Various maize yield losses and their dynamics triggered by drought thresholds based on Copula-Bayesian conditional probabilities

SUMMARYTwo sets of experiments examined the effects of weeds on maize yields using weeding methods typical of small farms in Zambia where oxen are used for cultivation. Maize yield losses of 30% due to weeds were evident with common weeding practices. A critical period of competition, during which the crop should be kept clean, was demonstrated from 10 to 30 days after emergence. This is a period of peak labour demand and the prospect of using chemical weed control to ease the situation is considered. The value of weed competition data, given its variability between sites, is discussed.

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Identifying indicators for extreme wheat and maize yield losses

Agricultural and Forest Meteorology ◽

10.1016/j.agrformet.2016.01.009 ◽

2016 ◽

Vol 220 ◽

pp. 130-140 ◽

Cited By ~ 31

Author(s):

Tamara Ben-Ari ◽

Juliette Adrian ◽

Tommy Klein ◽

Pierluigi Calanca ◽

Marijn Van der Velde ◽

...

Keyword(s):

Maize Yield ◽

Yield Losses

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Exploring entomopathogenic fungi from South Sumatra (Indonesia) soil and their pathogenicity against a new invasive maize pest, Spodoptera frugiperda

Biodiversitas Journal of Biological Diversity ◽

10.13057/biodiv/d210711 ◽

2020 ◽

Vol 21 (7) ◽

Author(s):

Siti Herlinda ◽

OCTARIATI Noni ◽

Suwandi Suwandi ◽

Hasbi Hasbi

Keyword(s):

Entomopathogenic Fungi ◽

Spodoptera Frugiperda ◽

Fall Armyworm ◽

Maize Yield ◽

Yield Losses ◽

The Third ◽

Pest Insects ◽

Dark Green ◽

Yellowish White ◽

Third Instar Larvae

Abstract. Herlinda S, Octariati N, Suwandi S, Hasbi. 2020. Exploring entomopathogenic fungi from South Sumatra (Indonesia) soil and their pathogenicity against a new invasive maize pest, Spodoptera frugiperda. Biodiversitas 21: 2955-2965. Fall armyworm (Spodoptera frugiperda) is a new invasive maize pest in Indonesia that can cause maize yield losses of 18 million tons/year. To overcome the pest, local-specific entomopathogenic fungi are needed. This study aimed to explore entomopathogenic fungi from soil in South Sumatra and to determine their pathogenicity against S. frugiperda larvae. The fungi exploration was carried out in the lowlands and highlands of South Sumatra and the pathogenicity of obtained isolates were tested against the third instar larvae. The entomopathogenic fungi found were Metarhizium spp. and were successfully isolated as many as 14 isolates. All of the isolates were pathogenic to S. frugiperda larvae (70.67−78.67% mortality), the most pathogenic caused 78.67% mortality and significantly suppressed the emergence of adults up to 81.2%. Unhealthy larvae had a dry, shrunken, shrinking, odorless body, and its integument was covered in mycelia and conidia like yellowish-white powdery mixed with dark green. The unhealthy pupae and adults were in the abnormal and malformation shape. The abnormal pupae were shorter in size, bent, the to-be wings got wrinkled, and darker color, while the unhealthy adults had folded wings and were unable to fly. The two most pathogenic isolates were found from the lowland (PirOI) and highland (CasPsPGA) soil of South Sumatra. In conclusion, both of these isolates had the potential to be developed into local-specific mycoinsecticides to control pest insects in the highlands and/or lowlands in Indonesia.

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Quantifying Agroforestry Yield Buffering Potential Under Climate Change in the Smallholder Maize Farming Systems of Ethiopia

Frontiers in Agronomy ◽

10.3389/fagro.2021.609536 ◽

2021 ◽

Vol 3 ◽

Author(s):

Abel Chemura ◽

Amsalu Woldie Yalew ◽

Christoph Gornott

Keyword(s):

Climate Change ◽

National Level ◽

Climate Change Impacts ◽

Farming Systems ◽

Maize Yield ◽

Agroforestry System ◽

Climatic Conditions ◽

Yield Losses ◽

Climate Regulation ◽

Maize Yields

Agroforestry is a promising adaptation measure for climate change, especially for low external inputs smallholder maize farming systems. However, due to its long-term nature and heterogeneity across farms and landscapes, it is difficult to quantitatively evaluate its contribution in building the resilience of farming systems to climate change over large areas. In this study, we developed an approach to simulate and emulate the shading, micro-climate regulation and biomass effects of multi-purpose trees agroforestry system on maize yields using APSIM, taking Ethiopia as a case study. Applying the model to simulate climate change impacts showed that at national level, maize yield will increase by 7.5 and 3.1 % by 2050 under RCP2.6 and RCP8.5, respectively. This projected increase in national-level maize yield is driven by maize yield increases in six administrative zones whereas yield losses are expected in other five zones (mean of −6.8% for RCP2.6 and −11.7% for RCP8.5), with yields in the other four zones remaining stable overtime. Applying the emulated agroforestry leads to increase in maize yield under current and future climatic conditions compared to maize monocultures, particularly in regions for which yield losses under climate change are expected. A 10% agroforestry shade will reduce maize yield losses by 6.9% (RCP2.6) and 4.2 % (RCP8.5) while 20% shade will reduce maize yield losses by 11.5% (RCP2.6) and 11% (RCP8.5) for projected loss zones. Overall, our results show quantitatively that agroforestry buffers yield losses for areas projected to have yield losses under climate change in Ethiopia, and therefore should be part of building climate-resilient agricultural systems.

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Maize Yield Losses Due to Farmers' Use of Own Seed Saved from Previous Maize Crop

East African Agricultural and Forestry Journal ◽

10.1080/00128325.1995.11663273 ◽

1995 ◽

Vol 61 (2) ◽

pp. 209-211 ◽

Cited By ~ 1

Author(s):

J.A.W. Ochieng ◽

H.M. Tanga

Keyword(s):

Maize Yield ◽

Yield Losses ◽

Maize Crop

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Field assessment of corn yield losses and compensatory yield for infested plants by Lepidopteran stem borers in different sowing dates at El-Behiera governorate, Egypt.

JOURNAL OF ADVANCES IN BIOLOGY ◽

10.24297/jab.v13i.8807 ◽

2020 ◽

Vol 13 ◽

pp. 31-40

Author(s):

Al-Eryan M. A. S ◽

Abu- Shall Amany M. H. ◽

Ibrahiem H. K. ◽

Huessein Hanaa S.

Keyword(s):

Total Yield ◽

Maize Yield ◽

Simple Linear Regression ◽

Yield Losses ◽

Stem Borers ◽

Yellow Corn ◽

Maize Varieties ◽

Increase Rate ◽

Economic Injury

Whenever the determination of yield loss and economic injury levels are essential tools for initiating integrated pest management (IPM) programs in the maize field, the assessment of compensatory yield is very important for determinate the accurate losses in the field and the recovery power for the maize verity. The present study aimed to estimate the yield losses of three maize varieties due to Sesamia critica and Ostrinia nubilalis, infestation; regression between maize yield losses and percent of infestation and determine the compensatory yield arising in intact plants as a result of absence or dead (caused by infestation) of adjacent plants under field conditions in El-Behiera governorate. The present results showed that yield losses resulting from S. cretica infestation in early sowed maize ranged from 5.29 – 32.17%. In case of maize that sowed in recommended date “June”, yield losses due to S. cretica was slightly decreased, and it accompanied with O. nubilalis infestation in two fields, which increased the total yield losses. A simple linear regression turned out between the percentage of infestation of S. cretica or O. nubilalis and percentage of yield losses, with R2 values 0.84 and 0.45, respectively. The yellow corn was more tolerant to stem borers infestation than white corn with percentages of increase rate in compensatory yield 27.07 %. Whenever the determination of yield loss and economic injury levels are essential tools for initiating integrated pest management (IPM) programs in the maize field, the assessment of compensatory yield is very important for determinate the accurate losses in the field and the recovery power for the maize verity. The present study aimed to estimate the yield losses of three maize varieties due to Sesamia critica and Ostrinia nubilalis, infestation; regression between maize yield losses and percent of infestation and determine the compensatory yield arising in intact plants as a result of absence or dead (caused by infestation) of adjacent plants under field conditions in El-Behiera governorate. The present results showed that yield losses resulting from S. cretica infestation in early sowed maize ranged from 5.29 – 32.17%. In case of maize that sowed in recommended date “June”, yield losses due to S. cretica was slightly decreased, and it accompanied with O. nubilalis infestation in two fields, which increased the total yield losses. A simple linear regression turned out between the percentage of infestation of S. cretica or O. nubilalis and percentage of yield losses, with R2 values 0.84 and 0.45, respectively. The yellow corn was more tolerant to stem borers infestation than white corn with percentages of increase rate in compensatory yield 27.07 %.

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Risk analysis of maize yield losses in mainland China at the county level

Scientific Reports ◽

10.1038/s41598-020-67763-3 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Xuan Li ◽

Shibo Fang ◽

Dong Wu ◽

Yongchao Zhu ◽

Yingjie Wu

Keyword(s):

Risk Analysis ◽

Mainland China ◽

Maize Yield ◽

County Level ◽

Yield Losses

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Economic losses from soil degradation in agricultural area in Albania

Agricultural Economics (Zemědělská ekonomika) ◽

10.17221/12/2013-agricecon ◽

2014 ◽

Vol 60 (No. 6) ◽

pp. 287-293 ◽

Cited By ~ 1

Author(s):

A. Binaj ◽

P. Veizi ◽

E. Beqiraj ◽

F. Gjoka ◽

E. Kasa

Keyword(s):

Soil Compaction ◽

Soil Conservation ◽

Soil Degradation ◽

Maize Yield ◽

Agricultural Area ◽

Economic Losses ◽

Plant Nutrient ◽

Yield Losses ◽

Nutrient Losses ◽

Production Methods

Soildegradationis aserious and widespread problemin Albania. Itmanifests itselfin manyformsandcauses arange ofeffects. The aim of this study was to analyze the economic losses from soil erosion and compaction in relationship to agriculture in Albania. On-site effects of these two degradative processes affect farmers directly through reducingproductionand increasingthe costsof farming. Calculation ofeconomic losses was performed by using the replacement and lost production methods. According to our assessments, the wheat and maize yield losses due to the soil compaction are112 164 tons or US$ 40.2 million, and the plant nutrient losses due to the water erosion are 69 609 tons or US$ 98million. Economic losses from the erosion and compaction in the agricultural area in Albania are at least US$ 138.2 million per year or about 5.5% of the agricultural GDP. Based on the assessed economic losses from soil degradation, it can be concluded that the soil conservation in Albania is economically viable.    

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Uncertainties In The Effectiveness of Biological Control of Stem Borers Under Different Climate Change Scenarios In Eastern Africa

10.21203/rs.3.rs-876884/v1 ◽

2021 ◽

Author(s):

Ines Gwendolyn Jendritzki ◽

Henri E. Z. Tonnang ◽

Paul-André Calatayud ◽

Christian Borgemeister ◽

Tino Johansson ◽

...

Keyword(s):

Climate Change ◽

Biological Control ◽

Insect Pests ◽

Maize Yield ◽

Stem Borer ◽

Eastern Africa ◽

Climate Change Scenarios ◽

Agricultural Crop ◽

Yield Losses ◽

Stem Borers

Abstract Climate change (CC) is expected to significantly affect biodiversity and ecosystem services. Adverse impacts from CC in the Global South are likely to be exacerbated by limited capacities to take adequate adaptation measures and existing developmental challenges. Insect pests today are already causing considerable yield losses in agricultural crop production in East Africa. Studies have shown that insects are strongly responding to CC by proliferation, shift in distribution or by altering their phenology, which is why an impact on agriculture can also be expected. Biological control (BC) has been proposed as an alternative measure to sustainably contain insect pests but few studies predict its efficacy under future CC. Using the species distribution modelling approach Maxent, we predict the current and future distribution of three important lepidopteran stem borer pests of maize in eastern Africa, i.e., Busseola fusca (Fuller, 1901), Chilo partellus (Swinhoe, 1885) and Sesamia calamistis (Hampson, 1910), and two of their parasitoids that are currently used for BC, i.e., Cotesia flavipes (Cameron, 1891) and Cotesia sesamiae (Cameron, 1906) . Based on these potential distributions and data collected during household surveys with local farmers in Kenya and Tanzania, future maize yield losses are predicted for a business-as-usual scenario and a sustainable development scenario. Accordingly, we found that BC of the three stem borer pests by C. flavipes and C. sesamiae will be less effective under more severe CC resulting in a reduced ability to curb maize yield losses caused by the stem borers. These results highlight the need to adapt BC measures to future CC to maintain its potential for environmentally-friendly pest management strategies. The findings of this research are thus of particular relevance to policy makers, extension officers and farmers in the region and will aid the adaptation of smallholder agricultural practices to current and future impacts of CC.

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