Managing the soil water balance of hot pepper (Capsicum annuum L.) to improve water productivity

A series of field, rainshelter, growth cabinet and modelling studies were conducted to investigate hot pepper response to different irrigation regimes and row spacings; to generate crop-specific model parameters; and to calibrate and validate the Soil Water Balance (SWB) model. Soil, climate and management data of five hot pepper growing regions of Ethiopia were identified to develop irrigation calendars and estimate water requirements of hot pepper under different growing conditions. High irrigation regimes increased fresh and dry fruit yield, fruit number, harvest index and top dry matter production. Yield loss could be prevented by irrigating at 20-25% depletion of plant available water, confirming the sensitivity of the crop to mild soil water stress. High plant density markedly increased fresh and dry fruit yield, water-use efficiency and dry matter production. Average fruit mass, succulence and specific leaf area were neither affected by row spacing nor by irrigation regimes. There were marked differences among the cultivars in fruit yields despite comparable top dry mass production. Average dry fruit mass, fruit number per plant and succulence were significantly affected by cultivar differences. The absence of interaction effects among cultivar and irrigation regimes, cultivars and row spacing, and irrigation regimes and row spacing for most parameters suggest that appropriate irrigation regimes and row spacing that maximize productivity of hot pepper can be devised across cultivars. To facilitate irrigation scheduling, a simple canopy cover based procedure was used to determine FAO-type crop factors and growth periods for different growth stages of five hot pepper cultivars. Growth analysis was done to calculate crop-specific model parameters for the SWB model and the model was successfully calibrated and validated for five hot pepper cultivars under different irrigation regimes or row spacings. FAO basal crop coefficients (Kcb) and crop-specific model parameters for new hot pepper cultivars can now be estimated from the database, using canopy characteristics, day degrees to maturity and dry matter production. Growth cabinet studies were used to determine cardinal temperatures, namely the base, optimum and cut-off temperatures for various developmental stages. Hot pepper cultivars were observed to require different cardinal temperatures for various developmental stages. Data on thermal time requirement for flowering and maturity between plants in growth cabinet and open field experiments matched closely. Simulated water requirements for hot pepper cultivar Mareko Fana production ranged between 517 mm at Melkassa and 775 mm at Alemaya. The simulated irrigation interval ranged between 9 days at Alemaya and 6 days at Bako, and the average irrigation amount per irrigation ranged between 27.9 mm at Bako and 35.0 mm at Zeway.Thesis (PhD)--University of Pretoria, 2010.Plant Production and Soil Scienceunrestricte

Effect of Deficit Irrigation Levels at Different Growth Stages on Yield and Water Productivity of Onion (Allium cepa L.) at Raya Azebo Woreda, Northern Ethiopia

አህፅሮት በደረቅና ከፊል በረሃማ አካባቢዎች ለግብርና ዕድገት ከፍተኛ ማነቆ የሆነው የውኃ እጥረት ነው፡፡ በእንደዚህ ያሉ ሁኔታዎች ውስጥ የሚገኘውን ውኃ ኢኮኖሚያው እና ውጤታማ በሆነ መንገድ የመጠቀም አስፈላጊነት የማይካድ ነው፡፡  በእነዚህ ውኃ አጠር አካባቢዎች፤ የውኃ ምርታማነትን ለማሳደግና የውኃ አጠቃቀምን ውጤታማነት ለማሻሻል፤ የመስኖ ውኃ አሳንሶ መስጠት ሁነኛ መፍትሄ እና የመስኖ ስትራቴጂ ነው፡፡ የመስክ ሙከራው የተከናወነው በመሆኒ ግብርና ምርምር ማዕከል በመስኖ  ሲሆን፤ ዓላማው ደግሞ የመስኖ ውኃ አሳንሶ መስጠት  በሽንኩርት የውኃ ምርታማነት ላይ የሚያመጣው ተፅዕኖን ለማጥናትና የትኛው የሽንኩርት የዕድገት ደረጃ ለውኃ ዕጥረት ይበልጥ ሊጎዳ እንደሚችል ጥናት ለማድረግ ነበር፡፡ ሙከራው አራት አይነት የሽንኩርት የዕድገት ደረጃ (መጀመሪያ፣ ዕድገት ላይ፣ ማኮረቻና መድረሻ ወቅት) እና አራት ዓይነት የመስኖ ውሃ መጠን (40፣ 60፣ 80 እና 100%) ያካተተ ሲሆን ትክለኛውን የጥናት ንድፍ በመጠቀም ተከናዉኗል፡፡ ተጨባጭ የሰብል ውኃ አጠቃቀም በዕለታዊ የአየር ንብረት መረጃን በመጠቀም ተገምቷል፡፡ የሙከራው ውጤት እንደሚያሳየው ከሆነ የመስኖ ውኃ መጠን ማሳነስ ከተለያዩ የዕድገት ደረጃዎች እና የእነሱ መስተጋብር በሽንኩርት ምርት ላይ ከፍተኛ ተፅዕኖ ሊፈጥር ችሏል፡፡ ከፍተኛ የሆነ ምርት የተገኘው መቶ በመቶ የሰብሉ የመስኖ ውኃ መጠን በዕድገት ወቅት በመጠቀም ሲሆን የምርቱ መጠን 30.67 ቶን በሄ/ር ነው፤ ይህም በመጀመሪያና መድረሻ ወቅቶች ላይ 60በመቶ ቅናሽ የመስኖ ውኃ መጠን በመጠቀም ከተገኘው ምርት ጋር ሲነፃፀር በስታትስቲክስ ቁጥር መረጃ መሰረት ልዩነት የለውም፡፡ የጥናቱ ውጤት እንደሚያሳየው ብዙ ምርት ሳይቀንስ በመጀመሪያና መድረሻ ወቅቶች ላይ የመስኖ ውሃ አሳንሶ መስጠትን ለመተግበር ትክክለኛ ወቅቶች ናቸው፡፡ በመድረሻ ወቅት 60በመቶ ቅናሽ የመስኖ ውኃ መጠን በመጠቀም ከፍተኛ የውኃ ምርታማነት (8.96 ኪ.ግ/ሜ3) የተገኘ ስሆን 0.17 ሄ/ር ተጨማሪ ቦታ ማልማት የሚችል የመስኖ ውኃ መቆጠብም ችሏል፡፡ በዕድገትና ማኮረቻ ወቅቶች ቅናሽ የመስኖ  ውኃ መጠቀም በሽንኩርት ምርት ላይ ከፍተኛ የሆነ ተፅዕኖ ሲኖረው፤ ቅናሽ መስኖ በትክክለኛ ወቅቶች ላይ መጠቀም ግን የውኃ ምርታማነት ከመጨመር ባሻገር በተቆጠበው ውኃ ተጨማሪ የመስኖ ቦታ ማልማት ይቻላል፡፡    Abstract The scarcity of water is the most severe constraint for the development of agriculture in arid and semi-arid areas. Under such conditions, the need to use the available water economically and efficiently is unquestionable. The important strategy for increasing water productivity and improving water use efficiency in the area of water scarcity was deficit irrigation. A field experiment was conducted at Mehoni Agricultural Research Center during offseason aimed at investigating the effect of deficit irrigation levels on water productivity of onion (Bombey Red variety) and the most sensitive growth stages of onion crop. The experiment was carried out in split plot design with sixteen treatment combinations and three replications. The treatments include four growth stages (initial, development, bulb formation and maturation) as main plot, and three deficit irrigation levels (80%, 60% and 40% of evapotranspiration of crop (ETc)), and one control irrigation of 100% ETc as a subplot. Crop water requirement was estimated using actual daily climatic data. The result showed that deficit irrigation levels, time of deficit irrigation and their interaction had a significant (p< 0.01) effect on bulb yield and yield components. The treatment received 100% ETc at the time of development stage gave the highest total bulb yield of 30.67 t/ha with no significant difference from 60% deficit treatments during initial and maturation stages. The result showed that initial and maturation stages were the right time to practicing deficit irrigation without significant yield reduction. Water productivity was the highest with 60% deficit irrigation at the maturation stage (8.96 kg/m3), and 0.17ha additional area to be irrigated by saved water. The yield response factor (Ky) was higher (1.98) when 40% deficit occurred at the development stage. The result revealed that onion bulb yield was most sensitive to water deficit that occurred at development and bulb formation stages. While maximum yield was obtained when the whole crop water requirement was applied, implementing deficit irrigation at appropriate stage could increase the irrigated area as a result of high water productivity

Growth and yield components of tomato as influenced by nitrogen and phosphorus fertilizer applications in different growing seasons

Tomato is an important cash crop in Central Rift Valley of Ethiopia. However, the yield is constrained by poor soil fertility management and lack of appropriate/adequate fertilizers rates recommendation. Experiments were conducted at Melkassa on station with the objectives of evaluating effect of N and P fertilizer applications on growth and yield, and determining optimal requirements for tomato. The experiments were conducted under both cool season furrow irrigated and rain-fed conditions with variable fertility status of the fields. The treatments consisted of four rates of nitrogen (0, 50, 100 and 150 kg N ha-1) and four rates of P (0, 46, 92 and 138 kg ha-1). The experiments were laid out in a CRBD in a factorial arrangement and replicated three times using Melkashola variety. Data on growth and canopy characteristics such as plant height and stem diameter, main lateral branch length, canopy width and depth were measured from selected plants. Some of the growth and yield components such plant height, canopy diameter, canopy width, stem diameter, lateral branch length, total dry mass above the ground per plot, shoot fresh and dry weight, marketable and unmarketable fruit yield and total yield at harvest were measured were assessed. Maximum fruit yield was estimated from regression lines of applying 105 kg N ha-1 and 85 kg P ha-1 under furrow irrigated experiment (continuously cultivated field). However, the highest fruit yield was from application of 40 kg N ha-1 and 10 kg ha-1 for the rainfed experiment (relatively fertile field). Thus, results of both experiments were averaged to propose on farm verification of N and P requirement of tomato, N 73 kg ha-1 and P 48 kg ha-1 around Melkassa and similar soil types.Keywords: furrow irrigated, rain-fed, season, tomato, inorganic N and P fertilize

INFLUENCE OF TREATMENT OF SEED POTATO TUBERS WITH PLANT CRUDE ESSENTIAL OIL EXTRACTS ON PERFORMANCE OF THE CROP

Farmers in most developing countries store seed potato ( Solanum tuberosum L.) tubers in traditional storage that invariably leads to rapid deterioration in the quality of the seed tubers due to sprouting and aging. Thus, potato seed tubers senesce and are past their prime when planted. A pot experiment was conducted at Sirinka Agricultural Research Centre, in north-eastern Ethiopia, to evaluate the effect of treating seed potato tubers with crude plant essential oil extracts, on the growth and yield of the potato crop. Treatments consisted of seed potato tubers treated with dill weed, spearmint, black cumin and eucalyptus crude essential oil extracts, each applied at 45, 90 and 135 mg kg-1 of potato tubers for one month, plus a control treatment. The control consisted of untreated tubers. Results revealed that potato plants grown from seed tubers treated with oil extracts from dill weed, spearmint, and eucalyptus at 135 mg kg-1, took the longest time to sprout, flower, and tubers to mature. Potato plants grown from seed tubers treated with dill weed, spearmint, black cumin and eucalyptus crude essential oil extracts at 135 mg kg-1 were 23 - 38% taller than plants from the untreated seed tubers. Similarly, potatoes from these treatments had 21 - 89% more numbers of leaves compared to plants from the untreated seed tubers. Crude essential oils from dill weed at the concentrations of 90 and 135 mg kg-1 and eucalyptus at 135 mg kg-1, had the greatest positive effects on growth and yield of the potato crop.Dans plusieurs pays en d\ue9veloppement, les paysans conservent les tubercules de pomme de terre ( Solanum tuberosum L.) en stockage traditionnel, ce qui est responsable de la d\ue9t\ue9rioration rapide de la qualit\ue9 des semences due au vieillissement et au bourgeonnement des tubercules. Alors, les tubercules de pomme de terre vieillissent et perdent leur fra\ueecheur avant d\u2019\ueatre plant\ue9. Une exp\ue9rimentation en pots a \ue9t\ue9 conduite au Centre de Recherche Agricole de Sirinka au North-Est de l\u2019Ethiopie pour \ue9valuer l\u2019effet du traitement des tubercules de pomme de terre avec des huiles essentiels sur la croissance et le rendement la culture subs\ue9quente. Les traitements consistaient en l\u2019utilisation des huiles essentielles de la fenouille, la menthe verte, du cumin noir et de l\u2019eucalyptus \ue0 diff\ue9rente concentrations (45, 90 et 135 mg kg-1) pour traiter les tubercules de pomme de terre pendant un mois, et un traitement t\ue9moin (tubercules non trait\ue9s). Les r\ue9sultats ont montr\ue9 que les plants de pomme de terre trait\ue9s \ue0 l\u2019huile essentielle de fenouille, menthe verte, et eucalyptus \ue0 135 mg kg-1 ont le plus retard\ue9 le bourgeonnement, la floraison, et la maturation des tubercules. Les plants de pomme de terre cultiv\ue9s apr\ue8s traitement \ue0 l\u2019huile essentielle de fenouille, menthe verte, cumin noir et eucalyptus \ue0 135 mg kg-1 \ue9taient 23 \ue0 38% plus grands que les plants provenant de tubercules non trait\ue9es. De la m\ueame fa\ue7on, les plants trait\ue9s avaient 21 \ue0 89% plus de feuilles que les plants non trait\ue9s. Les huiles essentielles de fenouille \ue0 90 et 135 mg kg-1 et de l\u2019eucalyptus \ue0 135 mg kg-1 ont entrain\ue9 une croissance plus accrue et un rendement plus \ue9lev\ue9 de la culture subs\ue9quente de pomme de terre

Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BackgroundDisorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021.MethodsWe estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined.FindingsGlobally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer.InterpretationAs the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed

Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation

Prevalence of vernal keratoconjunctivitis and its associated factors among children in Gambella town, southwest Ethiopia, June 2018.

IntroductionVernal keratoconjunctivitis is a chronic bilateral severe form of allergic conjunctivitis which affects normal activities in school/work. It is a severe form of allergies in warm and dry tropical and sub-tropical countries. Its prevalence in Ethiopia ranges from 5.2% to7.3%. Most studies are institution based and do not address specific factors associated with vernal keratoconjunctivitis. There is no a study that shows the magnitude of vernal keratoconjunctivitis in the study area.ObjectiveTo assess the prevalence of vernal keratoconjunctivitis and its associated factors among children in Gambella town, Southwest Ethiopia, 2018.Methods and materialsA community based cross-sectional study was conducted from April 25 to May 12, 2018, in Gambella town. A total of 578 study participants were selected using a systematic random sampling technique. A pre-tested semi-structured questionnaire, torch, and magnifying loop were used to collect data. The data was entered into epidemiological information 7.1 and exported to statistical package for social science for analysis. Binary logistic regression analysis model was fitted to identify factors associated with vernal keratoconjunctivitis. Odds ratio with respected 95% CI was used to identify the direction and strength of association.ResultsA total of 574 children participated in this study representing a response rate of 99.30%. The mean age of the participants was 9.74±4.0 years. The prevalence of vernal keratoconjunctivitis was 11.10% (95% CI: 8.70, 13.90). Male sex (adjusted odds ratio = 4.12(95% CI: 1.42, 11.91)), close animal contact (adjusted odds ratio = 3.45(95% CI: 1.14, 10.41)), dust exposure (adjusted odds ratio = 3.38(95% CI: 1.31, 10.04)), and personal systemic allergy history (adjusted odds ratio = 4.82(1.40, 16.72) were independently associated with vernal keratoconjunctivitis.ConclusionThe prevalence of VKC was high among children in Gambella town. Sex being male, close animal contact, personal systemic allergy history, and dust exposure were positively associated with vernal keratoconjunctivitis independently

Sugarcane yield and juice quality as affected by harvest age and chemical ripeners in Central Rift Valley of Ethiopia

SUPPLEMENTARY MATERIAL : FIGURE S1. Monthly total rainfall (mm) (RF), relative humidity (RH), the mean maximum (Tmax), and minimum (Tmin) temperature (°C) during the study period at Metahara in the late (A), Kessem in the late (B) and Kessem in the early (C) periods. TABLE S1. Dates of planting, application of ripeners, and harvesting. TABLE S2. Main effects of variety and age of harvesting by ripener combination on stalk height and stalk weight of sugarcane at Metahara and Kessem sugarcane plantations. TABLE S3 Main effects of variety and age by ripener combination on cane yield, sucrose content and sucrose yield at Metahara and Kessem sugarcane plantations. TABLE S4 Main effects of variety and age by ripener combination on sucrose content and sucrose yield at Metahara and Kessem sugarcane plantations.TABLE S5 Partial budget analysis for sucrose yield of four harvest ages in the late (June) period harvesting at Metahara sugarcane plantation.Chemical ripening is a promising technology at Metahara and Kessem sugarcane plantations where conditions are not optimal for natural ripening in the early and late period of sugarcane processing. However, the harvest age at which sucrose yield could be maximized with application of ripeners has not been established. Thus, field experiments were conducted to determine the effects of harvest age and chemical ripeners on yield and juice quality of sugarcane. The experiments were conducted in the late period (June) harvesting at Metahara, and in the early (October) and late period (June) harvesting at Kessem. A split plot design with three replications was used where the main plot treatments were two sugarcane varieties, viz. B52-298 and SP70-1284, and the sub-plot treatment consisted of combinations of four harvest ages (10, 12, 14 and 16 months) and two ripener treatments [Moddus™ at 250 g ai ha−1 + Fusilade Forte™ (M + FF) at 25.6 g ai ha−1 combination sequentially sprayed and unsprayed control]. The results showed significant difference between the varieties for stalk height and stalk weight in early period study at Kessem with variety SP70-1284 being superior as compared to variety B52-298. Furthermore, harvest age and ripener combination significantly affected all yield and quality parameters, while there was a significant cane and sucrose yield response at Kessem at both sites and seasons. The highest cane yield was recorded in the unsprayed 16-month harvest age treatment, while the highest sucrose yield was recorded in the M + FF ripener combination 12-month harvest age treatment in all the studies. The economic analysis showed the highest marginal rate of return and net revenue in the M + FF ripener combination 12-month harvest age treatment and represents the best cane quality management practice for varieties B52-298 and SP70-1284 at these plantations.Ethiopian Sugar Corporation.https://link.springer.com/journal/400032024-08-10hj2023Plant Production and Soil ScienceSDG-15:Life on lan

Ripening Response of Sugarcane Varieties to Chemical Ripeners and Economic Benefits during the Early Period of Harvesting at Wonji-Shoa and Metahara Sugarcane Plantations, Central Rift Valley of Ethiopia

Wonji-Shoa and Metahara sugarcane plantations experience reduced sucrose content (%) during the starting period of sugarcane crushing due to the combined influence of high (>27°C) temperature and the presence of high residual soil moisture. Studies elsewhere showed the potential of chemical ripeners in boosting the sucrose content (%), where natural ripening is deterred by these challenges. Accordingly, a field experiment was conducted to evaluate the responsiveness of selected sugarcane varieties to chemical ripeners at both plantations. The treatments consisted of a factorial combination of four sugarcane varieties (B52298, NCo334, C86-56, and SP70-1284) and six ripener treatments: (1) Ethephon™(720 g ai ha−1), (2) Fusilade Forte™(25.6 g ai ha−1), (3) Moddus™ (250 g ai ha−1), (4) Ethephon™ (720 g ai ha−1) + Fusilade Forte™ (25.6 g ai ha−1), (5) Moddus™ (250 g ai ha−1) + Fusilade Forte™ (25.6 g ai ha−1), and (6) Unsprayed (control). The experiment was laid out in a randomised complete block design in a factorial arrangement with three replications. The results showed a significant (p=0.025) and highly significant (p=0.001) variety by ripener interaction in stalk height and sucrose content, respectively, while the main effect ripener highly significantly affected stalk weight (p=0.001) and sucrose yield (p=0.003). The variety C86-56 sprayed with combinations of Ethephon™ + Fusilade Forte™ and Moddus™ + Fusilade Forte™ had the shortest stalk heights of 1.27 and 1.29 m, respectively, compared with the control. Ethephon™ + Fusilade Forte™ combination resulted in the highest reduction of stalk weight (8.36%), while the lowest was recorded in the sole Moddus™ treatment (6.31%). From the ripener treatments, the Moddus™ + Fusilade Forte™ combination and Ethephon™ + Fusilade Forte™ combination improved sucrose yield by 1.42 and 1.34 t ha−1, respectively, compared with the control. However, in economic terms, the Moddus™ + Fusilade Forte™ combination treatment resulted in the highest marginal rate of return of 1244%. Therefore, the Moddus™ + Fusilade Forte™ combination ripener treatment was found to be promising to be evaluated at a commercial scale on immature sugarcane varieties B52-298, NCo334, and SP70-1284