Classification Of Products Research Articles

Breed of cow and herd productivity affect milk nutrient recovery in curd, and cheese yield, efficiency and daily production

Little is known about cheese-making efficiency at the individual cow level, so our objective was to study the effects of herd productivity, individual herd within productivity class and breed of cow within herd by producing, then analyzing, 508 model cheeses from the milk of 508 cows of six different breeds reared in 41 multi-breed herds classified into two productivity classes (high v. low). For each cow we obtained six milk composition traits; four milk nutrient (fat, protein, solids and energy) recovery traits (REC) in curd; three actual % cheese yield traits (%CY); two theoretical %CYs (fresh cheese and cheese solids) calculated from milk composition; two overall cheese-making efficiencies (% ratio of actual to theoretical %CYs); daily milk yield (dMY); and three actual daily cheese yield traits (dCY). The aforementioned phenotypes were analyzed using a mixed model which included the fixed effects of herd productivity, parity, days in milk (DIM) and breed; the random effects were the water bath, vat, herd and residual. Cows reared in high-productivity herds yielded more milk with higher nutrient contents and more cheese per day, had greater theoretical %CY, and lower cheese-making efficiency than low-productivity herds, but there were no differences between them in terms of REC traits. Individual herd within productivity class was an intermediate source of total variation in REC, %CY and efficiency traits (10.0% to 17.2%), and a major source of variation in milk yield and dCY traits (43.1% to 46.3%). Parity of cows was an important source of variation for productivity traits, whereas DIM affected almost all traits. Breed within herd greatly affected all traits. Holsteins produced more milk, but Brown Swiss cows produced milk with higher actual and theoretical %CYs and cheese-making efficiency, so that the two large-framed breeds had the same dCY. Compared with the two large-framed breeds, the small Jersey cows produced much less milk, but with greater actual and theoretical %CYs, similar efficiencies and a slightly lower dCY. Compared with the average of the specialized dairy breeds, the three dual-purpose breeds (Simmental and the local Rendena and Alpine Grey) had, on average, similar dMY, lower actual and theoretical %CY, similar fat and protein REC, and slightly greater cheese-making efficiency.

Custos da produção de madeira de paricá na região de Paragominas, PA

A potencialidade silvicultural e econômica do paricá (Schizolobium amazonicum) tem incentivado a expansão desta cultura, principalmente na região norte do país, despertando a necessidade de estudos sobre a espécie. Deste modo, objetivou-se neste trabalho estimar a produção de paricá na região de Paragominas, PA, aos 5, 6 e 7 anos, em três classes de produtividade, considerando cinco arranjos de plantas, sendo identificados os principais custos de produção, além dos mais afetados pelos arranjos das plantas. A estimativa volumétrica foi obtida pela modelagem em nível de povoamento e a análise dos custos, por meio da metodologia do custo operacional. Foi possível inferir que o arranjo das plantas 3 m x 2 m foi superior em volume, diante dos outros arranjos analisados. O custo operacional efetivo representou, em média, 65% dos custos totais de produção, sendo o transporte o custo individual mais expressivo em todos os arranjos de plantas analisados. A manutenção, dentre o conjunto de atividades, foi a mais significativa no plantio, fato que pode estar relacionado ao número e ao longo período para a execução das atividades. Os menores arranjos das plantas apresentaram os menos custos totais de produção, dependentes ou não da remuneração pelo uso dos capitais permanente e circulante.

Forest Site Classification in the Southern Andean Region of Ecuador: A Case Study of Pine Plantations to Collect a Base of Soil Attributes

Forest site classification adapted to the respective site conditions is one prerequisite for sustainable silviculture. This work aims to initiate the forest site classification for pine plantations in the southern Andean region of Ecuador. Forest productivity, estimated by the dominant height of 20-year-old trees (DH20), was related to data from climate, topography, and soil using 23 plots installed in pine plantations in the province of Loja. Forest site productivity was classified as: low (class C: 13.4 m), middle (class B: 16.6 m), and high (Class A: 22.3 m). Strong determinants to differentiate the forest site classes were: the short to medium term available Ca and K stocks (organic layer + mineral soil standardized to a depth of 60 cm), soil acidity, the C:N ratio, clay and sand content, forest floor thickness, altitude, and slope. The lowest forest productivity (Class C) is mainly associated with the lowest short to medium term available K and Ca stocks. Whereas, in site classes with the highest forest productivity, pines could benefit from a more active microbial community releasing N and P, since the soil pH was about 1 unit less acidic. This is supported by the lowest forest floor thickness and the narrowest C:N ratio.

The economic impact of optimising final stand density for structural saw log production on the value of the New Zealand plantation estate

Abstract Final crop stand density is an important determinant of plantation value. A relatively simple model, based on productivity indices, has recently been developed that can spatially optimise final crop stand density S opt , of the widely planted plantation species Pinus radiata D. Don for stands grown for structural grade timber. When applied to New Zealand this model shows S opt to be ca . 100 stems ha −1 higher than the current final stand densities. Using a comprehensive set of model simulations, the objectives of this research were to (i) examine the accuracy of predictions of S opt from the simple model and (ii) determine the potential economic gain of thinning structural grade regimes to optimal stand densities. Simulations included 15 combinations of the metrics Site Index and 300 Index that cover the productivity envelope occupied by New Zealand plantations and assumed a rotation age of 28 years. For each combination of Site Index and 300 Index, simulations included S opt and eight stand densities that were 200, 150, 100 and 50 stems ha −1 lower and higher than S opt . Composite financial metrics, weighted by the proportion of the plantation estate in each productivity class, showed marked increases from stand densities 200 stems ha −1 lower than S opt to S opt which levelled off above S opt . This levelling off after S opt suggests that the simple model provides an accurate estimate of S opt . Gains in gross value, net value, internal rate of return and net present value that could be realised through increasing stand density by 100 stems ha −1 were, respectively, $5183 ha −1 ($77,891–$83,074 ha −1 ), $2319 ha −1 ($28,740–$31,059 ha −1 ), 0.44% (8.05–8.49%) and $294 ha −1 ($108–$402 ha −1 ). When scaled up to the plantation estate potential gains in net and gross value that could be realised through thinning to S opt were respectively, $1.7 and $3.8B, which when discounted back to the current time equate to respective gains of $156 and $349 M.

Improving Lidar-based aboveground biomass estimation of temperate hardwood forests with varying site productivity

Accurate quantification of forest aboveground biomass (AGB) is the foundation to the responses of diverse forest ecosystems to the changing climate. Lidar-based statistical models have been used to accurately estimate AGB in large spatial extents, especially in boreal and temperate softwood forest ecosystems. However, the few available models for temperate hardwood and hardwood-dominated mixed forests are low in accuracy due both to the deliquescent growth form of hardwood trees and the strong site-to-site variations in height-diameter relationship. In this study, we established multiplicative nonlinear regression models that incorporated both lidar-derived metrics and soil-based site productivity classes (high and low productivity sites) to estimate aboveground biomass in temperate hardwood forests. The final optimized model had high accuracy (R2=0.81; RMSE=45.5Mgha−1) with reliable performance in ABG estimation by integrating relative height metrics at 75 and 70 percentiles (RH75 and RH70), canopy coverage and site productivity class. An optimized model that included an index of site productivity explained 14% more variance than the best-fit model without the term. Moreover, the relationship between AGB and lidar-based metrics was nonlinear on low productivity sites and nearly linear on high productivity sites, further indicating the importance of including direct or indirect measures of site productivity in lidar-based biomass models, particularly for those applied to temperate hardwood forests. Our new lidar-based model provides a potential framework to integrate lidar-based structural information and soil-based site productivity to improve AGB estimation in temperate hardwood forests.

Does debarking intensity during the first cork extraction affect future cork thickness?

The use of increasing debarking during the first harvest of cork oak trees ( Quercus suber L.) had no effect on the secondary cork calliper (thickness) in one of the trials and had a small negative effect in a second trial. Little evidence was found that debarking coefficient is a useful index for the management of cork oak stands. The Portuguese national legislation defines, without the support of scientific data or knowledge, maximum values of debarking coefficients (ratio of debarking height and perimeter at breast height measured over cork). For the first debarking, this value is limited to 2.0. The aim of this study was to determine the impact of increasing cork debarking coefficient on the calliper of the secondary cork extraction. Trees were located in two sites, in distinct regions characterized by low or high productivity classes. Three debarking coefficients were considered: 1.5, 2.0 and 2.5. The debarking coefficient for the first cork extraction was randomly selected for each tree. During the second debarking, a cork sample was taken from each tree. The samples were used for assessing secondary cork calliper. Differences in cork calliper were analysed using both correlation analysis and modelling approaches. Debarking intensity increase had a small negative effect on secondary cork thickness in the most inland site, while no effect was detected in the more coastal site. In our experiment, debarking intensity had a significant but small effect in one site and no effect in other sites. Debarking coefficients not only should be defined according to legal constraints but also instead should be adapted considering tree and site characteristics.

Vicious circles of gender bias, lower positions, and lower performance: Gender differences in scholarly productivity and impact.

It is often argued that female researchers publish on average less than male researchers do, but male and female authored papers have an equal impact. In this paper we try to better understand this phenomenon by (i) comparing the share of male and female researchers within different productivity classes, and (ii) by comparing productivity whereas controlling for a series of relevant covariates. The study is based on a disambiguated Swedish author dataset, consisting of 47,000 researchers and their WoS-publications during the period of 2008-2011 with citations until 2015. As the analysis shows, in order to have impact quantity does make a difference for male and female researchers alike—but women are vastly underrepresented in the group of most productive researchers. We discuss and test several possible explanations of this finding, using a data on personal characteristics from several Swedish universities. Gender differences in age, authorship position, and academic rank do explain quite a part of the productivity differences.

Fertility traits of Holstein, Brown Swiss, Simmental, and Alpine Grey cows are differently affected by herd productivity and milk yield of individual cows

Milk yield has a strong effect on fertility, but it may vary across different herds and individual cows. Therefore, the aim of this study was to assess the effects of breed and its interaction with level of milk production at the herd level (Herd-L) and at a cow-within-herd level (Cow-L) on fertility traits in dairy cattle. Data were gathered from Holstein (n = 17,688), Brown Swiss (n = 32,697), Simmental (n = 27,791), and Alpine Grey (n = 13,689) cows in northeastern Italy. The analysis was based on records from the first 3 lactations in the years 2011 to 2014. A mixed model was fitted to establish milk production levels of the various herds (Herd-L) and individual cows (Cow-L) using milk as a response variable. The interval fertility traits were interval from calving to first service, interval from first service to conception, and number of days open. The success traits were nonreturn rate at 56 d after first service, pregnancy rate at first service, and the number of inseminations. The interval from calving to first service, interval from first service to conception, and number of days open were analyzed using a Cox's proportional hazards model. The nonreturn rate at 56 d after first service, pregnancy rate at first service, and the number of inseminations were analyzed using logistic regression. There was a strong interaction between breed and productivity class at both Herd-L and Cow-L on all traits. The effects of herd and cow productivity differed from each other and differed among breeds. The dual-purpose Simmental and Alpine Grey breeds had better fertility than the specialized Holstein and Brown Swiss dairy cows; this difference is only partly attributable to different milk yields. Greater herd productivity can result in higher fertility in cows, whereas higher milk yield of individual cows within a herd results in lower fertility. These effects at both Herd-L and Cow-L are curvilinear and are stronger in dual-purpose breeds, which was more evident from low to intermediate milk yield levels than from central to high productivity classes. Disentangling the effects of milk productivity on fertility at Herd-L and Cow-L and taking the nonlinearity of response into account could lead to better modeling of populations within breed. It could also help with management-for example, in precision dairy farming of dairy and dual-purpose cattle. Moreover, assessing the fertility of various breeds and their different responses to herd and individual productivity levels could be useful in devising more profitable crossbreeding programs in different dairy systems.

Technical efficiency with multi-output, heterogeneous production: a latent class, distance function model of english football

This study combines the output distance function approach with a latent class model to estimate technical efficiency in English football in the presence of productive heterogeneity within a stochastic frontier analysis framework. The distance function approach allows the researcher to estimate technical efficiency including both on-field and off-field production, which is important in the case of English football where clubs are generally thought to maximize something other than profit. On-field production is measured using total league points, and off-field production is measured using total revenue. The data set consists of 2177 club-level observations on 88 clubs that competed in the four divisions of professional football in England over the 29-season period from 1981/82 to 2009/10. The results show evidence of three separate productivity classes in English football. As might be expected, technical efficiency estimated using the latent class model is, on average, higher than technical efficiency using an alternative method which confines heterogeneity to the intercept coefficient. Specifically, average efficiency for the sample is 87.3 and 93.2% for the random-intercept model and the latent class model respectively.

Practical assessment of soil degradation on smallholder farmers' fields in Zimbabwe: Integrating local knowledge and scientific diagnostic indicators

Crop production on smallholder farms in Southern Africa is increasingly being constrained by deteriorating land quality. Assessing soil degradation at farm-level is therefore important to enable formulation and better targeting of rehabilitation options. In this study, farmers' local indicators and scientific diagnostic parameters were combined to develop criteria for assessing soil degradation on croplands in Hwedza smallholder farming area in Eastern Zimbabwe. Farmers used common weed species, crop performance aspects and soil physical attributes to categorize arable soils into four main productivity classes: productive, moderately productive, degraded and severely degraded. Broad-leafed weeds, that included Commelina benghalensis L., Bidens pilosa L. and Leucas martinicensis (Jacq.) Ait. f., were considered as main indicators of productive soils, while grass weeds, Melinis repens (Willd.) Zizka and Eragrostis minor Host, were perceived as typifying severely degraded soils. Maize grain yields of 6 to 8scotch cartsha−1 (3 to 4tha−1) and <2scotch cartsha−1 (<1tha−1) were indicative of productive and degraded soils, respectively. Consistent with farmer criteria, broad-leafed weeds contributed most of the weed biomass on productive soils, with diversity higher on productive and moderately productive than on degraded soils. Properties of soils sampled from field productivity classes differed significantly (p<0.05) and the magnitude of the differences was also influenced by farmer resource endowment. Soil organic carbon (SOC), mineralizable nitrogen (N), available phosphorus (P), exchangeable calcium (Ca) and effective cation exchange capacity (ECEC) decreased from productive to severely degraded soils, and from resource-endowed (RG1) to resource-constrained (RG3) farms. Most of the soil properties showed a decline (negative degradation indices) when compared with uncultivated lands. Exchangeable Ca and mineralizable N showed a strong relationship with SOC (R2>0.5) across the soil productivity classes and farmer resource groups. Principal components analysis of 16 soil physico-chemical and biological properties revealed mineralizable N, microbial biomass N, exchangeable bases and available P as the most important parameters influencing soil productivity. Drawing on the relationship between weed species populations and soil properties observed in this study, a soil degradation assessment scheme is proposed for enhancing decision-making on options for rehabilitation of croplands by smallholder farmers in similar agro-ecologies in Southern Africa.

Functional Zoning of National Nature Park "Vizhnitsky" and Forest Productivity in the Zone Context

Conservation areas are an important element of natural ecosystems conservation. Objects of multifunctional purpose, in particular, national natural parks (NNP) are of particular importance because they maintain the ecological balance in the regions, preserve specificity and use of affecting ecosystems properties. One must have detailed information on the vegetation biomass and its dynamics to determine the deposited carbon stocks in forest ecosystems of a given region. Mainly biomass supply in the forests depends on forest plantations productivity. Our research aims at analyzing the current state of the NNP Vizhnitsky functional zoning and main taxation indicators affecting forest productivity (species composition, age, supply and productivity class). To ensure protection, regeneration and recreational use of natural complexes and objects of the NNP Vizhnitsky its territory is divided into such functional zones as reserve zone, regulated recreation zone, stationary recreation zone, and economic zone. Functional zones of the park are characterized by different wide woody forest-forming composition with a predominance of white fir, beech and Norway spruce. The average values of forest stands productivity class in all functional zones show high index– І-Іа. In addition, regulated recreation zone has the largest area and supply, 4992, 3 ha and 1796.75 m³ respectively. According to age distribution of the plantations in all functional zones of the park middle-aged plantations predominate, there are the least ripe and overripe plantations. Furthermore, the highest percentage of middle-aged and young stocks is in economic zone – 75.7 and 16.3% respectively. Half-ripe, ripe and overripe forest stands predominate in reserve zone – 26.0 and 3.9%. To conclude, the data obtained during the research will be used to assess the status and dynamics of bioproductivity in the functional zones of the park forests. It will contribute significantly to the preservation of the unique biodiversity of the region, as well as the solution of environmental problems in the region.

Measurement of Productivity and Liability Level of Crops

Crop productivity is the capacity of an area to produce crops; a manifestation of complex interaction of various factors of production that together determine the existing condition of the farm environment. Without proper idea of the present productivity level, effective measures for further improvement cannot be initiated. Geographers and agricultural economists have long been engrossed in measuring agricultural productivity. Here I discuss a new method of measuring crop productivity, i.e. determining crop productivity level of an area with respect to the maximum achievable productivity limit under existing conditions of the farm environment. The method also measures the productivity deficiency level of various crops which makes the selection of liable crops much more sound and logical, and is helpful to formulate both the overall and crop-specific developmental strategies. Standard classes of crop productivity, yield achievement, yield deficit and crop liability levels have been prepared separately based on their index values.

Breed of cow and herd productivity affect milk composition and modeling of coagulation, curd firming, and syneresis

Milk coagulation properties (MCP) have been widely investigated in the past using milk collected from different cattle breeds and herds. However, to our knowledge, no previous studies have assessed MCP in individual milk samples from several multi-breed herds characterized by either high or low milk productivity, thereby allowing the effects of herd and cow breed to be evaluated independently. Multi-breed herds (n=41) were classified into 2 categories based on milk productivity (high vs. low), defined according to the average milk net energy yielded daily by lactating cows. Milk samples were taken from 1,508 cows of 6 different breeds: 3 specialized dairy (Holstein-Friesian, Brown Swiss, Jersey) and 3 dual-purpose (Simmental, Rendena, Alpine Grey) breeds, and analyzed in duplicate (3,016 tests) using 2 lactodynamographs to obtain 240 curd firming (CF) measurements over 60min (1 every 15 s) for each duplicate. The 5 traditional single-point MCP (RCT, k20, a30, a45, and a60) were yielded directly by the instrument from the available CF measures. All 240 CF measures of each replicate were also used to estimate 4 individual equation parameters: RCT estimated according to curd firm change over time modeling (RCTeq), asymptotic potential curd firmness (CFP), curd firming instant rate constant (kCF), and syneresis instant rate constant (kSR) and 2 derived traits: maximum curd firmness achieved within 45min (CFmax) and time at achievement of CFmax (tmax) by curvilinear regression using a nonlinear procedure. Results showed that the effect of herd-date on traditional and modeled MCP was modest, ranging from 6.1% of total variance for k20 to 10.7% for RCT, whereas individual animal variance was the highest, ranging from 32.0% for tmax to 82.5% for RCTeq. The repeatability of MCP was high (>80%) for all traits except those associated with the last part of the lactodynamographic curve (i.e., a60, kSR, kCF, and tmax: 57 to 71%). Reproducibility, taking into account the effect of instrument, was equal to or slightly lower than repeatability. Milk samples collected in farms characterized by high productivity exhibited delayed coagulation (RCTeq: 18.6 vs. 16.3min) but greater potential curd firmness (CFP: 76.8 vs. 71.9mm) compared with milk samples collected from low-productivity herds. Parity and days in milk influenced almost all MCP. Large differences in all MCP traits were observed among breeds, both between specialized and dual-purpose breeds and within these 2 groups of breeds, even after adjusting for milk quality and yield. Milk quality and MCP of samples from Jersey cows, and coagulation time of samples from Rendena cows were better than in milk from Holstein-Friesian cows, and intermediate results were found with the other breeds of Alpine origin. The results of this study, taking into account the intrinsic limitation of this technique, show that the effects of breed on traditional and modeled MCP are much greater than the effects of herd productivity class, parity, and DIM. Moreover, the variance in individual animals is much greater than the variance in individual herds within herd productivity class. It seems that improvement in MCP depends more on genetics (e.g., breed, selection) than on environmental and management factors.

Carbon stocks and accumulation rates in Pacific Northwest forests: role of stand age, plant community, and productivity

AbstractForest ecosystems are removing significant amounts of carbon from the atmosphere. Both abiotic resource availability and biotic interactions during forest succession affect C accumulation rates and maximum C stocks. However, the timing and controls on the peak and decline in C accumulation rates as stands age, trees increase in size, and canopy gaps become prevalent are not well‐understood. Our study examines measured change in live and dead woody C pools from 8767 inventory plots on 9.1 million ha of Pacific Northwest National Forest lands to determine how the balance of tree growth, mortality, and dead wood decomposition varied by stand age, plant community type, and site productivity; and to compare the contribution of different tree sizes to C accumulation. Maximum non‐mineral soil C for old‐growth stands varied significantly by productivity class within plant community types, but on average stands accumulated 75% of maximum stocks by age 127 ± 35 yr. We did not see a decline in net primary production of wood (NPPw) with age in moderate and low‐productivity classes, but found a 33% reduction in high‐productivity classes. Mortality increased with stand age such that net change in live tree biomass, and change in total woody C, was not significantly different from zero in old‐growth stands over age 400 (0.15 ± 0.64 Mg C·ha−1·yr−1for woody C). However, significant though modest C accumulation was found in forests 200–400 yr old (0.34–0.70 Mg C·ha−1·yr−1, depending on age class). Mortality of trees &gt;100 cm diameter exceeded or equaled NPPw, but trees were growing into the larger sizes at a high‐enough rate that a net increase in large tree C was seen across the region. Although large trees accumulated C at a faster rate than small trees on an individual basis, their contribution to C accumulation rates was smaller on an area basis, and their importance relative to small trees declined in older stands compared to younger stands. In contrast to recent syntheses, our results suggest that old‐growth and large trees are important C stocks, but they play a minor role in additional C accumulation.

Did early logging or changes in disturbance regimes promote high tree densities in river red gum forests?

Density of woody plants is thought to have increased in many ecosystems in Australia since European colonisation. Globally, there has been much debate as to whether this phenomenon is driven by the process of post-disturbance recovery – whereby historical logging resulted in the replacement of large, mature trees with smaller, younger trees – or by the process of encroachment – whereby cessation of disturbance events reduced the mortality of seedlings and saplings. We examined the extent to which historical changes in forest structure are compatible with each of these models. The study was conducted in river red gum Eucalyptus camaldulensis Dehnh. floodplain forest on the River Murray at Millewa Forest, southern New South Wales. We compared ‘historical’ (~1860s) stand structure to ‘current’ structure in 45 one-hectare quadrants randomly stratified between three forest productivity classes. Historical trees were determined by stumps or stags likely to have been cut during the late 1800s. Size and position of each historical and current tree was recorded, and used to calculate stem density, basal area, canopy cover and the area of the ‘zone of influence’ (the peripheral extent of the root zone). Current stand structure was vastly different from historical structure. Stem density has increased 9-fold, from a mean of 17 (historical) to 147 (current) trees ha–1. However, basal area increased only slightly, from 13.0 to 15.3 m2 ha–1. Canopy cover increased substantially from 22.1 to 33.5% cover, as did zone of influence, from 55 to 81% cover. Evidence for both the post-disturbance recovery and encroachment hypotheses was found. The 9-fold increase in stem density between historical and current stands was attributable largely to the replacement of large trees with small trees, because basal area had increased only slightly (by 18%). However, the increase in basal area was associated with a substantial increase in canopy cover and area of the zone of influence, supporting the encroachment hypothesis. Regardless, the post-disturbance recovery hypothesis accounts for the bulk of changes in this river red gum forest.

AN ECONOMIC ANALYSIS FOR THE RE-ALLOCATION OF WINTER TOMATOES PRODUCTION IN EGYPT

land classification according to productivity is important to help decision-makers in determining the zones suitable for cultivating each crop based on its productivity, as well as making the plans for carrying out soil improvement programs. The study results showed an increase of the economic variables for winter tomatoes for both of the first period of (1991-1995) and the second period of (2009-2013). Besides, the index of the net return per feddan at current prices and fixed prices increased to reach about 408.2% and 0.407%, respectively and this increase was due to the increase in productivity and farm-gate prices. The study revealed that the total area of winter tomato after neglecting the districts cultivated during less than three years and dividing the governorates into five productive classes during the period of (2009-2013) reached about 335 thousand feddans, with a total production capacity of about 3.9 million tons. Moreover, the results showed a decrease of the area in the first, second and fifth productive classes at a decreasing change amounted to about 72.9%, 98.7% and 1.3%, respectively whereas, the area increased for both of the third and fourth productivity classes by about 188% and 171.7%, respectively. However, the effects of standard productivity on the cultivated to improve both of the third and fourth productivity classes reached about 36 tons and 21.4 tons, respectively whereas, the effects of standard productivity on the area cultivated to the deterioration of both the first, second and fifth productivity classes amounted to about -4.4, 6.8 and 0.8 tons, respectively. Finally, the study indicated that the re-allocation of resources through the distribution of the districts’ areas with lower productivity among the districts of high productivity will increase the income earned from winter tomatoes to about L.E. 6.5 million, will release an area of about 157.4 thousand feddans, and will save about 308.5 million m3 of water.

Stand Age and Productivity Control Soil Carbon Dioxide Efflux and Organic Carbon Dynamics in Poplar Plantations

Establishment of hybrid poplar (HP) plantations has been advocated as an effective method for sequestering CO2 from the atmosphere. However, how carbon (C) cycling in HP plantations changes during stand development under different soil fertility and climatic conditions is poorly understood. We studied the dynamics of soil respiration (Rs) and its heterotrophic (Rh) and autotrophic (Ra) components and soil organic C (SOC) content in HP plantations of different stand ages established on soils with different productivity (Class 1 vs. Class 3 soils) in Alberta (AB) and Ontario (ON), Canada. The Rs was the highest for AB-Class 1 (high-productivity) soils, followed by AB-Class 3 and ON-Class 3 (low-productivity) soils. Annual Rs, Rh, and Rh/Rs decreased in the first 3 yr in AB-Class 1 and 6 yr in AB-Class 3 soils after plantation establishment and increased thereafter, but they increased with stand age after plantation establishment in ON-Class 3 soils. The SOC content in the AB-Class 1, AB-Class 3, and ON-Class 3 sites decreased in the first 3, 5, and 1.5 yr, respectively, after plantation establishment and then increased, reaching the pre-establishment level after 6, 10, and 3 yr, respectively. From this first attempt to understand C cycling across multiple sites with different soil fertility levels, we conclude that stand age and soil productivity play a significant role in affecting C cycling, and such effects should be considered in regional and global C cycling models, especially when assessing the C sequestration potential of HP plantations.

Carbon accretion in unthinned and thinned young-growth forest stands of the Alaskan perhumid coastal temperate rainforest

BackgroundAccounting for carbon gains and losses in young-growth forests is a key part of carbon assessments. A common silvicultural practice in young forests is thinning to increase the growth rate of residual trees. However, the effect of thinning on total stand carbon stock in these stands is uncertain. In this study we used data from 284 long-term growth and yield plots to quantify the carbon stock in unthinned and thinned young growth conifer stands in the Alaskan coastal temperate rainforest. We estimated carbon stocks and carbon accretion rates for three thinning treatments (basal area removal of 47, 60, and 73 %) and a no-thin treatment across a range of productivity classes and ages. We also accounted for the carbon content in dead trees to quantify the influence of both thinning and natural mortality in unthinned stands.ResultsThe total tree carbon stock in naturally-regenerating unthinned young-growth forests estimated as the asymptote of the accretion curve was 484 (±26) Mg C ha−1 for live and dead trees and 398 (±20) Mg C ha−1 for live trees only. The total tree carbon stock was reduced by 16, 26, and 39 % at stand age 40 y across the increasing range of basal area removal. Modeled linear carbon accretion rates of stands 40 years after treatment were not markedly different with increasing intensity of basal area removal from reference stand values of 4.45 Mg C ha−1 year−1to treatment stand values of 5.01, 4.83, and 4.68 Mg C ha−1 year−1 respectively. However, the carbon stock reduction in thinned stands compared to the stock of carbon in the unthinned plots was maintained over the entire 100 year period of observation.ConclusionsThinning treatments in regenerating forest stands reduce forest carbon stocks, while carbon accretion rates recovered and were similar to unthinned stands. However, that the reduction of carbon stocks in thinned stands persisted for a century indicate that the unthinned treatment option is the optimal choice for short-term carbon sequestration. Other ecologically beneficial results of thinning may override the loss of carbon due to treatment. Our model estimates can be used to calculate regional carbon losses, alleviating uncertainty in calculating the carbon cost of the treatments.Electronic supplementary materialThe online version of this article (doi:10.1186/s13021-015-0035-4) contains supplementary material, which is available to authorized users.

Impacts of soil sealing on potential agriculture in Egypt using remote sensing and GIS techniques

This paper highlights the impacts of soil sealing on the agricultural soils in Nile Delta using remote sensing and GIS. The current work focuses on two aims. The first aim is to evaluate soil productivity lost to urban sprawl, which is a significant cause of soil sealing in Nile Delta. The second aim is to evaluate the Land Use and Land Cover Changes (LU LC) from 2001 to 2013 in El-Gharbia governorate as a case study. Three temporal data sets of images from two different sensors: Landsat 7 Enhanced Thematic Mapper (ETM+) with 30 m resolution acquired in 2001 and Landsat 8 acquired in 2013 with 30 m resolution, and Egypt sat acquired in 2010 with 7.8 m resolution, consequently were used. Four different supervised classification techniques (Maximum Likelihood (ML), Minimum Distance, Neural Networks (NN); and Support Vector Machine (SVM) were applied to monitor the changes of LULC in the investigated area. The results showed that the agricultural soils of the investigated area are characterized by high soil productivity depending on its chemical and physical properties. During 2010–2013, soil sealing took place on 1397 ha from the study area which characterized by soil productivity classes ranging between I and II. It is expected that the urban sprawl will be increased to 12.4% by 2020 from the study area, which means that additional 3400 ha of productive soils will be lost from agriculture. However, population growth is the most significant factor effecting urban sprawl in Nile Delta.

A semi-quantitative technique for mapping potential aquifer productivity on the national scale: example of England and Wales (UK)

The development and validation of aquifer productivity and depth-to-source maps for England and Wales are described. Aquifer productivity maps can provide valuable support for the assessment, planning and management of groundwater and renewable heat energy resources. Aquifer productivity is often mapped using geostatistical interpolation techniques such as kriging, but these techniques tend to be unsuitable for mapping at the national scale due to the high data (and time) demands. A methodology is outlined for mapping aquifer productivity at the national scale using existing national-scale data sets. Pumping test data are used to characterise the potential borehole yields that different geological formations of varying lithologies and ages can provide. Based on this analysis and using expert knowledge, the corresponding map codes on the geological map are assigned to potential productivity classes. The subsurface (concealed) extent of aquifer units is mapped from geophysical data, and together with the attributed geological map, provide the bedrock-aquifer productivity map. Drilling and pumping costs can be an important consideration when evaluating the feasibility of developing a groundwater source. Thus, a map of the approximate depth to source is developed alongside the aquifer productivity map. The maps are validated using independent data sets, and map performance is compared against performance from maps derived by random and uniform attribution. The results show that the maps successfully predict potential productivity and approximate depth to the water source, although utility of the depth-to-source map could be improved by increasing the vertical discretisation at which depth intervals are mapped.