scholarly journals Understanding Crop Response to Climate Variability with Complex Agroecosystem Models

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Nathaniel K. Newlands ◽  
Gabriela Espino-Hernández ◽  
R. Scott Erickson
Keyword(s):  
Climate Variability ◽  
Crop Production ◽  
Crop Productivity ◽  
Data Availability ◽  
Prediction Skill ◽  
Model Complexity ◽  
Wheat Crop ◽  
Climate Conditions ◽  
Short Time

Agroecosystem modeling studies often rely on relatively short time-series historical records for training/tuning empirical parameters and to predict long-term variation in crop production associated with trends in climate and hydrological forcing. While ecosystem models may exhibit similar prediction skill in validation studies, their sensitivity to climate variability can differ significantly. Such discrepancy often arises due to the need to tradeoff model complexity with data availability. We examine the sensitivity in predicting spring wheat crop productivity across agricultural sites with differing soil and climate conditions where long-term agronomic and climate records are available. We report significant changes in the model sensitivity accompanying changing climatic regime. If not corrected for, this can lead to substantial predictive error when simulating across time and space. Our findings lend further support for a hierarchical (componentwise) approach for reducing model complexity and improving prediction skill.

scholarly journals CLIMATE VARIABILITY AND CHANGE: FARMER PERCEPTIONS AND UNDERSTANDING OF INTRA-SEASONAL VARIABILITY IN RAINFALL AND ASSOCIATED RISK IN SEMI-ARID KENYA

2011 ◽  
Vol 47 (2) ◽  
pp. 267-291 ◽  
Author(s):  
K. P. C. RAO ◽  
W. G. NDEGWA ◽  
K. KIZITO ◽  
A. OYOO
Keyword(s):  
Climate Variability ◽  
Crop Production ◽  
Smallholder Farmers ◽  
Crop Productivity ◽  
General Tendency ◽  
Climate Variability And Change ◽  
Negative Impacts ◽  
Probabilistic Nature ◽  
Semi Arid

SUMMARYThis study examines farmers’ perceptions of short- and long-term variability in climate, their ability to discern trends in climate and how the perceived trends converge with actual weather observations in five districts of Eastern Province in Kenya where the climate is semi-arid with high intra- and inter-annual variability in rainfall. Field surveys to elicit farmers’ perceptions about climate variability and change were conducted in Machakos, Makueni, Kitui, Mwingi and Mutomo districts. Long-term rainfall records from five meteorological stations within a 10 km radius from the survey locations were obtained from the Kenya Meteorological Department and were analysed to compare with farmers’ observations. Farmers’ responses indicate that they are well aware of the general climate in their location, its variability, the probabilistic nature of the variability and the impacts of this variability on crop production. However, their ability to synthesize the knowledge they have gained from their observations and discern long-term trends in the probabilistic distribution of seasonal conditions is more subjective, mainly due to the compounding interactions between climate and other factors such as soil fertility, soil water and land use change that determine the climate's overall influence on crop productivity. There is a general tendency among the farmers to give greater weight to negative impacts leading to higher risk perception. In relation to long-term changes in the climate, farmer observations in our study that rainfall patterns are changing corroborated well with reported perceptions from other places across the African continent but were not supported by the observed trends in rainfall data from the five study locations. The main implication of our findings is the need to be aware of and account for the risk during the development and promotion of technologies involving significant investments by smallholder farmers and exercise caution in interpreting farmers’ perceptions about long-term climate variability and change.

scholarly journals Climate change and drought effects on rural income distribution in the Mediterranean: a case study for Spain

2015 ◽  
Vol 3 (7) ◽  
pp. 4353-4389
Author(s):  
S. Quiroga ◽  
C. Suárez
Keyword(s):  
Climate Change ◽  
Income Distribution ◽  
Rural Areas ◽  
Crop Production ◽  
Crop Productivity ◽  
Social Aspect ◽  
Adaptation Measures ◽  
Effects Of Drought ◽  
The Impact

Abstract. This paper examines the effects of climate change and drought on agricultural outputs in Spanish rural areas. By now the effects of drought as a response to climate change or policy restrictions have been analyzed through response functions considering direct effects on crop productivity and incomes. These changes also affect incomes distribution in the region and therefore modify the social structure. Here we consider this complementary indirect effect on social distribution of incomes which is essential in the long term. We estimate crop production functions for a range of Mediterranean crops in Spain and we use a decomposition of inequalities measure to estimate the impact of climate change and drought on yield disparities. This social aspect is important for climate change policies since it can be determinant for the public acceptance of certain adaptation measures in a context of drought. We provide the empirical estimations for the marginal effects of the two considered impacts: farms' income average and social income distribution. In our estimates we consider crop productivity response to both bio-physical and socio-economic aspects to analyze long term implications on both competitiveness and social disparities. We find disparities in the adaptation priorities depending on the crop and the region analyzed.

Evidence for high-frequency late Glacial to mid-Holocene (16,800 to 5500 cal yr B.P.) climate variability from oxygen isotope values of Lough Inchiquin, Ireland

2006 ◽  
Vol 65 (1) ◽  
pp. 78-86 ◽  
Author(s):  
Aaron F. Diefendorf ◽  
William P. Patterson ◽  
Henry T. Mullins ◽  
Neil Tibert ◽  
Anna Martini
Keyword(s):  
Climate Variability ◽  
High Frequency ◽  
Younger Dryas ◽  
Late Glacial ◽  
Climate Anomaly ◽  
Climate Conditions ◽  
Late Glacial Period ◽  
High Frequency Variability ◽  
Western Ireland

AbstractA 7.6-m core recovered from Lough Inchiquin, western Ireland provides evidence for rapid and long-term climate change from the Late Glacial period to the Mid-Holocene. We determined percentage of carbonate, total organic matter, mineralogy, and δ18Ocalcite values to provide the first high-resolution record of climate variability for this period in Ireland. Following deglaciation, rapid climate amelioration preceded large increases in GISP2 δ18Oice values by ∼2300 yr. The Oldest Dryas (15,100 to 14,500 cal yr B.P.) Late Glacial event is documented in this record as a decrease in δ18Ocalcite values. Brief warming at ∼12,700 cal yr B.P. was followed by characteristic Younger Dryas cold and dry climate conditions. A rapid increase in δ18Ocalcite values at ∼10,500 cal yr B.P. marked the onset of Boreal warming in western Ireland. The 8200 cal yr B.P. event is represented by a brief cooling in our record. Prior to general warming, a larger and previously undescribed climate anomaly between 7300 and 6700 cal yr B.P. is characterized by low δ18Ocalcite values with high-frequency variability.

scholarly journals DOES CONCOCTION OF ORGANIC AND INORGANIC FERTILIZATION HAVE POTENTIAL TO ENHANCE WHEAT YIELD?

2019 ◽  
Vol 52 (3) ◽  
pp. 312-319
Author(s):  
A. JAMAL ◽  
D. MUHAMMAD ◽  
M. FAWAD
Keyword(s):  
Crop Production ◽  
Nutrient Management ◽  
Wheat Yield ◽  
Crop Productivity ◽  
Growth And Yield ◽  
Wheat Crop ◽  
Agricultural System ◽  
Inorganic Fertilizers ◽  
Combined Application ◽  
Organic And Inorganic Fertilizers

Soil fertility and maximum crop production can only be achieved through proper fertilization. Proper and balanced fertilization have a considerably positive effect on plant growth and yield. Due to continuous use of chemical fertilizers, the organic matter and nutrient content of the soil decreased gradually. Therefore, in modern era, agriculture scientists are now engaged to establish an agricultural system, which can not only lower the production cost, but also conserve the natural resources. Soil, as a source of nutrients, must be protected from various kinds of external factors, especially from the addition of fertilizers in excessive rates. Any degradation in the quality of soil can significantly produce many undesirable changes in the environment and also reduces the overall crop yield. So, the concoction of organic and inorganic fertilization is an alternative and most effective method for sustainable and cost-effective management for maximum crop production, without effecting the environment. The Integrated Nutrient Management provides an excellent opportunity not only for sustainability of the soil, but also enhances the overall crop productivity. The present review study was carried out with the main aim to evaluate the role of combined application of organic and inorganic fertilizers on wheat crop production. The outcome of the study concluded that combined application of both organic and inorganic fertilizers significantly improve the wheat crop production, as compared with the sole application of either organic or inorganic fertilizers.

scholarly journals Effect of Long Term Fertilization on Content and Uptake of Macro Nutrients in Sorghum-Wheat Cropping Sequence - A Review

2018 ◽  
Author(s):  
Jayalakshmi Mitnala
Keyword(s):  
Crop Production ◽  
Chemical Properties ◽  
Central India ◽  
Crop Productivity ◽  
Npk Fertilizers ◽  
Intensive Farming ◽  
Physico Chemical ◽  
Food Grain ◽  
High Yielding Varieties

Sorghum and wheat are the premier food grain crops of the peninsular central India and in particular of Maharashtra. There has been a phenomenal increase in its production after mid sixties with the introduction of high yielding varieties. Increase in production was achieved through increase in area as well as productivity. Inputs like improved seeds, irrigation, fertilizers etc. has given a boost to productivity. Continuous addition of chemical fertilizers poses problems like toxicity due to high amounts of salts as residues of fertilizer and deterioration of the physico-chemical properties. Organic manure ameliorates this problem as organic matter helps in increasing adsorptive power of soil for cations and anions particularly phosphate and nitrate. Long term manuring and fertilizer experiments conducted in India showed declining trend in productivity even with the application of NPK fertilizers under modern intensive farming. Neither organic source alone nor inorganic fertilizers can achieve sustainability in crop production under intensive agriculture, where nutrient turnover in soil-plant system is much higher. However, their combined use appeared promising in enhanced crop productivity besides improving soil fertility.

Tillage and growth of a wheat crop in a loamy sand

1982 ◽  
Vol 33 (6) ◽  
pp. 887 ◽  
Author(s):  
AP Hamblin ◽  
D Tennant ◽  
H Cochrane
Keyword(s):  
Dry Matter ◽  
Crop Productivity ◽  
Loamy Sand ◽  
Wheat Crop ◽  
Root Extension ◽  
Matter Production ◽  
Below Ground ◽  
Direct Drilling ◽  
Initial Sampling

In the fourth consecutive year of a long-term tillage trial in a loamy sand in Western Australia above- and below-ground growth of a wheat crop (cv. Gamenya) was monitored. The grain yield was nearly 20% greater in the crop sown after ploughing than in those crops sown by direct drilling. A similar trend had been noted in each preceding year. Cumulative water use was 15 and 9 mm less with zero and minimum tillage than with ploughing. The ploughed treatment had lower soil strengths, not only in the seedbed but also to 50 cm in the subsoil, until 8 weeks after seeding. These lower soil strengths coincided with more-rapid wetting of the subsoil under ploughing, and faster root extension rates. Dry matter production was significantly greater in the ploughed crop from the initial sampling date, and direct-drilled crops were not able to compensate in the later part of the season, despite using slightly more water during that period. The slower wetting of the profile under direct drilling was a persistent feature over several seasons in this soil type. It was considered responsible for the increased soil strength and slower root extension rates. The implications of direct-drilled sandy soils for crop productivity, and drainage control of recharge soils in saline catchments, are discussed.

scholarly journals Climate change and drought effects on rural income distribution in the Mediterranean: a case study for Spain

2016 ◽  
Vol 16 (6) ◽  
pp. 1369-1385 ◽  
Author(s):  
Sonia Quiroga ◽  
Cristina Suárez
Keyword(s):  
Climate Change ◽  
Income Distribution ◽  
Rural Areas ◽  
Crop Production ◽  
Crop Productivity ◽  
Adaptation Measures ◽  
General Acceptance ◽  
Rural Income ◽  
The Impact

Abstract. This paper examines the effects of climate change and drought on agricultural incomes in Spanish rural areas. Present research has focused on the effects of these extreme climatological events through response functions, considering effects on crop productivity and average incomes. Among the impacts of droughts, we focused on potential effects on income distribution. The study of the effects on abnormally dry periods is therefore needed in order to perform an analysis of diverse social aspects in the long term. We estimate crop production functions for a range of Mediterranean crops in Spain and we use a measure of the decomposition of inequality to estimate the impact of climate change and drought on yield disparities. Certain adaptation measures may require a better understanding of risks by the public to achieve general acceptance. We provide empirical estimations for the marginal effects of the two impacts considered: farms' average income and income distribution. Our estimates consider crop production response to both biophysical and socio-economic aspects to analyse long-term implications on competitiveness and disparities. As for the results, we find disparities in the adaptation priorities depending on the crop and the region analysed.

scholarly journals Biochar influences on agricultural soils, crop production, and the environment: A review

2016 ◽  
Vol 24 (4) ◽  
pp. 495-502 ◽  
Author(s):  
Ahmed Ahmed ◽  
Jiby Kurian ◽  
Vijaya Raghavan
Keyword(s):  
Crop Production ◽  
Agricultural Soil ◽  
Agricultural Soils ◽  
Current Knowledge ◽  
Crop Productivity ◽  
Long Term Effects ◽  
Increase In Productivity ◽  
Water Holding ◽  
Biochar Amendment

Given its high pore volume and adsorption capacity, and when applied as an agricultural soil amendment, its ability to enhance the soil’s nutrient- and water- holding capacities, biochar has become a focus of research interest. In most applications, crop productivity is significantly increased after agricultural soils are amended with biochar. In addition to increasing soil quality, the biochar amendments sequester carbon within the soil. However, the long-term effects of amending agricultural soils with biochar are difficult to predict, because the mechanisms behind the increase in productivity of biochar amended soils are not yet fully understood. Long-term detrimental effects on soil and the environment can occur if biochar is applied haphazardly. Current knowledge and the additional experimental work required to thoroughly understand the influence of biochar amendment on the behavior of agricultural soils processes are reviewed. Further, studies on the post production processing of biochar are discussed in the context of the possible engineering of biochar for particular states of soil degradation.

scholarly journals Climate variability and long-term expansion of peatlands in Arctic Norway during the late Pliocene (ODP Site 642, Norwegian Sea)

2016 ◽  
Vol 12 (4) ◽  
pp. 1043-1060 ◽  
Author(s):  
Sina Panitz ◽  
Ulrich Salzmann ◽  
Bjørg Risebrobakken ◽  
Stijn De Schepper ◽  
Matthew J. Pound
Keyword(s):  
Climate Variability ◽  
Boreal Forest ◽  
Climatic Conditions ◽  
Forest Zone ◽  
Climate Conditions ◽  
Norwegian Sea ◽  
Late Pliocene ◽  
Cool Temperate ◽  
Vegetation And Climate

Abstract. Little is known about the terrestrial response of high-latitude Scandinavian vegetation to the warmer-than-present climate of the late Pliocene (Piacenzian, 3.60–2.58 Ma). In order to assess Piacenzian terrestrial climate variability, we present the first high-resolution reconstruction of vegetation and climate change in northern Norway between 3.6 and 3.14 Ma. The reconstructions are derived from pollen assemblages in the marine sediments of ODP Hole 642B, Norwegian Sea (67° N). The palynological assemblages provide a unique record of latitudinal and altitudinal shifting of the forest boundaries, with vegetation alternating between cool temperate forest during warmer-than-present intervals and boreal forest similar to today during cooler intervals. The northern boundary of the nemoral to boreonemoral forest zone was displaced at least 4–8° further north, and warmest-month temperatures were 6–14.5 °C higher than at present during warm phases. Warm climatic conditions persisted during the earliest Piacenzian (ca. 3.6–3.47 Ma) with diverse cool temperate nemoral to boreonemoral forests growing in the lowlands of the Scandinavian mountains. A distinct cooling event at ca. 3.47 Ma resulted in a southward shift of vegetation zones, leading to the predominance of boreal forest and the development of open, low alpine environments. The cooling culminated around 3.3 Ma, coinciding with Marine Isotope Stage (MIS) M2. Warmer climate conditions returned after ca. 3.29 Ma, with higher climate variability indicated by the repeated expansion of forests and peatlands during warmer and cooler periods, respectively. Climate progressively cooled after 3.18 Ma, resembling climatic conditions during MIS M2. A high variability of Norwegian vegetation and climate changes during the Piacenzian is superimposed on a long-term cooling trend. This cooling was accompanied by an expansion of Sphagnum peatlands that potentially contributed to the decline in atmospheric CO2 concentrations at the end of the Piacenzian warm period and facilitated ice growth through positive vegetation–snow albedo feedbacks. Correlations with other Northern Hemisphere vegetation records suggest hemisphere-wide effects of climate cooling.

scholarly journals Impacts of Temperature Trends and SPEI on Yields of Major Cereal Crops in the Gambia

2021 ◽  
Vol 13 (22) ◽  
pp. 12480
Author(s):  
Fanta F. Jabbi ◽  
Yu’e Li ◽  
Tianyi Zhang ◽  
Wang Bin ◽  
Waseem Hassan ◽  
...  
Keyword(s):  
Food Security ◽  
Climate Variability ◽  
Crop Production ◽  
Crop Yields ◽  
Crop Productivity ◽  
The Gambia ◽  
Yield Response ◽  
Climate Trends ◽  
Local Climate ◽  
Climate Resilience

Variations in the climate constitute a significant threat to the productivity of food crops in the Gambia. A good understanding of the influence of climate variability on crop production is vital for climate resilience and improved food security. This study examined the trends, relationships, and the extent to which growing season temperatures and the SPEI (Standardized Precipitation and Evapotranspiration Index) impacted sorghum, millet, maize, and rice yields in three agro-ecological regions of the Gambia during 1990–2019. Mean temperatures and the SPEI exhibited increasing trends while observed yields showed a decline across all regions. The SPEI had a significant positive relationship with yields, and temperatures were negatively associated with yields. Though yield response to climate variability differs among regions, 20% to 62% of variations in the four crop yields were due to climate trends. The combined effect of the SPEI and temperatures decreased yields from 3.6 kg ha−1 year−1 to 29.4 kg ha−1 year−1, with the most severe decline observed in rice and maize yields in the Sahelian zone. Although uncertainties might arise from not considering related extreme climate events, this study highlights how past climate trends affect cereal yields in the Gambia; thus, any unfavorable change in the local climate could have severe repercussions on the country’s food security. There is a need for concerted efforts to increase investments in adaptation strategies to lessen the effects of the climate for improved crop productivity.

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