Percentage Yield Loss Research Articles

Assessment of major insect pests of golden melon (Cucumis melo L.) and control with commercial Beauvaria bassiana in Abeokuta Southwestern, Nigeria

Pest infestation is a major challenge in production of golden melon, this study evaluated the performance of Beauvaria bassiana, a non-residual bio-pesticide, for effectiveness against insect pests of golden melon. The field experiment was carried out in 2022 to establish the effect of B. bassiana sprayed at different growth stages on the abundance of insect pests, damage, agronomic characteristics and fruit quality of golden melon. The results showed Aulacophora spp., Aphis gossypii, Epilachna chrysomelina, Bemisia tabaci Coridius viduatus and Zonocerus variegatus as the insect pests attacking golden melon in the study area. However, the population densities of Aulacophora spp. and E. chrysomelina were significantly lower in golden melon sprayed with B. bassiana at all compared to other spray treatments and the control. Percentage leaf damage and yield loss (20.81% and 327.70 g) in golden melon sprayed with B. bassiana at all stages were similar to lambda-cyhalothrin-sprayed plot (13.68 % and 318. 70 g). Also, highest percent leaf damage and yield losses (81.54 % and 1395.70 %) were obtained in the control plots relative to other spray treatments. Number of leaves and percentage increase in vine length were significantly higher in the golden melon sprayed with B. bassiana at all stages. There was 215.80 % increase in yield of golden melon sprayed with B. bassiana at all stages over the control in the study. Also, the nutritional composition of the fruits from the untreated plots was similar to that of the treated plots

Potential yield losses caused by the adults of Schizonycha ruficollis on pomegranate (Punica granatum) flowers

Pomegranate is an important fruit crop that is capturing international attention for its rich antioxidants and nutraceutical value. The demand for the fruit is rapidly increasing in major national and international markets. Therefore, any serious pest is of great importance and here we report the severe incidence of adult beetles of Schizonycha ruficollis that resulted in potential yield loss due to its feeding on pomegranate flowers in Devanahalli, Karnataka. Usually June/July adult beetle emerge and feed on hosts like neem and Melia rubra which the farmers plant them as wind breaks along the borders. These attract the beetles into pomegranate field and the pomegranate flowers are then infested by the adult beetles. The pomegranate on an average possess 223 female flowers per tree, which when damaged fails to set fruits causing economic loss. A documentation study during 2023 was taken up to evaluate the crop loss caused by S. ruficollis in pomegranate resulted in potential seven percent yield loss accounting to ₹ 53215/acre at the farm gate price. This loss can be avoided by initiating a management practice at the first site of the beetles especially after the first monsoon rain. This study also helped us to alert pomegranate exporters and extension officials about the need of preventive measures to avoid the yield loss.

Performance test of the combine harvester machine for rice harvesting in Indrapuri, Aceh Besar District

Paddy is a very important agricultural crop for mankind because more than half of the world’s population and almost the entire population of Indonesia depend on this plant as a source of food. Harvesting is a very important process in rice production, because in this process it is alleged that the level of yield loss is very high. Paddy harvesting can be done by modern farming (combine harvester) and conventional (manual), therefore it is necessary to know the effectiveness by analyzing the performance and efficiency of the two ways. This study aims to examine the performance of rice harvesting using a combine harvester and conventional machines in Indrapuri District, Aceh Besar District. The results of the combine harvester research show that the theoretical field capacity is 0.42 ha/hour, the effective field capacity is 0.25 ha/hour, efficiency is 60.03%, the working capacity is 743.54 kg/hour, the fuel consumption is 10.25 L/hour, and yield loss of 1.31%. Conventional harvesting shows a field capacity of 0.0049 ha/hour/person, thresher working capacity of 172.6908 kg/hour, thresher efficiency of 98.5417%, thresher fuel consumption of 0.5147 L/hour, and the percentage of yield loss is 3.8776%. Based on data on harvesting capacity, the combine harvester shows a better performance then conventional harvesting.

Integrated Management of Charcoal Rot and Its Influence on Seed Yield and Quality in Soybean

Charcoal rot (Macrophomina phaseolina) causes high grain yield loss in major soybean-growing nations worldwide. The present study aimed to reveal the effect of stage-wise charcoal rot incidence and their root and stem severity index on the yield criteria of soybean varieties. Additionally, an attempt was made to derive integrated management practices and their influence on seed quality. All the twelve varieties were affected by charcoal rot, and its incidence and root and stem severity index were high in Shivalik (48.5% and 3.7, respectively). In yield estimation, the percentage of yield loss ranged from 8.7% (JS 20-98) to 53.9% (Shivalik). Percent yield loss had a strong significant positive relation with percent incidence (0.912**) and Root and Stem severity index (0.813**) of charcoal rot. Seed treatment of Penflufen 13.28% + Trifloxystrobin 13.28 % FS @ 1ml/kg followed by spraying of tebuconazole 25% EC @ 0.1 % spraying at 45,60,75 days was significantly superior in reducing charcoal rot (19.7%) in comparison to untreated (37.3%). The highest seed germination (80.0 %) and least association with M. phaseolina (13.33%), Aspergillus flavus (3.33%), Fusarium sp., (13.34%) in comparison to control (50, 36.67, 23.33 and 36.67 %, respectively) were also resulted from the seed obtained from above treatment. In bioagent, seed treatment of T. harzianum @ 10 gm/kg followed by foliar spray of tebuconazole 25% EC @ 0.1% at 45,60,75 days was the second-best combination among all treatments in all respects. The effect of these fungicides and bio agents as seed treatment also improved the number of branches, pods, 100 seed weight and yield. Hence, these combinations could be applied to minimize charcoal rot and yield losses in soybean.

Incidence and epidemiology of rice (<i>Oryza sativa</i>) false smut caused by <i>Ustilaginoidea virens</i> in northern India

False smut of rice (Oryza sativa L.) caused by Ustilaginoidea virens (Cooke) Takah., 1896 is an important emerging disease of rice. An experiment was conducted during 2018–19 and 2019–20 at Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh to study the U. virens prevalence and morphological variability in northern India with the effect of weather variables on the percentage disease incidence (PDI) of false smut of rice. The study revealed that the false smut incidence was higher in Varanasi district of Uttar Pradesh (53.64%). The lowest percentage (20.68–27.55%) of infected tillers was found in Kangra district of Himachal Pradesh, and Tehri Garhwal district of Uttarakhand. The grain replacement percentage was highest in the Moti cultivar (51.17%), while the highest yield loss percentage was in the Pusa Basmati (57.11 %) variety. The majority of the isolates in our investigation had fluffy, raised, and irregular colony morphology. The correlation between the false smut disease incidence and weather has been evaluated in the Varanasi district, and found that the temperature of 20.36°C with an RH of 85.13% and low rainfall of 8.92 mm was conducive to disease initiation and positively correlated with the PDI. Other epiphytotic factors like sunshine hours, and wind speed were all found to be negatively linked with PDI. In this investigation, for the first time, the viability of spores was also checked. It was found that 2-year-old spores were not viable because they did not retain any Brilliant Cresyl blue colour dye, which stains the stored food material in spores, while 1-month-old spores were found to be 100% viable. All the isolates were further confirmed with the specific ITS marker.

Progress in developing and deploying drought-tolerant and insect-pest resistant climate-resilient droughtTEGO® and TELA® maize varieties

Currently, drought stress and associated insect-pest damage pose a huge threat to food and nutrition security for over 300 million people in Africa who depend on maize as their main food source. Recurrent drought events cause an annual 17 to 25 percent yield loss of maize in Africa [1]. Compounding the impact of drought, is the ravaging effect of insect-pests infestation on maize production, especially for pests whose population pressure is highly triggered under dry conditions. The crop under weakened conditions created by drought stress and pest effect further becomes constrained biologically and physiologically, thus limiting the crop’s ability to use already limited water and nutrients from the soil. The major insect pests of maize in Africa are fall armyworm (FAW, Spodoptera frugiperda) and various stem borer species (Spotted stem borer (Chilo partellus), African stem borer (Busseola fusca), and the pink stemborer (Sesamia Calamistis). For instance, in Kenya alone, an average of 13 percent or 400,000 tons of maize is lost to stem borer, which is equivalent to the annual maize imports, valued at USD 90 million [2]. The FAW, a transboundary pest, first observed in the continent in 2016, is a maize pandemic that if not controlled adequately, could potentially destroy up to 20 million metric tons of maize annually, enough to feed 100 million people in Africa [3].

Analisis Kecepatan Putar Silinder Perontok Terhadap Kinerja Mini Power Thresher Hasil Rekayasa UPJA Desa Sungai Kelambu

<p><em>Various types of power threshers have been developed to suit conditions in the field. The development of the power thresher was also carried out by UPJA Sungai Kelambu Village, Sambas Regency by making a mini power thresher that was designed to suit the conditions of the land and the needs of local farmers. The purpose of this research was to obtain a relationship between threshing rotational speed and performance on the mini power thresher. The threshing cylinder rotational speed was varied at 669 and 778 rpm. The measured performance of the mini power thresher was feeding capacity, threshing capacity, cleanliness, percentage of grain not threshed, percentage of scattered grain, threshing efficiency, percentage of yield loss, fuel consumption, and increase in cracked grain. The test sample used was IR 64 rice. Based on the test results, the rotational speed of the thresher cylinder has a very significant effect on the threshing performance of the mini power thresher. Changes in threshing cylinder rotational speed from 669 rpm to 778 rpm can improve the performance of the mini-power thresher in terms of feed capacity, threshing capacity, threshing cleanliness, percentage of grain scattered, and percentage of yield loss.</em> <em>The decrease in performance is found in fuel consumption and the percentage of cracked grain. The variables that relatively unchanged were the percentage of grain not threshed and threshing efficiency. The operation of this mini power thresher is recommended at a thresher cylinder rotational speed of 778 rpm.</em></p>

Development of Short Duration, Tolerance to High Temperature and Bipolaris Leaf Blight, and Moderately Susceptible to Blast Disease of Wheat Genotype with Trials in Various Agroecological Zones in Bangladesh

Wheat production in Bangladesh faces to the detrimental effects of biotic and abiotic stresses that have been exacerbated by climate change. The development of short duration, high temperature and disease tolerant wheat variety is the most importance to produce higher yield combating the deleterious effects of the stresses. Some wheat lines (line was expressed by E) were evaluated at the different research stations of Bangladesh Wheat and Maize Research Institute (BWMRI) and farmers’ fields in consecutively three years under irrigated timely sowing (ITS) and irrigated late sowing (ILS) conditions. The days to heading (DH), days to maturity (DM), plant height (PH), spikelet spike-1 (SPS), grain spike-1 (GPS), thousand grain weight (TGW), and grain yield were depicted comparatively higher in ITS and ILS than ITS, but the severity of Bipolaris leaf blight (BpLB) and blast diseases were exhibited lower in BAW 1194 (E9) line than check varieties and other lines same conditions (BAW = Bangladesh Advanced Wheat). Those phenotypic and yield contributing characters, and BpLB and blast diseases were also observed lower in ILS than other genotypes. Further, E9 exhibited the lower percentage of yield loss in the ILS compared to ITS than check and other genotypes indicated its high temperature tolerance. In addition, E9 exhibited relatively higher grain yield than other genotypes in the candidate variety demonstration and multiplication yield trials. Therefore, BAW 1194 line may be released as a short duration, tolerance to high temperature and BpLB, and moderately tolerance to blast disease wheat variety to accelerate wheat production.

An intelligent fuzzy system to manage western flower thrips population under biological treatment in roses yield

Experimentation centers in the French Riviera (SCRADH, Florisud, and others) are keen on informing growers about the propitious weather conditions relative to pest risk growth. The only existing method used nowadays is sending notifications to their mobile phones. In this study, we are interested in developing a system for Western Flower Thrips (WFT) risk assessment. We propose a fuzzy logic approach to build an intelligent system that supplies rose growers with an estimate of the next day’s risk in their greenhouses. The system relies on today’s data (data of the day) to predict the next day’s risk, under the presence of bio-control agents, in particular, harmless fungi called Beauveria Bassiana. We could recapitulate the study’s outcomes in the following elements. The most significant aspect is estimating a daily risk index that provokes premature detection of WFT. Besides, considering the utilization of biological treatment aids in reducing the pulverization of pesticides. In addition, the system incorporates a small number of sensors usually found in almost all greenhouses. Thanks to continuous monitoring of the weather conditions (real-time system), the system could help mitigate the percentage of yield loss. Finally, this is the first attempt to employ fuzzy logic to predict WFT subjected to biological treatment. We compared the obtained results to actual data. The model’s accuracy was determined by three statistical indicators (coefficient of determination (R2), root mean squared error (RMSE), and mean absolute error (MAE)) showing a noticeable performance. The fuzzy model showed satisfactory results (R2=0.9, RMSE= 10%, and MAE=7.3%) making it reliable and robust for pest monitoring.

Differential Responses of Cherry Tomatoes (Solanum lycopersicum) to Long-Term Heat Stress

As global warming increases day/night temperatures as well as frequencies of heat waves, studying physiological responses in long-term heat stress is required for sustainable yield production in the future. In this study, effects of long-term heat stress on photosynthetic, morphological, and yield parameters of three cherry tomato accessions, HR17, HR22, and HR24, were evaluated. The experiment was conducted under two temperature greenhouse conditions, where temperature set-point for ventilation was 30 °C and 35 °C during the day for 57 days, respectively. Plants were harvested on the 35th days and 57th days after heat treatments, and their physiological and morphological characteristics and yield traits were measured. Under control conditions, HR17 and HR22 had 0.5–0.6 harvest index, while HR24 had 0.3 harvest index. On 35th days after heat treatment, although yield loss percentage of HR17 was high (43%), it produced the highest fruit yield among all three accessions. However, after longer heat treatment, HR24 produced the highest fruit yields among all accessions with the smallest yield loss (34%). Furthermore, yield loss was highly associated with reductions in nitrogen use efficiency and water content in plant body under heat stress. The results of this study will provide breeders with a new insight into selecting heat-tolerant genotypes in cherry tomatoes.

Comparative Metabolomic Profiling of Horse Gram (Macrotyloma uniflorum (Lam.) Verdc.) Genotypes for Horse Gram Yellow Mosaic Virus Resistance.

Horse gram (Macrotyloma uniflorum (Lam.) Verdc.) is an under-utilized legume grown in India. It is a good source of protein, carbohydrates, dietary fiber, minerals, and vitamins. We screened 252 horse gram germplasm accessions for horse gram yellow mosaic virus resistance using the percent disease index and scaling techniques. The percentage values of highly resistant, moderately resistant, moderately susceptible, susceptible, and highly susceptible were 0.34, 13.89, 38.89, 46.43, and 0.34, respectively. Repetitive trials confirmed the host-plant resistance levels, and yield loss was assessed. The present disease index ranged from 1.2 to 72.0 and 1.2 to 73.0 during the kharif and rabi seasons of 2018, respectively. The maximum percent yield loss was noticed in the HS (75.0 -89.4), while HR possessed the minimum (1.2-2.0). The methanolic leaf extracts of highly resistant and highly susceptible genotypes with essential controls were subjected to gas chromatography-mass spectrometry analysis. Differential accumulation of metabolites was noticed, and a total of 81 metabolites representing 26 functional groups were identified. Both highly resistant and susceptible genotypes harbored eight unique classes, while ten biomolecules were common. The hierarchical cluster analysis indicated a distinct metabolite profile. Fold change in the common metabolites revealed an enhanced accumulation of sugars, alkanes, and carboxylic acids in the highly resistant genotype. The principal component analysis plots explained 93.7% of the variation. The metabolite profile showed a significant accumulation of three anti-viral (octadecanoic acid, diphenyl sulfone, and 2-Aminooxazole), one insecticidal (9,10-Secocholesta-5,7,10(19)-triene-3,24,25-triol), one antifeedant (cucurbitacin B), and six metabolites with unknown biological function in the highly resistant genotype.

Studying the Yield and Yield Parameters of Mungbean in Response to Different Weed-Crop Competition Periods

Impact of weed-crop competition periods on the yield and yield parameters of mungbean was investigated during the spring and summer season of 2018 at Agronomic Research Farm, Bahauddin Zakariya University, Multan. Treatments comprised of different weed-crop competition periods, weeds were allowed to compete for 15, 30, 45 and 60 days with mungbean after sowing. For comparison, weed free and weedy check plots were also maintained. Results revealed the importance of controlling weeds for getting better grain and other yield contributing traits during both the seasons. Uncontrolled weeds caused about 50 percent yield losses. Whereas similar results of grain yield and other yield related parameters were also recorded in weed free plots and weed-crop competition period for 15 days after sowing plots, while there is a gradual decline in yield and other yield related parameters if weed-crop competition periods were prolonged. These studies highlighted the importance of controlling weeds with further indication of controlling weeds till 15-30 days after sowing to get better yield of mungbean crop in both the spring and summer seasons.

Weed control and sustainable rice production through rice intensification system and conventional practices of weed competition periods and age of transplanted seedlings

Rice is an important cereal crop of global interest based on its daily uses. It was observed that the average yield of rice is low than its potential production due to the traditional growing techniques and weed intensification. Recently, the rice intensification system (RIS) has emerged as an alternative to the conventional rice cultivation system. A two-year field study was carried out to investigate the impact of seedling age (14, 21 & 28 days) and the weed competition periods (weedy check, 20, 40, 60, 80 DAT and weed-free throughout the growing season) in rice cultivated through RIS. Weedy check and weed-free for the growing season were kept as a control treatment. The results of our study revealed that a maximum dry weight (108.7 and 111.79 gm-2) and weeds density (101.7 and 110.6 plants m-2) of weed recorded in weedy check plot where 28 days old seedlings was transplanted while minimum dry weight (11.01 and 10.3 gm-2) and weeds density (9.7 and 10.9 m-2) were achieved in plots where 21 days old seedlings were transplanted and remain weed free. It was noted that weed density and weed dry biomass were gradually increased with increasing weed competition period at all ages of the rice seedling. Purple nutsedge (C. rotundus) exhibited maximum relative proportion in total weed’s density and dry biomass and also ranked first by weed summed dominance ratio (WSDR). Agronomic yield and yield contributing traits such as number of fertile tillers per hills (58.1 and 56.0), plant height (130.5 cm and 125.6 cm), kernels per plant (186.4 and 179.4), straw yield (7.8 t ha-1 and 7.5 t ha-1) and kernel yield (5.2 and 5.0 t ha-1) were maximum in plot that remained weed-free throughout the growing season with a seedlings age of 21 days during 2010 and 2011 respectively. Percent yield losses were minimum in plots with 21 days old seedling transplantation and at 20 days of weed competition period. Hence, present study concludes that 21 days old fine rice seedlings should be transplanted and weeds should be controlled within 20 DAT under SRI for effective weed control to avoid yield losses.

Critical-point yield loss models based on incidence and severity of wheat head blast epidemics in the Brazilian Cerrado

Wheat head blast (WHB), caused by the fungus Pyricularia oryzae Triticum pathotype, is one of the most damaging diseases of wheat. In Brazil, the disease has limited the expansion of wheat in the tropical regions of the Cerrado biome. In this study, wheat yield (Y) and visual estimates of WHB incidence (I) and severity (S) (assessed 25 to 30 days after flowering) were measured in a single location in the Cerrado (Minas Gerais state) where field experiments were conducted during seven sequential years (2013 to 2019) using three cultivars and 12 planting dates each year. Pearson correlation (r) analysis, used to study the association between each of the three disease variables (I, DHS = diseased-head severity and S) and Y, under a meta-analytic framework, showed the strongest association between incidence and yield (rI-Y = −0.92) and severity and yield (rS-Y = −0.90). The functional relationship between WHB intensity (I or S) and Y was studied based on the fit of a random coefficients model to I or S and the log-transformed Y data. The population average estimated intercept and slope for the I or S and log-Y relationships were 7.798 log units (2436.6 kg/ha) and − 0.020 for the I-Y relationship and 7.721 log units (2255.5. kg/ha) and − 0.030 for the S-Y relationship. The relative (percent) yield loss when I or S reaches 10% was predicted at 18.4% and 26.1%, respectively. This study provides a basis for understanding and predicting yield losses due to wheat blast based on the visual assessment of two disease variables assessed at a single time during the epidemics.

Integrated Potential of Microbial, Botanical, and Chemical Pesticides for the Control of Viral Disease Vector Whiteflies (Hemiptera: Aleyrodidae) on Tomato under Greenhouse and Field Perspectives

Whiteflies are one of the most devastating horticultural pests attacking tomatoes. Although there are several control methods for the control of whitefly pests, the integrated application of entomopathogenic fungi (IPM) with chemical and botanical insecticides has proven more effective than individual control agents. This study was carried out to evaluate individual and combined treatments of entomopathogens B. bassiana, M. anisopliae, B. thuringiensis, Hunter 40 EC, and neem oil for the control of whitefly species on tomato (Solanum lycopersicum) under greenhouse and field condition. The greenhouse study showed that the different treatments resulted in a 58.48 to 100% reduction of nymphs and a 52.06 to 100% reduction of adults on both Galilea and Melkashola tomato varieties under greenhouse conditions. The combined treatments of AAUMB-29 + Neem oil displayed a higher yield (423.3 g fruits/plant) on the Gelilea tomato variety, and AAUDM-43 + Hunter 40 EC displayed a yield of (376.66 g/plant) on the Melkashola tomato variety. Under field conditions, the application of AAUMB-29 + Hunter 40 EC + Neem oil significantly decreased the whitefly population by 91.93% (P<0.001) after 10 days of the fourth spray. The result of fruit yield of tomato was significantly higher in all treatments (31.17 t to 70.42 t·ha−1) compared to untreated control (25.83 t·ha−1). Among the treatments, AAUMB-29 + Hunter 40 EC + Neem oil gave the highest fruit yield of 70.42 t·ha−1 followed by AAUMB-29 + Hunter 40 EC (64.50 t·ha−1) on the Galilea tomato variety under field conditions. The combined treatment of AAUMB-29 + Hunter 40 EC + Neem oil was the most effective with lower whitefly infestation, higher marketable yields, and less percentage of yield losses. Further investigations are required to determine the optimization and practicability of this integrated application of treatments for the control of both sucking and chewing insect pests under field conditions.

Evaluation of efficacy of Phyto-synthesized iron oxide nanoparticles in contributing drought resilience in wheat (Triticum aestivum L.)

Wheat is the majorly cultivated staple crop worldwide. The world witnesses a great percentage of yield loss of wheat due to drought stress. The present study aimed at evaluating the efficacy of phytosynthesized iron oxide nanoparticles (FeONPs) in contributing to drought resilience in wheat (Triticum aestivum L.) under rain-fed conditions. FeONPs were biosynthesized by using leaf extract of Prosopis cineraria as a reducing and capping agent. The synthesized nanoparticles were characterized to evaluate the structural and biochemical aspects. The FeONPs were found to be irregularly spherical in shape with a mean size of 42.6 nm. The concentration of nanoparticles in the sample was found to be 164.01 mg l−1. An experimental setup was laid out in a randomized-plot design with 3 replications for Rabi season 2020–2021. Five dosages of nanoparticles were prepared as 12.5, 25, 50, 75 and 100 ppm from the stock solution. The wheat crop varieties grown in the field were subjected to a total of 3 treatments; Nanopriming, foliar application of FeONPs at seedling development stage (20 DAS), and tillering stage (30 DAS). Plants that were not treated with NPs were considered as control. No irrigation regime was followed as the effect of NPs on the crop was to be assessed under rain-fed conditions only. Plant growth parameters were recorded. The obtained results revealed that the application of FeONPs positively affected all the morphological and yield attributes in the wheat crop. The highest concentrations used were found to be most effective and showed a significantly pronounced effect as compared to the control at p ≤ 0.05. The study concluded that the FeONPs can contribute to drought resilience in wheat.

Observed Changes in Crop Yield Associated with Droughts Propagation via Natural and Human-Disturbed Agro-Ecological Zones of Pakistan

Pakistan’s agriculture and food production account for 27% of its overall gross domestic product (GDP). Despite ongoing advances in technology and crop varieties, an imbalance between water availability and demand, combined with robust shifts in drought propagation has negatively affected the agro-ecosystem and environmental conditions. In this study, we examined hydro-meteorological drought propagation and its associated impacts on crop yield across natural and human-disturbed agro-ecological zones (AEZs) in Pakistan. Multisource datasets (i.e., ground observations, reanalysis, and satellites) were used to characterize the most extensive, intense drought episodes from 1981 to 2018 based on the standardized precipitation evaporation index (SPEI), standardized streamflow index (SSFI), standardized surface water storage index (SSWSI), and standardized groundwater storage index (SGWI). The most common and intense drought episodes characterized by SPEI, SSFI, SSWSI, and SGWI were observed in years 1981–1983, 2000–2003, 2005, and 2018. SPEI yielded the maximum number of drought months (90) followed by SSFI (85), SSWSI (75), and SGWI (35). Droughts were frequently longer and had a slower termination rate in the human-disturbed AEZs (e.g., North Irrigated Plain and South Irrigated Plain) compared to natural zones (e.g., Wet Mountains and Northern Dry Mountains). The historical droughts are likely caused by the anomalous large-scale patterns of geopotential height, near-surface air temperature, total precipitation, and prevailing soil moisture conditions. The negative values (<−2) of standardized drought severity index (DSI) observed during the drought episodes (1988, 2000, and 2002) indicated a decline in vegetation growth and yield of major crops such as sugarcane, maize, wheat, cotton, and rice. A large number of low-yield years (SYRI ≤ −1.5) were recorded for sugarcane and maize (10 years), followed by rice (9 years), wheat (8 years), and cotton (6 years). Maximum crop yield reductions relative to the historic mean (1981–2017) were recorded in 1983 (38% for cotton), 1985 (51% for maize), 1999 (15% for wheat), 2000 (29% for cotton), 2001 (37% for rice), 2002 (21% for rice), and 2004 (32% for maize). The percentage yield losses associated with shifts in SSFI and SSWSI were greater than those in SPEI, likely due to longer drought termination duration and a slower termination rate in the human-disturbed AEZs. The study’s findings will assist policymakers to adopt sustainable agricultural and water management practices, and make climate change adaptation plans to mitigate drought impacts in the study region.

Effect of dust and cleaning methods on mono and polycrystalline solar photovoltaic performance: An indoor experimental study

Photovoltaic modules are affected by the weather and are sensitive to dust accumulation. The accumulation of dust causes obvious losses in the produced yield. To reduce these losses to a minimum, it is recommended to clean the photovoltaic units periodically by several cleaning methods. In this practical study, the accumulated dust was collected for a period of two months (March and April/2021) from five sites in the Wilayat of North Al Batinah – Oman. The dust components were examined, and the sources of these components were determined and their proportions in the dust of each city. The study adopted the examination of the effect of each component separately on the performance of monocrystalline and polycrystalline PV modules. The results showed that the contamination of 5 g/m2 on the monocrystalline PV module caused a decrease in the produced power by 12%, 6%, 6%, 7%, 3%, 4%, and 4%, for ash, calcium carbonate, limestone, cement, sulfur, sawdust, and brown soil, respectively. For polycrystalline module, at the same contamination (5 g/m2), the measured deteriorations were 5%, 4%, 4%, 1%, 2%, and 2% for ash, sand, limestone. sawdust, black silicon carbide and silica gel, respectively.The best manual cleaning methods were also studied to choose the optimal ones for each PV module and city. Polycrystalline are more affected than monocrystalline by the accumulated dust, with an average of not less than 10% at an accumulation rate of 50 g/m2 and 5.28% at an accumulation rate of 5 g/m2. The best way to clean PV modules to recover the largest percentage of yield losses is the sodium solution with rubber and cloth brushes. The study suggests, depending on the practical results, periodic cleaning periods from 10 days (for polycrystalline module in the cities of Liwa, Sohar and Barka) to 15 days (for monocrystalline module for all the cities studied).

Yield gap in bitter gourd production: A perspective of farm-specific efficiency in Narsingdi district in Bangladesh

The concept of yield gaps arose from IRRI experiments undertaken in the 1970s. The yield gap in this study refers to the discrepancy between prospective farm yield and actual average farm yield. This study aims to find the yield gap by studying the efficiency, abiotic and biotic factors. Simple random sampling techniques were used to collect data, and a total of 72 respondents were interviewed for this purpose. The study revealed that 90.70%, 80.30%, and 73% of farmers were technical, allocative, and cost-efficient for bitter gourd production. The yield gap was 15, 245 kg/ha due to the non-transferable component of technology, whereas 3914 kg/ha was due to existing inefficiency at the farm level. Moreover, combined biotic and abiotic factors were responsible for the 19.91 percent yield loss, constituting a mean yield gap of 6598 kg/ha. Low price of bitter gourd, high labor wage rate, and high input price was the main socio-economic constrain for improving bitter gourd production where excessive rainfall, attack by insect and disease, lack of quality seed, and lack of proper utilization of irrigation facilities were identified as main biophysical constraints for bitter gourd production. Government intervention by providing training, maintaining an effective marketing system, and ensuring quality input can greatly remove the problem mentioned by farmers.

Farmers’ Perception on Potato Pests and Yield Loss Assessment by Red Ant and White Grub on Potato in Ramechhap, Nepal

Survey was conducted to assess the knowledge and practices of potato growing farmers’ on the details of potato pests in Gokulganga Rural Municipality of the Ramechhap district. Fifty farmers’ were randomly selected and interviewed using structured open-ended questionnaire for collecting the information. Similarly, field yield loss by red ant and white grub on Cardinal and Rosita variety was assessed from one meter square area of thirty fields of the survey site. Survey revealed red ant followed by white grub were the major pest of potato. The average percentage yield loss by the red ant and white grub was 17.3% and 10.5%, respectively. It was also found that, Rosita variety was better in terms of yield than Cardinal. The percentage yield loss on Cardinal and Rosita variety was 15.59% and 6.11% by red ant and 2.01% and 4.16% by white grub, respectively. There is not significant difference in yield loss by red ant and white grub in between Cardinal and Rosita variety. The correlation between white grub population and percentage yield loss is moderately positive in both Cardinal (0.448) and Rosita (0.246) variety whereas correlation between red ant population and percentage yield loss is negative in Cardinal (-0.15) and less positive in Rosita (0.023) variety. Farmers’ knowledge and practices on potato pest management and field loss information can be useful to design integrated pest management strategy for potato pest management.