276 research outputs found
Economics of Share-Cropping in Haryana (India) Agriculture
This study shows that most share -croppers are small farmers.
There is some evidence that technical efficiency is lower on
share-cropping farms. There is significant allocative inefficiency on
both share-cropping and owner-operated farms, but neither group has
definite advantage in allocating every input. Above all, there does not
seem to be any inherent inefficiencies in the "voluntary sharecropping
system". Share-croppers make intensive use of labour, and in the absence
of gainful off-farm employment opportunities, share-cropping provides
them necessary supplementary income
"Economics of Share-Cropping in Haryana (India) Agriculture" - Rejoinder
Salam [I8] raised a number of questions about my paper, and
these can be briefly summarized here. (1) Inadequate description of
sample. (2) Treatment of irrigated and unirrigated parts of a farm under
same management as separate subfarms is questionable. (3) What prices
have been used for farm products and byproducts consumed on the farm.
(4) Many heterogeneous inputs have been aggregated together. (5) How the
production expenditure presented in Table 3 has been estimated, and what
wage rates have been used in these calculations' (6) Data presented in
Table 2 and its interpretation are confusing and misleading. (7) The
explanation provided for the relatively lower use of purchased inputs on
share cropping farms (Table 5) is incorrect. (8) The estimation and
discussion of returns to scale is redundant. (9) Some of the explanatory
variables e.g. cropping intensity, number of fragments per farm, and
managerial ability have been omitted from the model. (10) Operational
size of farm is not an appropriate explanatory variable. (II) The effect
of farm size on relative economic efficiency has been overlooked. (I2)
Aggregation of gross value of output for multicrop farms is likely to
bias the results in an unknown direction, because crop composition may
not be uniform across farms, and (I3) Measurement of inputs in value
terms are affected by prevailing market imperfections
Comment on "Mechanical analog of temperature for the description of force distribution in static granular packings"
It has been proposed by Ngan [Phys. Rev. E 68, 011301 (2003)] that the
granular contact force distribution may be analytically derived by minimizing
the analog of a thermodynamic free energy, in this case consisting of the total
potential energy stored in the compressed contacts minus a particular form of
entropy weighted by a parameter. The parameter is identified as a mechanical
temperature. I argue that the particular form of entropy cannot be correct and
as a result the proposed method produces increasingly errant results for
increasing grain rigidity. This trend is evidenced in Ngan's published results
and in other numerical simulations and experiments.Comment: 4 pages, 1 figure, minor editorial correction
Effects of chemical treatments on infestation of Alternaria spp. and Fusarium spp. in correlation with technological wheat quality
In this study, the time of infestation by fungi from genus Alternaria spp. and Fusarium spp. was investigated in different stages of wheat maturity (milk, waxy, and technological maturity); the effects of different fungicides on the yield, technological properties, and content of mycotoxin DON were studied also. The results showed that Alternaria spp. attacked spike and kernel in f lowering and end-f lowering stage, as it was already known for Fusarium species. Fungicide treatment increases the yield up to 20%, test weight by 3.7%, and thousand-kernel weight up to 19.1%. High content of mycotoxin DON, above tolerable limits, was detected only in the treatment with fungicide Caramba and in untreated control
Safe food and feed through an integrated toolbox for mycotoxin management: the MyToolBox approach
There is a pressing need to mobilise the wealth of knowledge from the international mycotoxin research conductedover the past 25-30 years, and to perform cutting-edge research where knowledge gaps still exist. This knowledgeneeds to be integrated into affordable and practical tools for farmers and food processors along the chain inorder to reduce the risk of mycotoxin contamination of crops, feed and food. This is the mission of MyToolBox – a four-year project which has received funding from the European Commission. It mobilises a multi-actorpartnership (academia, farmers, technology small and medium sized enterprises, food industry and policystakeholders) to develop novel interventions aimed at achieving a significant reduction in crop losses due tomycotoxin contamination. Besides a field-to-fork approach, MyToolBox also considers safe use options ofcontaminated batches, such as the efficient production of biofuels. Compared to previous efforts of mycotoxin reduction strategies, the distinguishing feature of MyToolBox is to provide the recommended measures to theend users along the food and feed chain in a web-based MyToolBox platform (e-toolbox). The project focuseson small grain cereals, maize, peanuts and dried figs, applicable to agricultural conditions in the EU and China. Crop losses using existing practices are being compared with crop losses after novel pre-harvest interventionsincluding investigation of genetic resistance to fungal infection, cultural control (e.g. minimum tillage or cropdebris treatment), the use of novel biopesticides suitable for organic farming, competitive biocontrol treatment and development of novel modelling approaches to predict mycotoxin contamination. Research into post-harvestmeasures includes real-time monitoring during storage, innovative sorting of crops using vision-technology, novelmilling technology and studying the effects of baking on mycotoxins at an industrial scale
Force correlations and arches formation in granular assemblies
In the context of a simple microscopic schematic scalar model we study the
effects of spatial correlations in force transmission in granular assemblies.
We show that the parameters of the normalized weights distribution function,
, strongly depend on the spatial extensions,
, of such correlations. We show, then, the connections between
measurable macroscopic quantities and microscopic mechanisms enhancing
correlations. In particular we evaluate how the exponential cut-off,
, and the small forces power law exponent, , depend
on the correlation length, . If correlations go to infinity, weights are
power law distributed.Comment: 6 page
Average stresses and force fluctuations in non-cohesive granular materials
A lattice model is presented for investigating the fluctuations in static
granular materials under gravitationally induced stress. The model is similar
in spirit to the scalar q-model of Coppersmith et al., but ensures balance of
all components of forces and torques at each site. The geometric randomness in
real granular materials is modeled by choosing random variables at each site,
consistent with the assumption of cohesionless grains. Configurations of the
model can be generated rapidly, allowing the statistical study of relatively
large systems. For a 2D system with rough walls, the model generates
configurations consistent with continuum theories for the average stresses
(unlike the q-model) without requiring the assumption of a constitutive
relation. For a 2D system with periodic boundary conditions, the model
generates single-grain force distributions similar to those obtained from the
q-model with a singular distribution of q's.Comment: 18 pages, 10 figures. Uses aps,epsfig,graphicx,floats,revte
Stress and Strain in Flat Piling of Disks
We have created a flat piling of disks in a numerical experiment using the
Distinct Element Method (DEM) by depositing them under gravity. In the
resulting pile, we then measured increments in stress and strain that were
associated with a small decrease in gravity. We first describe the stress in
terms of the strain using isotropic elasticity theory. Then, from a
micro-mechanical view point, we calculate the relation between the stress and
strain using the mean strain assumption. We compare the predicted values of
Young's modulus and Poisson's ratio with those that were measured in the
numerical experiment.Comment: 9 pages, 1 table, 8 figures, and 2 pages for captions of figure
Internal states of model isotropic granular packings. I. Assembling process, geometry and contact networks
This is the first paper of a series of three, reporting on numerical
simulation studies of geometric and mechanical properties of static assemblies
of spherical beads under an isotropic pressure. Frictionless systems assemble
in the unique random close packing (RCP) state in the low pressure limit if the
compression process is fast enough, slower processes inducing traces of
crystallization, and exhibit specific properties directly related to
isostaticity of the force-carrying structure. The different structures of
frictional packings assembled by various methods cannot be classified by the
sole density. While lubricated systems approach RCP densities and coordination
number z^*~=6 on the backbone in the rigid limit, an idealized "vibration"
procedure results in equally dense configurations with z^*~=4.5. Near neighbor
correlations on various scales are computed and compared to available
laboratory data, although z^* values remain experimentally inaccessible. Low
coordination packings have many rattlers (more than 10% of the grains carry no
force), which should be accounted for on studying position correlations, and a
small proportion of harmless "floppy modes" associated with divalent grains.
Frictional packings, however slowly assembled under low pressure, retain a
finite level of force indeterminacy, except in the limit of infinite friction.Comment: 29 pages. Published in Physical Review
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