scholarly journals Variabilities in Rainfall Onset, Cessation and Length of Rainy Season for the Various Agro-Ecological Zones of Ghana

Climate ◽  
2015 ◽  
Vol 3 (2) ◽  
pp. 416-434 ◽  
Author(s):  
Leonard Amekudzi ◽  
Edmund Yamba ◽  
Kwasi Preko ◽  
Ernest Asare ◽  
Jeffrey Aryee ◽  
...  
2019 ◽  
Vol 11 (2) ◽  
pp. 241-248
Author(s):  
Olumuyiwa Idowu OJO ◽  
Charity C. TEMENU ◽  
Masengo Francois ILUNGA

The ever increasing population and consequently increase in demand for food and the increasing exploitation of the land justifies the need for adequate studies on rainfall as an important factor affecting agricultural production. The date of the onset of rains is an important factor in planning agricultural operations such as land preparation and sowing. The study conducted agro-statistical analysis of rainfall characteristics over three different zones of Nigeria. Daily rainfall data were collected for the period between 1971 and 2005 for 6 stations and were subjected to standard analysis to determine trends and variations in the onset dates, cessation dates, length of rainy season, number of wet days, drought episodes. The results showed that the inter-annual variability of the onset dates is higher than that of cessation dates with a progressive shift in both onset and cessation dates. The length of rainy season varied from 77-291 days in Guinea zone, 77-243 days for Savannah and 73-155 days for the Sahel. Changes in the length of growing season ranged between -9 and -10 for Guinea zone, -21 and 11 days for Savannah zone and -28 and 20 days for the Sahel. Similarly, the numbers of wet days have declined over Nigeria. The information presented in this study are to serve as input for proper land and water resources management for productive agricultural enterprise across the three major agro-ecological zones of Nigeria.


2021 ◽  
Vol 13 (12) ◽  
pp. 6910
Author(s):  
Adil Dilawar ◽  
Baozhang Chen ◽  
Arfan Arshad ◽  
Lifeng Guo ◽  
Muhammad Irfan Ehsan ◽  
...  

Here, we provided a comprehensive analysis of long-term drought and climate extreme patterns in the agro ecological zones (AEZs) of Pakistan during 1980–2019. Drought trends were investigated using the standardized precipitation evapotranspiration index (SPEI) at various timescales (SPEI-1, SPEI-3, SPEI-6, and SPEI-12). The results showed that droughts (seasonal and annual) were more persistent and severe in the southern, southwestern, southeastern, and central parts of the region. Drought exacerbated with slopes of −0.02, −0.07, −0.08, −0.01, and −0.02 per year. Drought prevailed in all AEZs in the spring season. The majority of AEZs in Pakistan’s southern, middle, and southwestern regions had experienced substantial warming. The mean annual temperature minimum (Tmin) increased faster than the mean annual temperature maximum (Tmax) in all zones. Precipitation decreased in the southern, northern, central, and southwestern parts of the region. Principal component analysis (PCA) revealed a robust increase in temperature extremes with a variance of 76% and a decrease in precipitation extremes with a variance of 91% in the region. Temperature and precipitation extremes indices had a strong Pearson correlation with drought events. Higher temperatures resulted in extreme drought (dry conditions), while higher precipitation levels resulted in wetting conditions (no drought) in different AEZs. In most AEZs, drought occurrences were more responsive to precipitation. The current findings are helpful for climate mitigation strategies and specific zonal efforts are needed to alleviate the environmental and societal impacts of drought.


2021 ◽  
Vol 312 ◽  
pp. 107317
Author(s):  
Nirmalendu Basak ◽  
Biswapati Mandal ◽  
Ashim Datta ◽  
Manik Chandra Kundu ◽  
Arvind Kumar Rai ◽  
...  

2021 ◽  
Vol 3 (2) ◽  
pp. 383-393
Author(s):  
Patient Farsia Djidjonri ◽  
Nukenine Elias Nchiwan ◽  
Hartmut Koehler

The present study investigates the effect of intercropping (maize-cowpea, maize-okra, maize-okra-cowpea, okra-cowpea) compared to insecticide application on the level of infestation of insect pests and the final yield of maize, cowpea and okra. Field experiments were conducted during the 2016 and 2017 cropping seasons in the Guinean Savannah (Dang-Ngaoundere) and Sudano Sahelian (Gouna-Garoua) agro-ecological zones in Cameroon. Our experimental design was a split plot arrangement in a randomized complete block with four replications. The main factor was assigned to the use of insecticide (Cypermethrin) and sub plots were devoted for cropping systems. We compared the efficiency of intercropping to that of Cypermethrin application on the Yield of maize, cowpea and okra as influenced by insect pest damages. The comparison of monocropped sprayed by Cypermethrin to unsprayed showed that, in Dang, insect pests reduced maize yield by 37% and 24% in 2016 and 2017, respectively, whereas in Gouna, it was lower than 8% during the both years. Reduction in seed yield by insect pests on cowpea in Dang represented 47% and 50% in 2016 and 2017, respectively, whereas in Gouna, it was 55% and 63% in 2016 and 2017, respectively. For okra, insect pests reduced okra fruit yield by 25% and 44% in Dang and 23% and 28% in Gouna, respectively, in 2016 and 2017. Crop yield was lower in intercropping compared to monoculture due to competition of plants in association on different resources. Considering the total yields obtained from each intercropping, intercropping trials resulted generally in higher yields compared to mono-culture (LER > 1) in both sites and years but the respective yields were quite different. On the basis of the results obtained, we recommend maize-cowpea intercropping as a sustainable solution to reduce the infestation level of their pest insects.


2017 ◽  
Vol 33 (7) ◽  
pp. 713-722
Author(s):  
Hongyan Wang ◽  
Qiangzi Li ◽  
Xin Du ◽  
Longcai Zhao ◽  
Na Wang

2021 ◽  
pp. 127369
Author(s):  
Fazlullah Akhtar ◽  
Rana Ali Nawaz ◽  
Mohsin Hafeez ◽  
Usman Khalid Awan ◽  
Christian Borgemeister ◽  
...  

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