Long-term Yield Research Articles

Adaptation patterns of sixteen alfalfa (Medicago sativa L.) cultivars across contrasting environments of Algeria and implications for the crop improvement

The additive main effects and multiplicative interaction analysis was applied to assess the genotype × environment interaction (GEI) effects and stability for 4-year dry matter yield (DMY) of 16 alfalfa (Medicago sativa L.) cultivars of diversified geographic origin grown in four Algerian environments given by the combination of two water managements (rainfed and irrigated) and two evaluation sites, viz. the sub-humid location of Alger and the semi-arid, salinity-affected site of Hmadna. The analysis of variance (ANOVA) revealed significant variation among cultivars and environments (P<0.001). The GEI was significant (P<0.001) and the environment main effect had greater influence than the genotype effect on long-term yield according to ANOVA. Rainfed conditions had 41.6% and 48.5% lower yield than the irrigated ones in Alger and Hmadna, respectively. Alfalfa cropping in the semiarid location caused lower DMY than in the sub-humid one (– 38.0% under irrigated and –45.2% under rainfed conditions) and a slightly lower persistence over the 4-year period. Outstanding environment-specific cultivar responses were observed, fully justifying the large GEI effects, although the Italian cultivar Sicilian ecotype had remarkable yield stability and good mean yield. The American variety Ameristand 801S and the Moroccan landrace Erfoud 1 were the most salt-tolerant cultivars. The evaluated germplasm, and particularly some exotic cultivars, could be used as parents to breed new varieties more adapted to drought and salinity in the Mediterranean basin.

Investigation of the long-term yield of auditing for conformity with the ISO 15189:2012 quality standard in a hospital pathology laboratory

IntroductionPathology laboratories are increasingly seeking accreditation to quality standards to assure Quality of Service (QoS). However, there is little data available regarding the value of this in laboratories with well-established Quality Management Systems (QMS). Moreover, critics of accreditation claim it redirects resources toward trivial issues. Our objective was to investigate the value of auditing for conformity with the ISO 15189:2012 standard in such laboratories. Designand Methods: In total, 483 Audit-Identified Non-Conformities (AINCs) were documented within our department since transitioning to an ISO 15189:2012 compliant QMS. The potential consequences of these were assessed by three clinical laboratorians who assigned them into categories based on their likely impact. These were: Unlikely (no clear consequences); Possible (potential for poor QoS/harm); and Probable (Likely to cause poor QoS/harm). Additionally, total numbers/severity of Real-Time Non-Conformities (RTNCs) detected outside of auditing were examined to provide additional insight into the effects of accreditation on QoS. ResultsAccording to majority decision: 395 (81.8%) of AINCs were classified Unlikely, 88 (18.2%) were Possible, and none were Probable. The relative proportion of Unlikely AINCs also rose over time. Total numbers and severity of RTNCs dropped in the short-term following transition to an ISO 15189:2012 QMS, but steadily rose thereafter. ConclusionsOur data suggest auditing for conformity with ISO 15189:2012 standards may be effective in attaining accreditation, but may have diminishing returns in the long-term once the QMS is established, unless there is continual improvement in the audit process to promote better use of resources.

The effects of cropping sequence, fertilization and straw management on the yield stability of winter wheat (1986–2017) in the Broadbalk Wheat Experiment, Rothamsted, UK

AbstractThe development of resilient cropping systems with high yield stability is becoming increasingly important due to future climatic and agronomic challenges. Consequently, it is essential to compare the effects of different agronomic management practices, such as cropping sequences and nutrient supply, on the stability of crop yields. Long-term experiments are a valuable resource for investigating these effects, as they provide enough time to accurately estimate stability parameters. The objective of the current study was to compare the effects of different cropping sequencing (#1: continuous v. rotational), fertilization (#2: mineral v. organic) and straw management techniques (in the case of continuous wheat; #3: removal v. incorporation) on the yield stability of winter wheat; yield risk (the probability of yield falling below a threshold yield level) and inter-annual yield variability were used as stability indicators of the effects. Long-term yield data from the Broadbalk Wheat Experiment (Rothamsted, UK) were analysed using a mixed model. Overall, the results showed that rotational cropping combined with sufficient mineral N fertilizer, with or without organic manure, ensured stable wheat yields while reducing yield risk. In contrast, higher yield risks and inter-annual yield variabilities were found in continuous wheat sections with less mineral N fertilizer or with organic manure only.

GENERAL ANALYSIS OF LONG-TERM INTEREST RATES

We introduce here the idea of a long-term swap rate, characterized as the fair rate of an overnight indexed swap (OIS) with infinitely many exchanges. Furthermore, we analyze the relationship between the long-term swap rate, the long-term yield, (F. Biagini, A. Gnoatto & M. Härtel (2018) Affine HJM Framework on [Formula: see text] and long-term yield, Applied Mathematics and Optimization 77 (3), 405–441, F. Biagini & M. Härtel (2014) Behavior of long-term yields in a lévy term structure, International Journal of Theoretical and Applied Finance 17 (3), 1–24, N. El Karoui, A. Frachot & H. Geman (1997) A note on the behavior of long zero coupon rates in a no arbitrage framework. Working Paper. Available at Researchgate: https://www.researchgate.net/publication/5066730) , and the long-term simple rate (D. C. Brody & L. P. Hughston (2016) Social discounting and the long rate of interest, Mathematical Finance 28 (1), 306–334) as long-term discounting rate. Finally, we investigate the existence of these long-term rates in two-term structure methodologies, the Flesaker–Hughston model and the linear-rational model. A numerical example illustrates how our results can be used to estimate the nonoptional component of a CoCo bond.

Learning, Equilibrium Trend, Cycle, and Spread in Bond Yields

Some key features in the historical dynamics of U.S. Treasury bond yields – a trend in long-term yields, business cycle movements in short-term yields, and a level shift in yield spreads – pose serious challenges to existing equilibrium asset pricing models. This paper presents a new equilibrium model to jointly explain these key features. The trend is generated by learning from the stable components in GDP growth and inflation, which share similar patterns to the neutral rate of interest (r Star) and trend inflation (pi Star) estimates in the literature. Cyclical movements in yields and spreads are mainly driven by learning from the transitory components in GDP growth and inflation. The less-frequent inverted yield curves observed after the 1990s are due to the recent secular stagnation and procyclical inflation expectation.

Heterogeneity in Corporate Debt Structures and the Transmission of Monetary Policy

We study how differences in the aggregate structure of corporate debt affect the transmission of monetary policy in a panel of euro area countries. Consistent with the bank lending view of transmission, we find the cost of bank loans to rise relative to the cost of corporate bonds in response to a standard monetary policy tightening shock. The strength of this effect depends on the financing structure prevailing prior to the shock. In economies with a high initial share of bond finance, the cost of credit rises by less as firms resort to bonds as a `spare tire' to compensate for the loan supply contraction and a smaller portion of firm credit is remunerated at the loan rate. In economies with a low share of bond finance, firms face a more limited scope to replace loans with bonds and the rise in the cost of credit is reinforced by a shift in the composition of credit demand towards bank loans. As a consequence, a higher share of bond finance goes along with a weaker transmission of standard monetary policy shocks to real activity. By contrast, the transmission of monetary policy shocks to longer-term yields tends to strengthen with the share of bond finance in the economy.

The Market Stabilization Role of Central Bank Asset Purchases: High-Frequency Evidence from the COVID-19 Crisis

This paper uses confidential high-frequency data to investigate the dynamic effects on the government bond market of the central bank asset purchases carried out in Italy during the COVID-19 pandemic crisis. We find that in response to an outright purchase of long-term bonds: (i) long-term yields drop by 4 to 5 basis points per billion euros on impact and tend to remain subdued over the trading day; (ii) short- and medium-term bond yields are also strongly affected; (iii) the yield curve shifts downwards and flattens owing to a reduction in the credit and liquidity risk premia embedded in sovereign spreads; (iv) market liquidity improves steadily. We also show that: (v) the yield impact of a purchase is substantially larger in times of heightened market stress; (vi) asset purchases operate similarly and effectively in quieter times as well. These results suggest that actual purchases affect market prices over and above purchase announcements, and that adjusting their pace and composition according to market conditions can boost the overall effectiveness of a programme.

The Transmission of Euro Area Interest Rate Shocks to Asia -- Do Effects Differ When Nominal Interest Rates are Negative?

ABSTRACT This paper proposes a non-linear factor-augmented vector autoregressive model to evaluate spillovers to Asia from an unexpected rate cut in the euro area. We focus on potential asymmetries in the transmission of the shock that could arise due to prevailing negative interest rates in the euro area. Our findings indicate significant and negative effects on short-and long-term interest rates throughout selected Asian economies. While the cross-country impact on yields is quite homogeneous when the policy rate in the euro area is positive, large heterogeneity emerges when the shock occurs under a negative interest rate environment in the euro area. For several countries, the effects on Asian long-term yields are stronger, this implies that not only relative yield differentials play a role for international investors but also the absolute yield level. In this sense, negative interest rate policies can act as an amplifier of international portfolio rebalancing.

Conservation Agriculture Improves Long-term Yield and Soil Quality in Irrigated Maize-oats Rotation

Conservation agriculture, characterized by minimal tillage, permanent soil cover and crop diversification, has been widely adapted under rainfed conditions, but adoption under irrigated conditions is limited. An experiment initiated in 1997 to evaluate the level of tillage and the amount of soil cover needed for conservation agriculture to work under irrigated conditions in the highlands of San Luis Potosí, Mexico. The trial encompassed seven treatments: conventional tillage, two types of reduced tillage and permanent raised beds (PB), which are untilled, with four levels of soil cover in an irrigated rotation with maize (Zea mays L.) in the summer and fodder oats (Avena sativa L.) in the winter. Maize and oats yielded significantly more under PB than with tillage. Maize yielded on average 1.2 Mg ha−1 more in PB with the hybrid used from 1997 to 2008 and 3.9 Mg ha−1 more with the hybrid used from 2012 to 2017. Permanent raised beds generated on average $18,424 MXN ha−1 more profit than the tilled treatments and increased soil organic carbon on average 63% at 0 to 5 cm depth and 32% at 5 to 30 cm depth. The trial shows that conservation agriculture, with PB and little residue cover, is a viable and sustainable option in similar production systems.

Performance of roof-top PV systems in Germany from 2012 to 2018

The photovoltaic (PV) sector is a central pillar for the global energy transition process which aims to reach the climate change mitigation goals. Roof-mounted systems in particular can make a significant contribution to greenhouse gas-free energy generation. By the end of 2018, more than 1.5 million rooftop systems have been installed in Germany. The yield data measured by monitoring systems and provided by web-based online systems from 2012 to 2018, as well as the configuration information of 23,944 PV systems, are evaluated in this publication. Long-term indicators are derived from the spatial and temporal distribution of the yield data. The yield analysis shows a typical south-north gradient in Germany. 2018 was the year with the highest yield, 2013 the year with the lowest. The annual specific yield varies between 816 kWh/kWp in 2017 at the Baltic Sea and 1049 kWh/kWp in 2018 in Bavaria. If analysis of data evaluation is narrowed to one to two years, a deviation of five percent and more from the long-term yield can be observed. In order to obtain detailed information on the quality of PV systems, at least five years of data are required. The yield data evaluation can be used by PV system operators and owners to identify an undersupply of their PV system and to initiate countermeasures.

LEADING CULTURE IN THE SYSTEM OF BIOLOGIZATION OF AGRICULTURE

We consider the biologization of agriculture as a system for enhancing the role of the biological factor in the reproduction of soil fertility and increasing the productivity of agricultural production. Due to the unique economic and biological features, a very positive component of many parts of this system is lu-pine. Our research during 1996 -2018 on sod-podzolic sandy loamy low fertile soils of the experimental field of VNIIOU and in a number of farms in the Vladimir region on agrobiological evaluation of various varieties of annual lupine from the All-Russian Research Institute of Lupine showed that at the present stage of agricultural production development in Non-chernozem zone, which takes place in difficult eco-nomic conditions, it should be considered as the most effective universal culture with high environment-forming properties, feed production and resource-saving potential. Among varieties studied, the varieties of the narrow-leaved lupine Vityaz and Crystal have been shown to be priority. With an average long-term yield of grain of about 25 kg / ha and green mass of 400 kg / ha, they form a powerful root system that penetrates the soil profile to the parent rock, accumulating only in the arable horizon of organic dry mass up to 50 kg / ha, providing a reduction in the decrease in soil humus content, improvement of their physicochemical properties, carbon and mineral nutrition of plants in crop rotation. In addition, lupine forms about 30 kg / ha of straw, which is characterized by a narrower ratio of nitrogen to carbon than cereal straw, it can be used for fertilizer without compensating nitrogen additives. Among annual leg-umes, lupine is a priority nitrogen fixer. With a nitrogen fixation coefficient of 60-70, it accumulates up to 300 kg / ha of symbiotic nitrogen in the biomass; therefore, it is a good sideral crop in rotations and a donor crop in mixed and cover crops. For the same reason, it can be used as a phytomeliorant on soils contaminated with animal waste. Lupine has a high feed value - in seeds it accumulates 35-40% of well-digestible protein, in green mass - up to 20%.

Yields and resilience outcomes of organic, cover crop, and conventional practices in a Mediterranean climate

Adaptive management practices that maximize yields while improving yield resilience are required in the face of resource variability and climate change. Ecological intensification such as organic farming and cover cropping are lauded in some studies for fostering yield resilience, but subject to criticism in others for their low productivity. We implemented a quantitative framework to assess yield resilience, emphasizing four aspects of yield dynamics: yield, yield stability, yield resistance (i.e., the ability of systems to avoid crop failure under stressful growing conditions), and maximum yield potential. We compared the resilience of maize-tomato rotation systems after 24 years of irrigated organic, cover cropped, and conventional management in a Mediterranean climate, and identified crop-specific resilience responses of tomato and maize to three management systems. Organic management maintained tomato yields comparable to those under conventional management, while increasing yield stability and resistance. However, organic and cover cropped system resulted in 36.1% and 35.8% lower maize yields and reduced yield stability and resistance than the conventional system. Our analyses suggest that investments in ecological intensification approaches could potentially contribute to long-term yield resilience, however, these approaches need to be tailored for individual crops and systems to maximize their benefits, rather than employing one-size-fits-all approaches.

US and Chinese yield curve responses to RMB exchange rate policy shocks

Purpose Using a discrete-time version of the arbitrage-free Nelson–Siegel (AFNS) term structure model, the authors examine how yield curves in the US and China react to exchange rate policy shocks as China introduces gradual reforms to make its exchange rate regime more flexible. The paper aims to discuss this issue. Design/methodology/approach The authors characterize the specification of the discrete-time AFNS model, prove the uniqueness of the solution for model identification, perform specification analysis on its canonical form and detail the MCMC estimation method with a fast and reliable prior extraction step. Findings Model decomposition reveals that in the US yield responses, changes in risk premia for medium- to long-term yields dominate changes in yield expectation for short- to medium-term yields, indicating that the portfolio rebalancing effect due to varying risk perception is stronger than the signaling effect due to policy rate expectation. Practical implications The results are helpful in diagnosing market sentiment and exchange rate risk pricing as China further internationalizes its currency. Originality/value The methodology can be easily extended to study yield curve responses to other scenarios of policy shocks or regime changes.

41 Management effects on long-term crop yield stability in central and eastern nebraska

Abstract The sustainability and resilience of cropping systems will depend on how different management practices impact yield stability over the long-term. Here, we summarize the effects of crop rotation, tillage, crop residue removal, and nitrogen fertilizer rate on corn and soybean yield responses from several long-term research experiments maintained by the USDA-Agricultural Research Service in eastern and central Nebraska. Across all study sites, we found that yield stability is affected most by crop rotation, then tillage, then residue management, where stability can be further improved in all systems by using the optimum N fertilizer rate. While crop rotation and rotation complexity tend to have the greatest impact on long-term yield stability in the western Corn Belt, nearly all combinations of management can produce stable yields if well managed.

Long-term Yields Implied by Stochastic Discount Factor Decompositions

We use the framework developed by Christensen (2017) and Hansen and Scheinkman (2009) to study the long-term interest rates in the US and Brazil. We apply a nonparametric estimator to US and Brazilian data to identify how the yield of a long-term zero-coupon bond responds to the initial state of the economy. Using a flexible specification for the state process leads to an interesting non-linear response of the yield to changes in the initial state. As a by-product of our work, we assess the performance of Christensen's estimator using Monte Carlo simulations based on two widely adopted asset pricing models (rare disasters and habit formation).

Forecasting U.K. Yield Curve Dynamics Using Macroeconomic and Asset Pricing Factors: A No-Arbitrage Approach

We propose a no-arbitrage affine Gaussian model that links term structure dynamics to the evolution of asset pricing measures along with conventional macroeconomic and latent factors. In contrast to generic factors in FAVAR-type models, our economic factors exploit concept-specific rich data. For the U.K. economy, we find that medium and long-term yields respond more to shocks in asset pricing than real activity. The out-of-sample predictive analysis reveals that the proposed model outperforms traditional no-arbitrage affine Gaussian approaches with conventional macroeconomic and latent factors during the 2007-2010 crisis and post-crisis periods; the contribution of asset pricing measures to forecast accuracy is most pronounced at intermediate and long forecasting horizons. However, models with concept-specific factors only outperform models with generic FAVAR-type factors in the crisis and post-crisis periods, indicating that investors pay closer attention to specific sources of economic risks during periods of heightened economic uncertainty.

Do Term Premiums Matter? Transmission Via Exchange Rate Dynamics

The macroeconomic effect of term premiums is a controversial issue both theoretically and quantitatively. In this paper, we explore the possibility that term premiums affect inflation and the real economy via exchange rate dynamics. For this purpose, we construct a small open economy model with limited asset market participation, focusing on the empirical fact that uncovered interest parity (UIP) holds better for longer-term interest rate differentials. A quantitative exercise using Japanese and U.S. data shows that changes in term premiums of both Japanese and U.S. long-term yields have sizable effects on Japanese inflation rates via exchange rate dynamics.

What is multispecies MSY? A worked example from the North Sea.

The concept of an optimum yield at intermediate levels of fishing (the so called maximum sustainable yield or MSY) has been with us since the 1930s and is now enshrined in legislation as a key objective of fisheries management. The concept seems intuitively reasonable and is readily applicable to a single stock treated in isolation and assuming a constant environment. However, translating this concept into a mixed and multispecies fishery, where there are complex trade‐offs between fleets and stocks and in general no simple optimum solution, has been problematic. Here I introduce a framework for thinking about multispecies MSY in terms of an integrated risk of stock depletion and expected long‐term yield. Within this framework I consider the performance of a set of simple harvest control rules based upon a single‐limit fishing mortality rate (F) which is common to all stocks and a target biomass which is a set fraction of a stock's virgin biomass. Using a multispecies management strategy evaluation, I compare expected outcomes for a set of these harvest control rules with alternative scenarios, in which each stock has its own F based on the assessment process. I find that the simple framework can produce outcomes that are similar to those from the more sophisticated estimates of F. I therefore conclude that achieving multispecies MSY may depend more upon setting reasonable biomass targets and faithfully applying a harvest control rule approach rather than determining the best possible Fs for each stock.

Channels of US monetary policy spillovers to international bond markets

We show significant US monetary policy (MP) spillovers to international bond markets. Our methodology identifies US MP shocks as the change in short-term Treasury yields around Federal Open Market Committee meetings and traces their effects on international bond yields using panel regressions. We emphasize three main results. First, US MP spillovers to long-term yields have increased substantially after the 2007–2009 global financial crisis. Second, spillovers are large compared with the effects of other events, and at least as large as the effects of domestic MP after 2008. Third, spillovers work through different channels, concentrated in risk-neutral rates (expectations of future MP rates) for developed countries, but predominantly on term premia in emerging markets. In interpreting these findings, we provide evidence consistent with an exchange rate channel, according to which foreign central banks face a trade-off between narrowing MP rate differentials or experiencing currency movements against the US dollar. Developed countries adjust in a manner consistent with freely floating regimes, responding partially with risk-neutral rates and partially through currency adjustments. Instead, emerging countries display patterns consistent with foreign exchange interventions, which cushion the response of exchange rates but reinforce capital flows and their effects in bond yields through movements in term premia. Our results suggest that the endogenous effects of currency interventions on long-term yields should be added into the standard cost-benefit analysis of such policies.

Uncertainty Shocks, Monetary Policy and Long-Term Interest Rates

We study the relationship between monetary policy and long-term rates in a structural, general equilibrium model estimated on both macro and yields data from the United States. Regime shifts in the conditional variance of productivity shocks, or "uncertainty shocks", are an important model ingredient. First, they account for countercyclical movements in risk premia. Second, they induce changes in the demand for precautionary saving, which affects expected future real rates. Through changes in both risk-premia and expected future real rates, uncertainty shocks account for about 1/2 of the variance of long-term nominal yields over long horizons. The remaining driver of long-term yields are changes in in ation expectations induced by conventional, autoregressive shocks. Long-term in ation expectations implied by our model are in line with those based on survey data over the 1980s and 1990s, but less dogmatically anchored in the 2000s.