Improved Soil Management Research Articles

Characteristics of soils under conventional farming practices in a part of South Western Nigeria

The need to ensure food security has threatened sustainable agriculture in many regions; hence recent studies have focused on sustainable farm practices. The study compared soil properties and quality under five different farm practices in a part of the southwest Nigeria. This study indicated that fewer soil properties accounted for more percentage change in total variance at the fallow and mono-cropping plots than at the forest, crop rotation and alley farming systems. It also showed that soils under fallow and mono-cropping systems exhibited the lowest quality values among the farm practices system studied. The study recommends improved soil management approaches in plots under mono-cropping practices, and extensive soil recovery programmes for fallow lands.

Characteristics of soils under conventional farming practices in a part of South Western Nigeria

The need to ensure food security has threatened sustainable agriculture in many regions; hence recent studies have focused on sustainable farm practices. The study compared soil properties and quality under five different farm practices in a part of the southwest Nigeria. This study indicated that fewer soil properties accounted for more percentage change in total variance at the fallow and mono-cropping plots than at the forest, crop rotation and alley farming systems. It also showed that soils under fallow and mono-cropping systems exhibited the lowest quality values among the farm practices system studied. The study recommends improved soil management approaches in plots under mono-cropping practices, and extensive soil recovery programmes for fallow lands.

Matching policy and science: Rationale for the ‘4 per 1000 - soils for food security and climate’ initiative

At the 21st session of the United Nations Framework Convention on Climate Change (UNFCCC, COP21), a voluntary action plan, the ‘4 per 1000 Initiative: Soils for Food Security and Climate’ was proposed under the Agenda for Action. The Initiative underlines the role of soil organic matter (SOM) in addressing the three-fold challenge of food and nutritional security, adaptation to climate change and mitigation of human-induced greenhouse gases (GHGs) emissions. It sets an ambitious aspirational target of a 4 per 1000 (i.e. 0.4%) rate of annual increase in global soil organic carbon (SOC) stocks, with a focus on agricultural lands where farmers would ensure the carbon stewardship of soils, like they manage day-to-day multipurpose production systems in a changing environment. In this paper, the opportunities and challenges for the 4 per 1000 initiative are discussed. We show that the 4 per 1000 target, calculated relative to global top soil SOC stocks, is consistent with literature estimates of the technical potential for SOC sequestration, though the achievable potential is likely to be substantially lower given socio-economic constraints. We calculate that land-based negative emissions from additional SOC sequestration could significantly contribute to reducing the anthropogenic CO2 equivalent emission gap identified from Nationally Determined Contributions pledged by countries to stabilize global warming levels below 2 °C or even 1.5 °C under the Paris agreement on climate. The 4 per 1000 target could be implemented by taking into account differentiated SOC stock baselines, reversing the current trend of huge soil CO2 losses, e.g. from agriculture encroaching peatland soils. We further discuss the potential benefits of SOC stewardship for both degraded and healthy soils along contrasting spatial scales (field, farm, landscape and country) and temporal (year to century) horizons. Last, we present some of the implications relative to non-CO2 GHGs emissions, water and nutrients use as well as co-benefits for crop yields and climate change adaptation. We underline the considerable challenges associated with the non-permanence of SOC stocks and show how the rates of adoption and the duration of improved soil management practices could alter the global impacts of practices under the 4 per 1000 initiative. We conclude that the 4 per 1000 initiative has potential to support multiple sustainable development goals (SDGs) of the 2030 Agenda. It can be regarded as no-regret since increasing SOC in agricultural soils will contribute to food security benefits that will enhance resilience to climate change. However, social, economic and environmental safeguards will be needed to ensure an equitable and sustainable implementation of the 4 per 1000 target.

Seeing below the surface: making soil processes visible to Ugandan smallholder farmers through a constructivist and experiential extension approach

Ugandan smallholder farmers need to feed a growing population, but their efforts are hampered by declining soil fertility rates. Agricultural extension can facilitate farmers’ access to new practices and technologies, yet farmers are understandably often hesitant to adopt new behaviors. New knowledge assimilation is an important component of behavior change that is often overlooked or poorly addressed by current extension efforts. We implemented a Fertility Management Education Program (FMEP) in central Uganda to investigate smallholder farmers’ existing soil knowledge and their assimilation of new scientific concepts into their knowledge framework. Qualitative data were collected through participant observation, farmer interviews, and focus groups, and coded for using a priori and emergent themes. Our exploration revealed some notable similarities between farmers’ soil knowledge and scientific concepts, particularly in regards to soil health concepts, a discovery that could facilitate communication between extension agents and farmers. However, certain scientific concepts are either unknown to farmers or discordant with existing soil knowledge; these concepts are unlikely to be assimilated by farmers without convincing and concerted extension efforts. Importantly, we found that the combination of new scientific knowledge and hands-on experimentation with novel practices gave farmers far greater confidence in implementing improved soil management practices. Our study provides evidence that extension programs should engage directly with farmers’ existing soil knowledge to develop their understanding of key biological concepts and confidence in implementing improved practices.

Mitigating droughts effects on tropical agriculture systems: The role of improved soil management practices in regulating soil moisture, temperature and carbon losses

Climate change is unequivocal and its threat on rain fed agriculture in the tropics is a fact. Changes in temperature, sparse and irregular rainfall, runoff patterns entail droughts extremes, excess evapotranspiration and loss of soil moisture. These items drive soil degradation, crop production, distribution, and supply of food, and subsequently food riot and social stability. Therefore, it urges to develop and improve cost effective agricultural water management and soil conservation in order to increase its resilience and adaptation to climate change. This study focused on the pre-wetted straw amendments effects on soil temperature (ST, °C), moisture content (SMC, %), soil organic carbon density (SOCD, t/ha) and core relationships SOCD versus ST and SMC under short-term field experiment in Nigeria. Results indicated significant difference of treatments on each parameter evaluated (p<0.001). Three best treatments were identified. Their responses (TR, %) to each variable were soil temperature (ST, °C) reduction was up to 20 %, soil moisture content (SMC, %) increase about 41%. Similarly, SOCD (t/ha) had increased to 40.3%. Moreover, the study revealed strong evidence of SOCD linear decrease with ST increase (r = -0.8), but polynomial increase with SMC increase (r = 0.9). It was then concluded that this approach is vital for agricultural water management and soil conservation indispensable to adapt to droughts extremes on tropical rain fed agro-ecosystems in sub Saharan Africa (SSA), while increasing resilience to food insecurity and adaptation to climate change. Key words: Climate change, droughts, food security, mitigation, adaptation, soil conservation, sub Saharan Africa (SSA).

The potential of reducing tillage frequency and incorporating plant residues as a strategy for climate change mitigation in semiarid Mediterranean agroecosystems

Improved soil management in rainfed Mediterranean agroecosystems can be a powerful strategy to mitigate the current atmospheric CO2 increase, through soil carbon sequestration and stabilization. In this work, we assess the effects of different soil management practices (conventional tillage, CT, reduced tillage, RT, reduced tillage plus green manure, RTG, and no tillage, NT) on soil CO2 flux dynamics and carbon sequestration in two organic rainfed almond (Prunus dulcis Mill.) orchards under semiarid conditions. Soil CO2 flux, temperature, and moisture were measured monthly over two-three years, and shortly after tillage operations. The soil aggregation distribution (including micro-aggregates occluded within macro-aggregates) and associated organic carbon content were measured after four years of implementation. No significant differences in CO2 emissions among the soils subjected to the distinct management practices were observed at either site. On the one hand, shifting from CT to RT or RTG increased the OC content by 56% on average in all aggregate sizes. On the other hand, suppressing tillage only increased the OC content (by 24%) in the macro-aggregates. Moreover, improved soil management practices modulated the response of soil CO2 flux to temperature and moisture in these semiarid Mediterranean agroecosystems. According to our results, soil CO2 flux under the conventional tillage treatment was more sensitive to temperature increments than with the reduced tillage treatments, indicating that bare soils will be more vulnerable to organic carbon mineralization with ongoing global warming. On the contrary, the incorporation of plant residues under the reduced tillage treatments promoted soil aggregation and organic carbon preservation, making soils more resilient to abrupt changes in temperature and moisture under these treatments.

Comparison of soil amendments for reforestation with a native multipurpose tree under semiarid climate: Root and root tuber response of Spondias tuberosa

The Caatinga biome, characterized by a species-rich seasonally dry tropical forest, but highly disturbed covers most of Brazil's Northeast. Endemic to this biome is the multipurpose tree Spondias tuberosa Arr., which forms numerous root tubers to resist drought stress. In order to develop improved soil management for reforestation with S. tuberosa the response of its root system to different soil amendments was studied with 52 seedlings, using goat manure, clay substrate, biochar as soil amendments, and mineral fertilizer. The default root architecture of three-year-old S. tuberosa and the relation between soil physical parameters and fine root dry matter (≤2mm), root length density, root tuber volume, root tuber fresh weight, and shoot-root ratio were analyzed.Seedlings still formed a tap root with a maximum rooting depth of 63cm and a maximum horizontal extent of 35cm, developing 2–4 root tubers per seedling. Fine root dry matter in 3000cm3 soil samples differed significantly, ranging from 0.23g in the control to 0.03g in the treatment combining manure with biochar and mineral fertilizer. According to the orthogonal contrast, manure was the pivotal soil amendment affecting fine root dry matter negatively. Simultaneously, manure application led to increased soil water content compared to treatments without . The shoot-root ratio increased by 32% compared to the control, when S. tuberosa was grown in wet soils. Root tuber growth was significantly enhanced by manure addition. This effect is attributed to a reduction of soil bulk density as root tuber volume exhibited a negative correlation with soil bulk density. There was no statistical relationship between root tuber volume and seedling survival during the field experiment. Compared with the control, neither clay, biochar nor solely mineral fertilization significantly affected root growth.Soil management focused on improving water availability is suspected of hampering fine root growth of S. tuberosa seedlings, whereas reducing soil bulk density enables better root tuber development and could, therefore, be a promising measure to increase S. tuberosa drought resistance in the long term for more successful reforestation. Disregarding its negative impact on fine root growth, we assume manure is the most promising amendment among the tested treatments, due to its positive effect on root tuber growth.

Study of changes in soil chemical properties of Asma village of Valsad district

A study was carried out to examine the changes in soil chemical properties and crop yields in a area of Asma village of Valsad district (Gujarat). The result showed that the mean values of soil pH and EC were increased with time. Although, average values of organic carbon, available P and available K were decreased year by year. Also difference between maximum and minimum values of soil pH, EC, organic carbon, available P and available K become larger with time due to greatly different in fertilizer application between farmers. Though the yields of crops were increased with cultivation of hybrid varieties but the changes in soil nutrient status have shown there might be need to improve soil management with application of organic and biofertilisers to sustain the fertility of the soil.

Soil and water conservation on Central American hillsides: if more technologies is the answer, what is the question?

Climate change is likely to lead to increased water scarcity in the coming decades and to changes in patterns of precipitation. The result will be more short-term crop failures and long-term production declines. Improved soil management is key to climate change adaptation and mitigation efforts. There is growing interest in the promotion of climate smart agricultural practices. Many of these are the same practices that were promoted in the 1980s and 1990s under the guise of soil and water conservation. Farmer non-adoption of soil conservation technologies was rife and suggests that different approaches are needed today. Much can be learnt from these past endeavors to ensure that current efforts are better designed and implemented. We use the example of Central America to highlight some of these lessons and suggest alternative ways forward. Technology per se is not the limiting factor; many suitable technologies and practices are extant. What is required is a more nuanced approach to soil conservation efforts. There is a need to focus less on capturing soil once it has been eroded, via the use of cross-slope soil conservation practices, and more on improving soil quality of the soil that remains through improved soil cover. It is also critical to understand farming systems as a whole i.e. the full range of interlinked activities and the multiplicity of goals that farm households pursue. Furthermore, it is important to engage farmers as active players in conservation efforts rather than passive adopters of technologies, and to adopt a board value chain approach and engage a plethora of value chain actors (researchers, extension agents, equipment manufacturers, input suppliers, farmers, traders, and processors) in an agricultural innovation system.

Three-year study of fast-growing trees in degraded soils amended with composts: Effects on soil fertility and productivity

Currently, worries about the effects of intensive plantations on long-term nutrient supply and a loss of productivity have risen. In this study two composts were added to degraded soils where this type of intensive crops were growing, to avoid the soil fertility decrease and try to increase biomass production. For the experiment, two degraded soils in terms of low organic carbon content and low pH were selected in South-West Spain: La Rábida (RA) and Villablanca (VI) sites. Both study sites were divided into 24 plots. In RA, half of the plots were planted with Populus x canadensis “I-214”; the other half was planted with Eucalyptus globulus. At the VI site, half of the plots were planted with Paulownia fortunei, and the other plots were planted with Eucalyptus globulus. For each tree and site, three treatments were established (two organic composts and a control without compost), with four replications per treatment. The organic amendments were “alperujo” compost, AC, a solid by-product from the extraction of olive oil, and BC, biosolid compost. During the three years of experimentation, samples of soils and plants were analyzed for studying chemical and biochemical properties of soil, plant growth and plant nutritional status and biomass production. The composts increased total organic carbon, water-soluble carbon, nutrients and pH of soil only in the most acidic soil. Soil biochemical quality was calculated with the geometric mean of the enzymatic activities (Dehydrogenase, β-glucosidase, Phosphatase and Urease activities) determined in soils. The results showed a beneficial improvement in comparison with soils without compost. However, the best results were found in the growth and biomass production of the studied trees, especially in Eucalyptus. Nutritional levels of leaves of the trees were, in general, in the normal established range for each species, although no clear effect of the composts was observed. The results of this study justify the addition of compost to guarantee good biomass production and maintain or improve soil management in degraded soils, especially in acid soils.

Effect of shade tree planting and soil management on rehabilitation success of a 22-year-old degraded cocoa (Theobroma cacao L.) plantation

Since productivity of current cocoa plantations is stagnating or declining, increasing global demand for cocoa products puts pressure on tropical, primary forests to be cut for new plantations. To address this problem, sustainable increase of cocoa yield on current plantations is needed. On a 22-year-old, 61ha cocoa plantation in peninsular Malaysia, shade tree planting and soil management treatments, including targeted mineral fertilization, intense organic fertilization and combinations of these with compost application and cover crop (Centrosema pubescens) planting, were assessed as a rehabilitation strategy of degraded cocoa plantations with sub-optimum yield. Treatment effects on cocoa yield and on proxy indicators soil fauna abundance and diversity, and soil nutrient status, was tested 3.5 years after implementation in four harvesting rounds between 28 November 2014 and 12 March 2015. Across all treatments, large differences were found in the yield of the two clones tested (PBC130 and PBC123). The effect of shade trees (mainly Musa sp., with some permanent shade trees) on yield interacted with the factor ‘clone’. Mean wet bean yield of PBC123 trees in full-sun cultivation was 0.74kg as compared with 1.08kg for trees in the agroforestry system (46% increase). Mean wet bean yield of PBC130 trees, however, was 20% lower in the same agroforestry system (0.08kg) in comparison with mean wet bean yield of trees in full-sun cultivation (0.10kg). Soil management treatments did not result in clear yield improvement as compared with common-practice, control plots. However, cover crop treatment had a positive effect on proxy indicators soil nutrient status and endogeic soil fauna diversity. It is concluded that in the rehabilitation of degraded cocoa plantations, possible yield impact of applying a straightforward agroforestry system, as the one in our experiments, is high. Furthermore, it was shown that in a degraded plantation with a long history of intensive fertilization, improved soil management has little effect. Positive effects of shade trees on cocoa yield are therefore probably linked with the creation of an environment that improves cocoa crop physiology and reduces pressure of pests and diseases, rather than with the improvement of soil quality as a consequence of intercropping with trees.

Contamination and health risks from heavy metals in cultivated soil in Zhangjiakou City of Hebei Province, China.

A total of 79 topsoil samples (ranging from 0 to 20 cm in depth) were collected from a grape cultivation area of Zhangjiakou City, China. The total concentrations of As, Cd, Hg, Cr, Cu, Mn, Ni, Pb, and Zn in soil samples were determined to evaluate pollution levels and associated health risks in each sample. Pollution levels were calculated using enrichment factors (EF) and geoaccumulation index (I geo). Health risks for adults and children were quantified using hazard indexes (HI) and aggregate carcinogenic risks (ACR). The mean concentrations of measured heavy metals Cd, Hg, and Cu, only in the grape cultivation soil samples, were higher than the background values of heavy metals in Hebei Province. According to principal component analysis (PCA), the anthropogenic activities related to agronomic and fossil fuel combustion practices attributed to higher accumulations of Cd, Hg, and Cu, which have slightly polluted about 10-40% of the sampled soils. However, the HI for all of the heavy metals were lower than 1 (within safe limits), and the ACR of As was in the 10(-6)-10(-4) range (a tolerable level). This suggests the absence of both non-carcinogenic and carcinogenic health risks for adults and children through oral ingestion and dermal absorption exposure pathways in the studied area. It should be also noted that the heightened vulnerability of children to health risks was accounted for higher HI and ACR values. Consequently, heavy metal concentrations (e.g., Cd, Hg, Cu) should be periodically monitored in these soils and improved soil management practices are required to minimize possible impacts on children's health.

Soil Degradation: Will Humankind Ever Learn?

Soil degradation is a global problem caused by many factors including excessive tillage, inappropriate crop rotations, excessive grazing or crop residue removal, deforestation, mining, construction and urban sprawl. To meet the needs of an expanding global population, it is essential for humankind to recognize and understand that improving soil health by adopting sustainable agricultural and land management practices is the best solution for mitigating and reversing current soil degradation trends. This research editorial is intended to provide an overview for this Special Issue of Sustainability that examines the global problem of soil degradation through reviews and recent research studies addressing soil health in Africa, Australia, China, Europe, India, North and South America, and Russia. Two common factors—soil erosion and depletion of soil organic matter (SOM)—emerge as consistent indicators of how “the thin layer covering the planet that stands between us and starvation” is being degraded. Soil degradation is not a new problem but failing to acknowledge, mitigate, and remediate the multiple factors leading to it is no longer a viable option for humankind. We optimistically conclude that the most promising strategies to mitigate soil degradation are to select appropriate land uses and improve soil management practices so that SOM is increased, soil biology is enhanced, and all forms of erosion are reduced. Collectively, these actions will enable humankind to “take care of the soil so it can take care of us”.

Carbon storage capacity of semi-arid grassland soils and sequestration potentials in northern China.

Organic carbon (OC) sequestration in degraded semi-arid environments by improved soil management is assumed to contribute substantially to climate change mitigation. However, information about the soil organic carbon (SOC) sequestration potential in steppe soils and their current saturation status remains unknown. In this study, we estimated the OC storage capacity of semi-arid grassland soils on the basis of remote, natural steppe fragments in northern China. Based on the maximum OC saturation of silt and clay particles <20μm, OC sequestration potentials of degraded steppe soils (grazing land, arable land, eroded areas) were estimated. The analysis of natural grassland soils revealed a strong linear regression between the proportion of the fine fraction and its OC content, confirming the importance of silt and clay particles for OC stabilization in steppe soils. This relationship was similar to derived regressions in temperate and tropical soils but on a lower level, probably due to a lower C input and different clay mineralogy. In relation to the estimated OC storage capacity, degraded steppe soils showed a high OC saturation of 78-85% despite massive SOC losses due to unsustainable land use. As a result, the potential of degraded grassland soils to sequester additional OC was generally low. This can be related to a relatively high contribution of labile SOC, which is preferentially lost in the course of soil degradation. Moreover, wind erosion leads to substantial loss of silt and clay particles and consequently results in a direct loss of the ability to stabilize additional OC. Our findings indicate that the SOC loss in semi-arid environments induced by intensive land use is largely irreversible. Observed SOC increases after improved land management mainly result in an accumulation of labile SOC prone to land use/climate changes and therefore cannot be regarded as contribution to long-term OC sequestration.

Realizing the Potential to Achieve Global Food Security of G×E×M

Realizing the Potential to Achieve Global Food Security of G×E×M

Monitor Soil Degradation or Triage for Soil Security? An Australian Challenge

The Australian National Soil Research, Development and Extension Strategy identifies soil security as a foundation for the current and future productivity and profitability of Australian agriculture. Current agricultural production is attenuated by soil degradation. Future production is highly dependent on the condition of Australian soils. Soil degradation in Australia is dominated in its areal extent by soil erosion. We reiterate the use of soil erosion as a reliable indicator of soil condition/quality and a practical measure of soil degradation. We describe three key phases of soil degradation since European settlement, and show a clear link between inappropriate agricultural practices and the resultant soil degradation. We demonstrate that modern agricultural practices have had a marked effect on reducing erosion. Current advances in agricultural soil management could lead to further stabilization and slowing of soil degradation in addition to improving productivity. However, policy complacency towards soil degradation, combined with future climate projections of increased rainfall intensity but decreased volumes, warmer temperatures and increased time in drought may once again accelerate soil degradation and susceptibility to erosion and thus limit the ability of agriculture to advance without further improving soil management practices. Monitoring soil degradation may indicate land degradation, but we contend that monitoring will not lead to soil security. We propose the adoption of a triaging approach to soil degradation using the soil security framework, to prioritise treatment plans that engage science and agriculture to develop practices that simultaneously increase productivity and improve soil condition. This will provide a public policy platform for efficient allocation of public and private resources to secure Australia’s soil resource.

Applying Spatial Geostatistical Analysis Models for Evaluating Variability of Soil Properties in Eastern Shiraz, Iran

ABSTRACT- The information on the spatial properties of soil is vital to improve soil management and to increase the crop productivity. Geostatistical analysis technique is one of the most important methods for determining the spatial properties of soil. The aim of this study was to investigate spatial variability of soil chemical and physical attributes for field management in eastern Shiraz, Iran, in 2010. In the study area, for applying geostatistical analysis, eighty soil samples were taken randomly. The variability of saturation percentage (SP), electrical conductivity (EC), soil pH, sand%, silt%, clay%, nitrogen (N), phosphorus (P) and potassium content (K) of the soil used to determine the spatial properties of soil by geostatistical analysis techniques. Soil properties were analyzed both geostatistically and statistically on the basis of the Semivariogram models. Thus, each soil parameter was used for different Semivariogram models such as spherical, circular and exponential because of their different spatial structures. The results showed that the best model to generate soil properties map was ordinary kriging with spherical and exponential Semivariogram models. The best model for soil pH, SP, K and N was the spherical model whereas for sand%, silt%, clay%, EC and P, the best model was the exponential model. Based on the models, the range of spatial dependency was found to vary within soil parameters. EC had the longest (134 meter) and pH had the shortest (19.1 meter) range of spatial dependency. Additionally, spatial patterns may vary among soil parameters in the study area. Therefore, Semivariogram models can be useful tools to determine spatial variability of parameters, preparing soil map and field management strategy.

English

Climate variability and change is regarded as having major impacts on key sustainable socio-economic and environmental indicators in Sub-Saharan West Africa. Because of these concerns, we investigated smallholders knowledge, skills, and aspirations about managing climate change, and document adaptation strategies used in the semi-arid regions coming from Burkina Faso, Chad and Niger. We analyzed climate data from the 1950’s to the present, including daily and aggregated rainfall and temperature variability, trends and extremes. We also examined farmer perceptions of climate, particularly with what was expected and what was actually observed. Field data was collected through: (i) a semi-structured survey administered to 478 head households; (ii) from focus groups through discussion and consultation with local stakeholders by using a risk matrix. The main agro-climatic risks for farmers in these countries are: Increasing maximum and minimum temperatures; high rainfall variability; and, extreme droughts and floods. We were able to work with communities to identify and prioritize authentic climate change adaptation measures that were deemed to be both strategic and complementary to prudent natural resource management and enhanced agricultural production. Identified innovative adaptation practices that may be up-scaled include: expanding irrigation systems, adjusting crop planting times to suit localized weather and climate forecasts, plant breeding to establish more heat-stress tolerant crops and associated agroforestry. In dryland rainfall systems, it was acknowledged there is a need for greater reliance on water-stress tolerant crops, better soil and water conservation techniques associated with broad catchment management and agroforestry, and improving soil management through prudent fertilizers in sorghum crops. To address climate change, such practices need immediate wider-scale implementation. Key words: Climate variability and change, farmers perceptions, agro-climatic risk, adaptation, Sahel, Africa.

Soil Fertility under Improved and Conventional Management Practices in Sanga, Kavrepalanchowk District, Nepal

A study was carried out to compare the fertility of soils under improved soil management practice with that of prevailing conventional practice and to assess the farmers’ perception on the improved practice in the upland farming system. The study was carried out in Nasikasthan Sanga of Kavrepalanchok district of Nepal. Soil samples were collected from fields under improved conventional practice. Samples were taken at 0-15 and 15-30 cm depths and were analyzed for various physico-chemical properties to compare the fertility status of the soils under both the practices. Altogether 68 farmers were interviewed to have information on farming practices and information pertinent to improved soil management practice being adopted by them. Results from soil physico-chemical analysis showed higher fertility of soils under improved practice in terms of more favorable pH level, contents of exchangeable bases, available phosphorus and soil organic matter compared to prevailing conventional soil management practice. Moreover, majority of the farmers believed that soil fertility and physical condition of their upland soils had improved and that the productivity of major upland crops had also increased after the adoption of improved soil management practice. Improved practice could play an important role in the sustainable management of upland soils in the mid hills of Nepal. It is however, desirable to conduct long-term research to further ascertain the effect of the practice on soil fertility of different soil types and land uses.Nepal Agric. Res. J. Vol. 9, 2009, pp. 27-39DOI: http://dx.doi.org/10.3126/narj.v9i0.11639

Relevance of use-invariant soil properties to assess soil quality of vulnerable ecosystems: The case of Mediterranean vineyards

Vineyard landscapes in Mediterranean areas represent a strong cultural legacy and support a crucial socio-economic sector. The sustainability of these landscapes is threatened by rapid changes of soil quality, in the context of global change and intensive management practices. Considering the Languedoc-Roussillon region of southern France as representative of Mediterranean soil and climate conditions, we evaluated the topsoil quality of vineyards at the regional scale, based on a set of 31 physical, chemical and biological soil indicators measured on 164 commercial vineyard plots. Almost all soil parameters were highly variable among plots. Biological activity was low but no systematic perturbation of the trophic web was noticed. The regional variability of use-invariant soil properties (such as calcium carbonate content and texture) was characterized and taken into account for the analysis of dynamic indicators. Invariant soil properties explained up to 25% of the variance of dynamic chemical and biological indicators. Consequently as a tool to improve soil management decision and recommendations, we proposed a grouping of the 164 vineyard plots into functional soil groups determined by soil invariant properties. Information redundancy between different dynamic indicators was analyzed, and their interpretation and limitations as indicators of topsoil quality were discussed. Our study has produced detailed topsoil indicator baselines that can be immediately used as references for winegrowers to appraise the topsoil quality of their vineyard in comparison with others.