The use of low ammonia emission equipment for slurry distribution has become mandatory in a number of countries. However, the effects of different application methods on dry matter (DM) yield, nitrogen (N) utilisation, botanical composition and forage quality are still debated. This study offers a comprehensive assessment of the effect of various slurry application methods on forage production. Slurry distribution equipment (broadcast; band-spread; trailing-shoe), as well as slurry consistency (unaltered or extra dilution), timing (immediately or delayed after preceding cut) and sward types (with or without legumes) were tested at two sites. Low-emission equipment significantly increased DM yield and N utilisation at one of the two sites. Slurry dilution proved positive for N utilisation and DM yield, while early application timing had marginal effects. Low-emission equipment had no effect on the proportion of legume species, and at one site, it had only irrelevant effects on the proportion of undesired species. Silage quality was not negatively affected by low-emission equipment but was indicated to be positively influenced by extra diluted slurry and early application. We conclude that the use of low-emission slurry distribution equipment can be advantageous in intensively managed grasslands in terms of N utilisation and yield. However, these positive effects are not guaranteed. Negative effects on forage quality are very unlikely with such equipment, provided that the general recommendations for silage production are followed. Slurry dilution is also advantageous, particularly when broadcast or band-spread equipment is used.

Grass-legume leys combine multiple agronomic benefits, several of which are associated with symbiotic nitrogen (N) fixation. However, the best combinations of legume abundance and N fertilisation to achieve high productivity at low nitrate leaching are not yet established. Nitrate leaching risk of pure grass swards (Grs), grass -legume mixtures (Mix) and pure legume swards (Leg) at a fertiliser level of either 50, 150 or 450 kg N ha-1 yr- 1 (N50, N150 and N450) was studied during two key periods: the intact ley for forage production and after tilling for subsequent winter wheat in crop rotation. The risk of nitrate leaching was determined from (i) monitoring of the nitrate concentration in the soil solution (NCSS) and (ii) the soil mineral N (SMN) content. Furthermore, the soil surface N balance was assessed by measuring N input from fertiliser and symbiosis, and N output with harvested biomass. During the period of intact plant cover, soil surface N balance of Grs swards was strongly negative at N50 and N150 with negligible NCSS and SMN. At N450, the positive N balance of Grs swards resulted in a high leaching risk after three years of cultivation (NCSS <= 13 mg NO3-N L-1 and SMN <= 20 kg N ha-1). For Mix swards, the N balance was close to zero at N50 and N150, which led to similarly low NCSS and SMN. At N450, the N balance of Mix swards was beyond zero, resulting in significantly increased NCSS and SMN (<= 30 mg NO3-N L-1 and <= 35 kg N ha-1). For Leg swards, the N balance was far beyond zero at all fertilisation levels, resulting in a leaching risk even at N50 (<= 8 mg NO3-N L-1 and <= 23 kg N ha-1). During the period following tilling the leys, SMN was similar or lower for Mix compared to Grs swards (<= 43 vs. <= 62 kg N ha-1 at N50 and N150, 72 vs. 68 kg N ha-1 at N450), while it was significantly higher for Leg swards (SMN <= 95 kg N ha-1). We conclude that grass-legume mixtures combine high yields, low fertiliser requirements, and low nitrate leaching better than either pure grass or pure legume swards. This holds true both during the period with intact plant cover and after tillage for the subsequent crop.

When slurry is applied, a great number of bacteria (e.g. clostridial spores) are spread on both the soil and forage. An experiment conducted at Agroscope Tanikon in 2013 and 2014 investigated the influence of three different slurry application techniques (broadcast, band-spread and trailingshoe) on silage quality. In both years, samples were taken of three different cuts (in 2013, pure-grass sward; in 2014, mixed grass-clover sward). The forage was pre-wilted and ensiled in laboratory silos. Besides dry matter and nutrient content, clostridial spores were also determined in the fresh forage. With the silages, in addition to the most important nutritional parameters, special focus was placed on butyric acid content, in order to determine the influence of the individual slurry application methods. Although the 2013 forage samples exhibited low counts of clostridial spores, somewhat higher clostridial spore counts were determined in 2014. Despite the low number of clostridial spores, differences were detected between the various treatments. For the two treatments 'broadcast' and 'band-spread', there were slightly higher counts for the late slurry application date than for the early date. Furthermore, there were indications of a negative influence of the thicker as opposed to the thinner slurry. Nevertheless, the correlation between the clostridial spore count in the forage and the butyric acid content in the silages was very low. The degree of pre-wilting of the forage as well as the age of the forage respectively the crude-fibre content at the time of ensiling were vital factors for silage quality.

Concerted use of legumes and of functional diversity in grassland forage systems can provide major contributions to the challenges of agricultural systems being productive yet environmental friendly. Acquisition and transformation of nitrogen (N) resources by legumes and grasses were studied in a temperate grassland experiment near Zurich (Switzerland) to investigate mechanisms driving effects of functional diversity in mixed swards and to optimise mixtures for efficient resource use.Grass-legume interactions and N availability were varied by manipulating legume percentage of the sward (0-100%) and N fertiliser application (50,150 or 450 kg of N ha(-1) year(-1)). N-15 technology quantified N derived from symbiotic (Nsym) and non-symbiotic (Nnonsym) sources.Generally, acquisition of Nsym by the entire mixture was stimulated by grasses. As a result, strong overyielding of Nsym occurred (e.g. 75 and 114% for year 1 and 2 at N150) and mixtures with only 60% and 37% legumes (year 1 and 2) already attained the same Nsym yield as pure legume stands. Legumes stimulated Nnonsym acquisition by the entire mixture, largely via increased uptake by the grass component. Thus, overyielding of Nnonsym of 31% occurred in year 1 (N150).Mutual grass-legume interactions stimulated acquisition of Nsym, acquisition of Nnonsym and efficient transformation of N into biomass compared to either monocultures. These effects of functional diversity can substantially contribute to productive and resource efficient agricultural grassland systems and were maximised in mixtures with 40-60% legumes. (C) 2010 Elsevier B.V. All rights reserved.

SummaryIncreasing plant species richness often increases biomass production in nutrient‐poor semi‐natural grasslands. If such positive diversity–productivity effects also apply to nutrient‐rich agricultural grasslands, mixtures could improve resource‐use efficiency in the vast area used for forage production. We therefore quantified the diversity–productivity effects in nutrient‐rich agricultural grasslands using four‐species grass–legume mixtures.The sown overall density and species proportions ofLolium perenne,Dactylis glomerata,Trifolium pratenseandTrifolium repenswere varied in a 3‐year field experiment to investigate the effects of species richness (1, 2, 4 species) and species proportion (0, 3, 10, 25, 40, 50, 70, 90, 100% sowing proportion) on productivity under a nitrogen fertilization of 50, 150 or 450 kg N ha−1 year−1.The four‐species mixtures reached up to twice the yield of the average of the four species’ monocultures (overyielding up to 106%), predominantly due to combining grass and legume species. Mixtures were up to 57% more productive than the most productive monoculture (transgressive overyielding). Both these diversity–productivity effects appeared across a broad range of species proportions and persisted at the two lower levels of N fertilization for 3 years.Mixtures fertilized with 50 kg N ha−1 year−1produced yields comparable to grass monocultures fertilized with 450 kg N ha−1 year−1, if the legume proportion was about 50 to 70%. Diversity–productivity effects were reduced at the highest level of N fertilization, where they virtually disappeared in the third year. Increased N fertilization also accelerated the observed general trend towardsD. glomeratadominated and legume‐poor swards.Synthesis and applications. Diversity–productivity effects led to consistent transgressive overyielding in intensively managed grasslands, suggesting a highly increased resource‐use efficiency in mixtures. Performance better than monocultures can be achieved with grass–legume mixtures that have a low number of species, across a wide range of species proportions and in nutrient‐rich conditions. Processes such as niche complementarity and positive interspecific interactions leading to diversity effects proved to be highly relevant and widely applicable for intensive forage production. Such diversity–productivity effects could allow reduced inputs of N fertilizer without loss of productivity in different grassland production systems.

Cabalzarite, Ca-M1(M2)(Mg,Al,Fe3+),((AsO4)-As-X)(2)(H2O,OH)(2), is a new mineral of the tsumcorite group occurring in altered Mn ore at the abandoned Falotta mine (Swiss Alps). Together with other arsenates, cabalzarite documents the mobility of As during the retrograde stage of the Tertiary Alpine metamorphism under lowest to sub-greenschist facies conditions. Cabalzarite crystals vary in morphology from hatchet-like to fibrous and tabular. The color is light-brownish to salmon pink or orange brown, and the average refractive index is around 1.7. Cabalzarite is chemically inhomogeneous, with the main variations occurring on the octahedral M2 site occupied by Mg, Al, Fe3+, and Mn3+.Al and Mg are the dominant M2 cations, with Al/(Al + Mg) ratios varying between 0.31 and 0.59 (92 analyses). Cabalzarite is the first member of the tsumcorite group with octahedral Mg and Al as major constituents. Single-crystal X-ray structure refinements were performed on two differ ent crystals. Cabalzarite is monoclinic, space group C2/m, Z = 2. The cell parameters for the type crystal CABA11.5, of composition (Ca1.00Sr0.02)(Al0.80Mg0.77Fe0.23Mn0.03) (Sigma 1.83)(AsO4)(2)(H2O1.26OH0.74)(2), and are a = 8.925(2) Angstrom, b = 6.143(1) Angstrom, c = 7.352(1) Angstrom, beta = 115.25(3)degrees rho(calc) = 3.73 g/cm(3). The structure of cabalzarite is isomorphic with that of tsumcorite. The site M1 (Ca) is eightfold-coordinated (6 + 2) with average M1-O = 2.549 Angstrom; M2 is octahedral with an average M2-O = 2.010 Angstrom; and the average As-O distance of the arsenate group is 1.689 Angstrom. Charge balance for the simultaneous occupation of M2 by two- and three-valent cations is achieved by H2O as well as OH contributing to the M2 coordination.

Abstract The Inorganic Crystal Structure Database (ICSD) was searched for Si-OH groups with ordered H positions leading to 31 structures with 46 Si-OH groups. The geometrical characteristics of these partly hydroxylated SiO4 tetrahedra were analyzed. Depending on the condensation of the tetrahedra, the protonization of one tetrahedral apex allows variations in Si-O bond lengths and distorts the tetrahedron. The Si-OH distance decreases with the number of bridging O atoms (Si-O-Si) from average values of 1.668 Å for orthosilicates to 1.604 Å for tetrahedra with three bridging O atoms, whereas the 〈Si-O〉 distances of the non-hydroxylated Si-O bonds remain constant at 1.62 Å. This behavior was modeled by differences in bond strength sums of the tetrahedral O atoms. In the orthosilicates, the non-hydroxylated tetrahedral apices tend to be underbonded and the O of the silanol group is overbonded to satisfy the charge requirements of Si4+. In contrast, an Si-OH bearing tetrahedron with three bridging O atoms is characterized by a more regular bond strength distribution consistent with minor bond length distortion.

The structure of mozartite, CaMn3+O[SiO3OH], was refined in space group P2(1)2(1)2(1) from X-ray single-crystal data collected at 100 K (R = 2.45%, R-w = 2.62%), 300 K (R = 2.60%, R-w = 2.68%), and 500 K (R = 2.79%, R-w = 2.81%). The Mn3+O6 octahedron shows approximately orthorhombic geometry, which is explained by a combination of a tetragonally compressed Jahn-Teller effect with lattice-induced stress. Comparison with isostructural vuagnatite, CaAl(OH)SiO4, which shows no distortions due to electronic effects, indicates that the distorted octahedral geometry in mozartite causes shifts in valence sums of the O atoms that are hydrogen bonded. As a result, the OH group in mozartite is located at the isolated SiO4 apex and is not linked to the octahedron as reported for isostructural minerals. Isostructural minerals of the adelite group with tetrahedral As5+ and V5+ exhibit a different Jahn-Teller distortion with tetragonally elongated geometry for octahedral Cu2+O6.The O-H ... O distance of < 2.5 Angstrom in mozartite is one of the shortest hydrogen bonded O ... O distances in minerals and leads to a diffuse FTIR absorption peak (stretching mode) polarized parallel to b between 1300 and 1700 cm(-1).

Kanoite, ideally MnMgSi2O6, donpeacorite (Mg,Mn)MgSi2O6, and tirodite Mn2Mg5Si8O22(OH)(2), form augen-shaped grains or clusters in an oxidized quartzite (quartz + hematite + pyrophanite + ferrian-braunite), which is the granulite-facies equivalent of a chert-hosted sedimentary manganese deposit. Mn-bearing minerals were studied by electron microprobe analysis and single-crystal X-ray methods. Pyroxenes from these rocks vary in composition between Mn0.89Mg0.89Fe0.103+Ca0.07Na0.05Si2O6 and Mn0.60Mg1.30Fe0.023+Ca0.05Na0.01Si2O6, with the Mn-rich compositions comprising clinopyroxenes (kanoite) and the Mg-rich compositions comprising orthopyroxenes (donpeacorite). Clino- and orthopyroxenes were distinguished by X-ray single-crystal methods. Two kanoite single crystals were employed for X-ray crystal-structure refinement (a = 9.725(2), b = 8.876(2), c = 5.263(1) Angstrom, beta = 108.53(2), Z = 4, space group P2(1)/c) leading to the crystal chemical formula (Mn0.02Mg0.98)(Mn0.78Mg0.15Ca0.07)Si2O6 which confirms that the studied samples are highly Mn, Mg ordered clinopyroxenes. Tirodite, with the average composition Na0.27Ca0.15Mn2.12Mg4.37Fe0.193+Al0.10 Si8.07O22(OH)(2), is a retrogressive alteration product replacing kanoite and donpeacorite either along their rims or even completely in some cases.

Abstract Nchwaningite, Mn2+2 SiO3(OH)2 · H2O, is an orthorhombic chain silicate [space group Pca21 Z = 4, a = 12.672(9), b = 7.217(3), e = 5.341(2) Å], occurring as aggregates shaped like pin cushions, together with calcite, bultfonteinite, and chlorite at N'chwaning mine, located in the Kalahari manganese field, northern Cape Province, South Africa. The aggregates consist of light brown, transparent needles, which average 1.0 × 0.1 × 0.05 mm in size. Nchwaningite is named after the mine N'chwaning II, where it was found first. Nchwaningite is biaxially negative with the refractive indices α= 1.681(2), β = 1.688(2), γ= 1.690(2), 2Vx = 54.4(4)°. The optical orientation is X = b, Y = a, Z = c. Nchwaningite has two perfect cleavages parallel to (010) and (100). The calculated density is 3.202 glcm3. The chemical composition, as determined by electron microprobe analyses, indicates minor substitutions of Mg for Mn. The crystal structure, including H positions, was solved and refined from X-ray singlecrystal data to R = 2.14%, Rw = 2.91%. The nchwaningite structure consists of double layers of laterally linked so-called truncated pyroxene-building units formed by a double chain of octahedra, topped with a Zweier single chain of Si tetrahedra. Symmetry-equivalent units are linked laterally but turned upside down. This yields a double-layer structure with H bridges linking the layers. A striking feature of the structure is that one Mn06 comer is formed by a H2O molecule. The tetrahedral chain and octahedral distortion of the new mineral is compared with pyroxenes having MnH in Ml [synthetic MnSiO3 (P21/c clinopyroxene) and johannsenite CaMn(SiO3)2]' To test a complete Ca and Mg substitution for Mn in the new nchwaningite structure type, distance least-square refinements were performed. It was found that Ca and Mg analogues would also yield reasonable interatomic distances and polyhedra.

Nchwaningite, Mn~+Si03(OH)2' H20, is an orthorhombic chain silicate [space group Pea2 Z = 4, a = 12.672(9), b = 7.217(3), e = 5.341(2) A], occurring as aggregates shaped like pin cushions, together with calcite, bultfonteinite, and chlorite at N'chwaning mine, located in the Kalahari manganese field, northern Cape Province, South Africa. The aggregates consist of light brown, transparent needles, which average 1.0 x 0.1 x 0.05 mm in size. Nchwaningite is named after the mine N'chwaning II, where it was found first. Nchwaningite is biaxially negative with the refractive indices ex= 1.681(2), fJ = 1.688(2), 'Y= 1.690(2), 2 ~ = 54.4(4)°. The optical orientation is X = b, Y = a, Z = c. Nchwaningite has two perfect cleavages parallel to (010) and (100). The calculated density is 3.202 glcm3. The chemical composition, as determined by electron microprobe analyses, indicates minor substitutions of Mg for Mn. The crystal structure, including H positions, was solved and refined from X-ray singlecrystal data to R = 2.14%, Rw = 2.91%. The nchwaningite structure consists of double layers of laterally linked so-called truncated pyroxene-building units formed by a double chain of octahedra, topped with a Zweier single chain of Si tetrahedra. Symmetry-equivalent units are linked laterally but turned upside down. This yields a double-layer structure with H bridges linking the layers. A striking feature of the structure is that one Mn06 comer is formed by a H20 molecule. The tetrahedral chain and octahedral distortion of the new mineral is compared with pyroxenes having MnH in Ml [synthetic MnSi03 (P2/e clinopyroxene) andjohannsenite CaMn(Si03)2]' To test a complete Ca and Mg substitution for Mn in the new nchwaningite structure type, distance least-square refinements were performed. It was found that Ca and Mg analogues would also yield reasonable interatomic distances and polyhedra. OCCURRENCEAND ORIGIN sedimentation of the distinct Fe and Mn formations resulted from the different conditions of solubility and preThe Kalahari manganese field is the largest continental cipitation of Fe and Mn, related to cyclic sea-level changes. Mn deposit on the Earth, located in the northern Cape Furthermore, Beukes and Gutzmer (personal communiProvince, South Africa. Three Mn layers are interbedded cation) assumed a primary precipitation of braunite towith Fe formations of the Hotazel Formation of the gether with calcium manganese carbonates, whereas Bau Transvaal Sequence. These layers cover an area of about (personal communication), using REE-data, postulated a 35 x 15 km, and the ore varies in thickness from 6 to primary MnH precipitate with braunite as a secondary 45 m, with reserves of about 1.3 billion tons (Taljaardt, product. Using trace-element profiles in the Ongeluk la1982). vas, Schuette and Cornell (1992) postulated an early alSeveral controversial theories about the primary sedi- teration of fresh andesites caused by heated sea water, mentary origin of the Mn ores exist: Beukes (1983) and leading to the precipitation of Fe and Mn. Nel et al. (1986) postulated a volcanogenic or volcano- The majority of the ore, the so-called Mamatwan type, exhalative source for Fe and Mn, related with submarine is a fine crystalline sedimentary laminated braunite and volcanism in a basin west of the Kapvaal craton. The kutnohorite lutite of relatively low grade, containing a precipitation of Fe and Mn resulted from an upwellingof maximum of -38 wt% Mn. A small portion of the ore 02-undersaturated, Fe- and Mn-rich bottom waters on is developed as coarse crystalline massive Wessels-type the shelf in a photic zone with the first O2 producers. The ore of relatively high grade with Mn contents between 42

Nchwaningite, Mn~+Si03(OH)2' H20, is an orthorhombic chain silicate (space group Pea2" Z = 4, a = 12.672(9), b = 7.217(3), e = 5.341(2) A), occurring as aggregates shaped like pin cushions, together with calcite, bultfonteinite, and chlorite at N'chwaning mine, located in the Kalahari manganese field, northern Cape Province, South Africa. The ag- gregates consist of light brown, transparent needles, which average 1.0 x 0.1 x 0.05 mm in size. Nchwaningite is named after the mine N'chwaning II, where it was found first. Nchwaningite is biaxially negative with the refractive indices ex= 1.681(2), fJ = 1.688(2), 'Y= 1.690(2), 2 ~ = 54.4(4)°. The optical orientation is X = b, Y = a, Z = c. Nchwaningite has two perfect cleavages parallel to (010) and (100). The calculated density is 3.202 glcm3. The chemical composition, as determined by electron microprobe analyses, indicates mi- nor substitutions of Mg for Mn. The crystal structure, including H positions, was solved and refined from X-ray single- crystal data to R = 2.14%, Rw = 2.91%. The nchwaningite structure consists of double layers of laterally linked so-called truncated pyroxene-building units formed by a double chain of octahedra, topped with a Zweier single chain of Si tetrahedra. Symmetry-equiv- alent units are linked laterally but turned upside down. This yields a double-layer structure with H bridges linking the layers. A striking feature of the structure is that one Mn06 comer is formed by a H20 molecule. The tetrahedral chain and octahedral distortion of the new mineral is compared with pyroxenes having MnH in Ml (synthetic MnSi03 (P2/e clinopyroxene) andjohannsenite CaMn(Si03)2)' To test a complete Ca and Mg substitution for Mn in the new nchwaningite structure type, distance least-square refinements were performed. It was found that Ca and Mg analogues would also yield reasonable interatomic distances and polyhedra.