Clayey Loam Research Articles

Geospatial Distribution of Some Phosphorus and Potassium Forms as Influenced by Period of Irrigation in the Kano River and the Hadejia Valley Irrigation Schemes, Nigeria.

This study was carried out at Kano River Irrigation Project (KRIP) (latitudes 11º 36ʹ 0.05ʺ N to 11º 49ʹ 57.97ʺ N and longitudes 8º 28ʹ 17.02ʺ E to 8º 29ʹ 41.82ʺ E) and Hadejia Valley Irrigation Project (HVIP) (latitudes 12º 17ʹ 48.75ʺ N to 12º 24ʹ 58.28ʺ N and longitudes 9º 51ʹ 31.29ʺ E to 10º 2ʹ17.42ʺ E). The soils are largely deep, well-drained Calcic Luvisols. The aim was to assess the geospatial distribution of some plant-nutrition related forms of P and K. A total of 37 and 19 irrigation sectors were identified in KRIP and HVIP respectively. Google earth was used to tag 109 and 41 sampling points randomly within both developed and undeveloped sectors of KRIP and HVIP respectively. With the aid of projects’ sitemaps, the sectors were demarcated into six periods of irrigation: 0 years (Non -irrigated), 1-10 years, 10-19 years, 20-29 years, 30-39 years and ≥ 40 years as applicable. GPS was used to track the tagged points at the time of sampling. Sur- face soil samples were collected by augering to 30 cm depth with fabricated steel augers. Samples were analyzed for physical and chemical properties. Available (AP) and total (TP) forms of P as well as water-soluble (WSK), exchangeable (Ex. K) and non-exchangeable (NEK) forms of K were analyzed. Basic soil prop- erties were compared by ANOVA using JMP version 12. Geostatistical analysis and Geospatial variability of various forms of P and K were performed with the GS+ software (version 10). Ordinary Kriging was used for the spatial interpola- tion. Texturally, the soils of the KRIP was sandy loam while that of the HIVP was predominantly sandy clayey loam. The pH (mean = 6.68) and EC (mean = 0.21 dsm-1) values across the sites indicated that despite the years of irrigation the areas are not under immediate salinization risk. There was no specific pattern of distribution of basic cations in both the two schemes. There is an observable tendency in the distribution of the forms of P and K evaluated of their being at higher concentrations in longer-periods irrigated lands in both the scheme. The nugget to sill ratio revealed a strong spatial dependence (< 25 %) for WSK. Moderately spatial dependence (25 to 75 %) was observed for available P, total P, noN-exchangeable K and exchangeable potassium. It was concluded that there may be a stronger influence of the irrigation method on the spatial distribution of the forms of the nutrients over other factors such as parent material and weathering.

Продуктивність сортів пшениці озимої залежно від фону живлення в умовах Південного Степу України

У статті наведені результати досліджень, проведених в 2011-2016 рр. на чорноземі південному в умовах Південного Степу України, з вивчення ефективності оброблення посівів пшениці озимої сучасними рістрегулюючими препаратами по фону внесення мінеральних добрив. Вивчали вплив сортових особливостей пшениці озимої та варіантів живлення на формування показників структури врожаю та рівень урожайності зерна культури. Визначено, що за внесення під передпосівну культивацію пшениці озимої мінерального добрива в дозі N 30 P 30 (фон) та застосування позакореневого підживлення посівів на початку відновлення весняної вегетації та початку виходу рослин у трубку комплексними органо-мінеральними добривами Органік Д2 та Ескор – біо створюються сприятливі умови для формування оптимальних показників структури врожаю та відповідно найвищого рівня врожайності зерна досліджуваних сортів. Так, у середньому за роки досліджень, рослинами пшениці озимої сорту Кольчуга у даних варіантах удобрення сформовано 4,42-4,48 т / га зерна, а сорту Заможність 4,96-4,99 т / га, що перевищило показники контролю на 52,9-55,0 та 62,6-63,6 % відповідно. Із досліджуваних сортів пшениці озимої за комплексом показників кращим визначено сорт Заможність.

Experimental and numerical investigations for optimal emitter spacing in drip irrigation

AbstractWith the goal of determining optimal emitter spacing in drip irrigation, experiments were performed to examine the effects of emitter discharge on the wetted perimeter and spacing of emitters. Four types of soils were investigated using emitter discharge of 1.0, 2.0, 3.0 and 4.0 l h−1. Wetting diameter was measured at six equal time intervals of water application. An equal volume of water was applied. After 1 h of supply of water, wetted soil was cut to observe the maximum wetted width and depth. Wet soil samples were taken from every patch of 10 × 10 cm to find the percentage of moisture by the gravimetric method. Empirical equations were developed for wetted depth and radius. Additional experiments with emitter discharge of 1–18 l h−1 were performed in sandy loam to obtain more data for accurate estimation of the coefficients of the empirical equations. Two computer programs based on trial and error and the generalized reduced‐gradient non‐linear‐optimized technique were used to find values of the coefficients. Root mean square error between the measured and simulated wetted radius and depth was minimized in optimization. Optimal emitter spacing for each type of soil was determined from the recorded data, which was found to be 35, 40, 40 and 45 cm in sandy loam, loam, clayey loam and clay respectively. © 2018 John Wiley & Sons, Ltd.

Comparison of Single- and Sequential-Solvent Extractions of Total Extractable Benzo[ a]pyrene Fractions in Contrasting Soils.

The fate and behavior of polycyclic aromatic hydrocarbons (PAHs) in soil are of interest in the risk assessment of contaminated land and are usually based on determinations of fractions extracted from soil. For decades, either single- or sequential-solvent extractions have been used to determine PAH extractability in soils; however, there is a lack of certainty as to which fractions are being extracted by these techniques. This study is the first report of differences and similarities in the extractability of benzo[ a]pyrene (B[ a]P) in four contrasting soils (sandy loam, loamy sand, clayey loam, and sandy) when determined using both single-solvent (dichloromethane/acetone (DCM/Ace) mixture) and sequential-solvent (butanol followed by DCM/Ace) extraction. Residues after extraction were subjected to methanolic saponification (MeKOH). Butanol (BuOH) extractability and total extractability of B[ a]P following sequential-solvent extraction decreased significantly ( p < 0.05) with time after addition of B[ a]P. The decrease in BuOH extractability was particularly marked in the organic-matter-rich clayey-loam soil, which also had the largest (>40%) amounts of nonextractable residues. The cumulative amounts of B[ a]P extracted in each soil by single- and sequential-solvent extractions were similar ( p > 0.05) at each aging period, which indicated access to similar B[ a]P fractions in soil by both solvent extractions. The similarities in the amounts of B[ a]P nonextractable residues recovered by MeKOH from pre-extracted soils, through either of the extraction methods, confirms that the total extractable B[ a]P fractions from both methods are similar.

Inter-laboratory comparison of cryogenic water extraction systems for stable isotope analysis of soil water

Abstract. For more than two decades, research groups in hydrology, ecology, soil science, and biogeochemistry have performed cryogenic water extractions (CWEs) for the analysis of δ2H and δ18O of soil water. Recent studies have shown that extraction conditions (time, temperature, and vacuum) along with physicochemical soil properties may affect extracted soil water isotope composition. Here we present results from the first worldwide round robin laboratory intercomparison. We test the null hypothesis that, with identical soils, standards, extraction protocols, and isotope analyses, cryogenic extractions across all laboratories are identical. Two standard soils with different physicochemical characteristics along with deionized (DI) reference water of known isotopic composition were shipped to 16 participating laboratories. Participants oven-dried and rewetted the soils to 8 and 20 % gravimetric water content (WC), using the deionized reference water. One batch of soil samples was extracted via predefined extraction conditions (time, temperature, and vacuum) identical to all laboratories; the second batch was extracted via conditions considered routine in the respective laboratory. All extracted water samples were analyzed for δ18O and δ2H by the lead laboratory (Global Institute for Water Security, GIWS, Saskatoon, Canada) using both a laser and an isotope ratio mass spectrometer (OA-ICOS and IRMS, respectively). We rejected the null hypothesis. Our results showed large differences in retrieved isotopic signatures among participating laboratories linked to soil type and soil water content with mean differences compared to the reference water ranging from +18.1 to −108.4 ‰ for δ2H and +11.8 to −14.9 ‰ for δ18O across all laboratories. In addition, differences were observed between OA-ICOS and IRMS isotope data. These were related to spectral interferences during OA-ICOS analysis that are especially problematic for the clayey loam soils used. While the types of cryogenic extraction lab construction varied from manifold systems to single chambers, no clear trends between system construction, applied extraction conditions, and extraction results were found. Rather, observed differences in the isotope data were influenced by interactions between multiple factors (soil type and properties, soil water content, system setup, extraction efficiency, extraction system leaks, and each lab's internal accuracy). Our results question the usefulness of cryogenic extraction as a standard for water extraction since results are not comparable across laboratories. This suggests that defining any sort of standard extraction procedure applicable across laboratories is challenging. Laboratories might have to establish calibration functions for their specific extraction system for each natural soil type, individually.

English

English

Acumulación de biomasa en yuca (Manihot esculenta C.) ante la respuesta a la aplicación de fertilizantes NPK y biofertilizantes en condiciones de invernadero en dos tipos de suelo

El cultivo de la yuca en el Caribe colombiano es un sistema productivo con un bajo nivel de integración de tecnologías modernas sustentables que permitan incrementar la rentabilidad del cultivo. La validación de prácticas asociadas a la fertilización conforma una de las alternativas para incluir en las estrategias de manejo integrado del cultivo. El objetivo de este estudio fue evaluar a nivel de casa malla, la respuesta de acumulación de biomasa en plantas de yuca a la fertilización NPK en dos tipos de suelos (arenoso y franco-arcilloso) y en presencia de tres biofertilizantes. El efecto de diferentes inoculantes microbianos comercialmente disponibles, Azobac® (Azotobacter chrococcum), Fosforiz® (Pseudomonas fluorescens) y micorrizas arbusculares (Safer Micorrizas ®), fue evaluado en mezcla con diferentes niveles de fertilización inorgánica (100, 75, 50, 25 y 0%), más los testigos sin inoculación en un arreglo factorial 2×3×5. Los resultados obtenidos indican que el nivel de fertilización NPK en el que se alcanza la mayor acumulación relativa de biomasa ocurre al 25% de la mezcla. Los mayores valores de acumulación de biomasa se alcanzan con la presencia de micorrizas. Azobac® y Fosforiz ® no exhibieron ningún efecto sobre la acumulación de biomasa. Los resultados obtenidos sugieren que los biofertilizantes comerciales basados en micorrizas pueden ser usados para maximizar la respuesta a la fertilización con NPK.

A simple greenhouse experiment to explore the effect of cryogenic water extraction for tracing plant source water

AbstractStable isotopes of water (2H and 18O) are useful tracers for determining root water uptake depths. In such studies, plant and soil water are extracted most commonly by cryogenic vacuum distillation. However, recent studies have suggested that cryogenic extraction conditions (extraction time, temperature, and vacuum) and soil physicochemical properties affect the isotopic composition of extracted soil water. Here, we perform a simple greenhouse trial with 2 plant species (Taraxacum officinale and Pelargonium spp.) in 2 soil types (clayey loam and sand) to test our ability to match plant water to its putative soil water source(s) by using different extraction conditions (30–240 min, 80–200 °C, 0.1 Pa). We irrigated plants with water of known isotopic composition, sampled root crowns and soils at 2 depths, and varied the cryogenic water extraction conditions.Our isotope results from the sandy soils were unaffected by cryogenic extraction conditions. In contrast, extraction parameters affected the isotope composition of waters recovered from clayey soil. This influenced the estimates of plant water sourcing, where δ2H and δ18O returned different results from each other. With higher extraction temperatures and longer extraction times, we gradually extracted more enriched soil water, which reflected the source water of both plant species. Our results imply that longer extraction times and temperatures for clayey soils are needed to reduce fractionation effects during the extraction procedure. Future studies should explore how these effects apply to natural clay‐rich soils as well as plant tissue isotope composition.

MULTIVARIATE ANALYSIS OF PEANUT MECHANIZED HARVESTING

ABSTRACT The peanuts harvesting mechanization is affected by the soil physical characteristics and it may increase the losses due to the production of pods in subsurface. The objective of the experiment was to identify the clusters through multivariate exploratory approaches from similarity in six soil textures (very clayey, clayey, silty clayey loam, clayey loam, sandy loam and sandy) in the state of Sao Paulo, Brazil, determining the main agronomic variables that most influenced the clustering division to assist the decision-making process in peanuts mechanized harvesting. The data were analyzed by the multivariate exploratory that is performed to simplify the description of a set of interrelated variables, using: yield, maturity, soil and pod moisture content, windrow width and height, visible and invisible digging losses, and gathering losses, as agronomic indicators of quality. The low and high clay content were grouped into clusters I and III, respectively, according to the agronomic traits of the peanut crop. The principal components analysis (PC) allowed a single distribution of accesses since only two eigenvalues were higher than “one”: the highest eigenvalues of 4.51 and 1.79, resulted in a Biplot that explained 70% of the original variability, 50.11% and 19.89% of which in the PC1 and PC2, respectively. The multivariate analysis indicated that high peanut yields in soils with low clay are correlated with the losses during the peanut mechanized harvesting operation.

Effect of humic acid on growth and crop nutrient status of wheat on two different soils

ABSTRACTThe effect of plant-derived humic acid (PDHA) and coal-derived humic acid (CDHA) on wheat growth was tested on two alkaline calcareous soils in pots. Humic acid derived from plant and coal materials was applied at the rate 0 (control), 50 and 100 kg/ha to wheat in pots carrying two soils viz. clayey loam soil and sandy loam soil separately. Data was collected on plant growth parameters such as spike weight, grain and straw weight, and plant nutrients (macronutrients and micronutrients). Results showed that spike weight increased by 19%, 15%, and 26%, and 11% with application of PDHA at the rate of 50 and 100 mg/kg in clayey loam and sandy loam soil, respectively. Grain yield show an increase of 21% and 11% over control with application of PDHA and CDHA at the rate of 50 mg/kg on both soils, respectively, and 10% and 22% with application of PDHA and CDHA at the rate of 100 mg/kg on both soils.

Growth and yield of an eucalyptus subtropical plantation in a Northeastern Mexico degraded land soil

Over the past three decades, woody species potentially useful for reforestation, fuelwood, coal and timber production have been over-exploited along the Gulf of Mexico, which has led to a gradual decline in the plant population and the progressive degradation of the environment. The present research evaluated the establishment, growth, and production of fuelwood from a plantation of five eucalyptus species planted in randomly arranged plots on a cleared clayey loam alkali soil in a semi-arid region of northeastern Mexico for a 20 year period. Eucalyptus camaldulensis, E. tereticornis and E. microtheca showed the highest average height growth rate (1.07 m year-1, 0.93 m year-1 and 0.85 m year-1, respectively). E. camaldulensis showed the highest volume values at 20 years (58.55 m3 ha-1), followed by E. tereticornis (54.15 m3 ha-1) and E. microtheca (51.91 m3 ha-1). E. sideroxylun and E. crebra yielded the lowest tree volumes (35.12 m3 ha-1 and 30.45 m3 ha-1, respectively). The results have shown that the adaptability of eucalyptus species to the climate of the subtropical regions allows their use in combination with the native vegetation to colonize degraded areas offering services in timber and non-timber products to the local population. In addition, the production of exotic trees with large trunk diameter with few side branches may increase the volume of the wood exploited and the income to the owner of the land and, thus, reduce the pressure on the native species.

Effects of tillage practice on soil structure, N2O emissions and economics in cereal production under current socio-economic conditions in central Bosnia and Herzegovina.

Conservation tillage is expected to have a positive effect on soil physical properties, soil Carbon (C) storage, while reducing fuel, labour and machinery costs. However, reduced tillage could increase soil nitrous oxide (N2O) emissions and offset the expected gains from increased C sequestration. To date, conservation tillage is barely practiced or studied in Bosnia and Herzegovina (BH). Here, we report a field study on the short-term effects of reduced (RT) and no tillage (NT) on N2O emission dynamics, yield-scaled N2O emissions, soil structure and the economics of cereal production, as compared with conventional tillage (CT). The field experiment was conducted in the Sarajevo region on a clayey loam under typical climatic conditions for humid, continental BH. N2O emissions were monitored in a Maize-Barley rotation over two cropping seasons. Soil structure was studied at the end of the second season. In the much wetter 2014, N2O emission were in the order of CT > RT > NT, while in the drier 2015, the order was RT > CT > NT. The emission factors were within or slightly above the uncertainty range of the IPCC Tier 1 factor, if taking account for the N input from the cover crop (alfalfa) preceding the first experimental year. Saturated soils in spring, formation of soil crusts and occasional droughts adversely affected yields, particularly in the second year (barley). In 2014, yield-scaled N2O emissions ranged from 83.2 to 161.7 g N Mg-1 grain (corn) but were much greater in the second year due to crop failure (barley). RT had the smallest yield-scaled N2O emission in both years. NT resulted in economically inacceptable returns, due to the increased costs of weed control and low yields in both years. The reduced number of operations in RT reduced production costs and generated positive net returns. Therefore, RT could potentially provide agronomic and environmental benefits in crop production in BH.

Sustainable Irrigation Allocation Model for Dry and Wet Periods using Reservoir Storage and Inflow

The dry period agriculture is inevitable both for the farmers for their earning, and for the soil for its fertility by crop-rotation. In tropical countries like INDIA, dry period agriculture becomes difficult because of less (or) no rain fall. Hence a simple water balancing model for irrigation scheduling, using the measure “Volumetric Reliability” is prepared in this paper, with the storage and inflow of a reservoir both for the dry and wet periods. The case-study is done for a reservoir in INDIA with thirty one years of hydrological data(from 1982 to 2012). The objective of this paper is to prepare a simple water balance model taking 10 days periods of demand and supply for ID crop(Irrigated Dry crop, ground nut) with usage of volumetric reliability concept for the periods of deficiency and adoption of less water requirement crops to reduce the water-stress during critical periods of crop growth, and finally arrive at a feasible allocation schedule for the success of agriculture and the yield throughout the year both for wet and dry crops with the available storage on the start of irrigation for a particular year. The reservoir is divided for storages such as full, deficient and critical storages. The starting storage for the dry period from January is used after adequate allocation for wet crops, the quantity for riparian rights and for drinking water, for the sustainability. By the water-balancing, the time-series for thirty one years, it is found that for twenty two years the demand for the ID crops is satisfied with the storage in the reservoir, and in the remaining years of deficient inflows, for three years (1986,1996,2004)the demand is managed by using the safe reliability factor for demand which can nullify the deficit in demand for the whole supply period. But it is genuine to assure that the reduction in the amount of water for each 10 days periods should not exceed the survival limit of the crop. Necessary soil-moisture must be ensured in the crop in its root zone.. A safe volumetric reliability factor of 0.75 is taken in this attempt to extend the success of dry period agriculture. The soil moisture balance in the clayey loam soil due to continuous irrigation can manage the deficiency, so that the soil-water does not go below the wilting point but must be checked with the soil-moisture sensors. The methods to reduce the evaporation from the soil, such as usage of drip irrigation and the mulching, which can reduce the crop water requirements in comparison with the conventional irrigation which is being followed at present in the spot of the case-study is suggested. In addition to these methods less water requirement crops like flowers, vegetables having less crop-period and provision of windbreak to reduce evapo-transpiration rates and other efficient methods of water management can make success of dry period agriculture even in the years critical storage level in the reservoir. The rainfall is not taken in this model which if in a year with ample quantity can be used for pre-sowing and for managing the water-stress. Augmentation of water with ground water, percolation tank can boost the level of success of agriculture. As the irrigation water allocation for the whole year, particularly for the ID crops is prepared for the full, deficient and critical storages, this paper can help to achieve sustainable growth of crops throughout the year.

Moringa oleiferaLam., a promising crop species for arid conditions of Saudi Arabia andMoringa peregrina(Forssk.) Fiori, a native wild species for crop improvement

Moringa oleifera Lam. is one of the world's most nutritious crops, belonging to the family Moringaceae. Recent inventions of new products and the multiple uses of moringa have attracted attention of researchers, development workers, policy makers and farmers to select this multipurpose tree species as a commercial crop. The government of the Kingdom of Saudi Arabia (KSA) is now encouraging people to cultivate this crop. Some entrepreneurs have already started large scale plantations of moringa in northeastern and southwestern provinces of the KSA. Moringa typically grows in semi-dry deserts with well-drained sandy loam or clayey loam and it tolerates a range of pH between 5.0 and 9.0. It can grow with very little moisture because its roots can store moisture for prolonged periods of time. It grows best between 25 to 35°C, but will tolerate up to 48°C in the shade and can survive light frost. Moringa peregrina (Forssk.) Fiori, a native wild species of Saudi Arabia and neighboring countries also possesses many economically important properties and is very much adapted to arid and hyper arid conditions of desert countries. Biochemical studies conducted by many workers reported that both species have similar chemical components at varying concentrations. Moringa spp. are commercially grown for two main useful parts: leaves and pods. M. peregrina has deciduous leaflets and produces lesser number of pods compared to M. oleifera. Selection, cloning and crop improvements have been feebly attempted in this species. M. peregrina, an arid environment species can be used as mother plant in crop improvement programs for producing plants with best yielding traits, suitable for the desert climatic conditions. The available micropropagation techniques of moringa species can be applied to the newly developed hybrids for clonal propagation. This article reviews morphological, and phytochemical properties, ecological requirements, and propagation including in vitro culture studies of M. oleifera and M. peregrina. Based on the assessment of their viability as a promising crop in Saudi Arabia, M. oleifera is proposed as an economically potential crop species, while M. peregrina is considered as a potential candidate for crop improvement programs.

Impact of severe rain storms on soil erosion: Experimental evaluation of wind-driven rain and its implications for natural hazard management

Prediction and risk assessment of hydrological extremes are great challenges. Following climate predictions, frequent and violent rainstorms will become a new hazard to several regions in the medium term. Particularly agricultural soils will be severely threatened due to the combined action of heavy rainfall and accompanying winds on bare soil surfaces. Based on the general underestimation of the effect of wind on water erosion, conventional soil erosion measurements and modeling approaches lack related information to adequately calculate its impact. The presented experimental-empirical approach shows the strong impact of wind on the erosive potential of rain. The tested soils had properties that characterize three environments 1. Silty loam of semi-arid Mediterranean dryfarming and fallow, 2. clayey loam of humid agricultural sites and 3. cohesionless sandy substrates as found at coasts, dune fields and drift-sand areas. Total erosion was found to increase by a factor of 1.3 to 7.1, depending on site characteristics. A complementary laboratory procedure was applied to quantify explicitly the effect of wind on raindrop erosion as well as the influence of substrate, surface structure and slope on particle displacement. These tests confirmed the impact of wind-driven rain on total erosion rates to be of great importance when compared to all other tested factors. To successfully adapt soil erosion models to near-future challenges of climate change induced rain storms, wind-driven rain should be included into the hazard management agenda.

Produire des lames de hache en dolérite au Néolithique en Mayenne. La carrière-atelier de Beulin à Saint-Germain-le-Guillaume

Produire des lames de hache en dolérite au Néolithique en Mayenne. La carrière-atelier de Beulin à Saint-Germain-le-Guillaume

Vineyard row orientation and grape ripeness level effects on vegetative and reproductive growth characteristics of Vitis vinifera L. cv. Shiraz/101-14 Mgt

Abstract Effects of vineyard row orientation (NS, EW, NE-SW, NW-SE) and harvesting dates/grape ripeness levels (23 °B, 25 °B and 27 °B) on vegetative and reproductive growth characteristics of vertically trellised, shoot positioned Vitis vinifera L. cv. Shiraz, grafted onto rootstock 101–14 Mgt, were investigated for seven consecutive seasons on a flat site of approximately 3 ha with uniform clayey loam soil at the experiment farm of ARC Infruitec-Nietvoorbij in the Breede River Valley, Robertson, South Africa. Primary and secondary shoot characteristics showed minor differences between row orientations and canopy sides. Primary shoot lengths and primary leaf area:secondary leaf area ratios averaged 110–120 cm and 0.80–0.90, respectively. Secondary leaf area of primary shoots on S and SW sides tended to be lower. The SW canopy side displayed generally lower values for most characteristics. Higher cane mass was obtained for NS and EW orientations. Bud fertility, berry set and general morphology of bunches were largely unaffected by row orientation. Bunch and berry mass and volume progressively decreased during ripening for all row orientation treatments. The EW row orientation resulted in consistently higher berry mass and volume. Leaf area (10–12 cm 2 )/g fresh mass values showed equal balance for differently orientated vines, aligned with generally acknowledged criteria. Average yields of three ripeness levels over row orientations and seasons were 19.2, 17.4 and 15.9 tons/ha. Overall total yield losses from ripeness level 1–2 and 2–3 averaged 9.5% and 8.6%, respectively, with an overall total yield loss from ripeness level 1–3 of 17.3%. This is mainly attributed to a decrease in berry mass; rachis mass showed high stability. The NS orientated vines had highest yields over seasons and at all ripeness levels; it also displayed most stable yields over the years of study and may be considered the most ideal row orientation for yield within the terroir of study. Yields of the other row orientations varied according to season/ripeness level: at ripeness level 1, NE-SW was followed by NW-SE and EW; at ripeness level 2, NW-SE was followed by EW and NE-SW; and at ripeness level 3; EW was followed by NW-SE and NE-SW. The NW-SE row orientation was stable at an average level and EW and NE-SW orientations were variable. Overall average yields (over ripeness levels) of NS, EW, NE-SW and NW-SE orientations were 18.2, 17.1, 17.1 and 17.4 ton/ha, respectively. Despite minor differences in vegetative characteristics, yield:cane mass ratios indicated that growth balances were affected by row orientation. These trends are of great significance in considerations of an optimal ripeness level for a specific product objective and are very important aspects of sustainability. Results showed significant trends that can globally be used as guidelines for row orientation choices, even when multiple (straight or curved) row orientations per vineyard are used and when vineyards are established in more complex terrains/terroirs. The study provided the first comprehensive and much needed scientific evidence on the role of row orientation in vegetative and reproductive growth of the grapevine and as viticulture practice.

EFFECTS OF SOIL CHARACTERISTICS AND DATE PALM MORPHOLOGICAL DIVERSITY ON NUTRITIONAL COMPOSITION OF PAKISTANI DATES

SUMMARYThe use of date palm (Phoenix dactyliferaL.) has been closely connected with the survival of people in arid areas given their fruits´ high concentration of energy, fibre, minerals, vitamins and 16 amino acids. The arid climate and sandy or clayey loam soils in many parts of Pakistan are ideal for the cultivation of date palm, which contributes to feeding the country's rapidly growing population. To fill knowledge gaps on the effects of cultivar diversity and cultivation sites on the nutritional properties of dates, the present project studied dates and related physical and chemical soil properties across six districts in four provinces of Pakistan: Jhang, Muzaffargarh and Bahawalpur in Punjab; Dera Ismail Khan (D. I. Khan) in Khyber Pakhtunkhwa (KPK); Khairpur in Sindh and Panjgur in Baluchistan. To this end, during 2012–2013, a total of 170 households (HHs) were selected using a snowball sampling approach. Thirty-nine different date palm cultivars with diverse nutritional properties are grown in the study area. In these total soluble solids (TSS) were highest in Muzawati and Koharba cultivars, while cultivars and site conditions significantly affected TSS, minerals (calcium and magnesium), acidity, and firmness of dates. Concentration of CaCO3and bulk density (BD) of soils varied widely, while hydraulic conductivity (HC) was similar across sites (p= 0.128). Mean soil pH was highest in Panjgur (8.3) and lowest in Muzaffargarh (7.6), soil organic matter content was highest in Jhang (0.8%) and lowest in D. I. Khan (0.6%) and plant available phosphorous (P) was highest in Muzaffargarh (7.8 mg kg−1) and lowest in Panjgur (6.0 mg kg−1). As indicated by correlation analysis BD and cation exchange capacity of soils seemed to affect TSS, whereas concentration of CaCO3and available P were correlated with calcium concentration of dates. HC and electrical conductivity, however, seemed to have little effect on dates´ nutritional properties.

Digital soil mapping using reference area and artificial neural networks

Digital soil mapping is an alternative for the recognition of soil classes in areas where pedological surveys are not available. The main aim of this study was to obtain a digital soil map using artificial neural networks (ANN) and environmental variables that express soil-landscape relationships. This study was carried out in an area of 11,072 ha located in the Barra Bonita municipality, state of Sao Paulo, Brazil. A soil survey was obtained from a reference area of approximately 500 ha located in the center of the area studied. With the mapping units identified together with the environmental variables elevation, slope, slope plan, slope profile, convergence index, geology and geomorphic surfaces, a supervised classification by ANN was implemented. The neural network simulator used was the Java NNS with the learning algorithm back propagation. Reference points were collected for evaluating the performance of the digital map produced. The occurrence of soils in the landscape obtained in the reference area was observed in the following digital classification: medium-textured soils at the highest positions of the landscape, originating from sandstone, and clayey loam soils in the end thirds of the hillsides due to the greater presence of basalt. The variables elevation and slope were the most important factors for discriminating soil class through the ANN. An accuracy level of 82% between the reference points and the digital classification was observed. The methodology proposed allowed for a preliminary soil classification of an area not previously mapped using mapping units obtained in a reference area.

Caractérisation écologique de l’habitat naturel du Trèfle souterrain (Trifolium subterraneum L., Fabaceae) dans le Nord-Est de l’Algérie

Ecological characterization of the Subterraneum Clover (Trifolium subterraneum L., Fabaceae) natural habitat in Northeastern Algeria. Within the framework of the evaluation and valorization of the plant genetic resources bearing a fodder and pastoral interest in Algeria, a study was carried out about the ecological characterization of the Subterraneum Clover natural habitat. Following a prospecting and collecting mission conducted in the northeastern part of the country, thirty nine (39) Subterraneum Clover sites were identified. For each site, three soil samples were taken randomly (117 samples). Sixteen (16) physical and chemical parameters of soils (pH, electric conductivity, total limestone, total nitrogen, potassium, phosphorus, carbon, organic matter, C/ N ratio, particle composition) were analysed. Two (02) additional variables, linked to the topography (altitude) and to the climate (rainfall) of the natural habitat of the species were as well taken into account. The variance analysis showed highly significant results for the whole physical and chemical characteristics of the soils taken into consideration. Thus, the Subterraneum Clover seems to be adapted to unsalted and calcareous soils, characterized by rather diverse textures (clay, clayey loam, loamy sand, sandy clay loam, loam) and a pH varying from 6.46 to 8.64 (slightly acid, neutral, slightly alkaline, alkaline). The record of Algerian populations of Subterranean Clover on frankly alkaline soils appears as the first one for some subspecies and/ or varieties of the species T. subterraneum. The Subterraneum Clover seems as well to tolerate soils whose phosphorus and potassium content are variable and the C/ N ratio relatively high. Significant relations were noticed between altitude and rainfall, on the one hand and some soil physical and chemical parameters on the other, with a relatively stronger influence of the first factor (altitude). The pH seems to vary with the natural habitat altitude of the different populations of Subterraneum Clover. The use and valorization of this clover, in different edaphical and climatic conditions, would permit the development of marginal regions, mainly the ones located in mountainous regions to which the species seems to be well adapted.