Soybean Yield Gap Analysis through Front Line Demonstration in Satpura Plateau of Madhya Pradesh

Front line demonstration is an effective and appropriate tool to demonstrate recommended technologies among the farmers. Krishi Vigyan Kendra, Betul (M.P.) conducted 78 demonstrations on soybean since 2004-05 to 2009-10 in six adopted villages. The critical inputs were identified in existing production technology through farmers meeting and group discussion with the farmers. The six years data revealed that an average yield of demonstration plot was obtained 18.35 q/ha over local check (11.85 q/ha) with an additional yield of 6.5 q/ha and the increase average soybean productivity by 60.93%. The average technologies gap and technological index were observed to be 11.65 q/ha and technological index 38.33% respectively

Does the Yield Spread Predict the Output Gap in the U.S.?

Yes, but only at short horizons from 1 to 3 quarters over the full post-World War II sample. The predictive relation between the yield spread and the output gap is characterized by parameter instability. Differently from the predictive models of the yield spread for output growth, structural instability is not due to a loss of predictive ability after 1985. Rather, the predictive relation estimated on post-1985 data holds for a range of horizons larger than for pre-1985 data. I also show that the information on current monetary policy is statistically irrelevant for the prediction of the output gap over the post-1985 subsample.output gap; yield spread; predictability

Yield gap and the shares of climate and crop management in yield and yield variability of staple crops in West Africa. [O-3330b-01]

" Yield gap " (Yg) is a key concept of agricultural science for identifying the room for improvement of yields through better management of the agroecosystem. in rainfed agriculture Yg is the difference between actual yield (Ya) and the theoretical water limited yield (Yw) that would be achieved if solar radiation, temperature and precipitations were the only factor limiting the crop's growth and yield. Changes in Yw over regions and years are due to climate-soil interactions that are not easily modified by crop management, whereas changes in Yg are due to limiting factors that are typically within the scope of crop management such as nutrient availability, weeds, and pests. We provide an example of yield gap estimates in semi-arid a frica, using yield and other agronomic data collected in famers' fields of Senegal in 1990 and 1991 and from 2006 to 2012. i t illustrates how contrarily to what most people would expect climate is not, on average, what most limits yields in that region: yet, actual yields are on average a quarter of water limited yield, and this is due to constraints whose reduction is technically possible albeit subject to the economic and environmental relevance of doing so. Most studies dealing with the impact of climate change on agriculture in West a frica compare Yw under present and future climate as predicted by climate models. t he magnitude of those predicted long term changes in Yw by 2050 is down to –20% in the worst scenario combining a +6°C change with a -20% rainfall change. s uch changes in water limited yields are certainly concerning, but they are remarkably small compared to the potential +390% increase that would result from closing the current yield gap. When considering yield variations observed across plots and years, and not anymore regional averages over a few years, what strikes is the stability of observed yields compared to variations of Yw. We used crop model simulations with historical series of 20 years of weather data to compare yield distributions over years of a crop grown using 3 contrasted levels of fertilisation and no incidence of weeds, pests or diseases. For each fertilisation level, the simulated yield reached a maximum value the 'best year' of the series. t he three fertilisation levels were chosen so that the maximum simulated yield reached 0.25 Yw, 0.5 Yw, and 0.75 Yw respectively. t he resulting simulated yield distributions show that even if management allows increasing the median yield, in many years the climate is the main limiting factor and fertilising has no or a slight impact only. i n other words, the way the current climate limits crop production in this region is by making uncertain the output of investing for high yields. Buying fertilizers or working hard for manure collection, transport and distribution do not translate, a certain number of years, into more production. For farmers struggling for the daily subsistence of their family, that kind of risk may not be justified while alternative use of family resources in cash and labour force provide less risky ways to produce subsistence means. Until recently, in many farming systems of West africa, the growth in food needs due to population growth in rural areas was matched thanks to increases in cultivated or pasted areas rather than increases in crop yields or livestock pressure on land (i.e extension rather than intensification of crop or livestock activities). When rural families reached the limits of this strategy, migrations of many kinds of distance and duration became the adjustment variable to the gap between resources available from farming and population needs. T his suggests that for many, it is less risky to leave home than to intensify cropping or livestock systems. Anyway, as job opportunities for migrants from the rural zones are currently low in West african cities and elsewhere, there are legitimate concerns about the way this strategy may soon reach its limit as well. i n terms of climate change, the worst scenario for farmers of that region would be if crop intensification became even more risky under future climate than at present. t here is thus an urgent need for joint agronomic and climate research to go beyond the prediction of Yw or of yield under unchanged crop management and determine whether or not the future climate will increase the yield risks associated with crop intensification in that region. But this should not divert from designing and implementing policies incentive to such intensification under present climate, as this might be much easier now than later. (Texte intégral

Yield trends and yield gap analysis of major crops in the world

This study aims to quantify the gap between current and potential yields of major crops in the world, and the production constraints that contribute to this yield gap. Using an expert-based evaluation of yield gaps and the literature, global and regional yields and yield trends of major crops are quantified, yield gaps evaluated by crop experts, current yield progress by breeding estimated, and different yield projections compared. Results show decreasing yield growth for wheat and rice, but still high growth rates for maize. The yield gap analysis provides quantitative estimates of the production constraints for a number of crops and regions and reveals the difficulty to measure and compare yield potentials and actual yields consistently under a range of environmental conditions, and it shows the difficulty to disentangle interacting production constraints. FAO yield growth projections are generally lower than what possibly could be gained by closing current yield gaps

Analysis of a quenched lattice-QCD dressed-quark propagator

Quenched lattice-QCD data on the dressed-quark Schwinger function can be correlated with dressed-gluon data via a rainbow gap equation so long as that equation's kernel possesses enhancement at infrared momenta above that exhibited by the gluon alone. The required enhancement can be ascribed to a dressing of the quark-gluon vertex. The solutions of the rainbow gap equation exhibit dynamical chiral symmetry breaking and are consistent with confinement. The gap equation and related, symmetry-preserving ladder Bethe-Salpeter equation yield estimates for chiral and physical pion observables that suggest these quantities are materially underestimated in the quenched theory: |<bar-q q>| by a factor of two and f_pi by 30%.Comment: 9 pages, LaTeX2e, REVTEX4, 6 figure

Characterizing Topological Order in Superconducting Systems

Two established frameworks account for the onset of a gap in a superconducting system: one is based on spontaneous symmetry breaking via the Anderson-Higgs-Kibble mechanism, and the other is based on the recently developed paradigm of topological order. We show that, on manifolds with non trivial topology, both mechanisms yield a degeneracy of the ground state arising only from the {\it incompressibility} induced by the presence of a gap. We compute the topological entanglement entropy of a topological superconductor and argue that its measure allows to {\it distinguish} between the two mechanisms of generating a superconducting gap.Comment: 8 pages, no figures. To appear in Phys. Rev.

Superconducting gap and vortex lattice of the heavy fermion compound CeCu_2Si_2

The order parameter and pairing mechanism for superconductivity in heavy fermion compounds are still poorly understood. Scanning tunneling microscopy and spectroscopy at ultra-low temperatures can yield important information about the superconducting order parameter and the gap structure. Here, we study the first heavy fermion superconductor, CeCu_2Si_2. Our data show the superconducting gap which is not fully formed and exhibits features that point to a multi-gap order parameter. Spatial mapping of the zero bias conductance in magnetic field reveals the vortex lattice, which allows us to unequivocally link the observed conductance gap to superconductivity in CeCu_2Si_2. The vortex lattice is found to be predominantly triangular with distortions at fields close to \sim 0.7 H_{c2}.Comment: 6 pages, 4 figures, revised version accepted for publication in PR

Increasing paddy yields and improving farm management: results from participatory experiments with good agricultural practices (GAP) in Tanzania

Rice is an increasingly important commodity in sub-Saharan Africa. In Tanzania, the rice yield gap is as high as 87%, due to a combination of production constraints and sub-optimal crop management. Reducing this yield gap may be partly achieved through the introduction and dissemination of good agricultural practices (GAP). We conducted 18 farmer-managed on-farm trials in Tanzania, to test a set of GAP components against conventional farmers' practices (FP) for two consecutive growing seasons in 2013 and 2014. The objectives were: (1) to understand farmers' capabilities in implementing GAP; (2) to acquire better insights into the merits, relevance and suitability of individual GAP components; and (3) to provide a case study showing that exposure to good practices combined with the farmers' own experimentations can serve to improve and, trigger a positive change in the participating farmers' crop management. Compared to the farmers' own practices, average yield increases of 1 t paddy ha−1 in 2013 and 2.7 t ha−1 in 2014 were achieved when following GAP. These yield advantages were mainly obtained by a higher panicle number, improved harvest index and improved weed control. Farmers experienced difficulties with land levelling, planting or sowing in lines and using rotary weeders, but they were convinced that these technologies are important to boost their rice yields. The case of Tanzania shows that paddy yields can be substantially improved by GAP and that adoption of GAP by smallholder rice farmers can be triggered by stimulating experimentations with such practices on their own farms

Investigating the relationships between the yield curve, output and inflation using an arbitrage-free version of the Nelson and Siegel class of yield curve models

This article provides a theoretical economic foundation for the popular Nelson and Siegel (1987) class of yield curve models (which has been absent up to now). This foundation also offers a new framework for investigating and interpreting the relationships between the yield curve, output and inflation that have already been well-established empirically in the literature. Specifically, the level of the yield curve as measured by the VAO model is predicted to have a cointegrating relationship with inflation, and the shape of the yield curve as measured by the VAO model is predicted to correspond to the profile (that is, timing and magnitude) of future changes in the output gap (that is, output growth less the growth in potential output). These relationships are confirmed in the empirical analysis on 50 years of United States data