Unfavorable Years Research Articles

English

It is possible to increase nitrogen for wheat productivity by adjusting the single and fractionated dose based on the condition of the agricultural year. The objective of this work is to study the  highest  amount of nitrogen used for the production of wheat using single dose  or fractionation under favorable and unfavorable cultivation years. The study was conducted in  2012, 2013 and 2014 in Augusto Pestana, Rio Grande do Sul, Brazil. The experimental design was a randomized block in a 4 × 3 factorial scheme with four replications. It consists of N-fertilizer rates (0, 30, 60 and 120 kg ha-1), forms of supply [single (100%), growth stage V3 (third expanded sheet); fractionated (70%/30%) growth stage V3/V6 (third and sixth expanded sheet); fractionated (70%/30%) phonological stage V3/E (third expanded leaf and early grain filling)]. In favorable, intermediate and unfavorable years, wheat cultivated with single dose of nitrogen is more effective than the grain fractionated, regardless of the succession system. Nitrogen use efficiency can be substantially reduced or increased in wheat based on  the condition of the year of cultivation and the use of the optimal dose of the nutrient may not necessarily express maximum grain yield with economic efficiency.   Key words: Triticum aestivum, relation C/N, meteorological condition, simulation.

Participatory Evaluation of Maize Cultivars under Conservation Agriculture and Conventional Practice for Moisture Deficit Areas of Southern Ethiopia

Maize is the main staple food and the dominant cereal in low moisture stress areas of Boricha and Loka Abaya districts of southern Ethiopia. The objective of this study was to test the adaptability and suitability of improved maize varieties under conservation agriculture (CA) and conventional farming practice (CP) and to recommend for further use by farmers. Seven improved maize varieties of which four were hybrids and the other three were open pollinated (OPV) tested using Participatory Varietal Selection (PVS)in the first year under CP whereas in the second year all the genotypes tested were hybrid varieties in the same districts. In addition, at Hawassa on station in CP, each variety was sown on an area of 22.95 m 2 replicated three times. In the first year under CP, hybrid variety Shala gave the highest yield (3.59 t/ha), followed by the OPV Gibe2 (2.72 t/ha) under farmers’ conditions. In the second year under CA conditions, varieties Shala and SC-403 gave highest yields 3.94 and 3.87 t/ ha, respectively. In researcher managed conditions, varieties Shala, BH-543 and MHQ-138 gave highest yields 9.21, 9.08, 8.81 t/ ha, respectively and ranked from first, second and third under CP. In both seasons variety Shala ranked first in yield under CA and CP which shows the variety’s good stability in favorable and unfavorable years. This variety was also farmers’ first choices in both years and locations based on their evaluation criteria.

Nitrogen efficiency in oats on grain yield with stability

ABSTRACT Nitrogen (N) is the nutrient most absorbed by the oat crop. Unfavorable climate conditions decrease its efficiency, generating instability and reduction in yield. The objective of this study was to improve N use efficiency in oat grain yield by the economic value of the product and of the input and by models that scale the stability, considering systems of succession of high and reduced residual-N release in favorable and unfavorable years for cultivation. The study was conducted in the years 2013, 2014 and 2015 in two systems of succession (soybean/oat, maize/oat) in randomized blocks with eight replicates, using the N-fertilizer doses of 0, 30, 60 and 120 kg ha-1. The N-fertilizer dose for maximum economic efficiency in oats should be considered based on the meteorological trends of the cultivation year. N use optimization by models that determine the stability is an innovative proposal to increase fertilization efficiency on the yield. The N-fertilizer dose of 60 kg ha-1 promotes greater efficiency with predictability and yield, regardless of the agricultural year and the system of succession.

Increased drought frequency alters the optimal management strategy of an endangered plant

Many rare plant and animal species require frequent habitat disturbance to ensure population persistence, but humans often suppress or modify natural disturbance regimes, such as floods and fires, which harms disturbance-adapted species. To manage these populations, demographic models are often used to quantify the optimal disturbance frequency of the habitat. Increasing drought frequency due to climate change could alter optimal management strategies by decreasing the benefit of a recently disturbed habitat. We ask whether disturbance and drought interactively affect population dynamics and optimal management of Astragalus bibullatus, a Federally endangered legume endemic to limestone cedar glades in Tennessee. We used matrix population models to determine the independent and interactive effects of drought and management of woody canopy cover on A. bibullatus' probability of extinction, time to extinction and future population size. Under current drought frequencies, A. bibullatus' probability of extinction was minimized with the most frequent management, since open habitats promote recruitment. However, as drought frequency increases, the probability of extinction was minimized with less frequent management, since canopy cover decreased mortality of older plants during droughts. We recommend managing disturbance-dependent habitats by maintaining two types of environments; those that promote high survivorship during climatically unfavorable years, and those that promote increased reproduction and recruitment during climatically favorable years. Varying management goals across the landscape will decrease species-wide risk by preventing a single drought from harming all populations.

English

The biomass productivity and wheat grains efficiency is determined by nitrogen dose adjustment (full or fractioned), environmental conditions, and cropping system. The aim of this study was to improve the efficiency of N-fertilizer usage on wheat to maximize the biomass productivity and grain yield by adjusting the full or fractioned nitrogen dose in favorable and unfavorable year conditions, in succession systems with high and reduced N-residual release. In this study, two experiments were conducted between 2012 and 2014. One was to quantify the biomass productivity rate and another to determine grain yield. The experimental design was a complete randomized block, with four replications, in a 4 × 3 factorial scheme to N fertilizer rates (0, 30, 60 and 120 kg ha-1) and supply forms of the nutrient [full dose (100%) in the V3 phenological stage (third expanded leaf); fractioned (70 and 30%) at the V3 and V6 phenological stages (third and sixth expanded leaf, respectively) and; fractionated (70 and 30%) at the V3 and E phenological stages (third expanded leaf and early grain filling), ] respectively, in soybean/wheat and maize/wheat cultivation systems. The nitrogen supply in wheat through single dose or fraction indicates linear tendency over the productivity biomass daily rate-1 with the increase of N-fertilizer, regardless of a favorable and unfavorable year and system of a succession of the high and reduced N-residual release. However, in favorable years, the use of full dose on V3 stage is indicated. In the maize/wheat system, the full dose at V3 stage is more efficient, especially with higher doses of the nutrient. For grain yield, the N-fertilizer fractioning was adjusted in intermediate cropping years, while the full dose became suitable at the V3 stage in favorable years. However, in unfavorable years, nitrogen investments should be minimized, regardless of the supply form and succession system. Key words: Triticum aestivum L., succession system, optimization, regression.

INDO-BLIGHTCAST – a model for forecasting late blight across agroecologies

ABSTRACTA late blight forecasting model “INDO-BLIGHTCAST” has been developed at the Central Potato Research Institute, Shimla, India using meteorological data and late blight appearance dates at four locations in the Indo-Gangetic plains. The model involves computation of physiological days (P-days) and mean relative humidity (RH) of the night, accrued over seven consecutive days. Late blight was predicted to appear within 15 days if moving cumulative effective temperature (P-days) and RH exceeded 52.5 and 525, respectively for seven consecutive days. The developed model was also tested against independent data sets at three locations in the plains, two in plateau region and three in the hills. Statistical comparisons of observed and predicted dates of late blight appearance showed that the mean absolute error was 10.48, while the residual mean square error was only 13.17 indicating that the errors were quite low. The Willmott D index was 0.84 which is quite close to unity thus indicating high accuracy of model predictions and its applicability across regions and seasons. Receiver operating characteristic analysis also confirmed the superiority of this combination (accuracy of 73.6%, AUC of 0.725) to predict late blight appearance as well as its non-appearance in unfavourable years.

Weather Conditions and Yield of Wheat in Bosnia and Herzegovina with Emphasis on Climatic Change and Tuzla Canton

The aim of this study was to test the impact of monthly precipitation and temperature regimes on winter wheat yields in Bosnia and Herzegovina (BH JAERI, 7(2): 1-9, 2016; Article no.JAERI.23994 2 Precipitation close to the 30-year average (663 mm, 642 mm and 636 mm) and their balanced monthly distribution characterized three growing seasons favorable for wheat (2007/2008, 2008/2009 and 2012/2013, respectively). Also, the temperature regime was without excessive cold or warm periods in these years. Under these conditions, wheat yields were considerably higher (3.7, 3.8 and 3.9 t ha, respectively) than in three estimated unfavorable years (2002/2003, 2009/2010 and 2013/2014 with 2.3, 2.7 and 2.9 t ha, respectively). Weather deviations as either drought or excessive precipitation in combination with high temperatures characterized estimated less favorable years. Tuzla Canton had about 5% of the national wheat harvested area, whereas yields were somewhat higher compared to the country average. Although it is evident that yields of wheat and weather conditions in B&H are very different between years, by performing simple correlation analysis there was found a minimal connection of precipitation and temperature with yields. Significant negative correlations were found only in level TC between yields and monthly values of precipitation in April (-0.88**), May (-0.70**) and total precipitation (-0.73**). Also, significant positive correlations were found between April (0.76**) and May (0.62*) temperature and yields.

English

High wheat yields, besides the genetic potential and edaphoclimatic conditions, are obtained by proper management and nitrogen use. The objective of the study was to define the most appropriate time for N-fertilizer application, considering the range of greatest wheat requirements, dependent on the succession system type and the predictability of favorable and unfavorable years. The study was carried out in the 2008 to 2012 years, in Augusto Pestana, Rio Grande do Sul, Brazil. The experimental design was randomized blocks with four replications, with N-fertilizer application at 0, 10, 30 and 60 days after emergence, considering the corn/wheat and soybean/wheat succession system. The study found that the best time for nitrogen fertilizer application on wheat is mostly influenced by the year of cultivation and is less influenced by the succession system type. The appropriate time for the N-fertilizer application in favorable years of cultivation was about 45 days after emergence. In unfavorable years, it must be anticipated. Regardless of the cultivation year and the succession system type, the N-fertilization at 30 days after emergence evidenced the highest means as the most stabile grain yield. Key words: Wheat Triticum aestivum, N-fertilizer time, optimization.

Extreme climate events and individual heterogeneity shape life‐history traits and population dynamics

Extreme climatic conditions and their ecological impacts are currently emerging as critical features of climate change. We studied extreme sea ice condition (ESIC) and found it impacts both life‐history traits and population dynamics of an Antarctic seabird well beyond ordinary variability.The Southern Fulmar (Fulmarus glacialoides) is an ice‐dependent seabird, and individuals forage near the ice edge. During an extreme unfavorable year (when sea ice area is reduced and distance between ice edge and colony is high), observed foraging trips were greater in distance and duration. As a result, adults brought less food to their chicks, which fledged in the poorest body condition. During such unfavorable years, breeding success was extremely low and population growth rate (λ) was greatly reduced. The opposite pattern occurred during extreme favorable years.Previous breeding status had a strong influence on life‐history traits and population dynamics, and their responses to extreme conditions. Successful breeders had a higher chance of breeding and raising their chick successfully during the following breeding season as compared to other breeding stages, regardless of environmental conditions. Consequently, they coped better with unfavorable ESIC. The effect of change in successful breeder vital rates on λ was greater than for other stages' vital rates, except for pre‐breeder recruitment probabilities, which most affected λ.For environments characterized by ordinary sea ice conditions, interindividual differences were more likely to persist over the life of individuals and randomness in individual pathways was low, suggesting individual heterogeneity in vital rates arising from innate or acquired phenotypic traits. Additionally, unfavorable ESIC tended to exacerbate individual differences in intrinsic quality, expressed through differences in reproductive status.We discuss the strong effects of ESIC on Southern Fulmar life‐history traits in an evolutionary context. ESICs strongly affect fitness components and act as potentially important agents of natural selection of life histories related to intrinsic quality and intermittent breeding. In addition, recruitment is a highly plastic trait that, if heritable, could have a critical role in evolution of life histories. Finally, we find that changes in the frequency of extreme events may strongly impact persistence of Southern Fulmar populations.

Stay-green effects on adaptability and stability in wheat

The delayed leaf senescence (stay-green) has been frequently attributed to significant yield gains in different crops, especially under stress conditions. The goal of the study was to elucidate if the delayed leaf senescence of the wheat plant through the expression of the stay-green character brings effective contributions to adaptability and stability parameters for yield and weight of a thousand grains, aiming for genetic gains in the selection of more stable and productive genotypes. The experiment was conducted on the years 2003, 2004 and 2005 under field conditions. The experimental design was random blocks with three repetitions involving lines selected for high grain yield and distinct maturation groups (presence and absence of stay-green). The delayed leaf senescence in wheat had a strong contribution on the stability and increment in grain yield, especially in unfavorable years due to reduced precipitation. However, no changes were detected for the character weight of a thousand grains. Therefore, the introduction of the stay-green character into elite lines and cultivars represent a promising strategy for more stable and higher yielding wheat genotypes. Key words: Triticum aestivum L., delayed senescence, grain yield, weight of thousand grains.

Agricultural diversity to increase adaptive capacity and reduce vulnerability of livestock systems against weather variability – A farm-scale simulation study

Greater diversity (i.e., variety, balance and disparity) within agricultural systems is often suggested as a solution to promote redundancy within such systems and therefore increase their adaptive capacity and reduce their vulnerability against climate change and variability. Yet this assumption relies upon the gathering and integration of field- and herd-scale results at the farm scale. We have conducted a farm-scale simulation-based study to evaluate the potential for increasing adaptive capacity and reducing vulnerability of livestock systems to weather variability through increase of their agricultural diversity. We manipulate in the simulation, factors of change in the livestock systems resulting in less diverse and more diverse livestock systems to be simulated. We assume, a priori, that certain combinations of the factored system components bring redundancy in the system and in turn increase its adaptive capacity and reduce its vulnerability against weather variability. Simulated factors of change are: F1: a change in the ratio of the area mechanically harvested (vs. grazed) to the whole farm area; F2: a change in the crops and grassland types grown or in the distribution of the area between crops and/or grassland types; F3: a change in calving periods from one season to another. The simulation plan includes a baseline scenario without changes and scenarios corresponding to all possible combinations of F1–F3. These scenarios are applied to four livestock systems located on a diagonal across France over a succession of four years with varying weather conditions. In these systems, self-sufficiency for forage is jeopardized by unfavorable years, and this may increase animal feeding costs. Thus we consider that adaptive capacity increases and vulnerability decreases as long as self-sufficiency for forage is achieved without increasing animal feeding costs. Results confirm the potential for increasing adaptive capacity and reducing vulnerability of livestock systems to weather variability through increase of their agricultural diversity. For instance, F2 has three main kinds of impacts on self-sufficiency for forage: (i) it yields significant average improvements by 34%, 43%, 36% and 36% across livestock systems for the four successive years, (ii) it buffers year-to-year variations and (iii) the final level of self-sufficiency is higher than the initial one even after two years with unfavorable weather conditions. Moreover, simulated changes do not increase animal feeding costs. Thus our results provide empirical evidence at the farm scale to supplement literature reviews based on field- and herd-scale results. They also confirm that through easily implementable on-farm changes, adaptive capacity can be increased and vulnerability of agricultural systems to weather variability decreased.

Pathogen impacts on plant diversity in variable environments

Environmental variability can promote species diversity when species respond differently to environmental conditions, via the storage effect. Pathogens, predators and other shared consumers can also facilitate coexistence when they differentially limit common species. However, it remains unclear how environmental variation and consumers interact to determine species diversity. Here, I use a model based on California annual grassland plants to show that a generalist pathogen with no host specificity can enhance the positive effect of environmental variability on diversity. The model predicts that pathogens can promote diversity by increasing the covariance between the environment and competition, enhancing the storage effect. However, pathogen impacts depend on life history. Pathogens that infect germinating seeds or plants tend to increase the storage effect, whereas those that infect dormant seeds can undermine the storage effect by eliminating population buffering during unfavorable years. These results suggest that pathogens may mediate plant responses to environmental variability and change, and in doing so may maintain diversity.

Hatching response to temperature along a latitudinal gradient by the fairy shrimp Branchinecta lindahli (Crustacea; Branchiopoda; Anostraca) in culture conditions

Branchinecta lindahli is a broadly distributed fairy shrimp, reported from a range of temporary wetland habitat types in arid western North America. This species’ eggs hatch after the habitat dries, refills from seasonal rain, and receives a strong cold shock during the winter low temperatures. I studied phenotypic variation in temperature responses in cultures collected from four populations across 8° of latitude with low average temperatures ranging from -8 to 8°C. Time to maturation, mature body size and first clutch size decreased, as temperature increased, with only minor body size variability at mortality, regardless of culture origin. No variation in individual egg size was observed, demonstrating that body size is sacrificed to produce at least a few normal eggs during unfavourable years. Latitudinal variation in hatching temperature demonstrated a pattern of adaptive significance, with some overlap between regional temperature hatching cues. Phenotypic hatching temperature and growth rate responses may cause genetic segregation, selecting one cohort for warmer, dryer years and one cohort for cooler, wetter years. Drier year selected cohorts can exploit habitats that have shorter hydroperiods even in wet years. This may lead to population specialisation and speciation by adapting to more extreme habitats

Adaptability of winter cereals and their varieties to abiotic winter ffactors

The studies have determined frost resistance and winter hardiness levels of current varieties of winter cereals, revealed their association with geographical origin of the varieties. The relations between winter cereals were defined by the value of variety winter hardiness, and the levels of their kinship were established on this basis.The necessity of screening of frost resistance of winter varieties under controlled conditions, which allows restricting the introduction of varieties with insufficient frost resistance in agricultural production, prevents considerable financial loss of enterprises due to winter-killing of crops, and increases the production efficiency of winter cereals, was proved.It is recommended to involve winter rye varieties and hybrids in the production and expand the area under this culture, which will provide secured overwintering of winter crops even in weather unfavorable years and will help stabilize the grain balance and food security of the country.

Sustainability of sunflower cultivation for biodiesel production in central Italy according to the Renewable Energy Directive methodology

The use of renewable energies as alternative to fossil fuels has value from different points of view and has effects at environmental, social and economic level. These aspects are often connected to each other and together define the overall sustainability of bioenergy. At European level, the Directive 2009/28/EC gives the basic criteria for the estimation of sustainability of biofuels and indicates a minimum threshold of 35% of greenhouse gas saving for a biofuel in order to be considered sustainable. The Directive gives the possibility to identify standard regional values for the cultivation steps that could be utilized for the certification. This paper aims to give a contribution to the definition of these values considering the RED methodology applied to the sunflower cropped in central Italy which is characterized by a hilly landscape and not-irrigated crops. To determine input and output of sunflower cultivation in the central Italy, the results of PROBIO project, carried out by the Authors, were used. The sustainability of biodiesel produced from sunflower grown in central Italy is variable and depends on the nitrogen input and seasonal climatic conditions that affect the yields. The greenhouse gases savings of the Italian chain is 40% in average, greater than the required 35% and would be possible to assign this value as standard to the biofuel chain <em>biodiesel from sunflower cultivated in central Italy</em>. Using an averaged regional standard value guards against the possibility of considering unsustainable harvesting in unfavourable years and seeing it overestimated in the favourable ones.

Growth and carbon isotopes of Mediterranean trees reveal contrasting responses to increased carbon dioxide and drought

Forest dynamics will depend upon the physiological performance of individual tree species under more stressful conditions caused by climate change. In order to compare the idiosyncratic responses of Mediterranean tree species (Quercus faginea, Pinus nigra, Juniperus thurifera) coexisting in forests of central Spain, we evaluated the temporal changes in secondary growth (basal area increment; BAI) and intrinsic water-use efficiency (iWUE) during the last four decades, determined how coexisting species are responding to increases in atmospheric CO2 concentrations (C(a)) and drought stress, and assessed the relationship among iWUE and growth during climatically contrasting years. All species increased their iWUE (ca. +15 to +21%) between the 1970s and the 2000s. This increase was positively related to C(a) for J. thurifera and to higher C(a) and drought for Q. faginea and P. nigra. During climatically favourable years the study species either increased or maintained their growth at rising iWUE, suggesting a higher CO2 uptake. However, during unfavourable climatic years Q. faginea and especially P. nigra showed sharp declines in growth at enhanced iWUE, likely caused by a reduced stomatal conductance to save water under stressful dry conditions. In contrast, J. thurifera showed enhanced growth also during unfavourable years at increased iWUE, denoting a beneficial effect of C(a) even under climatically harsh conditions. Our results reveal significant inter-specific differences in growth driven by alternative physiological responses to increasing drought stress. Thus, forest composition in the Mediterranean region might be altered due to contrasting capacities of coexisting tree species to withstand increasingly stressful conditions.

The North Atlantic Oscillation affects the quality of Cava (Spanish sparkling wine)

This study explores the possible effects of the North Atlantic Oscillation (NAO) on the quality of Spanish Cava. We found a significant negative relationship between the mean NAO for the months of March through August of each year between 1970 and 2008 and the probability of obtaining a top quality Cava. The NAO is associated with temperature and rainfall variations in the Cava region, which affect vine physiological processes during grape maturity. The probability of obtaining a top quality Cava was highest when the mean value of the NAO was negative, which causes the mean temperature in the Cava area to decrease, with positive consequences on Cava quality. Although the overall discrimination capacity and explanatory power of the model were low, 80% of clearly favorable years were classified correctly as corresponding to top quality Cava, and 70% of clearly unfavorable years were classified correctly as non top quality Cava.

Climate effects on productivity and resource-use efficiency of Norway spruce (Picea abies [L.] Karst.) and European beech (Fagus sylvatica [L.]) in stands with different spatial mixing patterns

Species mixing is widely held to stabilize productivity, increase resilience and contribute to risk minimization in forest stands in need of special as a result of longevity. However, research on the effects of mixing on productivity and resource consumption so far yielded fairly incoherent results rather than general findings. We focused on the effects of the spatial mixing pattern and the annual climate conditions on the mixing effect, which to date have seldom been considered as modifiers of mixing effects. Nine years of intensive survey of four pure stands of Norway spruce (Picea abies [L.] Karst.) and European beech (Fagus sylvatica [L.]) and two mixed plots with different mixing pattern showed: (1) mixing hardly changed annual net primary productivity at stand level when Norway spruce and European beech are cultivated group-wise but increased by 37 % on account of a higher efficiency of water and light use in individual tree-wise mixture. (2) Favourable climatic conditions increased the superiority of mixed versus pure stands productivity, while, in particular, water stress cancelled the benefit of mixing considerably. (3) An interaction between the spatial pattern and variable climatic conditions was revealed. Both improved light and water use were found in favourable years in close inter-specific intermingling. However, in unfavourable years the spatial pattern played a less pronounced role in terms of productivity.

The decreased competition in expanding versus mature juniper woodlands is counteracted by adverse climatic effects on growth

World-wide deforestation is being reversed in Mediterranean continental areas, where abandonment of traditional practises favours the expansion of valuable habitats, like Juniperus thurifera woodlands. We hypoth- esised that pre-existing trees facilitate establishment in expanding woodlands, whereas in mature woodlands, competition leads to patch disaggregation. We compared the imprint of these processes on growth, demographic and spatial structure of expanding and mature J. thurifera woodlands. We selected plots where we geopositioned, aged and quantified the morphological characteristics of all trees. In the mature woodland, trees arranged in clumps and randomly in the expanding woodland. Competition nega- tively affected growth, was greater in the mature woodland and led to disaggregation of juvenile clumps. Differences in growth between the mature and the expanding woodland disappeared in climatically unfavourable years, suggesting that adverse climate constrains growth more in expanding than in mature woodlands. We suggest that change in the dispersal agents and a decrease of facilitation underlay differences in spatial patters between the expanding and the mature woodland. Observed effective recruitment in less than 30 years into the expanding woodland evidenced that propagule arrival and sapling survival do not constrain woodland expansion. Furthermore, growth of juveniles established in these new areas is favoured by reduced intra- specific competition. However, we expect growth in expanding woodlands to be negatively impacted by climate change. We conclude that under current global change scenario, conservation of J. thurifera woodlands is favoured by changes in land use, but greater frequency and severity of drier than usual episodes could hamper natural reforestation.

Pinus halepensis Mill. crown development and fruiting declined with repeated drought in Mediterranean France

The objectives of this study were to describe and quantify Aleppo pine aerial primary growth processes and to assess their relationships with climate. Primary growth (branch length growth, branching rate, polycyclism, needle number and size, fruiting), i.e. crown development and reproduction, was reconstructed for the last 16 years in Mediterranean France. From 1998 to 2007, climate has been far hotter and drier than normal in South-eastern France. All variables related to crown development and fruiting, as well as radial growth, significantly declined after 2003 heat wave and during repeated droughts from 2004 to 2007. A partial recovery of most parameters occurred from 2008 to 2010 on vigorous branches while frail branches showed less improvement. The limited crown development during unfavourable years may significantly hold back tree potential photosynthetic biomass for several following years and contribute to a slower than expected recovery of tree growth or to delayed die-back.