Effects of the second crop on maize yield and yield components in organic agriculture

The second crop use in organic agriculture is a known method of maintaining the soil tilth, soil protection against environmental deterioration, soil nutrients conservation and even the weed control. The nitrogen conservation from previous leguminose crop is even more important, especially in the organic agriculture where use of N-fertilizers is the strictly forbiden, and second crops can be used as a catch crops for nutrients in rotation prior to the crops with the high N requirement. The choice of the proper second crop has, however, been insufficiently investigated, especially for agri-environmental conditions of the Panonian agricultural area in Croatia. The second crop experiment was established in Valpovo, Croatia, in the eutric brown soil type, during the years 2005 and 2006. The aim of the experiment was to investigate the effects of different second crops and their combinations on maize (Zea mais L.) yield and yield components in organic agriculture after soybean (Glycine max L.) in crop rotation. The experimental design was set up as a CRBD in four repetitions, with soybean as a previous crop in crop rotation. The six second crop treatments were: O – Control, without second crop; WW – winter wheat (Triticum aestivum L.) second crop; RY – rye (Secale cereale L.) second crop; FP – fodder pea (Pisum arvense L.) second crop; WP – mixture of the WW and FP; and RP – mixture of RY and FP. The WW treatment had the highest second crop dry mass, whereas FP had the lowest dry mass. The highest plant density was recorded for FP, and it was higher than the RP plant density, which also had the lowest plant height. The achieved maize yields were the highest for RY, but they were not significanlty different from the O, RP, and WW treatments. However, the yield achieved by RY treatment was significantly higher than the yields recorded for WP and FP treatments. The absolute mass and hectolitre mass did not show any statistical differences among treatments

Modelling the Yield Curve: A Two Components Approach

Using parametric return autocorrelation tests and non parametric variance ratio statistics show that the UK and US short-term interest rates are unit root processes with significant mean reverting components. Congruent with this empirical evidence, we develop a new continuous time term structure model which assumes that the dynamics of the instantaneous interest rate are given by the joint effect of a (stationary) mean reverting component and a (nonstationary) martingale component. We provide a closed-form solution for the equilibrium yield curve when the temporary component is modelled as an Ornstein-Uhlenbeck process and the permanent component is modelled as an Arithmetic Brownian motion process.Term structure, Mean reversion, Random walk, Brownian motion, Variance ratio, Linear regression

QTL Mapping of Yield, Yield Components, and Morphological Traits in Rice (Oryza Sativa L.) Using SSR Marker

The experiment was aimed at identifying QTL (quantitative trait loci) controlling ten traits of yield, yield component and plant morphology of rice based on BC1F1 of IR75862-206-2-8-3-B-B-B//IR64 mapping population consisted of 115 plants. It was arranged in Completely Randomized Design with three replicates. Ninety three SSR markers spread across the twelve rice chromosomes were used to map the QTL. These markers were mostly segregated according to Mendel Law except for fourteen markers. There were eleven QTL detected in eight traits, i.e., heading date, flag leaf length, plant height, panicle length, panicle weight, seed set, weight of 100 grains, and grain weight per plant, meaning that one or two QTL were detected in each trait. These QTL were located at chromosome 2, 3, 4, 6, 11, and 12. Some QTL were located at the same chromosome even at the same location indicating the close association of the traits. It also indicated that there were common QTL which were found across genetic background and specific QTL which were found at specific genetic background. Further study was prospective for the molecular marker application in rice improvement

Yield determination in olive hedgerow orchards. I. Yield and profiles of yield components in north–south and east–west oriented hedgerows

A study of the vertical distribution of flowering and fruit set and of components of yield (fruit numbers, fruit size, and fruit oil content) was maintained for 2 years in N–S- and E–W-oriented olive hedgerows of comparable structure (row spacing 4m, hedgerow height to 2.5 m, width c. 1m) near Toledo, Spain (39.98N). Mean yield of the N–S orchard was 1854 kg oil/ha without difference between sides or years. Yield of the E–W orchard was greater in 2006, producing 2290 kg/ha, but only 1840 kg/ha in 2007, the same as the N–S orchard. The S side of the E–Worchard yielded more (59%) than the N side in 2007. In both orchards and years, most fruit was produced at 1.0–2.0m height and fruit density was the most influential component in these differences, reflecting more intense bud initiation in these upper layers. Other components that determined fruit number, fertile inflorescences, fruits per fertile inflorescence, and fruit drop were not significantly different between layers. Fruit characteristics depended on hedgerow position. In both N–S and E–W hedgerows, fruit high in the hedgerow was the largest, most mature, and with highest oil content. These differences were more marked in N–S than in E–W hedgerows. Fruit growth and development were concentrated from the middle of September until the end November. Oil content per fruit increased linearly during that period when 65% of final oil content was accumulated. Similar patterns were observed between sides. The results of yield and yield profiles are discussed in the general context of light interception. The results suggest the importance of hedgerow porosity, and distinct penetration patterns of direct-beam radiation through N–S and E–W hedgerows, as the basis for explanation of the high yield of the N side of E–W hedgerows

An assessment of wheat (Triticum aestivum L.) genotypes under saline and waterlogged compacted soil conditions, I: grain yield and yield components

A pot experiment was conducted to study effects of salinity and waterlogging under soil compaction conditions on grain yield and yield components of wheat. Treatments were arranged in a factorial layout assigned to a randomized complete design with three replications. Treatment combinations included: two sets of compaction levels, i.e. non-compacted and compacted soil; four abiotic stresses, i.e. non-saline aerobic (untreated silt loam texture soil having ECe = 3 dS m-1); saline × aerobic (S) (ECe 15 dS m-1); saline × waterlogged (S×W); and waterlogged alone (W) were applied; and two Iranian wheat genotypes i.e. Kouhdasht and Tajan. Compaction was achieved by dropping a 5 kg weight, 20 times from 70 cm height on a wooden block placed on top of soil-filled pots. In non-waterlogged treatments, soil water was maintained at 70% of available water holding capacity (AWHC). Waterlogging was achieved by maintaining water up to 110% of the soil’s AWHC for 25 days during tillering stage. Compaction significantly intensified effect of all other treatments, except waterlogging, on grain yield and yield components of wheat genotypes as compared to control. S×W caused significantly higher reduction in grain yield and yield components for both genotypes than other treatments

A yield curve perspective on uncovered interest parity

This article uses a dynamic multi-factor model of the yield curve with a rational-expectations, general-equilibrium-economy foundation to investigate the uncovered interest parity hypothesis(UIPH). The yield curve model is used to decompose the interest rate data used in the UIPH regressions into components that reflect rationally-based expectations of the cyclical and fundamental components of the underlying economy. The UIPH is not rejected based on the fundamental components of interest rates, but is soundly rejected based on the cyclical components. These results provide empirical support for suggestions in the existing theoretical literature that rationally-based interest rate and exchange rate dynamics associated with cyclical inter-linkages between the economy and financial markets may contribute materially to the UIPH puzzle

Kinetics of fat and protein secretion in dairy cattle, sheep, goats and buffaloes

The negative correlations of fat and protein concentrations and milk yield, existing in all ruminants dairy species (Oftedal, 1984; Mepham, 1987), reflect a deep mechanism regulating the respective kinetics of secretion of carrier (mainly lactose which is the major responsible for the water drawn to the milk) and of fat and protein. Whereas the correlation coefficients are low (from –0.2 to – 0.4), fat and protein daily yield and milk production are positively and strongly linked (r = 0.8÷0.9). It means that more productive animals have higher fat and protein yield, but their milk has lower concentration of these components. The aim of this work is to investigate the relationships between milk, fat and protein yield in all main ruminant dairy species by using a simple mathematical model

An Empirical Analysis of the Mexican Term Structure of Interest Rates.

We study the dynamics of the term-structure of interest rates in Mexico. Specifically, we investigate time variation in bond risk premia and the common factors that have influenced the behavior of the yield curve. We find that term-premia in government bonds appear to be time-varying. We then estimate a principal components model. We find that over 95% of the total variation in the yield curve can be explained by two factors. The first factor captures movements in the level of the yield curve, while the second one captures movements in the slope. Moreover, we find that the level factor is positively correlated with measures of long-term inflation expectations and that the slope factor is negatively correlated with the overnight interest rate.Term-Structure, Time-Varying Risk Premia, Principal Components

Study of yield components under heat stress conditions in wheat

High temperature tolerance can be characterised by measuring various plant productivity traits in different developmental stages. The present work investigated the effect of exposure to high temperature (30-35°C) at first node appearance, during early embryo development and in the grain-filling stage on the yield parameters of two winter wheat varieties. Periods of high temperature had diverse effects on wheat plants in different phenophases. The greatest differences between the various developmental stages were found for grain number, grain yield and thousand-kernel weight. Heat stress was demonstrated to have the least effect on total grain number and number of grains per spikelet on the main spike during the grain-filling period. The most pronounced reductions in the traits examined were detected when heat stress was applied during the early embryo development stage