Steep Land Research Articles

Downscaling MODIS LST in the East African mountains using elevation gradient and land-cover information

Land-surface temperature (LST) is strongly affected by altitude and surface albedo. In mountain regions where steep slopes and heterogeneous land cover are predominant, LST can vary significantly within short distances. Although remote sensing currently provides opportunities for monitoring LST in inaccessible regions, the coarse resolution of some sensors may result in large uncertainties at sub-pixel scales. This study aimed to develop a simple methodology for downscaling 1 km Moderate Resolution Spectroradiometer (MODIS) LST pixels, by accounting for sub-pixel LST variation associated with altitude and land-cover spatial changes. The approach was tested in Mount Kilimanjaro, Tanzania, where changes in altitude and vegetation can take place over short distances. Daytime and night-time MODIS LST estimates were considered separately. A digital elevation model (DEM) and normalized difference vegetation index (NDVI), both at 250 m spatial resolution, were used to assess altitude and land-cover changes, respectively. Simple linear regressions and multivariate regressions were used to quantify the relationship between LST and the independent variables, altitude and NDVI. The results show that, in Kilimanjaro, altitude variation within the area covered by a 1 km MODIS LST pixel can be up to ±300 m. These altitude changes can cause sub-pixel variation of up to ±2.13°C for night-time and ±2.88°C for daytime LST. NDVI variation within 1 km pixels ranged between –0.2 and 0.2. For night-time measurements, altitude explained up to 97% of LST variation, while daytime LST was strongly affected by land cover. Using multivariate regressions, the combination of altitude and NDVI explained up to 94% of daytime LST variation in Kilimanjaro. Finally, the downscaling approach proposed in this study allowed an improved representation of the influence of landscape features on local-scale LST patterns.

Remediation of soil past erosion effects through amendments and agronomic practices

In Pakistan there has been a trend to shift agriculture towards steep lands, where soil erosion is one of the most significant ecological restrictions to sustainable agricultural production. This study was focused to find ways to ameliorate the soil fertility degraded by past soil erosion. Different cropping patterns viz maize-wheat-maize rotation (C1), maize-lentil-maize rotation (C2) and maize-wheat+lentil intercrop-maize rotation (C3) and different soil treatments, namely, the control (T1), 50 % NP (also called the farmer’s practice) (T2), 100 % NPK or the recommended dose of NPK (T3) and 20 t ha-1 farmyard manure integrated with 50 % N and 100 % PK (T4) were tested in a randomized complete block (RCB) design with split plot arrangements. Integrated use of organic manure (farmyard manure) and inorganic NPK fertilizers (T4) produced the highest wheat grain yield (4730 kg ha-1), which was 9 % higher than the 100 % inorganic NPK (T3, 4349 kg ha-1) and more than twice the control (T1, 2072 kg ha-1). The increase in lentil grain yield in T4 (1112 kg ha-1) was 7.4 % higher than in the recommended NPK levels for lentils (T3, 1035 kg ha-1) and 79 % higher than the control. A significant nutrient enrichment and an improvement in soil fertility parameters was recorded by T4 over T3. This was further augmented by the application of cereal-legume rotation (C2) in the traditional cereal-cereal rotation (C1) and their combination showed a significantly improved residual effect on soil fertility in the subsequent year. In conclusion the degraded soil fertility of Missa gullied soil cannot be ameliorated to its full potential with only the recommended dose of mineral fertilizers. 50 % N from organic fertilizer sources and the inclusion of legumes in the crop rotation is necessary to ensure agricultural sustainability on such soils. DOI: http://dx.doi.org/10.4038/jnsfsr.v42i1.6680 J.Natn.Sci.Foundation Sri Lanka 2014 42 (1): 46-62

Mountain farmers׳ livelihoods and perceptions of forest resource degradation at Machiara National Park, Pakistan-administered Kashmir

High human pressures on Pakistan׳s Himalayan forests necessitate effective preservation of representative natural areas. Adjacent to Machiara National Park (MNP, 138km2, established in 1996) live >55,000 farmers who traditionally used park areas for grazing livestock and extracting forest products. Baseline information was needed for improved conservation plans of MNP and development extension to communities. A household survey was conducted with the objective to profile the farmer communities (demographic structure, livelihoods), appraise their forest resource uses and dependencies, and discern their perceptions on resource conditions and trends. Annual population growth was ≥2.3%; most households were poor by regional standards. High livestock densities (>2 animalsha−1) lead to pasture degradation in sensitive areas, especially outside MNP. Between 2004 and 2010 populations of sheep and goat (often using marginal pastures inside MNP), buffalo (mostly stall-fed), and equines (for transport) had markedly increased. In contrast, cattle numbers had decreased, as nutritious pastures became limited. Responses indicated slowly declining fodder supplies. Availability of timber, fuelwood and medicinal plants had diminished to critical levels; to collect these resources respondents had to walk 3–5 times as far in 2010 (~5–6km) as compared to 1980 (~1–2km). Measures which may alleviate human pressures on MNP natural resources include promotion of veterinary services and alternative energy sources, and establishment of afforestations, especially on steep lands unsuitable for pasturing. Legal enforcement should be improved, but better participation and environmental education may enhance management effectiveness and acceptance of park rules. Demographics need attention as population growth rates are unsustainable.

三峡库区植物篱系统土壤颗粒分布及粘粒与土壤理化性质关系

在调查分析长江三峡库区现有坡耕地植物篱的配置方式、生长状况和室内分析植物篱系统内土壤颗粒组成和土壤理化性质的基础上，对3种植物篱系统中土壤颗粒分布特征及土壤粘粒与土壤理化性质的关系进行了研究，结果表明：1) 植物篱系统中不同位置土壤颗粒含量存在显著差异，乔木类、草本类和灌木类植物篱带间坡耕地土壤砂粒含量比其对应的植物篱带内土壤砂粒平均含量分别高10.4%，13.7%和9.2%；而粘粒含量在植物篱带内富集，其平均含量比植物篱带间坡耕地土壤粘粒含量分别高14.3%，19.5%和10.7%；2) 植物篱系统内土壤粘粒含量与土壤孔隙度、土壤含水量、饱和导水率、土壤抗冲指数、土壤抗蚀指数、水稳性团聚体极显著正相关，而与土壤容重呈显著负相关关系。3) 土壤粘粒含量与土壤全氮、有效氮、土壤全钾、有效钾、全磷、有效磷和阳离子交换量具有极显著正相关关系。 To achieve the soil particle distribution characters and the relationship between physicochemical properties of hedgerow systems in the Three Gorges reservoir area, soil particle size composition and physicochemical properties of soil collected from different position in hedgerow systems with different species were tested, and the coefficient between soil silt concentration and physico-chemical properties were analyzed. The result revealed that 1) the particle size concentration in the hedgerow systems diversified significantly. The soil sand concentration in the steep land be- tween hedgerows with different species was higher than that of soil within hedgerows stipe, by 10.4%, 13.7% and 9.2% respectively. However, the soil silt concentration enriched within hedge- rows strip, and the mean value of soil silt concentration with different species increased by 14.3%, 19.5% and 10.7% respectively compared with the soil between hedgerow steeps. 2) The silt con- centration of soil in hedgerow systems were correlated positively and highly significantly (P

基于斑块评价的三峡库区腹地坡耕地优化调控方法与案例研究

The center of the Three Gorges Reservoir area is an ecologically sensitive, economically poorest, and environmentally fragile region,and hence become a research hotspot for many researchers. There is a large amount of cultivated slope land( part of them being abandoned by local farmer) in the region and it is very difficult and sometimes impossible to return the lands with gradient 25° to forests. So,it is necessary to explore the optimization control theory and methods for the slop land with different characteristics in this region. Cultivated slope land optimization should consider the demands of local people' s production and living,and it is also a selection process of the combined efforts of natural resources,geographical accessibility and socio-economic conditions. This paper suggested that the control and optimization scheme should not only combine the spatial distribution pattern and the ecological functions of cultivated slope land,but also consider the current distribution and future trends of sloping farmland. In addition,this paper promoted six principles about how to control and optimize thecultivated slope land,plus the evaluation methods integrating the spatial patternsuitability to quantitatively assess farmers demand pressures. By applying the principles and evaluation,this paper chose Caotangxi watershed,a typical watershed in thecenter of the Three Gorges reservoir area,as a case study. According to the characteristics of the watershed three indices were selected to evaluate the suitability of the system,namely,the accessibility,the ecological functions and the feasibility of changing slope land into terrace. The accessibility means the distance from the settlements roads to the land; the ecological function means the land degradation( the soil erosion) and the distance from water and the large forest patches( that is the distance away from the rivers and ecological sensitive area);while the feasibility from slope land to terrace means the size of the farmland patches,aspect and the slope gradient At the same time,the pressure index of cultivated land and supplementary capability of orchards to farmer's demand were selected as evaluation indexes of the quantity regulation system. Accordingly,the cultivated slope land of the Caotangxi watershed were divided into four types,namely,the optimization utilization type,the key consolidation type,the type of gradually returning( farmland to forest) and the type of preferentially returning,which accounted for 30. 5%,32. 9%,29. 7% and30. 5% respectively. Finally,at the premise of reducing steep inappropriate cultivated land and soil erosion,this paper suggested four returning scenarios without increasing the pressure of cultivated land,based on the distribution of abandoned land of local farmers. The rational and validity were verified according to the indices for these scenarios. The result of this study provides a theoretical basis for the current cultivated slope land optimization as well as a certain guidance to the cultivated slope land regulation in the Three Gorges Reservoir area.

PHYTODIVERSITY AND SOIL STUDY OF SHIWALIK HILLS OF ILAM, NEPAL: AN ECOLOGICAL PERSPECTIVE

The Siwalik range (locally known as Churia hills) in Nepal comprise a total area of 1,886,000 ha, equivalent to 13% of the country’s total area and consists of hills, steep land slopes, gorges, large spans of river and temporary streams. Study of different kinds of plants, soil and climate and the quantitative analysis of vegetation structure and composition as well as soil analysis at three Village Development Committees (VDCs) of Siwalik hills of Ilam was undertaken. A total number of 137 flowering plants and 8 pteridophytes are reported in the present study. Shorea robusta, Terminalia alata and Semecarpus anacardium are the most dominant species of the entire study area. The Siwalik range with late tertiary exposed rocks consists of fine grained sandstone with pockets of clay, shale, conglomerate and freshwater limestone. The vegetation is much more diverse and intact ecologically than expected from a distant observation. DOI: http://dx.doi.org/10.3126/eco.v18i0.9414Ecoprint: An International Journal of EcologyVol. 18, 2011 Page: Uploaded date: 12/22/2013

Responses of Runoff and Soil Erosion to Vegetation Removal and Tillage on Steep Lands

Land use and land cover change is a key driver of environmental change. To investigate the runoff and erosion responses to frequent land use change on the steep lands in the Three Gorges area, China, a rainfall simulation experiment was conducted in plots randomly selected at a Sloping Land Conversion Program site with three soil surface conditions: existing vegetation cover, vegetation removal, and freshly hoed. Simulated rainfall was applied at intensities of 60 (low), 90 (medium), and 120 mm h−1 (high) in each plot. The results indicated that vegetation removal and hoeing significantly changed runoff generation. The proportion of subsurface runoff in the total runoff decreased from 30.3% to 6.2% after vegetation removal. In the hoed plots, the subsurface runoff comprised 29.1% of the total runoff under low-intensity rainfall simulation and the proportion rapidly decreased with increasing rainfall intensity. Vegetation removal and tillage also significantly increased soil erosion. The average soil erosion rates from the vegetation removal and hoed plots were 3.0 and 10.2 times larger than that in the existing vegetation cover plots, respectively. These identified that both the runoff generation mechanism and soil erosion changed as a consequence of altering land use on steep lands. Thus, conservation practices with maximum vegetation cover and minimum tillage should be used to reduce surface runoff and soil erosion on steep lands.

Spatial Distribution and Composition of Trees in an Aging Coppice Forest in Japan

The importance of studying the ecology of coppice forests in Japan has risen recently amid growing demands to reestablish utilization of their tangible resources. The objective of the paper is to assess whether the spatial distribution of trees at an undisturbed agingcoppice follows some common pattern and how its composition changes with time. Coppice forests in Japan usually grow on steep lands and conventionally used forest inventory methods and methods used in ecological studies are time-consuming. Therefore, a rapid sampling approach based on measurements of angles and distances was used to achieve the objectives of this study. The field survey was conducted at coppice stands harvested 48, 60 and 77 years ago. Results suggest that distribution of the trees at aging-coppices shifts toward a regular spatial pattern. However, the process toward this regularity is slow and the distributions of individual trees were still not significantly different from a random pattern. Use of the combined angle-distance methodology is rapid and the data collected can be useful for planning ecologically-friendly management of coppice forests. Received March 19, 2012; Accepted October 24, 2012 ∗ Kyoto University, Japan

Sensible Farming on Sensitive and Steep Land - A Catchment Management Approach in Tauranga Harbour

Sedimentation of Tauranga Harbour was identified as the top environment issue in a 2006 environmental report. Research has indicated that 63.7% of the sediment yield from the 98 641 hectares of contributing catchments of the southern harbour was from pasture that covers only 34.7% of the catchment area. Bay of Plenty Regional Council has developed and implemented a catchment management framework to work alongside farmers and the rural community to address the issue. The approach involved firstly gaining accurate data, including modelling sediment movement and accurately "ground-truthing" 2190 km of waterways in 28 subcatchments. It included data analysis for Land Use Capability (LUC), erosion risk, land cover, existing protection status of land, as well as developing an effective communications plan to engage landowners. A perception survey was also undertaken to determine what farmers understood of their environmental responsibility and what the drivers for change were. Council now has a much better understanding of land cover, current land use, the community concerns and their knowledge of issues in Tauranga Harbour. This has enabled a more focused catchment management approach and better use of funds to support riparian protection and land use change. Keywords: Catchment, sedimentation, riparian, erosion

三峡库区植物篱系统土壤有机质分布及其与土壤 理化性质的关系

在调查分析长江上游现有坡耕地植物篱的配置方式、生长状况和室内分析植物篱系统内土壤有机质和土壤理化性质分析的基础上，对3种植物篱系统中土壤有机质分布特征及其与土壤理化性质的关系进行了研究，结果表明：坡耕地系统中不同位置土壤有机质含量存在显著差异，3种植物篱带间坡耕地土壤有机质平均含量为6.33 g∙kg−1，植物篱带上、带内和植物篱带下土壤有机质含量比植物篱带间坡耕地土壤有机质平均含量分别增加27.9%，67.3%和31.6%；植物篱系统内土壤有机质与土壤孔隙度、土壤含水量、饱和导水率、土壤抗冲指数、土壤抗蚀指数、水稳性团聚体极显著正相关，而与土壤容重呈显著负相关关系。土壤有机质与土壤全氮、水解氮、土壤全钾、有效钾、全磷、有效磷和阳离子交换量具有极显著正相关关系。 To achieve the soil organic matter distribution characters and the relationship between physicochemical properties of hedgerow systems in the Three Gorges reservoir area, soil organic matter and physicochemical properties of soil collected from different position in hedgerow systems with different species were tested, and the coefficient between soil organic matter and physicochemical properties was analyzed. The result revealed that 1) the mean value of soil organic matter of the steep land between hedgerows was 6.33 g∙kg−1, and the soil organic matter of soil before, within and behind the hedgerows were higher than that of soil in steep land between hedgerows, by 27.9%, 67.3% and 31.6% respectively. 2) The organic matter of soil in hedgerow systems was correlated positively and highly significantly (P < 0. 01) with the soil porosity, water content, soil saturated water conductivity, anti-erodibility, anti-scouribility and soil water stable aggregates content, and correlated negatively with soil bulk density. In addition, the organic matter of soil in hedgerow systems was highly correlated with soil nutrients, containing total and exchangeable nitrogen, total and exchangeable phosphorus, total and exchangeable potassium, and cation exchangeable capacity.

Geological and geotechnical constraints for urban planning and natural environment protection: a case study from Mekelle City, Northern Ethiopia

The study was conducted in the rapidly expanding city of Mekelle located in the northern part of Ethiopia, East Africa. An integrated approach including geomorphological, geological and engineering geological, geotechnical and hydrogeological methods were used to characterize the natural urban environment to be used as a baseline for protection and rational planning of development. Conventional field observation, test pits and drilled boreholes were used to collect soil, rock and water samples and standard laboratory procedures were applied. The results revealed that the main geologic constraints to sustainable development of the city are active erosion, instability of slopes, flood hazard, cyclic/alternating hard and weak rock layers, high swelling–shrinkage soils, shallow and unconfined groundwater with variable composition and high susceptibility to corrosion and pollution. It is recommended to avoid development and expansion of the city in areas of steep land forms, at the foot of steep slopes and in areas covered by black alluvial soil deposits. Development of a systematic multidisciplinary database aided by GIS, with continuous monitoring and updating is also highly recommended and will be useful for further refined geotechnical microzonation. It is the authors’ belief that this study highlights the basic constraints and hazards the city is facing, and provides baseline information and awareness to the city planners, decision makers, geo-environmentalists, engineers and the community for future expansion and rehabilitation plans and to tackle the existing hazards.

Impact of green manure and mineral fertilizer inputs on soil organic matter and crop productivity in a sloping landscape of Sri Lanka

Fields and Homegardens (representative of tropical smallholder extensive and intensive systems) were compared for soil quality and productivity of maize and mungbean in a hilly region of Sri Lanka (twinned 30 farms with Fields and Homegardens, each) over 2 years. The inclination categories were Flat (0–10%), Moderate (10–30%) and Steep (>30%). On half of the farms, green manure was added using Gliricidia leaves (3tonnesha−1 per season). Soil organic matter contents of Homegardens were at least 30% greater than in Fields, most pronounced in the Flat category. After 2 years of continuous maize and mungbean cropping in the major and minor rainy seasons, respectively, SOM generally declined; the greater depletion rate in Homegardens was positively correlated with crop yields. With recommended fertilizers (NPK), maize yield was always significantly higher in Homegardens than in Fields Flat and Moderate, this hold true at Steep lands only without NPK. Maize yield with NPK was on average two times higher than with Gliricidia alone, a respectable 4.5tonnesha−1 at Flat and Moderate, and 3.5tonnesha−1 even on Steep lands, seemingly the chemical soil fertility was more lacking than the physical properties. Gliricidia alone had no impact on yield in Fields but just in Homegardens, yield was increased by almost 30% in comparison to Zero fertilizer, an indication that chemical fertility was not directly supported by Gliricidia. Mungbean yields were generally less influenced by treatments, just the beneficial short term impacts of Gliricidia in Fields were relatively much higher than in maize. Conclusively, the long term input of organic manure in Homegardens was translated into a higher productivity in comparison to extensively managed Fields. However, the annual green manure supply supported yields mostly at marginal input levels and was overridden by mineral fertilizers independent of the inclination. Although, the usefulness of Gliricidia in degraded Steep lands was proven, the great risk of erosion remains in this landscape. Arable cropping there should be replaced by access to NPK on low inclined land once socio-economic conditions allow it.

Rehabilitation of a debris-flow prone mountain stream in southwestern China – Strategies, effects and implications

Rehabilitation of Shengou Creek, a small, steep mountain stream in southwestern China that is prone to debris flows, started more than 30. years ago through an integrated program of engineering applications (check dams and guiding dikes), biological measures (reforestation), and social measures (reducing human disturbance). Small and medium-sized check dams and guiding dikes were constructed on key upper and middle sections of the creek to stabilize hillslopes and channel bed. Meanwhile, Leucaena leucocephala, a drought-tolerant, fast-growing, and highly adaptive plant species, was introduced to promote vegetation recovery in the watershed. The collective community structure of tree, shrub, and herb assemblages in the artificial L. leucocephala forest, which developed after 7. years, enhanced soil structure and drastically reduced soil erosion on hillslopes. Cultivation of steep land was strictly controlled in the basin, and some inhabitants were encouraged to move from upstream areas to downstream towns to reduce disturbance. These integrated measures reduced sediment supply from both hillslopes and upstream channels, preventing sediment-related hazards. The development of natural streambed resistance structures (mainly step-pool systems) and luxuriant riparian vegetation aided channel stability, diversity of stream habitat, and ecological maintenance in the creek. These findings are compared with Jiangjia and Xiaobaini Ravines, two adjacent non-rehabilitated debris-flow streams which have climate and geomorphologic conditions similar to Shengou Creek. Habitat diversity indices, taxa richness, biodiversity, and bio-community indices are much higher in Shengou Creek relative to Jiangjia and Xiaobaini Ravines, attesting to the effectiveness of rehabilitation measures. 2011 Elsevier B.V.

(P1-5) How Does Land use Pattern could Effect to Mitigate the Risk Flash Floods” a Success Story on a Model Project Implementing at the Upper Catchments Area of Badullu River in Sri Lanka

The watersheds are the home for our key natural resources and have been one of the basic elements in land use management systems throughout the hydraulic civilization of our country. “Badulla River” is one of the main watersheds in Sri Lanka extend about 1400sq.km consisting five sub catchments high steep lands. It mainly represents tea estates and agricultural lands with a weak land use pattern due to poor maintenance and unsuitable human involvements. This has contributed to reduce the rain water infiltration in to the soil increasing a huge amount of runoff water drainage. Situation has resulted frequent floods even in a small precipitation causing widespread damages to community. Hence, an initial project was started on surface water management, soil conservation and livelihoods development to control the frequent floods highlighting the urgent actions for an optimal land use management with support of field experts. Improved surface water drainage and soil conservation are the main options that might lead to mitigate the flash floods. Efforts were sharpened by integrating GIS Mapping for such initiation to enhance the effectiveness of the design. Results achieved could address many issues in relation to flood protection, habitat management, water protection and water quality management. Food risk generally related to the specific characters in a particular catchments and this model project proved that such issues can effectively be addressed through a joint program properly designed.

Spatial patterns of scale effect on specific sediment yield in the Yangtze River basin

This paper examines the spatial variation of sediment yield in the Yangtze basin in China, a large basin with complex geology, climate, land-use history, and extensive sediment monitoring. 287 stations with drainage area less than 10,000 km 2 were used to study the scale effects of sediment yield. In order to develop scale relations for regional sediment yield, the whole study area was divided into eight sub-basins. Relation between specific sediment yield and drainage basin area was built for each sub-basin. Regional scaling relation was analyzed based on landforms, geology, lithology and land-use of each sub-basin. Three regional trends were identified in relation to the drainage area: (1) a declining trend, due to soil erosion on heavily cultivated steep land and the storage of sediment in floodplains; (2) a flat trend, due to mass movement on the upper reach and heavy agricultural disturbance on the middle and lower reaches; and (3) an increasing trend, due to downstream recruitment of sediment from land downstream where slope farming and deforestation occurred. Using these developed relations, areally adjusted sediment yield maps were created over the entire Yangtze basin.

Integrated Sustainable Roof Design

‘Necessity is the mother of invention’…this proverb is very true with all great inventions that contribute to sustainable development. High density and steep land value have driven people to maximise liveable and productive spaces in urban settings. This include the reinvention of roofs’ functions extending from merely a protection from the elements to a platform housing sustainable building technologies such as green roof, rainwater harvesting and photovoltaic power generation. On one hand, researches or different sustainable technologies are competing for funding, resources, space and recognition. On the other hand, some of the green building rating criteria have immense influence on decision makers to choose only one between various sustainable building technologies. This paper explores the possibility of combining green roof, rain water harvest system and building integrated photovoltaic thermal power generation to explore integrated sustainable roof design (ISRD). Potential integration benefits including: i) The increase of roof ambient temperature due to the installation of building integrated photovoltaic thermal power generation can be offset by green roof. ii) The energy gained from building integrated photovoltaic thermal power generation can be utilised to operate irrigation system for green roof during draught season. iii) Polluted rainwater runoff can be cleaned via green roof and improve the quality of collected rainwater in rain water harvest system. iv) Harvested rain water can be utilised to irrigate green roof during hot weather. ISRD can be modified accordingly to suit specific needs. Researchers with different specialisations can work together to conduct research based on ISRD and to explore possibilities integrating other suitable sustainable technologies into ISRD.

The Andes basins: biophysical and developmental diversity in a climate of change

To understand how agriculture and poverty interact, we analysed water availability, productivity and institutions for the Andes basins. Water limits agricultural productivity in the southern basins but is plentiful in the northern basins where steep slopes or poor land and water management limit productivity. The dominance of small, steep basins results in important upstream–downstream linkages. The greatest challenge to improving the productivity of water in the Andes basins is to regulate water quality better for multiple uses and to negotiate fair and transparent compensation for upstream providers of water-based ecosystem services for the benefits that they provide to downstream users.

An investigation of soil translocation and erosion by conservation hoeing tillage on steep lands using a magnetic tracer

The mechanism of tillage erosion has been increasingly recognized for nearly two decades, irrespective of mechanized or non-mechanized agriculture areas. Yet, control measures on tillage erosion were relatively less studied. A type of conservation tillage approach, referred to as “non-overturning hoeing tillage” was studied in comparison with conventional tillage in hilly areas of Chongqing, near the Yangtse Gorges reservoir areas, southwestern China. The magnetic tracer was used to label experimental plots of soil to measure soil translocation in the tillage direction. A comparison experiment between conventional and conservation tillage was conducted on a series of hillslopes with slope gradients ranging from 0.08 to 0.65 m m −1, with paired plots at neighboring sites on the same hillslope. Mean soil displacement in the downslope direction by conservation tillage, being 0.11 m was much shorter than that by conventional tillage with 0.33 m. Tillage transport coefficients were 17 and 35 kg m −1 tillage pass −1 when conservation tillage was conducted, and 37 and 118 kg m −1 tillage pass −1 under conventional tillage, respectively, for k 3 and k 4. Tillage erosion rates by conservation tillage, estimated at 28 Mg ha −1 year −1 significantly decreased with a reduction of 63%, when compared to those by conventional tillage estimated at 78 Mg ha −1 year −1. The magnetic tracer method is an efficient and effective one for measuring tillage translocation, and therefore, estimating tillage erosion rate. It is suggested that non-overturning hoeing tillage largely diminishes soil downslope translocation and results in a significant reduction in tillage erosion.

X-RAY FLUORESCENCE DETECTED VARIATION IN NUTRACEUTIC-IMPLIED MINERAL DENSITY IN UNDERUTILIZED PLANTS MAPPED AS WOMEN-OPERATED SMALLHOLDER UNITS IN THE LAKE VICTORIA BASIN

Indigenous plant biodiversity plays a key role in providing nutritional and medicinal (nutraceutical) need for smallholder farming communities. The objective of this paper was to relate farming decisions, farm landscape morphology, crop species placement points, and the nutraceutical-implied micronutrient mineral (NIMM) density. The Kisumu (Kenya), Iganga (Uganda) and Bukoba (Tanzania) lake basins were the three eco-regional environs studied and were treated as the primary hierarchical level. Two visited sites (secondary level) for reconnaissance/collection were nested within the primary level. Fifteen dominantly female households were further nested within sites (tertiary level). By means of X-ray fluorescence (XRF) spectroscopy, indigenous variant plants (accessions) encountered were collected for density. XRF analyses were backed by key informant interviews. Empirically, indigenous/traditional plant species and, by extension, their diversity in NIMM density, was a three-factor dependent variable in terms of: (a) the ethnobotanic-based farming decisions by which the NIMM indigenous/ underutilized plant bio-resources encountered were purposively grown; (b) choices that were dictated by the topographic soil surface characteristics (terrain upland, steep and valley land properties); (c) near residence-referenced sequent activity occupancy (NR-SACO) episodes; and (d) natural cum farmer-guided plant selections. Women were found to be dominant players in smallholder operations and were NR-SACO-mapped with respect to their rigorous tillage operations close to the residential zone. Across the nearest residence tillage farm (NRTF), the transitional tillage (TITF) and the outlier tillage (OUTS) spectrum, the lowest percentage of tillage rigour occurred on slope, probably due to local soil aridity and reduced soil fertility. Valley-like plain sites, regardless of distance from residence, were most preferred for tillage. The 10-9-8 right-tailed nutraceutic-implied diversity cluster was the most conservative as only Corchorus olitorius ex. Bunafu (from Uganda) of all the Ugandan and Kenyan accessions fitted there with a score of 8. The 7-6-5 centre diversity cluster was less clustered. Patterns of tillage placement may be suggesting a likely influence of the topographic soil-surface effects on NIMM density via farming decisions. The above interrelationships are an efficient basis for tagging nutraceutic-implied variants on the farm by allocation to the physical tillage units for conservation and use.

The influence of traditional steep land agricultural practices on runoff and soil loss

The erosion of soil from subsistence agricultures on lands with steep slopes and shallow soil is poorly documented, particularly in Brazil. This paper details the hydrological and soil loss responses to traditional agriculture (shifting agriculture) of a steeply sloped sector (32° incline) classified by FAO has having Regosol soil. This sector is in Guarapuava, Brazil and is covered by a shallow, clayed soil that originates from basalt rock. All measurements were carried out between May 2003 and April 2004. Three replicate plots were established at three randomly selected land sites, which were under different phases of the rotational cycle: burned, fallow or shrubs. A total of 76 natural rainfall events were measured throughout the study period and the accumulated precipitation was 1538.9 mm. Rainstorms ≥30 mm were important for runoff and soil loss. The average runoff (expressed as a proportion of the total rainfall) over the 12-month investigation period for each of the three sites was determined to be 2.4%, 1.0%, and 1.4% for burned, fallow, and shrubs, respectively. The response to rainfall during the measurement period differed completely at each site. The average soil loss was as follows: for shrubs, fallow, and burned sites, average loss was 1.2 t/(ha year), 5.1 t/(ha year), and 6.1 t/(ha year), respectively. The results suggest that fire and traditional agriculture tillage practices affected the topsoil. Shifting cultivation patterns in the steeply sloped sectors cause a succession of high, intermediate, and low soil loss regimes, which are important for understanding contemporary landscape dynamics and land degradation in the Guarapuava region.