Declining Crop Yields Research Articles

Farmer knowledge and perception of production constraints in Northwest Cambodia

Upland farming in Northwest Cambodia has developed rapidly over the last 20 years, with limitations to the plough based system now apparent, including soil degradation and reductions in yield and profitability. A survey was conducted in order to prioritise the main constraints to production, to aid in future research planning, and to identify potential beneficial modifications to the current system. Three hundred and ninety one farmers were interviewed regarding their current farming system constraints, knowledge of conservation agriculture and their future plans in the Districts of Samlout in Battambang Province and Sala Krau in Pailin Province. Perceived major problems in the farming system were extreme climate events such as droughts and heavy rain, declining crop yields, and cash flow shortages, particularly in the pre-monsoon period. This is a plough based farming system, yet 66% of farmers had heard of conservation agriculture, and 59% wanted to learn more about conservation agriculture practices. Two thirds of farmers were interested in how to grow crops in the post-monsoon dry season on residual soil moisture. The survey highlighted opportunities for farmer education and adoption of farming system modifications to improve productivity and sustainability of the farming system in Northwest Cambodia, and assist with climate change adaptation.

Why do farmers still grow corn on steep slopes in northwest Vietnam?

Intense cultivation of annual crops on steep slopes in northwest Vietnam has resulted in widespread and severe erosion. This has led to myriad problems including siltation of dams critical for hydroelectricity generation, and increasing levels of rural poverty due to declining crop yields. The solution to these problems is sustainable land management, in particular sloping land agricultural technologies. Our study focuses on defining, and finding solutions to, a second-order problem: that farmers are reluctant to adopt sustainable land management practices, despite numerous projects demonstrating their effectiveness. Interviews with farmers in northwest Vietnam confirmed that intense corn cultivation on steep slopes provided the majority of income for most households. The financial security associated with growing corn (compared to alternative crops) was the deciding factor in land management choices. However, interviews also revealed that farmers were dissatisfied with growing corn because of low income and high input costs. Farmers’ replies indicated that they thought they had no alternative to growing corn. However, farmers were aware of alternative crops, and were particularly interested in growing grass, fruit trees and timber trees, although few farmers were keen to be first to adopt these alternative species extensively. Further research is required on development of production-to-commercialization chains for alternative crops, and more generally, to find ways to increase farmer financial security during transition to sustainable land management.

Soil Solution Aluminum, and Nutrient and Aluminum Uptake in Hibiscus Sabdariffa Under Nitrogen and Phosphorous Fertilizers

ABSTRACTThe result of intensive agriculture in cities is the decline in crop yields and depletion of the resource base. The aims of this study were to assess effects of nitrogen (N) or phosphorus (P) fertilization on bioavailable aluminum (Al) and their contribution on Al and nutrient uptake in Hibiscus sabdariffa. A pot experiment was led to supply a tropical soil with N and P fertilizers. P amendment decreased Al in soil solution, not N amendment. Fertilizers had effects on Al and nutrient uptake in roots and leaves of Hibiscus sabdariffa. The results also showed that the uptake of Al and nutrients depends on Al in soil solution or N supply or P supply. Only P uptake in roots and leaves was explained by combined effects of a nutrient supply × exchangeable Al. Furthermore, P supply does not limit the translocation of Al in shoots of plants in acid soils.

Towards sustainable pollution management

It is often overlooked pollution control itself may not be entirely free from adverse impact on the environment if considered from a more holistic perspective. For example mechanised wastewater treatment is energy intensive and so has a carbon footprint because of the need to move air to supply oxygen to the aerobic treatment process. The aerobic treatment process then results in excess bio-sludge which requires disposal and if such is not appropriately performed, then there is risk of surface and groundwater contamination. This presentation explores the changes which have been investigated and are beginning to be implemented in wastewater, sludge, and agro-industrial wastes management which are more environmentally benign. Three examples shall be used to illustrate the discussion. The first example uses the conventional sewage treatment system with a unit process arrangement which converts carbonaceous pollutants from soluble and colloidal forms to particulate forms with an aerobic process before attempting energy recovery with an anaerobic process. Such an arrangement does, however, result in a negative energy balance. This is not withstanding the fact there is potentially more energy in sewage than is required to treat it if that energy can be effectively harvested. The latter can be achieved by removing the carbonaceous pollutants before the aerobic process and thereby using the aerobic process for polishing instead of treating. The carbonaceous pollutants so recovered then becomes the feed for the anaerobic process. Unfortunately conventional anaerobic sludge digestion only removes 35-45% of the organic material fed. Since biogas production (and hence energy recovery) is linked to the amount of organic material which can be degraded anaerobically, the effectiveness of the anaerobic digestion process needs to be improved. Contrary to a commonly held belief wherein methanogenesis is the “bottleneck” in anaerobic processes, hydrolysis is in sludge digestion. Hydrolysis can be enhanced thermally, chemically and biologically. With better anaerobic digestion, the digestate would have more N and P released. The digestate can be blended with organic fertilizers which have been augmented with microbes capable of producing phytohormones. The latter enable crop plants to use inorganic fertilizers more effectively and hence reducing the quantity of inorganic fertilizers required significantly. Use of such organic fertilizers rejuvenates soils which have been subjected to prolonged application of inorganic fertilisers since the latter can result in stagnating or even declining crop yields.

PENENTUAN KONSENTRASI KEMATIAN KALUS TEBU (Saccharum officinarum) VARIETAS BL DAN PS-862 PADA SELEKSI In Vitro UNTUK KETAHANAN TERHADAP SALINITAS

<p>ABSTRACT</p><p>Salinity (salt stress) is one of the different causes of decline in crop yields and productivity of sugarcane. One strategy for optimizing the production of sugarcane on saline land required tolerant varieties of salinity. This research was conducted to determine NaCl concentration that caused more than > 90% callus death on sugarcane (S officinarum) tissue culture and to investigate the protein profile of sugarcane callus BL and PS-862 varieties on saline (NaCl) stress condition. Sugarcane BL and PS-862 varieties were obtained from tissue culture. and those callus were sub-cultured in salinity media with composition of MS (Murashige-Skoog) as base medium and NaCl in various concentration (0%; 0.25%; 0.5%; 0.75%; and 1%). The results showed condition of NaCl addition on media by 1% concentration cause alteration on morphology of callus that 75% part of whole tissues become dark brown coloured that indicating the tissues death. At four weeks after sub-culture, the calli on both varieties obtain score 4. Lethal percentage of both varieties BL and PS-862 in 1% NaCl was 91,67%. This result were supported by protein profile analysis. that a thinner protein band in 1% NaCl treatment compared with control. This is indicating that in salinity stress causing the decrement of protein expression.</p><p> </p>

Effects of walnut trees on biological nitrogen fixation and yield of intercropped alfalfa in a Mediterranean agroforestry system

While intercropping annual non nitrogen-fixing crops with deciduous hardwood species is now well documented, there is a need to investigate if nitrogen-fixing intercrops may succeed in agroforestry systems. Intercropping with trees usually leads to a decline in crop yield, and could in addition possibly reduce the biological N fixation (BNF) over time due to the competition for resources. In a Mediterranean experimental site, 17 year-old hybrid walnut trees (Juglans nigra x Juglans regia L.) planted in East-West oriented lines were intercropped with alfalfa (Medicago sativa L.) to assess the impact of competition for light and water on alfalfa yield and BNF. Alfalfa yield and shoot δ15N values (a proxy for the proportion of N derived from the air, %Ndfa) were measured during one year at different distances from the tree row in two directions (north and south). Alfalfa yield was reduced close to the tree row (−28% and −22% on the northern and southern sides respectively), but less than the reduction of irradiation (−59% and −33% respectively). Shading improved by 35% the apparent light use efficiency (LUE: aboveground biomass produced per unit of global radiation) of alfalfa, indicating that alfalfa was shade tolerant at this Mediterranean site. Alfalfa shoot δ15N values were lower close to the tree rows than at mid inter-row: BNF was stimulated close to the trees. Compensative and facilitative mechanisms between trees and alfalfa plants led to a rise in LUE and%Ndfa in shaded areas. These results contradict the frequent assumption that N fixation is reduced in the shade of trees. Appropriate tree canopy management may help maintain light competition between trees and alfalfa to a level that still enhance complementary, which would further improve the sustainability of the use of alfalfa as an intercrop in Mediterranean regions.

Crop Suitability Mapping for Rice, Cassava, and Yam in North Central Nigeria

<p>Agricultural production has contributed over time to food security and rural economic development in developing countries particularly supporting the countryside. Evidence of crop yield decline exist in the Lower River Benue Basin. This was a crop suitability mapping for rice, cassava, and yam to guide policy makers in strategic planning for sustainable agricultural development. Data was collected on various themes including climate, drainage, soil, satellite imagery, and maps. Remote Sensing was used to analyse satellite imagery to produce a digital elevation model, land use and land cover map, and normalised difference vegetation index map. GIS was used to produce thematic maps, weighted percentages of attribute data, and to produce crop suitability maps through weighted overlay. Soils in the study area require fertility enhancement with inorganic fertilisers for better crop yield. Soils in the Lower River Benue Basin are suitable for yam, cassava, and rice cultivation on maps of suitable areas. Some areas were found to be highly suitable for the cultivation of rice (34.22%), cassava (17.08%) and yam (16.08%). Some other areas were found to be moderately suitable for the cultivation of cassava (48.18%), rice (45.46%), and yam (48.85%). Areas with low suitability were 14.99% (rice), 33.68% (cassava), and 29.57% (yam). This study has demonstrated the importance of crop suitability mapping and recommends that farmers’ cooperative societies and policy makers utilise the information presented to improve decision making methods and policies for agricultural development.</p>

Land-Use Change Modelling in the Upper Blue Nile Basin

Land-use and land-cover changes are driving unprecedented changes in ecosystems and environmental processes at different scales. This study was aimed at identifying the potential land-use drivers in the Jedeb catchment of the Abbay basin by combining statistical analysis, field investigation and remote sensing. To do so, a land-use change model was calibrated and evaluated using the SITE (SImulation of Terrestrial Environment) modelling framework. SITE is cellular automata based multi-criteria decision analysis framework for simulating land-use conversion based on socio-economic and environmental factors. Past land-use trajectories (1986–2009) were evaluated using a reference Landsat-derived map (agreement of 84%). Results show that major land-use change drivers in the study area were population, slope, livestock and distances from various infrastructures (roads, markets and water). It was also found that farmers seem to increasingly prefer plantations of trees such as Eucalyptus by replacing croplands perhaps mainly due to declining crop yield, soil fertility and climate variability. Potential future trajectory of land-use change was also predicted under a business-as-usual scenario (2009–2025). Results show that agricultural land will continue to expand from 69.5% in 2009 to 77.5% in 2025 in the catchment albeit at a declining rate when compared with the period from 1986 to 2009. Plantation forest will also increase at a much higher rate, mainly at the expense of natural vegetation, agricultural land and grasslands. This study provides critical information to land-use planners and policy makers for a more effective and proactive management in this highland catchment.

ASSESSING THE ECONOMIC IMPACT OF CLIMATE CHANGE (MAXIMUM AND MINIMUM TEMPERATURE) ON PRODUCTIVITY OF SORGHUM CROP IN GADARIF STATE, SUDAN

This paper was prepared to estimate the current and projected relationship between climate change (temperature) and variability and the productinity of sorghum under rainfed mechanized farming system in Gadarif State. The study ultilized secondary data covering the period 1970-2014. The data analyzed using descriptive analysis, Bias Correction and Spatial Downscaling (BCSD) and Representative Concentration Pathways (RCPs). The most important results revealed that an increasing trend of temperature indicating the evidence of existance of climate change in the State.The results also showed a drop in crop yield associated with an increase in maximum and minimum level of temperatures. As with respect to projection of future temperature and yield, two scenarios based on greenhouse gas concentration in the atmosphere for the period 2020-2100 were used. The best scenario assumed an RCP of 2.6 and the worst one assumed an RCP of 8.5.The results of best scenario predicted an expected increase yearly in maximum and minimum temperatures at rate of 0.015 ° C and 0.010 ° C respectively; and consequent decrease in crop yield at rate of 1.121 kg/fed/year in case of maximum temperature; and at rate of 0.618 kg/fed/year in case of minimum temperature. The result of the worst scenario predicted an expected yearly increase in maximum and minimum temperatures at 0.074 ° C and 0.081 ° C respectively, with consequent decline in crop yield at a rate of 5.235 kg/fed/year associated with maximum temperature and at rate of 4.844 kg/fed/year associated with minimum temperature. The effect of increase greenhouse gas concentration in future leads to increase maximum and minimum temperatures and decrease yield of sorghum in Gadarif State.

Vulnerability and adaptation to climate change in the Comoe River Basin (West Africa).

Climate change is impacting water users in many sectors: water supply, farming, industry, hydropower, fishing, housing, navigation and health. Existing situations, like population growth, movement of populations from rural to urban areas, poverty and pollution can aggravate the impacts of climate change. The aim of the study is to evaluate the vulnerability of different water user groups to climate change and define communities’ adaptation strategies in the Comoe River Basin. Information was collected on communities’ concerns and perception on changes in climate and potential adaptation measures and strategies. Results show that 95 % of the sample in the study communities had heard of it and are aware that climate change is occurring. They have been experiencing changes in economic activity and cropping pattern, reduced water level in rivers, crop failure, delay in cropping season, new pests and diseases, food insecurity, drop in income and decline in crop yield. Results also show that communities employ various adaptation strategies including crops diversification, substitution and calendar redefinition, agroforestry, borrowing from friends and money lenders and increasing fertilizer application.

Spatial impacts of the CAP post-2013 and climate change scenarios on agricultural intensification and environment in Austria

We assess impacts of the latest CAP reform and regional climate change scenarios on agricultural land use intensification and environment in Austria for the period 2025–2040. A spatially explicit integrated assessment based on sequentially coupled models quantifies the impacts at a 1km grid resolution in order to take into account the heterogeneity of agricultural production and environment. The CAP post-2013 will lead to a shift in direct payments from cropland to grassland dominated production regions as well as to a slight decrease in regional producer surpluses in Austria. The economic impact of climate change scenarios depends on the spatial location and the precipitation scenario. The CAP post-2013 will lead to intensification of agricultural land use in favorable cropland and grassland regions as well as to extensification in marginal areas. Regional climate change amplifies land use intensification with increases in crop and forage yields, e.g. in Alpine regions, and land use extensification with declining crop yields, e.g. in eastern cropland regions. Environmental indicators deteriorate at national level in all scenarios. Spatially highly diverging impacts call for more targeted policy measures.

Field-Level Evidences of Climate Change and Coping Strategies of Smallholder Farmers in Molawin-Dampalit Sub-Watershed, Makiling Forest Reserve, Philippines

This article confirms that climate change is indeed a real phenomenon as observed and experienced by smallholder farmers in the Molawin-Dampalit Sub-Watershed. Using semi-structured interviews and focus group discussions, the smallholder farmers articulated their own indications of climate change. These include increasing temperature, stronger and more frequent typhoons, excessive rainfall, drought, early rainy season, and delayed dry season. Among the effects of climate change on their agricultural production include stunted growth of crops, aborted fruiting of trees, incidence of pests and diseases, and growth of unknown weeds. These have led to increase in the use and dosage of farm inputs, particularly pesticides and fertilizers; decline in crop yield; and ultimately, decline in farm income. To cope with these impacts, the farmers employed strategies such as replanting, use of chemical pesticides and fertilizers to control pests and improve crop growth, pruning, watering and diversion of water source, changing crops, and harvesting their crops earlier to minimize crop loss. Considering the vulnerability of smallholder farmers, the results suggest the need to enhance their adaptive capacities for climate change impacts using a holistic approach via human capital development, improvement of physical capital, and building their social capital.

Production duality, profitability, driving forces and constraints in organic peanut cultivation in India

Production duality in peanut cultivation is referred as conventional and organic method. A field survey was conducted in Gujarat state, India, to assess the cost and benefits of production duality in peanut; different organic formulations practised; and motivational factors and constraints in organic peanut cultivation. Thirty organic peanut growing and equal number of conventional farmers were selected through multistage sampling procedure, and face to face interview was conducted using pretested interview schedule. The results revealed that farmers were practising different organic formulations and their cost varied depending upon the inputs used. There were no significant differences in age, education and experience in farming between the organic and conventional farmers, but considerable differences were observed in the number of effective workers and livestock owned. It implies farm households with more family members and livestock are practising organic peanut cultivation. The total cost of cultivation in organic peanut was $699/ha, whereas it was $656/ha under conventional method. The total return in organic peanut was $1233/ha, whereas it was $1192/ha under conventional methods. The net returns realized by organic peanut growing farmers was $534/ha, whereas it was $536/ha by the conventional peanut farmers. There is no significant difference in the net return per hectare between organic and conventional methods, if organic and other inputs supplied from farmers own sources are imputed. However, if other sustainable benefits to the environment, ecology, landscape, consumers, etc. are included in valuation, the returns may outweigh in organic method. Besides traditional organic inputs like Farm Yard Manure (FYM) and compost, farmers used their own organic formulations like Panchamrut or Panchagavya, Jivamrut and Dharamrut and cost of these formulations ranged from $7.2/ha to $41.3/ha. The major factors that induced shift to organic peanut farming were soil improvement, awareness on hazards of conventional method and to reduce dependency on external inputs like chemical fertilizers and pesticides. The private institutions and individuals rather than the public institutions were the major motivational source for organic peanut cultivation, indicating the necessity of involvement of public institutions at different levels from farm to consumer for ordered growth of peanut cultivation. The initial decline in crop yield, high price of organic inputs supplied by the private companies and non-realization of premium price by farmers were the major constraints in organic peanut cultivation. These constraints have to be addressed by farmers themselves as well as by the government through appropriate policy intervention to upscale organic peanut cultivation in India.

English

The study analyzed the impacts of climate change among rural farmers in Imo State, Nigeria. Specifically, it ascertained the socioeconomic characteristics of the farmers, their level of awareness of climate change, the perceived causes of climate change and the perceived impacts of climate change. Multistage sampling technique was used to select a sample of 100 farmers for the study. Data were collected using structured questionnaire. The data were analyzed using frequency counts, percentages, mean score and bar charts. Results showed that a greater proportion (40.6%) of the respondents knew a little about climate change. Also, it showed that gas flaring (M = 2.07, S.D = 1.94), violation of local customs (M = 2.01, S.D = 1.83) and natural phenomenon (M = 2.00, S.D = 1.83) were perceived as causes of climate change. The result further showed that declining crop yields (49.0%), declining soil fertility (17.0%), drought events (17.0%) and increased heat wave (15.0%) were the perceived impacts of climate change on agriculture in the study area. It was recommended that relevant, timely and up-to-date information on climate change should be provided to the farmers to boost their adaptive capacity to climate change. Key words: Climate change, impacts, rural farmers, Imo State, Nigeria.

Weed infestation of soybean (Glycine max L. Merr.) under different tillage systems

Direct drilling is one of the methods to reduce tillage costs. Low labor intensity of this system also makes it possible to grow crops in locations where it is a problem to maintain optimal sowing time. However, the use of no-tillage can cause increased weed infestation of crop plants and as a consequence a decline in crop yields. The present study investigated the effect of two tillage systems, plough tillage and direct drilling, on the species composition, density and air-dry weight of weeds in crops of two soybean cultivars (‘Aldana’ and ‘Augusta’). A three-year field experiment was set up on loess-derived gray-brown podzolic soil. The study showed that the use of direct drilling for soybean cropping resulted in a significant increase in the density and dry weight of weeds relative to plough tillage. The study also found richer floristic composition of weeds and an increase in the numbers of dominant species under no-tillage conditions. <em>Elymus repens</em>, <em>Echinochloa crus-galli</em> and <em>Chenopodium album</em> were dominant weed species in all experimental treatments. <em>Chenopodium album</em> and <em>Galinsoga parviflora</em> were characterized by the highest constancy (constancy classes V and IV) in crops of both soybean cultivars, whereas <em>Echinochloa crus-galli</em> showed the highest constancy value in the ‘Aldana’ crop. Under direct drilling, most weed species were found to exhibit higher constancy compared to plough tillage.

Adverse Effects of Allelopathy from Legume Crops and Its Possible Avoidance

Plant releases many bioactive chemicals from its various parts such as leaves, stem, root and sometimes decomposed body through different mechanism into its surrounding environment. These bioactive chemicals are often termed as allelochemicals because they interact with the surrounding environment. This interaction is either positive or negative. Effects of allelochemicals to the agricultural and biological ecosystem are well documented. In leguminosae family many species are involved in releasing of allelochemicals. Many researchers found that this allelochemicals have both positive and detrimental effects on the successive legume crops. Legume monoculture is common in many parts of the world where they cause a numbers of ecological and economic problems such as decline in crop yield due to soil sickness, regeneration failure and replant problem. These negative effects of allelochemicals open a great concern on allelopathy research. This article reviews the adverse effects of allelochemicals, their extraction and isolation, mechanism inside the plant body. These all are done to find out the possible selection methods of succeeding crops to avoid the allelopathic effects in the next crop of a monoculture farm field. The main purpose of this article is to highlight the adverse allelopathic effects of legume crops to provide ways for sustainable development in agro-ecosystem.

Utilisation of cattle manure and inorganic fertiliser for food production in central Uganda

Fertiliser use in small-holder peri-urban crop-livestock farms in Uganda was investigated by conducting a socio-economic survey of 40 farms in the central districts of Wakiso and Kampala where cattle manure is commonly applied to address the issue of declining crop yields. The major benefits obtained from cattle manure application were increased yields and low cost, while negative effects were poor hygienic conditions and bad odour. The challenges associated with the use of cattle manure included its weight and bulkiness, lack of labour, insufficient quantities, high transportation and application costs, lack of storage facilities to maintain quality attributes of manure and the incidence of chaffer grubs and worms; a nuisance during application which affected crop growth. The survey indicated that of the farmers using cattle manure, only 5% also supplemented with inorganic fertilisers. Other animal manures applied included poultry, pig, goat and rabbit where available. The nutrient content of cattle manure was generally low, as a result of livestock diet and storage. There was little education available to farmers as to optimum strategies and rates of fertiliser (including both inorganic and organic fertilisers) to improve crop yield and this needed addressing to improve food security and economic development in Uganda. Keywords: cattle manure; fertiliser; urea

Effects of extreme climate events on tea (Camellia sinensis) functional quality validate indigenous farmer knowledge and sensory preferences in tropical China.

Climate change is impacting agro-ecosystems, crops, and farmer livelihoods in communities worldwide. While it is well understood that more frequent and intense climate events in many areas are resulting in a decline in crop yields, the impact on crop quality is less acknowledged, yet it is critical for food systems that benefit both farmers and consumers through high-quality products. This study examines tea (Camellia sinensis; Theaceae), the world's most widely consumed beverage after water, as a study system to measure effects of seasonal precipitation variability on crop functional quality and associated farmer knowledge, preferences, and livelihoods. Sampling was conducted in a major tea producing area of China during an extreme drought through the onset of the East Asian Monsoon in order to capture effects of extreme climate events that are likely to become more frequent with climate change. Compared to the spring drought, tea growth during the monsoon period was up to 50% higher. Concurrently, concentrations of catechin and methylxanthine secondary metabolites, major compounds that determine tea functional quality, were up to 50% lower during the monsoon while total phenolic concentrations and antioxidant activity increased. The inverse relationship between tea growth and concentrations of individual secondary metabolites suggests a dilution effect of precipitation on tea quality. The decrease in concentrations of tea secondary metabolites was accompanied by reduced farmer preference on the basis of sensory characteristics as well as a decline of up to 50% in household income from tea sales. Farmer surveys indicate a high degree of agreement regarding climate patterns and the effects of precipitation on tea yields and quality. Extrapolating findings from this seasonal study to long-term climate scenario projections suggests that farmers and consumers face variable implications with forecasted precipitation scenarios and calls for research on management practices to facilitate climate adaptation for sustainable crop production.

Tillage and residue management effects on temporal changes in soil organic carbon and fractions of a silty loam soil in the North China Plain

AbstractSoil degradation and associated depletion of soil organic carbon (SOC) have been major concerns in intensive farming systems because of the subsequent decline in crop yields. We assessed temporal changes in SOC and its fractions under different tillage systems for wheat (Triticum aestivum L.) – maize (Zea mays L.) cropping in the North China Plain. Four tillage systems were established in 2001: plow tillage (PT), rotary tillage (RT), no‐till (NT), and plow tillage with residues removed (PT0). Concentrations of SOC, particulate organic carbon (POC), non‐POC (NPOC), labile organic carbon (LOC), non‐LOC (NLOC), heavy fraction carbon (HFC) and light fraction carbon (LFC) were determined to assess tillage‐induced changes in the top 50 cm. Concentrations of SOC and C fractions declined with soil depth and were significantly affected by tillage over time. The results showed that SOC and its fractions were enhanced under NT and RT from 0 to 10 cm depth compared with values for PT and PT0. Significant decreases were observed below 10 cm depths (P < 0.05) regardless of the tillage system. The SOC concentration under NT for 0–5 cm depth was 18%, 8%, and 10% higher than that under PT0 after 7, 9, and 12 yr of NT adoption, respectively. Apparent stratification of SOC occurred under NT compared with PT and PT0 for depths >10 cm. All parameters were positively correlated (P < 0.01); linear regressions exhibited similar patterns (P < 0.01). Therefore, to maintain and improve SOC levels, residue inputs should be complemented by the adoption of suitable tillage systems.

The Effects of Biofuel Feedstock Production on Farmers’ Livelihoods in Ghana: The Case of Jatropha curcas

The widespread acquisition of land for large-scale/commercial production of biofuel crops in Ghana has raised concerns from civil society organizations, local communities and other parties, regarding the impact of these investments on local livelihoods. This paper assessed the effect of large-scale acquisition of land for production of Jatropha curcas on farmers’ livelihoods in Ghana. The study was conducted in 11 communities spanning the major agro-ecological zones and political divisions across Ghana. Methods of data collection included questionnaire survey, interviews and focus group discussions. Results show that several households have lost their land to Jatropha plantations leading, in some cases, to violent conflicts between biofuel investors, traditional authorities and the local communities. Most people reported that, contrary to the belief that Jatropha does well on marginal lands, the lands acquired by the Jatropha Companies were productive lands. Loss of rights over land has affected households’ food production and security, as many households have resorted to reducing the area they have under cultivation, leading to shortening fallow periods and declining crop yields. In addition, although the cultivation of Jatropha led to the creation of jobs in the communities where they were started, such jobs were merely transient. The paper contends that, even though the impact of Jatropha feedstock production on local livelihoods in Ghana is largely negative, the burgeoning industry could be developed in ways that could support local livelihoods.