scholarly journals Drought assessment on barley and millet production in Karnali Province, Nepal

2020 ◽  
Vol 8 ◽  
pp. 53-67
Author(s):  
Bina Ghimire ◽  
Nikita Maharjan ◽  
Jagdish Dotel
Keyword(s):  
Crop Yield ◽  
Yield Loss ◽  
Agricultural Drought ◽  
Drought Severity ◽  
Drought Intensity ◽  
Drought Assessment ◽  
Drought Tolerant ◽  
Spatio Temporal ◽  
The Impact ◽  
Drought Occurrence

Spatio-temporal characteristics of agricultural drought and its impact on the yield of winter barley and summer millet crops in Karnali Province of Nepal were evaluated. For this purpose, precipitation data from 1988 to 2018 of 18 stations and agricultural data from 2003 to 2018 were used for the analysis. Standardized Precipitation Indices (SPI-3 and SPI-4) were used for measuring drought intensity. Based on drought intensity, SPI<-1 was considered for drought occurrence. Similarly, Standardized Residual Yield Series (SYRS) was also calculated for crop yield change, eliminating other factors responsible for crop yield. The result shows that Salyan, Surkhet, and Jumla districts have more occurrence of summer and winter drought in comparison to other districts. Similarly, 1999, 2002, 2004-05, 2008-09, 2012, and 2015 were considered as drought years in most stations. Moreover, the province experienced more winter drought events than summer and winter droughts are increasing after 2015. Concerning the impact of drought occurrence on cereal yield loss, barley seems to be more affected. SPI-3 and SYRS (barley) are significantly correlated in Jumla, Humla, Mugu, Jajarkot, Dailekh, Surkhet, and Salyan districts at 95% confidence. With the exception, drought occurrence has a larger impact on barley yield loss than drought severity in the study area. However, millet yield loss doesn't seem to be affected due to drought occurrence and intensity in all districts except Rukum, as millet is a drought-tolerant crop. Therefore, for sustainable agriculture practices, drought-tolerant crops like millet could be suitable in Karnali Province, where drought frequency is very high.

scholarly journals A Yield-Related Agricultural Drought Index Reveals Spatio-Temporal Characteristics of Droughts in Southwestern China

2019 ◽  
Vol 11 (3) ◽  
pp. 714 ◽  
Author(s):  
Lu Wu ◽  
Liping Feng ◽  
Yizhuo Li ◽  
Jing Wang ◽  
Lianhai Wu
Keyword(s):  
Drought Index ◽  
Yield Loss ◽  
Production Systems ◽  
Global Climate ◽  
Climatic Variability ◽  
Agricultural Drought ◽  
Southwestern China ◽  
Drought Severity ◽  
Severe Drought ◽  
Spatio Temporal

Southwestern China (SWC), one of the major rain-fed wheat production zones in China, has become vulnerable to drought in recent years under global climate change. To quantify drought severity during the wheat growing season and its impact on yield loss, we selected the Agricultural Production Systems sIMulator (APSIM) model to simulate wheat growth between 1961 and 2010 in SWC. A new drought index was developed considering different weighting factors of drought for yield loss in three growing phases. The index was shown to be reliable in assessing drought severity in the region. On average, an abnormal drought mainly occurred in mid-west Guizhou with a frequency of 10–30%. Central SWC was subjected to moderate drought with a frequency of 10–30%, whereas severe drought often occurred in Southern Sichuan and the middle of Yunnan with a frequency >50%. Temporally, drought severity fluctuated before 1990, but increased significantly afterwards. Our assessment suggested that irrigation during the period from floral initiation to flowering would help to ameliorate the effects of water stress under climatic variability in the region.

scholarly journals The Pitfalls of Relating Weeds, Herbicide Use, and Crop Yield: Don't Fall Into the Trap! A Critical Review

2020 ◽  
Vol 2 ◽  
Author(s):  
Nathalie Colbach ◽  
Sandrine Petit ◽  
Bruno Chauvel ◽  
Violaine Deytieux ◽  
Martin Lechenet ◽  
...  
Keyword(s):  
Crop Yield ◽  
Weed Management ◽  
Crop Production ◽  
Yield Loss ◽  
Crop Yields ◽  
Cropping Systems ◽  
Crop Productivity ◽  
Arable Farming ◽  
Herbicide Use ◽  
The Impact

The growing recognition of the environmental and health issues associated to pesticide use requires to investigate how to manage weeds with less or no herbicides in arable farming while maintaining crop productivity. The questions of weed harmfulness, herbicide efficacy, the effects of herbicide use on crop yields, and the effect of reducing herbicides on crop production have been addressed over the years but results and interpretations often appear contradictory. In this paper, we critically analyze studies that have focused on the herbicide use, weeds and crop yield nexus. We identified many inconsistencies in the published results and demonstrate that these often stem from differences in the methodologies used and in the choice of the conceptual model that links the three items. Our main findings are: (1) although our review confirms that herbicide reduction increases weed infestation if not compensated by other cultural techniques, there are many shortcomings in the different methods used to assess the impact of weeds on crop production; (2) Reducing herbicide use rarely results in increased crop yield loss due to weeds if farmers compensate low herbicide use by other efficient cultural practices; (3) There is a need for comprehensive studies describing the effect of cropping systems on crop production that explicitly include weeds and disentangle the impact of herbicides from the effect of other practices on weeds and on crop production. We propose a framework that presents all the links and feed-backs that must be considered when analyzing the herbicide-weed-crop yield nexus. We then provide a number of methodological recommendations for future studies. We conclude that, since weeds are causing yield loss, reduced herbicide use and maintained crop productivity necessarily requires a redesign of cropping systems. These new systems should include both agronomic and biodiversity-based levers acting in concert to deliver sustainable weed management.

scholarly journals Standardized Drought Indices for Pre-Summer Drought Assessment in Tropical Areas

Atmosphere ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1209
Author(s):  
David Romero ◽  
Eric Alfaro ◽  
Roger Orellana ◽  
Maria-Engracia Hernandez Cerda
Keyword(s):  
Vegetation Index ◽  
Temporal Variations ◽  
Climatic Conditions ◽  
Drought Indices ◽  
Drought Severity ◽  
Severe Drought ◽  
Summer Drought ◽  
Tropical Zone ◽  
Drought Assessment ◽  
The Impact

The main climatic indices used for the determination of pre-summer drought severity were developed for temperate zones with very different climatic conditions from those found in the tropical climate zones, particularly with respect to seasonal rainfall variations. The temporal evolution of pre-summer drought leads the authors to compute the indices for each year over a defined period according to the climatic normals of each meteorological station and to consider the months inside the dry episode differently, according to the law of emptying the water reserves. As a function of this, standardized drought indices are proposed for the evaluation of the pre-summer drought in tropical zone. Two new indices were tested: one developed from precipitation and the other also considering temperature. These indices were validated by correlation with Advanced very-high-resolution radiometer (AVHRR) normalized difference vegetation index (NDVI) time series and used to identify the most severe drought conditions in the Yucatan Peninsula. The comparison between the indices and their temporal variations highlighted the importance of temperature in the most critical events and left indications of the impact of global warming on the phenomenon.

scholarly journals AGRICULTURAL DROUGHT AND SOIL MOISTURE ANALYSIS USING SATELLITE IMAGE BASED INDICES

2019 ◽  
Vol XLII-3/W6 ◽  
pp. 507-514
Author(s):  
S. Sreekesh ◽  
N. Kaur ◽  
S. R. Sreerama Naik
Keyword(s):  
Soil Moisture ◽  
Satellite Image ◽  
Condition Index ◽  
Agricultural Drought ◽  
Drought Severity ◽  
Severe Drought ◽  
Landsat Images ◽  
Moisture Conditions ◽  
The Impact ◽  
Meteorological Droughts

<p><strong>Abstract.</strong> The deficiency in rainfall leads to meteorological droughts. Its manifestations are visible both in the vegetation cover and soil moisture. The present study assessed the characteristics of agricultural drought following meteorological droughts. The study also assessed the severity of meteorological droughts and their manifestation on the agriculture and soil moisture in a semi-arid area. The study has been carried out for the Malaprabha sub-basin which partly covers three districts of North Interior Karnataka, India. India Meteorological Department’s (IMD) criteria have been used to identify the drought years, and its severity has been assessed through the Standard Precipitation Index (SPI). The IMD’s monthly rainfall data were used to identify the drought years and periods for the region. Among the drought years, the mild, moderate, and severe drought along with deficit and excess rainfall years were considered to assess and characterize the soil moisture conditions and the agricultural drought. The satellite image based indices for these selected years were constructed to determine the soil moisture conditions and the agricultural drought severity. The Temperature-Vegetation Dryness Index (TVDI) was used to determine the soil moisture conditions. The indices employed to determine the agriculture drought are NDVI, Thermal Condition Index (TCI), Vegetation Condition Index (VCI), and Vegetation Health Index (VHI). These satellite-based indices were calculated using the Landsat images of the selected drought and non-drought years. The results showed that the seasonal and annual drought are frequent in the study area. There are spatial and temporal variations in the drought years and their severity. The satellite-based indices clearly indicate the spatial variation in the agriculture droughts and its intensity. It has been found that the impact of drought on agriculture has significantly reduced due to the development of well-irrigation in the sub-basin. VHI is more appropriate in determining the agricultural drought and its characteristics.</p>

Climate Risk and the Price of Audit Services: The Case of Drought

2020 ◽  
Vol 39 (4) ◽  
pp. 167-199
Author(s):  
Cameron Truong ◽  
Mukesh Garg ◽  
Christofer Adrian
Keyword(s):  
State Level ◽  
Severity Index ◽  
Audit Fees ◽  
Climatic Conditions ◽  
Climate Risk ◽  
Drought Severity ◽  
Firm Risk ◽  
Audit Risk ◽  
Drought Intensity ◽  
The Impact

SUMMARY This study examines the impact of drought on the pricing of audit services for U.S. firms over the period 2001–2015. We employ the Palmer Drought Severity Index (PDSI) to determine drought intensity conditions at the state level on a yearly basis and regress audit fees on drought intensity after controlling for other known factors of audit fees. We document that auditors charge significantly higher audit fees for client firms headquartered in areas affected by drought. The effect of drought on audit fees is more pronounced among firms with lower accruals quality and among firms with high business operation concentration in their headquarter states. Collectively, our findings suggest that climate risk in the form of drought not only affects firm risk but also audit risk, thereby highlighting that externalities from climatic conditions are relevant to firms and auditors.

The impact of plant breeding on the grain yield and competitive ability of wheat in Australia

2004 ◽  
Vol 55 (8) ◽  
pp. 855 ◽  
Author(s):  
R. K. Vandeleur ◽  
G. S. Gill
Keyword(s):  
Crop Yield ◽  
Morphological Traits ◽  
Competitive Ability ◽  
Yield Loss ◽  
Light Interception ◽  
Leaf Length ◽  
Annual Ryegrass ◽  
Yielding Ability ◽  
The Impact ◽  
Crop Yield Loss

Fourteen wheat (Triticum aestivum L.) cultivars released to Australian growers over the last century were examined to determine the impact of crop breeding on competitive ability with weeds. In 1999 and 2000 the weed used in the field study was annual ryegrass (Lolium rigidum Gaud.) and in 2001 oats (Avena sativa cv. Marloo) was the weedy competitor. In 2 out of 3 years (1999 and 2001), when Puccinia recondita (leaf rust) infection was not a problem, there were consistent trends for improvement in yielding ability through breeding effort over time. In these 2 seasons the yielding ability of wheat increased by around 15 kg/ha.year as compared with a yield increase of only 4.7 kg/ha.year in 2000 due to a heavy P. recondita infection. In 1999 and 2000, when annual ryegrass was used as the weedy competitor, there was no systematic trend for changes in crop yield loss with time (r = 0.47 in 1999; r = 0.08 in 2000, P > 0.05). However, in 2001, when oat was used as the weed, there was a significant positive linear relationship (r = 0.81, P < 0.01) between the year of cultivar release and crop yield loss, indicating inferior competitive ability of the modern cultivars. Old cultivars such as Nabawa not only provided superior weed suppression, they were also more tolerant of weeds as indicated by the smaller yield loss. Plant height appeared to be an important contributor to the superior competitiveness of the standard height, older cultivars. Other morphological traits contributing to superior competitive ability included greater leaf length and width, light interception, and flag leaf length. To improve the competitive ability of modern wheats without compromising their yielding ability, morphological traits that enhance early crop vigour (size of leaf 1 and 2) and light interception without affecting harvest index may need to be incorporated from carefully selected germplasm.

scholarly journals Drought assessment in the Dongliao River basin: traditional approaches vs. generalized drought assessment index based on water resources systems

2015 ◽  
Vol 15 (8) ◽  
pp. 1889-1906 ◽  
Author(s):  
B. S. Weng ◽  
D. H. Yan ◽  
H. Wang ◽  
J. H. Liu ◽  
Z. Y. Yang ◽  
...  
Keyword(s):  
Water Resources ◽  
River Basin ◽  
Drought Severity ◽  
Severe Drought ◽  
Drought Duration ◽  
Assessment Index ◽  
Drought Assessment ◽  
Water Resources Systems ◽  
Traditional Approaches ◽  
The Impact

Abstract. Drought is firstly a resource issue, and with its development it evolves into a disaster issue. Drought events usually occur in a determinate but a random manner. Drought has become one of the major factors to affect sustainable socioeconomic development. In this paper, we propose the generalized drought assessment index (GDAI) based on water resources systems for assessing drought events. The GDAI considers water supply and water demand using a distributed hydrological model. We demonstrate the use of the proposed index in the Dongliao River basin in northeastern China. The results simulated by the GDAI are compared to observed drought disaster records in the Dongliao River basin. In addition, the temporal distribution of drought events and the spatial distribution of drought frequency from the GDAI are compared with the traditional approaches in general (i.e., standard precipitation index, Palmer drought severity index and rate of water deficit index). Then, generalized drought times, generalized drought duration, and generalized drought severity were calculated by theory of runs. Application of said runs at various drought levels (i.e., mild drought, moderate drought, severe drought, and extreme drought) during the period 1960–2010 shows that the centers of gravity of them all distribute in the middle reaches of Dongliao River basin, and change with time. The proposed methodology may help water managers in water-stressed regions to quantify the impact of drought, and consequently, to make decisions for coping with drought.

scholarly journals Monitoring and Assessment of Drought Focused on Its Impact on Sorghum Yield over Sudan by Using Meteorological Drought Indices for the Period 2001–2011

2018 ◽  
Vol 10 (8) ◽  
pp. 1231 ◽  
Author(s):  
Khalid. Elhag ◽  
Wanchang Zhang
Keyword(s):  
Natural Disaster ◽  
Crop Yield ◽  
Spatial Scales ◽  
Meteorological Drought ◽  
Agricultural Drought ◽  
Drought Indices ◽  
Observation Data ◽  
High Resolution Satellite Images ◽  
Trmm Precipitation ◽  
The Impact

Currently, the high-resolution satellite images in near real-time have gained more popularity for natural disaster detection due to the unavailability and difficulty of acquiring frequent ground observation data over a wide region. In Sudan, the occurrence of drought events is a predominant natural disaster that causes substantial damages to crop production. Therefore, monitoring drought and measuring its impact on the agricultural sector remain major concerns of policymakers. The current study focused on assessing and analyzing drought characteristics based on two meteorological drought indices, namely the Standardized Precipitation Index (SPI) and the Drought Severity Index (DSI), and inferred the impact of drought on sorghum productivity in Sudan from 2001 to 2011. To identify the wet and dry areas, the deviations of tropical rainfall measuring mission (TRMM) precipitation products from the long-term mean from 2001 to 2011 were computed and mapped at a seasonal scale (July–October). Our findings indicated that the dry condition fluctuated over the whole of Sudan at various temporal and spatial scales. The DSI results showed that both the Kordofan and Darfur regions were affected by drought in the period 2001–2005, whereas most regions were affected by drought from 2008 to 2011. The spatial correlation between DSI, SPI-3, and TRMM precipitation products illustrated a significant positive correlation in agricultural lands and negative correlation in mountainous areas. The relationship between DSI and the Standardized variable of crop yield (St. Y) for sorghum yield was also investigated over two main agricultural regions (Central and Eastern regions) for the period 2001–2011, which revealed a good agreement between them, and a huge drop of sorghum yield also occurred in 2008–2011, corresponding to extreme drought indicated by DSI. The present study indicated that DSI can be used for agricultural drought monitoring and served as an alternative indicator for the estimation of crop yield over Sudan in some levels.

Causes and implications of the unforeseen 2016 extreme yield loss in France’s breadbasket

2020 ◽  
Author(s):  
Tamara Ben Ari
Keyword(s):  
Crop Yield ◽  
Yield Loss ◽  
Root Zone ◽  
Wheat Yield ◽  
Grain Filling ◽  
Impact Modelling ◽  
Compound Events ◽  
Yield Forecasting ◽  
Crop Yield Forecasting ◽  
The Impact

&lt;p&gt;The 2016 wheat harvest in France suffered from an unforeseen and unprecedented production loss. At 5.4 tonnes ha&lt;sup&gt;-1&lt;/sup&gt;, wheat yield was the lowest recorded since 1986 and 30% below the five-year average.&amp;#160; Crop yield forecasting can be considered as near-real-time impact modelling, but unfortunately, none of the forecasting systems in place anticipated the extent of the impact. The 2015/2016 growing season was characterized by compounding warm autumn temperatures and abnormally wet conditions in the following spring. High rainfall and high temperatures leading to fungal diseases, soil water lodging and anoxia, low radiation affecting grain filling, and leaching of nitrogen from the root-zone have all been suggested as important factors ultimately leading to the yield loss. The use of binomial logistic regressions accounting for autumn and spring temperatures and precipitation, suggests that the odds of an extreme yield loss in 2016 was times 35 higher than expected. The challenge now is to further identify the variety of biotic and abiotic processes interacting at different timescales. Collecting relevant insights on the field or from trial experiments, and confronting these with statistical and biophysical crop modelling will be key to achieve this. Improved impact relevant indicators will need to be integrated into operational crop yield forecasting systems in preparation for future compound events.&lt;/p&gt;

Spring Wheat, Canola, and Sunflower Response to Persian Darnel (Lolium persicum) Interference

2004 ◽  
Vol 18 (3) ◽  
pp. 509-520 ◽  
Author(s):  
Johnathon D. Holman ◽  
Alvin J. Bussan ◽  
Bruce D. Maxwell ◽  
Perry R. Miller ◽  
James A. Mickelson
Keyword(s):  
Crop Yield ◽  
Spring Wheat ◽  
Weed Management ◽  
Management Practices ◽  
Yield Loss ◽  
Wheat Yield ◽  
Integrated Weed Management ◽  
Crop Density ◽  
The Impact ◽  
Number Of Branches

Integrated weed management practices, such as crop rotation and increased seeding rates, potentially improve weed management. Yet, few studies compare competitive interactions of weeds with different crops. This research quantified the impact of Persian darnel on spring wheat, canola, and sunflower yield across different seeding rates. Increasing crop density increased yield when Persian darnel affected crop yield early in physiological development. Crop yield loss was estimated to reach 83, 70, and 57% for spring wheat, canola, and sunflower, respectively, at high Persian darnel densities. Persian darnel reduced spring wheat yield by limiting the number of tillers per plant and seed per tiller; reduced canola yield by limiting the number of branches per plant, pods per branch, and seed per pod; and reduced sunflower yield by limiting the number of seed per plant. Persian darnel affected crop growth early in physiological development, indicating that interspecific interference occurred early in the growing season. Cultural and resource management aimed at reducing Persian darnel impact on resource availability and crop yield components will reduce Persian darnel impact on crop yield.

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