159 research outputs found
Effect of forage crops, soil type and soil fertility on productivity and chemical composition of roughage.
Varijabilnost produktivnosti i kvaliteta kabaste stoĉne hrane od lucerke i crvene deteline posledica je, izmeĊu ostalih faktora, specifiĉnosti mineralne ishrane biljnih vrsta u razliĉitim proizvodnim uslovima, koja se ogleda u razliĉitosti usvajanja i akumulacije mineralnih materija iz zemljišta, kako u pogledu vrste, tako i koliĉine elemenata.
Cilj rada je definisanje oĉekivanih prinosa i kvaliteta na odreĊenom tipu zemljišta i nivou plodnosti, ĉime se stvaraju modeli proizvodnje kabaste stoĉne hrane, koji omogućavaju optimizaciju tehnologije gajenja u cilju intenzivnije ratarske i stoĉarske proizvodnje. Ispitivanje uticaja krmnog useva, tipa i plodnosti zemljišta na produktivnost i hemijski sastav kabaste stoĉne hrane je izvedeno sa dve biljne vrste (lucerka (Medicago sativa L.) i crvena detelina (Trifolium pratense L.)) na šest razliĉitih tipova zemljišta (ĉernozem, vertisol, eutriĉni kambisol, fluvisol, humofluvisol i humoglej) i ĉetiri klase plodnosti (niska, srednja, visoka i vrlo visoka plodnost). Uzorkovanje zemljišta i biljnog materijala je izvršeno tokom maja 2011. godine.
Prinosi zelene mase i suve materije krmnih useva iz prvog otkosa pokazali su zavisnost u odnosu na biljnu vrstu, tip i plodnost zemljišta. Crvena detelina je imala veće prinose u odnosu na lucerku, s obzirom da ima manje zahteve prema plodnosti zemljišta, te dobru produktivnost ostvaruje i na zemljištima lošijeg kvaliteta. Proseĉan prinos krmnih useva je rastao sa povećanjem plodnosti zemljišta. Najveći prinosi ostvareni su na ĉernozemu.
Kvalitet krme je bio uslovljen heterogenošću tipova zemljišta, a rastao je sa povećanjem plodnosti zemljišta. Na zemljištima povoljnijih fiziĉko-hemijskih osobina krmiva su sadrţavala više sirovih proteina, fosfora, kalijuma, kalcijuma, sumpora, molibdena, a manje celuloze i nikla. MeĊutim, na zemljištu vrlo visoke plodnosti i sadrţaj nitrata u biljkama je bio najveći. Sadrţaj većine ispitivanih elemenata, kao i nitrata, bio je veći u suvoj materiji lucerke, u odnosu na crvenu detelinu...Variability of productivity and quality of alfalfa and red clover roughage results from specificities of mineral plant nutrition in various production conditions, among other factors, i.e. different uptake and accumulation of various mineral nutrients and quantities from the soil.
The aim of this dissertation was to define the expected yields and quality on a certain soil type and fertility level, which helps develop models of roughage production in order to enable optimization of growing technology for more intensive field and fodder crops production. Analysis of forage crop type, soil type and soil fertility effect on the productivity and chemical composition of roughage was carried out on two plant species (alfalfa (Medicago sativa L.) and red clover (Trifolium pratense L.)) on six different soil types (chernozem, vertisol, eutric cambisol, fluvisol, humofluvisol and humogley) and four soil fertility classes (low, medium, high and very high). Soil and plant material were sampled in May 2011.
Yields of fresh weight and dry matter of forage crops from the first cutting depended on the plant species, soil type and soil fertility. Red clover yielded more than alfalfa, since it has lower demands towards soil fertility and reaches good productivity even on poorer soils. Forage crops average yield increased as soil fertility increased; the highest yields were reached on chernozem soil.
Forage quality was conditioned by heterogeneity of the soil types and increased as soil fertility increased. On soils with favourable physical and chemical properties forages contained more crude proteins, phosphorus, potassium, calcium, sulphur, molybdenum, but less cellulose and nickel. However, on soils with very high fertility nitrates content in plants was the highest. Content of most tested elements, including nitrates, was higher in alfalfa dry matter than in red clover..
'Return to equilibrium' for weakly coupled quantum systems: a simple polymer expansion
Recently, several authors studied small quantum systems weakly coupled to
free boson or fermion fields at positive temperature. All the approaches we are
aware of employ complex deformations of Liouvillians or Mourre theory (the
infinitesimal version of the former). We present an approach based on polymer
expansions of statistical mechanics. Despite the fact that our approach is
elementary, our results are slightly sharper than those contained in the
literature up to now. We show that, whenever the small quantum system is known
to admit a Markov approximation (Pauli master equation \emph{aka} Lindblad
equation) in the weak coupling limit, and the Markov approximation is
exponentially mixing, then the weakly coupled system approaches a unique
invariant state that is perturbatively close to its Markov approximation.Comment: 23 pages, v2-->v3: Revised version: The explanatory section 1.7 has
changed and Section 3.2 has been made more explici
Single-photon-emitting optical centers in diamond fabricated upon Sn implantation
The fabrication of luminescent defects in single-crystal diamond upon Sn
implantation and annealing is reported. The relevant spectral features of the
optical centers (emission peaks at 593.5 nm, 620.3 nm, 630.7 nm and 646.7 nm)
are attributed to Sn-related defects through the correlation of their
photoluminescence (PL) intensity with the implantation fluence. Single
Sn-related defects were identified and characterized through the acquisition of
their second-order auto-correlation emission functions, by means of
Hanbury-Brown-Twiss interferometry. The investigation of their single-photon
emission regime as a function of excitation laser power revealed that
Sn-related defects are based on three-level systems with a 6 ns radiative decay
lifetime. In a fraction of the studied centers, the observation of a blinking
PL emission is indicative of the existence of a dark state. Furthermore,
absorption dependence from the polarization of the excitation radiation with
about 45 percent contrast was measured. This work shed light on the existence
of a new optical center associated with a group-IV impurity in diamond, with
similar photo-physical properties to the already well-known Si-V and Ge-V
emitters, thus providing results of interest from both the fundamental and
applicative points of view.Comment: 10 pages, 4 figure
Equilibration, generalized equipartition, and diffusion in dynamical Lorentz gases
We prove approach to thermal equilibrium for the fully Hamiltonian dynamics
of a dynamical Lorentz gas, by which we mean an ensemble of particles moving
through a -dimensional array of fixed soft scatterers that each possess an
internal harmonic or anharmonic degree of freedom to which moving particles
locally couple. We establish that the momentum distribution of the moving
particles approaches a Maxwell-Boltzmann distribution at a certain temperature
, provided that they are initially fast and the scatterers are in a
sufficiently energetic but otherwise arbitrary stationary state of their free
dynamics--they need not be in a state of thermal equilibrium. The temperature
to which the particles equilibrate obeys a generalized equipartition
relation, in which the associated thermal energy is equal to
an appropriately defined average of the scatterers' kinetic energy. In the
equilibrated state, particle motion is diffusive
Legal regulations of dangerous and harmful substances, the problem of pesticide residues in soil
Zemljište je neobnovijivi resurs i veoma dinamičan sistem, koji obavija mnogo funkcija i pruža usluge od vitalnog značaja za Ijudske delatnosti i opstanak ekosistema. Proizvodnja zdravstveno ispravne hrane, zaštita zdravlja Ijudi, životinjskog i biljnog svijeta, nesmetanog korištenja i zaštite prirode životne sredine mogući su jedino uz zaštitu poljoprivrednog zemljista od zagađenja. Zaštita poljoprivrednog zemljišta se sprovodi zabranom, ograničavanjem i sprečavanjem od direktnog unošenja te unošenja vodem i vazduhom štetnih materija i preduzimanjem drugih mera za očuvanje i poboljšanje njegove plodnosti. U radu su navedeni ključni aspekti regulatorne politike Srbije i zemalja u okruženju sa osvrstom na direktivu EU (91/414/EEC) za postojanost poljoprivrednih pesticida (aktivnih materija) u zemljištu. U radu je predstavijen Evropski regulatorni stav za zemljište po pitanju ne-ekstrahovanih ili vezanih pesticida i njihov uticaj na životnu sredinu kao i uticaj đubrenja na vezivanje pesticida u poljoprivrednom zemljištu.The paper set out key aspects of regulatory policy of Serbia and neighboring countries with regard to the EU directive (91/414/EEC) for the stability of agricultural pesticides (active substances) in soil. This paper presents European regulatory position regarding land for non-extracted or related
pesticides and their impact on the environment and the impact of fertilization on the binding of pesticides in agricultural soil
The Diffusion of the Magnetization Profile in the XX-model
By the -algebraic method, we investigate the magnetization profile in
the intermediate time of diffusion. We observe a transition from monotone
profile to non-monotone profile. This transition is purely thermal.Comment: Accepted for publication in Phys. Rev.
Influence of CAN fertilizer and seed inoculation with NS Nitragin on glycine max plant on pseudogley soil type
Soybean [Glycine max (L.) Merr.] is the most important legume because it is an essential source of dietary protein and oil for animal feed and food production. Good soil with wellplanned program of fertilization is the main factor of soybean production. Soybean yield will be reduced when essential nutrients are deficient. Sufficient soil fertility combined with a well-planned fertilization program is a main component for high soybean production. The aim of this investigation was to estimate the effects of fertilization and seed inoculation on height of soybean plant in humid year. Two factors were tested: 1. CAN fertilization and 2. seed inoculation. Four treatments of CAN fertilization were tested: Control - 0 kg N ha-1; 50 kg N ha-1; 100 kg N ha-1 and 150 kg N ha-1. Two factors of seed inoculation (SI) were tested: Without SI and with SI. Results showed that fertilizers and seed inoculation significantly increased the values of soybean productivity. Cost effective is the application of 50 kg N ha-1 and it is recommended on the basis of this study
Nonequilibrium Steady States and Fano-Kondo Resonances in an AB Ring with a Quantum Dot
Electron transport through a strongly correlated quantum dot (QD) embedded in
an Aharonov-Bohm (AB) ring is investigated with the aid of the finite-U
slave-boson mean-field (SBMF) approach extended to nonequilibrium regime. A
nonequilibrium steady state (NESS) of the mean-field Hamiltonian is constructed
with the aid of the C*-algebraic approach for studying infinitely extended
systems. In the linear response regime, the Fano-Kondo resonances and AB
oscillations of the conductance obtained from the SBMF approach are in good
agreement with those from the numerical renormalization group technique (NRG)
by Hofstetter et al. by using twice larger Coulomb interaction. At zero
temperature and finite bias voltage, the resonance peaks of the differential
conductance tend to split into two. At low bias voltage, the split of the
asymmetric resonance can be observed as an increase of the conductance plateau.
We also found that the differential conductance has zero-bias maximum or
minimum depending on the background transmission via direct tunneling between
the electrodes.Comment: 24 pages,17 figure
Thermodyamic bounds on Drude weights in terms of almost-conserved quantities
We consider one-dimensional translationally invariant quantum spin (or
fermionic) lattices and prove a Mazur-type inequality bounding the
time-averaged thermodynamic limit of a finite-temperature expectation of a
spatio-temporal autocorrelation function of a local observable in terms of
quasi-local conservation laws with open boundary conditions. Namely, the
commutator between the Hamiltonian and the conservation law of a finite chain
may result in boundary terms only. No reference to techniques used in Suzuki's
proof of Mazur bound is made (which strictly applies only to finite-size
systems with exact conservation laws), but Lieb-Robinson bounds and exponential
clustering theorems of quasi-local C^* quantum spin algebras are invoked
instead. Our result has an important application in the transport theory of
quantum spin chains, in particular it provides rigorous non-trivial examples of
positive finite-temperature spin Drude weight in the anisotropic Heisenberg XXZ
spin 1/2 chain [Phys. Rev. Lett. 106, 217206 (2011)].Comment: version as accepted by Communications in Mathematical Physics (22
pages with 2 pdf-figures
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