Smallholders’ Soil Fertility Management in the Central Highlands of Ethiopia: Implications for Nutrient Stocks, Balances and Sustainability of Agroecosystems

Low agricultural productivity caused by soil degradation is a serious problem in the Ethiopian Highlands. Here, we report how differences in soil fertility management between farming systems, based either on enset (Ensete ventricosum) or on teff (Eragrostis tef) as the major crops, affect the extent of nutrient stocks, balances and ecosystem sustainability. We collected information on farmers’ resources and nutrient management practices from stratified randomly selected households in two watersheds in the Central Highlands of Ethiopia. In addition, we collected soil samples from each land use and calculated nutrient stocks, partial and full nutrient balances (N, P and K) for one cropping season. Our results show that farmers in the two farming systems manage their soils differently and that nutrient inputs were positively related to farmers’ wealth status. The watershed with the enset-based system had higher soil N and K stocks than the watershed with the teff-based system, while P stocks were not different. Management related N?and K fluxes were more negative in the teff-based system (?28 kg N ha^?1 yr^?1 and ?34 kg K ha^?1 yr^?1) than in the enset-based system (?6 kg N ha^?1 yr^?1 and ?14 kg K ha^?1 yr^?1) while P fluxes were almost neutral or slightly positive. Within the enset-based system, a strong redistribution of N, P and K took place from the meadows and cereals (negative balance) to enset (positive balances). Although in the teff-based system, N, P and K were redistributed from meadows, small cereals and pulses to maize, the latter still showed a negative nutrient balance. In contrast to nutrient balances at land use level, nutrient balances at the watershed scale masked contrasting areas within the system where nutrient oversupply and deficiencies occurred.     

Influence of anionic form on thermooxidation of TMAHP–cellulose

With the help of DTA, DTG elementary analysis of carbonized residues and ESR spectroscopy the influence of anionic form on thermooxidation of trimethylammoniumhydroxyprophyl (TMAHP)–cellulose was studied. At 300°C the percentage of carbon in carbonized residue thermolyzed in oxidative atmosphere is higher than for the sample degraded in inert atmosphere. The percentage of hydrogen decreases simultaneously. The concentration of free radicals in thermolyzed residue also increases due to the presence of oxygen. We propose that oxygen is abstracting the hydrogen atoms from polysaccharide and unpaired electrons on carbon atoms are produced. At 400°C the percentage of carbon in residues prepared at inert atmosphere is higher than for residue formed at oxidative atmosphere. Also the concentration of free radicals in thermolyzed residues obtained in inert atmosphere is greater than for those from oxidative ones. That is why suppose that at this temperature oxygen is bonded to polysaccharide residue and free radicals are terminated. From the semiquantitative DTA we can make the following sequence of samples according to their increasing thermooxidative effect: unmodified cellulose < A–HSO < A–Br^? < A–I^? < A–NO < A–H₂PO < A–CH₃COO^? < A–HCO < A–F^? < A–Cl^?1 < A–OH^p?.     

Boolean factors as a means of clustering of interestingness measures of association rules

Measures of interestingness play a crucial role in association rule mining. An important methodological problem, on which several papers appeared in the literature, is to provide a reasonable classification of the measures. In this paper, we explore Boolean factor analysis, which uses formal concepts corresponding to classes of measures as factors, for the purpose of clustering of the measures. Unlike the existing studies, our method reveals overlapping clusters of interestingness measures. We argue that the overlap between clusters is a desired feature of natural groupings of measures and that because formal concepts are used as factors in Boolean factor analysis, the resulting clusters have a clear meaning and are easy to interpret. We conduct three case studies on clustering of measures, provide interpretations of the resulting clusters and compare the results to those of the previous approaches reported in the literature.     

Invariant‐set‐based fault diagnosis in Lure systems

In this paper, we present an invariant‐set‐based method for actuator and sensor fault detection and isolation in Lure systems. The Lure plant is controlled by an observer‐based feedback tracking controller, designed for the nominal (fault‐free) system. Suitable residual signals are constructed from measurable system outputs and estimates associated with the nominal observer. Faults are diagnosed by online contrasting the residual signal trajectories against sets of values that the residuals are shown to attain under healthy or faulty operation. These values are obtained via set‐invariance analysis of the system closed‐loop trajectories. Copyright © 2013 John Wiley & Sons, Ltd.     

Differentiating seawater and groundwater sulfate attack in Portland cement mortars

The study reported in this article deals with understanding the physical, chemical and microstructural differences in sulfate attack from seawater and groundwater. Portland cement mortars were completely immersed in solutions of seawater and groundwater. Physical properties such as length, mass, and compressive strength were monitored periodically. Thermal analysis was used to study the relative amounts of phases such as ettringite, gypsum, and calcium hydroxide, and microstructural studies were conducted by scanning electron microscopy. Portland cement mortars performed better in seawater solution compared to groundwater solution. The difference in performance could be attributed to the reduction in the quantity of the expansive attack products (gypsum and ettringite). The high Cl concentration of seawater could have played an important role by binding the C₃A to form chloroaluminate compounds, such as Friedel's salt (detected in the microstructural studies), and also by lowering the expansive potential of ettringite. Furthermore, the thicker layer of brucite forming on the specimens in seawater could have afforded better protection against ingress of the solution than in groundwater.     

X-ray crystal structure of the dye 2-cyano-4-bromo-4′-N,N-diethylaminoazobenzene

The crystal structure and molecular conformation of 2-cyano-4-bromo-4′-N,N-diethylaminoazobenzene (C₁₇H₁₇N₄Br, mol. wt. = 357·2 a.m.u) has been determined from X-ray diffraction data; triclinic, P$\text{1}$ (No. 2), a = 10·132(11) Å, b = 12·216(16) Å, c = 6·966(11) Å, α = 104·21(9)°, β = 92·67(12)°, γ = 97·22(7)°, V = 826·5(9) ų, Z = 2, D_c = 1·436 g cm^?3, F(000) = 378, λ(MoKα) = 0·71069 Å, μ(MoKα) = 26·0 cm^?1. The structure was solved by the multiple solution direct method and refined by full-matrix least-squares to R = 0·059 for 1538 independent observed reflections. The azobenzene skeleton is planar to within 0·06 Å. Most significant bonding data are: NN, 1·290(8) Å; BrC, 1·866(6) Å; mean CN (azo) 1·380(8) Å; NNC, 113·6(4) and 115·3(4)°; NCC (cis relative to NN) 125·9(4)° and 126·7(4)°; NCC (trans) 116·8°(5)° and 116·1(4)°.     

Subsoil <Superscript>15</Superscript>N-N<Subscript>2</Subscript>O Concentrations in a Sandy Soil Profile After Application of <Superscript>15</Superscript>N-fertilizer

Studies on emissions of nitrous oxide (N₂O) from agricultural soils mostly focus on fluxes between the soil and the atmosphere or are limited to the atmosphere in the topsoil. However, in soils with shallow water tables, significant N₂O formation may occur closer to the groundwater. The aims of this study were (i) to determine the importance of subsoil N₂O formation in a sandy soil; and (ii) to obtain a quantitative insight in the contribution of subsoil N₂O to the overall losses of N₂O to the environment. We applied ¹⁵N labeled fertilizer at a rate of 5.22 kg ¹⁵N ha⁻¹; 50% as Ca(NO₃)₂ and 50% as NH₄Cl, on a mesic typic Haplaquod seeded with potatoes (Solanum tuberosum L.), and traced soil N₂O concentrations and fluxes over a one-year period. Throughout the year, total N₂O and the amount of ¹⁵N recovered in soil N₂O were highest in the subsoil, with a maximum concentration at 48 cm depth in mid-February of 19900 μl m⁻³ and 24 μg ¹⁵N m⁻³, respectively. The maximum concentration coincided with the highest water-filled pore space of 71%. The cumulative flux of N₂O was 446 g N₂O-N ha⁻¹, the recovery of ¹⁵N in this flux was 0.06%. During the summer, maximum fluxes followed high soil N₂O concentrations. During winter, no such relation was found. We concluded that the formation of N₂O was the highest in the subsoil, largely controlled by water-filled pore space rather than NO₃⁻ concentration or temperature. Although high subsoil N₂O concentrations did not lead to high surface fluxes of N₂O in the winter, artificial draining may lead to high indirect N₂O emissions through supersaturated drainage water.     

Efficacy of iron fortification compared to iron supplementation among Vietnamese schoolchildren

Background  

Parents of six children are facing a trial on charges of aggravated manslaughter in the care a 5 1/2 month old infant who died suddenly and neglect of their four older children for causing them to be malnourished by feeding them all an exclusively raw foods vegan diet. Both parents declined plea bargains and plan to defend themselves in court.     

Kinetic folding mechanism of PDZ2 from PTP-BL

PDZ domains represent a large family of protein-interaction modules associated with a variety of unrelated proteins with different functions. We report a complete characterization of the kinetic folding mechanism of a fluorescent variant of PDZ2 from PTP-BL, investigated under a variety of different experimental conditions. For this purpose, we engineered a fluorescent variant of this protein Y43W (called pseudo-wild-type, pWT43). The results suggest the presence of a high-energy intermediate in the folding of PDZ2, as revealed by a pronounced non-linear dependence of the unfolding rate constant on denaturant concentration. Such an intermediate may or may not be detectable depending on the experimental conditions, giving rise to apparent two-state folding under stabilizing conditions (e.g. in the presence of sodium sulfate). Interestingly, even under these conditions, three-state folding can be restored by selectively destabilizing the native-like rate-limiting barrier by one specific mutation (V44A). Finally, we show that data taken on pWT43 under different experimental conditions (e.g. different pH values from 2.1 to 8.0 or in the presence of a stabilizing salt) and also data on a site-directed conservative mutant can be rationalized in terms of a simple reaction scheme involving a single set of intermediates and transition states.     

The pheromone of the eastern tent caterpillar,Malacosoma americanum (F.) (lepidoptera,Lasiocampidae)

The pheromone system of the eastern tent caterpillar,M. americanum, has been identified as a mixture of (E,Z)-5,7-dodecadienal and the corresponding alcohol. Field data on the attractiveness of the aldehyde alone were not consistent, but mixtures of aldehyde and alcohol in varying proportions were attractive to males. Addition of small amounts ofE,Z acetate toE,Z aldehyde had no effect on male response, but larger amounts reduced trap catch. Traps baited withZ,E, E,E, orZ,Z aldehydes were not more attractive than blank traps. Pherocon IC traps fortified with extra adhesive and baited with lures consisting of 500 µg (E,Z)-5,7-dodecadienal with either 250 or 100 µg of the corresponding alcohol trapped as many as 100 males/trap/night with means of 15–20. Lures prepared from purified (94%E,Z) aldehyde and alcohol were more attractive than those prepared from unpurified (58%E,Z) materials.DeceasedMention of a company name or proprietary product does not constitute an endorsement by the U.S. Department of Agriculture.