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Using 40-year experiment data from a mono-modal rainfall area of northern Togo, we analyzed soil fertility dynamics when 2 and 3-year fallows were alternated with 3-year rotation of groundnut, cotton and sorghum. The control treatment consisted to continuous cultivate the soil in a rotation of groundnut/cotton/sorghum without fallow periods. For each rotation, two fertilisation rates were applied: no fertilisation and mineral fertiliser application during the cropping and/or the fallow periods. Yields of unfertilised crops, which averaged 1 t ha-1 during the first years of cultivation, were often nil in the long-term. In the long-term, yields of fertilised cotton and sorghum decreased by 32 and 50 %, respectively compared to the average of 2.4 and 1.6 t ha-1 obtained during the first decade of cultivation. The long-term decline in crop productivity was mitigated when fallow periods were alternated with cropping periods, and consequently there was partial compensation in terms of production for the unproductive fallowed plots. Long-term yields of fertilised cotton and sorghum in the periodically fallowed plots were 40 and 50 % higher than those in continuously cropped plots, respectively; they were 90 and 60 % higher than those in continuously cropped plots without fertilisation. Like for crop productivity, soil C, N and exchangeable Ca and Mg decreased less in periodically fallowed plots than in continuously cropped plots. The limited soil C decline when fallows were alternated with crops appears to be the consequence of no-tillage period rather than the effect of the highest C inputs to the soil.

Bioenergy crops are well known for their ability to reduce greenhouse gas emissions and increase the soil carbon stock. Although such crops are often held to be in competition with food crops and thus raise the question of current and future food security, at the same time mitigation measures are required to tackle climate change and sustain local farming communities and crop production. However, in some cases the actions envisaged for specific pedo-climatic conditions are not always economically sustainable by farmers. In this frame, energy crops with high environmental adaptability and yields, such as giant reed (Arundo donax L.), may represent an opportunity to improve farm incomes, making marginal areas not suitable for food production once again productive. In so doing, three of the 17 Sustainable Development Goals (SDGs) of the United Nations would be met, namely SDG 2 on food security and sustainable agriculture, SDG 7 on reliable, sustainable and modern energy, and SDG 13 on action to combat climate change and its impacts. In this work, the response of giant reed in the marginal areas of an agricultural district of southern Italy (Destra Sele) and expected farm incomes under climate change (2021-2050) are evaluated. The normalized water productivity index of giant reed was determined (WP; 30.1gm-2) by means of a SWAP agro-hydrological model, calibrated and validated on two years of a long-term field experiment. The model was used to estimate giant reed response (biomass yield) in marginal areas under climate change, and economic evaluation was performed to determine expected farm incomes (woodchips and chopped forage). The results show that woodchip production represents the most profitable option for farmers, yielding a gross margin 50% lower than ordinary high-input maize cultivation across the study area.

The morphological responses of seedlings of eight African provenances of Vitellaria paradoxa (Shea tree or Karite) to imposed draught stress were compared under nursery experimental conditions. The potted seedlings were subjected to three different watering regimes (87 days after sowing): no water stress (100% of the field capacity, C), moderate water stress (75% of C) and severe water stress (50% of C). Before the application of the stress, we observed genotypical differences in the morphological variables at the scale of leaves and of above-ground parts. The six-month water stress affected aerial growth: all provenances responded to drought by down-regulating growth (in height and in diameter), leaf number and area. Katawki provenance of Uganda performed relatively poorly, possibly of it being a nilotica subspecies, contrary to the others (paradoxa subspecies). There was a lack of correlation between climate of seeds origin, seed characteristics, seeds germination and survival rate of seedlings. The study confirmed the importance of leaf area in the vigor of the initial growth in this species. Thus, Tamale and Karaba provenances performed better than other West African provenances due to their larger leaf area, which was found to be a determining factor of relative growth in height at the seedling stage.

Selection of sheep with low enteric methane (CH4) emissions is a greenhouse gas (GHG) mitigation option suitable for pastoral systems. However, the effect of breeding sheep with low enteric CH4 emissions on excreta output and associated CH4 and nitrous oxide (N2O) emissions and therefore total GHG emissions are not known. The objective of the current experiments were to determine excreta output, and estimate associated GHG emissions, from progeny of low and high enteric CH4 per unit of dry matter intake (DMI) selection line sheep (CH4/DMI). The animals were fed two qualities of cut perennial ryegrass-based pasture (very mature vs. vegetative, 12 animals per CH4/DMI line) in Exp. 1 and cut pasture in two repeated seasons (autumn and winter; 15 animals per CH4/DMI line × 2 seasons) in Exp. 2. Total faecal and urine output was determined on individual animals, followed by enteric CH4 emission measurements in respiration chambers. GHG emissions from urine (N2O) and faeces (CH4 and N2O) were estimated based on New Zealand Agricultural GHG Inventory methodology. There was no interaction between CH4/DMI selection line and diet quality in Exp. 1 or seasons in Exp.2. Total daily faecal output of DM, organic matter (OM) and neutral detergent fibre (NDF; all g/d) and associated calculated faecal CH4 emissions were greater for low compared to high CH4/DMI sheep in Exp. 1 (P 4/DMI selection lines in Exp. 2. Nitrogen (N) excretion and N partitioning into urine, faeces and body retention, and calculated excreta N emissions, were mostly similar between CH4/DMI selection line sheep in both experiments. Except, faecal N output (g/d and per unit of N intake) and associated calculated direct faecal N2O-N emissions (g/d) were greater in low compared to high CH4/DMI sheep in Exp. 1 (P 4 emissions were numerically 8% less (P = 0.15) in Exp.1 and 10% less (P = 0.004) in Exp. 2 and total animal level GHG emissions (CH4 and N2O) were numerically 7% less (P = 0.21) in Exp. 1 and 8% less (P = 0.006) in Exp.2 for progeny of the low compared to the high CH4/DMI line sheep. In conclusion, the magnitude of difference in enteric CH4 (expressed as CO2-equivalent) between low and high CH4/DMI selection line sheep were still present when CH4 from faeces and N2O emissions from urine and faeces were also accounted for. The animal genetic traits were expressed independent of environmental factors, i.e. pasture quality and season.

Decreasing nutrient losses from excessive synthetic fertilizer inputs is the direct and valid way to address low nutrient use efficiency and the related environmental consequences. Here, we established a comprehensive database of nitrogen (N), phosphorus (P), and carbon (C) losses from rice paddy fields in China, which we used to evaluate fertilization-induced losses and the impact of environmental factors, and to mitigate losses by adopting alternative fertilization options and setting input thresholds. Our results showed that most N-loss pathways had exponential increases with additional N input. In average, 23.8% of the N applied was lost via NH3 (16.1%), N2O (0.3%), leaching (4.8%), and runoff (2.6%). Total P loss was approximately 2.7% of the input, composed of leaching (1.3%) and runoff (1.4%). C lost as CH4 accounted for 4.9% of the organic C input. A relative importance analysis indicated that climate or soil variation rather than fertilizer rate was the dominant factor driving N and P leaching, and CH4 emissions. Based on the sensitivity of multiple N-loss pathways to N fertilization, we propose upper thresholds for N inputs of 142–191 kg N ha−1 across four rice types, which would avoid dramatic increases in N losses. Compared to conventional chemical fertilization, alternative fertilization options had diverse performances: enhanced-efficiency N fertilizer reduced N loss rate by 7.8 percent points and the global warming potential (GWP, considering N2O and CH4 emissions) by 28.8%; combined manure and chemical N fertilizer reduced N loss rate by 9.0 percent points but increased the GWP by 56.9%; straw return had no effect on total N loss but almost doubled the GWP. Using nutrient sources most appropriate to site-specific conditions is demonstrated as a robust way to decrease nutrient losses. Setting nutrient input thresholds would also contribute to the mitigation of environmental pollution, especially in regions with poor fertilization recommendation systems.

The Authors surveyed 6 industrial chipping operations for a whole work year, collecting data about machine usage, product output, fuel consumption and chipper knife wear. Despite the challenging work conditions offered by mountain operations, industrial chipping contractors manage to achieve a high machine use, ranging from 500 to over 2,500 h year(-1). Product output varies between 18,000 and over 120,000 m(3) loose chips per year. In order to acquire enough jobs, operators may travel between 1,500 to over 20,000 km in a year. Industrial chipping contractors adopt different operational strategies to achieve their production targets, and they equip accordingly. Some operators prefer to tap smaller local areas and opt for smaller tractor-powered chippers, which are less powerful and productive than larger independent-engine units, but cheaper and capable of negotiating low-standard forest roads. Others prefer to explore larger areas and achieve higher product outputs, and they opt for larger independent-engine chippers, often mounted on trucks. Long term productivity varies with machine type: tractor-powered units produce between 40 and 50 m3 loose chips per hour, whereas larger independent-engine chippers produce between 60 and 90 m3 loose chips per hour. Specific fuel consumption is about 0.5 L diesel per m3 loose chips, regardless of chipper type. A sharp knife set can process between 200 and 1,500 m3 loose chips before getting dull. Disposable knives last longer and are cheaper to manage than standard re-usable knives. (C) 2014 Elsevier Ltd. All rights reserved.

Biochars are products that are rich in carbon obtained by pyrolysis processes that consist in introducing a biomass (such as wood or manure) in a closed container and heating it with little or no available air. This paper reports the impacts of pyrolysis parameters on biochar characteristics. A preliminary examination of the scientific literature revealed that the type of feedstock, the temperature, the heating rate and the gas flow were the major parameters influencing the biochar characteristics. This review highlights the multitude of biochars that can be made and shows the importance of characterizing them before their use in soils. Then we assess how the input of biochars in soils can affect soil parameters. A review of the literature showed modifications on: i) the physical properties of soils (i.e. the modification in soil structure and water retention), ii) the chemical properties of soils (i.e. the modification of pH, cation exchange capacity, nutrient availability, the organic matter content) and iii) the biological properties (i.e. the changes in microbial and faunal communities). All these modifications can lead to an increase in crop productivity, which confirms the value of biochars as a soil amendment. Moreover, biochars can also provide an advantage for soil remediation. Indeed, biochars efficiently reduce the bioavailability of organic and inorganic pollutants. In addition, this review focuses on a specific plant that can be used to produce biochars: Miscanthus, a non-wood rhizomatous C4 perennial grass. Miscanthus presents advantages for biochar production due to: i) its lignocellulosic content, ii) its silicon content, which can mitigate environmental stresses (notably for plants grown on contaminated sites) and iii) the greater surface area of the Miscanthus biochars compared to the biochars produced with other feedstock.

Disturbance and soil fertility are some of the main drivers influencing the dynamics of herbaceous communities. Such communities are among the most biodiverse and represent a model for introducing species-rich and low-input green systems into anthropized environments, at the same time creating opportunities for conservation and restoration. Trials were set up to evaluate the effects of compost and mowing on the dynamics of purpose-sown herbaceous vegetation, inspired by the phytocenosis spontaneously growing in the nearby rural areas. Both soil properties (organic carbon, total nitrogen content, bulk density and pH) and plant species characteristics (density, biomass, height, functional traits) were determined. Our results showed that the addition of compost countered the soil compaction process with a positive effect on soil bulk density. Irrespective of compost and mowing, the amount of carbon and nitrogen in the soil was greatly influenced by the vegetation. Early season mowing increased the Shannon index and decreased the Simpson index, while over the years, with the increase in productivity, biodiversity decreased. Compost and mowing had a species-specific effect on seed mass and plant height