridity and salinity. It is planted to alleviate environmental damage due to the formation of the Aralkum desert and improve vegetation of the Aral Sea region. To investigate the environmental factors that determine seedling mortality and growth after rooting, we focused on soil...

Low molecular weight organic acids (LMWOAs) are key pools regulating carbon (C) stabilization and destabilization in tropical forest soils. The variation in clay contents and mineralogy between sites or within a profile might regulate magnitude of LMWOA sorption and biodegradation in tropical soils poor in short-range-order (SRO) Al/Fe oxides. We a...

Conservation agricultural (CA) systems based on the principles of minimal tillage, residue recycling and crop diversification for resource conservation and sustainable agriculture promote soil carbon restoration by tipping the balance in favor of carbon inputs relative to carbon outputs. Carbon sequestration in a soil can be achieved by maximizing...

Soil nitrogen (N) mineralization is generally limited by microbial N assimilation when microorganisms are exposed to substrates with high carbon-to-nitrogen (C/N) ratios. We hypothesized that microbial N release is also limited by repression of arginine-degrading activity in forest soils with the high C/N ratios. We analyzed the microbial assimilat...

Surin Province has long been used to cultivate Thai jasmine rice, yield of which is strongly affected by topographical positions of paddy fields. The present study was conducted to investigate the characteristics of Surin paddy soils at high and low topographical positions in Tha Tum and Chom Phra districts in Surin Province. Differences in nutrien...

Use of nitrogen (N) fertilizer is underway to increase in Sub-Saharan Africa (SSA). The effect of increasing N rates on ammonia (NH3) volatilization—a main pathway of applied-N loss in cropping systems—has not been evaluated in this region. In two soils (Alfisols, ALF; and Andisols, AND) with maize crop in the East African highlands, we measured NH...

Forest-savanna mosaic is widespread in tropical Africa mainly occurring on nutrient-poor Oxisols. Though sustainable agriculture is a major concern in this region, little is known about the effects of original vegetation (i.e., forest vs savanna) on nutrient losses from cropland. Hence, we evaluated basic cation losses and nutrient balance of Oxiso...

Understanding the composition of the soil solution of tropical peatlands is important because it directly affects nutrient availability and environmental degradation. The objectives of this study were to investigate temporal fluctuations in the soil solution composition in tropical peatlands in West Kalimantan and Riau, Indonesia and identify the f...

Soil phosphorus (P) forms have been practically defined as chemically fractionated pools. A knowledge of the abundance and diversity of P forms in soil, and the factors affecting them, will lead to better soil management. However, little is known about the differences in P forms among soils with different geological properties in tropical Africa. T...

This study focused on black saxaul (Haloxylon aphyllum) and tamarisk (Tamarix hispida), which are economically and environmentally important trees in one of the most arid parts of the Aral region. Black saxaul is the main local fuelwood species. However, its extraction was banned after it became critically endangered in the 1990s. Planting this spe...

The forest–savanna transition zone, which contains nutrient-poor soils (Oxisols), is found throughout central Africa. To evaluate the effect of deforestation on soil phosphorus dynamics, which regulate the plant growth in this area, we quantified the relationship between phosphorus (P) and carbon (C) in different fractions and compared their relati...

Tellurium (Te) isotopes were released into the environment with radioactive cesium (Cs) and radioactive iodine as a result of the accident at the Fukushima Daiichi Nuclear Power Plant. Te-127m and Te-129m, with half-lives of 109 and 33.6 days, may have moved from soil to foodstuffs and been ingested by local residents. Data on the transfer of Te to...

There are contrasting results regarding the effect of repeated drying–rewetting (DRW) cycles on microbial biomass carbon (MBC), and two fundamentally different mechanisms have been postulated. The first is a microbial stress mechanism which will reduce MBC as stress-sensitive microbes die, and the second is a substrate supply mechanism which will i...

The fates of carbon (C) input to soils widely vary under different nutrient availability. In this study, both initial substrate-induced respiration (SIR) rates and substrate-induced growth responses to nitrogen (N) and/or phosphorus (P) additions were investigated together because the two approaches had been assessed separately in previous studies....

Analysis of fixed ammonium (NH4⁺) in soils by the most common method requires the subsample to be ground to pass through a 100-mesh sieve. We tested a hypothesis that the ball milling pretreatment for the analysis of fixed NH4⁺ may influence the analytical results depending on the content of exchangeable NH4⁺. Five paddy soils collected from the su...

We lack an understanding of nitrogen (N) cycles in tropical forests of Africa, although the environmental conditions in this region, such as soil type, vegetation, and climate, are distinct when compared with other tropical forests. Herein, we simultaneously quantified N fluxes through precipitation, throughfall, and 0-, 15-, and 30-cm soil solutio...

Soil nitrogen (N) dynamics in croplands need to be improved for the increase of food production in sub-Saharan Africa. Our objective was to investigate the crop residue management in terms of quality and application method to improve soil N dynamics during the period of crop growth in maize croplands with special reference to soil textures in dry t...

This chapter provides an overall conclusion and summary of the volume with brief summaries of each chapter. Part I covered soil-forming processes on different continents, focusing on humid regions of Asia and equatorial Africa. Part II presented a comparative analysis of pedogenic acidification processes under different geologic and climatic condit...

The conditions for surface runoff generation, which is usually strongly related to the process of soil erosion, were analyzed in three plots at different cultivated sloping sites in North and Northeast Thailand using a runoff gauge connected to a data logger. In most of the cases, the rainfall intensity and the surface soil moisture contributed sig...

To clarify the various functions of the fallow phase in the shifting cultivation system in northern Thailand, the fluctuation of fertility-related properties of soils throughout land-use stages was analyzed and the soil organic matter (SOM) budget was quantitatively evaluated, with special reference to soil microbial activities. The factors that ha...

Geology and climate had a clear impact on the clay mineral composition for the soils in humid Asia. In soils derived from mica-free parent materials, such as mafic volcanic rocks, the clay mineral composition changes to the kaolin apex along the mineral axis of the 1.4-nm minerals. For other soils derived from the sedimentary rocks or felsic parent...

Based on the results of field studies in different regions of the tropics, land management strategies using shifting cultivation under different bioclimatic and soil conditions are comparatively discussed. Four regions are included in this study: eastern Zambia, northern Thailand, East Kalimantan of Indonesia, and eastern Cameroon. An increase in N...

Soil fertility was measured in contrasting regions of sub-Saharan Africa, i.e., Tanzania, Rwanda, western D. R. Congo, Cameroon, Nigeria, Burkina Faso, Ivory Coast, and others, with special reference to geological and climatic conditions. The general properties of the soils in each region of equatorial Africa could be summarized as follows: when co...

Soil-forming conditions in Tanzania, which is located near the Great Rift Valley, vary with geological and climatic conditions. In the present study, 95 surface soil samples were collected from croplands, forests, and savannas in different regions across Tanzania and the physicochemical and mineralogical properties of the samples were analyzed. Ref...

The main objective of this book is to integrate environmental knowledge observed in local agriculture, based on the understanding of soils science and ecology, and to propose possible technical solutions and a more integrated approach to tropical agriculture. The chapters describe and analyze the ecological and technical countermeasures available f...

This study tried to understand the mountainous households’ perception of climate change and its impacts on food security in the Lamjung district of Nepal. The study attempted to find out changes in households food security and daily activities in the face of climate change for the last twenty years. The study started with the 150 household surveys...

Core Ideas A unified interpretation of clay mineral distributions in Kalimantan was achieved. The conditions under which soil clay minerals formed in Kalimantan were clarified. Systematic sampling, considering parent material and climate, allowed clear analysis. Thermodynamic analysis of clay mineral stability was performed. The clarified mineralog...

Soil water erosion is a major agricultural concern in tropical Africa with high precipitation and low soil fertility where Oxisols are generally distributed. A field experiment was conducted in east Cameroon during the rainy season in 2013 to investigate the effects of surface mulching with the residues of Imperata cylindrica on soil losses and sur...

Tropical sandy soils are highly susceptible to acidification as a consequence of intensive farming. We analyzed the dominant processes of acidification and neutralization in a sandy soil of cropland system in northeast Thailand. Proton budgets in the soil (Typic Ustipsamments) were quantified for a sugarcane field and a mango plantation by measurin...

Water erosion is one of the main concerns driving land degradation in mountainous areas throughout the world, and its characteristics change widely with soil and climate conditions in different locations. To investigate the effects of soil and rainfall properties on surface runoff and soil loss, we installed runoff plots (width 0.8 m × slope length...

Land use intensity in the Cameroon plateaus, where Ferralsols and the associated highly weathered soils are dominant, has been steadily increasing, so that soil fertility status and its controlling factors on these plateaus should be elucidated to establish long-term land management strategies. Although it is known that Ferralsols have small, but v...

Drone: Male-bee, Unmanned Aerial Vehicle (UAV), Multicopter - New technology; Under the development of usages in various fields i.e.) Industries (media, infrastructure, agriculture, disaster relief) TV commercials, Movies, Monitoring solar panels at photovoltaic power plants, Surveying (river, land, disaster) i.e.) Studies (Land uses) A part of Rem...

Many surface soils, including those that have rarely experienced dry conditions, may experience more frequent and/or intense drying–rewetting (DRW) events in the future. Such DRW events are likely to induce large and sudden CO2 pulses derived from increased substrate availability owing to their release from non-biomass soil organic C (SOC) and micr...

Conservation agriculture (CA) is gaining momentum in the Indian Indo-Gangetic plains (IGP) to conserve resources and counteract the negative effects of soil nutrient mining while improving environmental quality. Understanding the farmer’s perspective has traditionally been seen as critical to influencing the adoption and up-scaling of CA-based clim...

Soil water erosion is a major agricultural concern in tropical Africa with high precipitation and low soil fertility where Oxisols are generally distributed. A field experiment was conducted in east Cameroon during the rainy season in 2013 to investigate the effects of surface mulching with the residues of Imperata cylindrica on soil losses and sur...

A total of 95 households from five mountainous villages in Hong Ha Commune, A Luoi District, Thua Thien Hue Province, Vietnam were surveyed to investigate the function and significance of home garden practices in their livelihood. The results showed that the average home garden size was about 1000m² with 30% of the households having fish ponds. Usi...

The present study examined the growth performance of a new cash crop in Central Vietnam to improve livelihoods. As a new cash crop, Vanilla planifolia was first Cultivated in Thua Thien Hue province in 2006 with the participation of Hong Ha farmers. In the study, farm trials were conducted in four villages belonging to the commune with about 59 hos...

Phosphorus (P) deficiency is one of the largest constraints to crop production in tropical Africa; so, it is necessary to better exploit soil P resources through increasing labile soil P using P-efficient plants. The aim of this study was to evaluate the effect of various P-efficient legumes on fractionated rhizosphere soil P in two contrasting tex...