Groundnut Pod Research Articles

Efficient Tillage Practice for Maximum Infiltration, Rainwater Use Efficiency, and Profitability from Groundnuts under Semiarid Vertisols in Western India

Field experiments were conducted on groundnuts (Arachis hypogea) at Rajkot, India, during kharif from 1996 to 2006 to assess the efficiency of four tillage treatments: (1) shallow ploughing, (2) deep ploughing every year, (3) deep ploughing alternate years, and (4) deep ploughing once every three years. The tillage treatments were assessed for their effects on rainwater use efficiency (RWUE), soil moisture at depths of 0–15 and 15–30 cm, cumulative depth of infiltration, pod and straw yields attained, and sustainability over the years based on the sustainability yield index (SYI) criterion. The rainfall received during the crop growing period (June to September) ranged from 210.9 to 1,119.5 mm with a mean of 582.4 mm and variation of 47.4% over the years. A significantly higher mean pod yield of 770 kg/ha and a straw yield of 2,134 kg/ha were attained under yearly deep ploughing than under shallow ploughing (664 and 1,840 kg/ha). Yearly deep ploughing resulted in a mean infiltration depth of 12.8 cm and a RWUE of 1.59 kg/ha/mm, which were significantly higher than those of shallow ploughing (8.8 cm and 1.37 kg/ha/mm). Regression models of pod and straw yield were calibrated through monthly rainfall received during June to September and cumulative rainfall of these four months to assess the sustainability of the models over the years. The models attained coefficient of determination values in the ranges of 0.41 to 0.53, based on monthly rainfall, and 0.71 to 0.76, based on cumulative rainfall, for predicting the pod and straw yields of groundnuts based on the long-term study. The SYI ranged from 19.7 to 24.8% based on monthly rainfall and 25.6 to 30.9% based on cumulative rainfall for attaining maximum pod yield, and from 35.7 to 40.5% based on monthly rainfall and 38.0 to 44.8% based on cumulative rainfall for straw yield. The deep ploughing done every year resulted in maximum gross returns of 22,661 Rupees per hectare with benefit-cost ratio of 1.53, compared to shallow ploughing, with 19,543 Rupees per hectare and 1.43, respectively. The study indicated that yearly deep tillage was superior to attain maximum groundnut pod and straw yields, SYI, RWUE, gross returns, and benefit-cost ratio, in addition to providing maximum depth of infiltration. The deep ploughing done every alternate year and every three years were found to be the second and third best treatments for different parameters based on the study.

Optimizing the Performance of a Manually Operated Groundnut (Arachis hypogaea) Decorticator

Shelling of groundnut pods using manual decorticators in Kenya is characterized by high kernel breakages and low shelling efficiencies. As a result, farmers get low income due to low cost of broken kernels and a lot of time is lost in the tedious shelling operation. To overcome this problem, pertinent parameters that influence shelling efficiency of manually operated groundnut decorticators were identified. Two manually operated decorticators were tested and modifications done on one of the decorticators to optimize its technical performance. Results of machine performance tests showed that for WBS (Wooden beater sheller) at a feed rate of 30 kg/hr and 22.6 mm clearance, shelling efficiency increased with decrease in moisture content for all the groundnut varieties. The highest shelling efficiency was 55.3% for ICGV 99568, 39.2% for ICRISAT Groundnut Variety (ICGV) 90704 and 29% for ICGV 12991 at moisture content of 5.92% wb. For RBS (Rod beater sheller) at a feed rate of 30 kg/hr and 22.6 mm clearance, the highest shelling efficiency was 58.3% for ICGV 99568, 42.7% for ICGV 90704 and 35% for ICGV 12991 at moisture content of 7% wb. Identification of the pertinent parameters showed that pod moisture content, clearance and sieve size influence performance of manually operated groundnut. Theoretical predictive models developed were optimized which showed that a maximum shelling efficiency of 88.73% can be achieved with percent damage of 4% when the sieve size is 11 mm and clearance is 16 mm with a regression coefficient of over 85%. With the modifications done on the WBS decorticator, the highest shelling efficiency of 87% was obtained at a clearance of 10 mm for ICGV 99568 which is the largest in size from the three varieties. The shelling efficiency of the modified decorticator is far above those of the RBS and WBS because the sieve sizes and clearances of the later were not optimized. The results of the theoretical optimization of the manually operated groundnut decorticator implies that farmers who shell for seeds can now obtain more seeds shelled with low breakage and therefore will get more income.

Efficacy and insecticidal properties of some essential oils against Caryedon serratus (Oliver)-a storage pest of groundnut.

During storage groundnut is attacked by number of stored grain pest and management of these insect pests particularly bruchid beetle, Caryedon serratus (Oliver) is of prime importance as they directly damage the pod and kernels. Hence, some essential oils were tested for their insecticidal and fungicidal properties. Highest total bruchid mortality was recorded with the application of neem oil and pongamia oil at 10% (v/w) concentration and lowest in eucalyptus oil at 5% (v/w). Number of eggs laid was recorded 2.3 in neem oil 10% (v/w) which was lowest and significantly superior over untreated control and was at par with castor oil 10% (v/w) which recorded 2.5 eggs per 100 g of groundnut pods. There was no adult emergence in the groundnut pods treated with castor oil, eucalyptus oil, neem oil and pongamia oil at 10% (v/w) concentration. Groundnut pods treated with castor oil, eucalyptus oil, neem oil and pongamia oil at 10% (v/w) and neem oil at 5% (v/w) concentrations recorded no damage to pods and kernels and also zero per cent weight loss. These oils effectively influenced groundnut bruchid establishment and reduce damage besides reduction in aflatoxin contamination.

Soil carbon sequestration and agronomic productivity of an Alfisol for a groundnut-based system in a semiarid environment in southern India

Soil organic carbon (SOC) is a strong determinant of soil quality and agronomic productivity especially under harsh arid and semiarid environments of the tropics. Thus, a 20-year experiment was used to assess the impact of rainfed groundnut (Arachis hypogeae) monocropping, fertilization and manuring on soil quality, SOC sequestration, and crop yield sustainability on an Alfisol in southern India. Five treatments with 4 replications were: (1) control (no fertilizer or manure), (2) 100% recommended dose of fertilizer (RDF, 20:40:40kgha−1 of N:P2O5:K2O), (3) 50% RDF+4Mgha−1 of groundnut shells (GNS), (4) 50% RDF+4Mgha−1 of farmyard manure (FYM) and (5) 5Mgha−1 of FYM. The SOC concentration to 1-m depth increased from 2.3 to 3.5gkg−1 (52.2%) in 50% RDF+4Mgha−1 GNS over control and mean SOC sequestration rate was 0.57MgCha−1yr−1. Higher mean pod yield of groundnut (Mgha−1) was obtained with 50% RDF+4Mgha−1FYM (1.03). The rate of increase in groundnut pod yield was 13kgha−1yr−1 for every one Mg increase in profile SOC stock. A minimum of 1.12MgCha−1yr−1 input was needed to maintain the zero change in SOC. Hence, combined use of chemical fertilizers and organic manure is essential to enhancing SOC sequestration in monocrop regions in semi arid tropical conditions.

The Impact of Gypsum Application on Groundnut Yield in Rainfed Pothwar: An Economic Perspective

This study presents an economic analysis of experimental on-farm data on the yield effect of gypsum on groundnut production in Pakistan’s Pothwar region. The data indicates that groundnut pod yield increases significantly with the application of gypsum at 500 kg/ha for both local and improved (chakori) varieties of groundnut. The higher net benefits generate a marginal rate of return of up to 132 percent for local and 202 percent for improved varieties of groundnut. We carry out a sensitivity analysis and minimum returns analysis, and find, respectively, that the recommended application is capable of withstanding price variability and variability in yield. Since price structure changes more rapidly than technology, recommendations should be based on an analysis of returns under varying input and output prices.

EFFECT OF SEED PRIMING AND MICRO-DOSING OF FERTILIZER ON GROUNDNUT, SESAME AND COWPEA IN WESTERN SUDAN

SUMMARYThe effect of seed priming and micro-dosing in groundnut, cowpea and sesame was studied for three years in on-farm and on station experiments under rainfed agriculture in North Kordofan, Sudan. The on-station trials showed that seed priming increased groundnut pod and hay yields by 18% and 20% respectively. Micro-dosing of 0.3, 0.6 and 0.9 g fertilizer per pocket increased groundnut pod yield across the three years by 36.7, 67.6 and 50.8% respectively compared to the control. The highest yield increases were consistently obtained when micro-dosing was combined with seed priming. A combination of seed priming and micro-dosing of 0.6 g increased groundnut yield by 106%. Priming alone did not significantly affect sesame seed or hay yield, but micro-dosing of 0.6 g per pocket increased the grain yield by 38% over the control. Cowpea grain yield in the on-station experiments was not significantly affected by seed priming or micro-dosing. However, both seed priming and micro-dosing increased cowpea hay yield. In the on-farm trials, seed priming increased groundnut and cowpea yields by 18.2 and 25.5% respectively, and seed priming combined with 0.3 g fertilizer increased their yields by 42.2 and 54.5% respectively compared to the control. For sesame the yield increase after 0.3 g fertilizer per pocket was 46.3%. The economic analyses of the on-station experiments showed that the highest gross margin was obtained when combining seed priming with 0.6 g micro-dosing for all the crops. These results show that the combination of micro-dosing and seed priming has the potential to increase productivity and improve net return in the crops tested.

Some observations on the culture of attached groundnut (Arachis hypogaea L.) gynophores in simplified nutrient solutions.

Attached groundnut gynophores of Virginia line Virginia bunch strain 1 (VB-1), Spanish line TMV-3 and Valencia line CBBR4 were cultured singly in aerated, simplified nutrient solutions consisting of (2 μM iron (Fe) and 0.5 μM zinc (Zn) with or without 100 μM calcium (Ca). In all lines, normal and apparently healthy pods were produced in solutions containing Ca, whereas, pod growth was severely restricted in solutions without Ca. Three of CBRR4 gynophores cultured in solution containing Ca formed healthy tap roots. It was concluded that a simplified solution containing only Ca, Zn and Fe could support healthy groundnut pod growth. Key words: Arachis hypogeae, groundnut gynophore, pod development, root formation, solution culture.

Effects of agricultural by-products as smoking fuels on the eating qualities of comminuted beef sausages

This study was carried out to assess the effects of alternative smoking fuel on the eating qualities of comminuted beef sausages. The sausages were produced with lean beef (2.5kg), minced, mixed with spices, chopped and stuffed into natural casings. They were five groups of sausages and each group was smoked with one of five fuel types: Sawdust (control, C), corn cobs (CC), groundnut pods (GNP), Soyabean residue (SBR) and rice husk (RH) for one hour, scalded, cooled and stored for assessment two days after production. The attributes assessed were colour, taste, flavour and texture of the smoked sausages. A five–point category scale was used for the evaluation. There were no significance differences among the fuel types for smoky flavour and texture but the colour and taste were significantly affected by the fuel types. The fuel types imparted a desirable brown or yellow colour and a moderate ‘smoky’ flavour in the sausages resulting in a pleasant taste. The alternative fuel exhibited different characteristic during the smoking process but have the potential for use in smoking comminuted beef sausages and could therefore serve as substitutes or supplementary fuel to the use of sawdust. The moistened GNP was observed to produce the best smoke among the fuel types. Key words: Smoking, fuel types, eating quality, beef sausages

Evaluation of Pseudomonas fluorescens and Trichoderma viride as Seed and Soil Treatment against Root Knot Nematode, Meloidogyne arenaria Infecting Groundnut

Studies on evaluation of biocontrol agents against Meloidogyne arenaria on groundnut under glasshouse conditions revealed that application of Pseudomonas fluorescens as seed treatment+soil application recorded significant increase in plant growth characters and groundnut pod yield compared to untreated control. Groundnut plants treated with P. fluorescens as both seed treatment+soil application recorded least number of galls/plant, egg mass/plant, eggs/egg-mass and soil population/200 g soil with corresponding reduction of 70.9, 34.4, 20.3 and 68.1 per cent, respectively, over untreated control. It was followed by P. fluorescens as soil application alone and carbofuran in reducing the root knot nematode infection in groundnut.

Extraction of Enzymes from Four Fungi and Their Use to Improve the Nutritive Value of Groundnut Pod for Broiler Feeding

4 Abstract: Enzymes were extracted from four fungi: Aspergillus niger, Trichoderma viride, Rhizopus stolonifer and Mucor mucedo. The purified enzyme extracts were used to degrade Groundnut Pod (GNP) in solid state. Undegraded GNP-, degraded GNP- and Roxazyme G2G-based diets were fed to starter and finisher broilers at the rates 70 and 100 g kg of diet, respectively. There was a production of a broad spectrum of enzymes -1 from the 4 fungi. Treatment of the GNP with the fungal enzyme extracts caused a more significant (p<0.05) reduction in the crude fibre and complex carbohydrate fractions and an increase in the crude protein, metabolizable energy and phosphorus in the GNP compared to the undegraded and Roxazyme treated GNP. The amounts of glucose, fructose, galactose and sucrose in the GNP were significantly (p<0.05) increased on biodegradation with the fungal enzyme extracts. Enzyme extracts from M. mucedo and R. stolonifer were more superior in this regard compared to extracts from the other fungi. Diets containing the degraded GNP resulted in significantly (p<0.05) reduced viscosity, better apparent nutrient digestibility and performance in broilers compared to the other diets. Results suggest the possibility of production of a multienzyme complex from some common tropical fungi. These enzyme complexes are more effective in biodegrading complex carbohydrates of by-products like GNP than Roxazyme which is specific for cereal based diets.

GROUNDNUT YIELD RESPONSE AND ECONOMIC BENEFITS OF FUNGICIDE AND PHOSPHORUS APPLICATION IN FARMER-MANAGED TRIALS IN NORTHERN GHANA

SUMMARYPrior on-station research showed that sowing dates, sowing density and applications of fungicide and phosphorus (P) increased groundnut (Arachis hypogaea) pod yield by 60–80%. Farmer-managed trials were conducted in the Wa district of the Upper West Region of Ghana from 2004 to 2007 to test the yield response to sowing density, fungicide and P and to assess economic returns of these technologies to farmers. Treatments included: an early maturing groundnut cultivar, Chinese, sown at farmers' density (5–8 plant m−2) without fungicide and without P application (T1, control), with fungicide sprays alone (T2), or with fungicide and P application (T3), cultivar Chinese sown at recommended (higher) density (20 plant m−2) with fungicide and P application (T4), and a full season cultivar, Manipinter, with fungicide and P application (T5). Soil fertility, sowing density, days from sowing to first weeding, incidence and severity of leaf-spot disease and plant population at final harvest were recorded. Relative to farmers' practice, pod yield of cultivar Chinese was significantly increased by 80% with fungicide sprays alone, 108% with fungicide and P application, and 113% with fungicide and P application at higher sowing density. Cultivar Manipinter treated with fungicide and P gave 107% increase in pod yield relative to farmers' practice. Correlation and stepwise regression analyses suggested that major determinants of groundnut pod yield in farmers' fields were plant density, leaf-spot disease and P availability. The increase in yield with fungicide and P application translated into a 4–5-fold increase in gross margin for farmers in the region. Returns to labour and labour productivity were doubled with combined use of fungicide and P fertilizer.

Sustainable rainfed crop sequence based on rainfall analysis under semi-arid vertisol

Based on field experiments conducted with 12 crop sequences (groundnut-groundnut, groundnut-cotton, groundnut-castor, groundnut-pearl millet, groundnut-sesame, cotton-cotton, cotton-castor, cotton-pearl millet, cottonsesame, castor-castor, pearl millet-pearl millet and sesame-sesame) with 3 fertilizer treatments (control, integrated nutrient management (INM) and recommended dose of fertilizer for different crops) during 1999 to 2005, a statistical selection is made to identify an efficient crop sequence for attaining maximum sustainable yield in a semi-arid Vertisol at Rajkot, Gujarat state. The results revealed that rainfall in individual month, differences of crop sequences, fertilizer treatments and their interaction were significant for groundnut pod equivalent yield. Based on ranking of crop sequences for mean yield and sustainable yield index, groundnut–sesame was found to be highly efficient.

The effects of alternative fuel types on the organoleptic qualities of smoked coarse pork sausages

This study was carried out to assess the effects of alternative smoking fuel types on the organoleptic qualities of coarse pork sausages. The sausages were produced with lean pork (2.5 kg) and pork fat (0.5 kg), minced, mixed with spices and stuffed into natural casings. They were grouped into four and each group was smoked with one of four fuel types: sawdust (control, C), corn cobs (CC), groundnut pods (GP) or soybean residue (SBR) for fifty minutes and stored for assessment in two batches on the day after production and fourteen days later. The attributes assessed were colour, taste, flavour and texture of the smoked sausages. The products were grilled to a core temperature of 70oC, sliced into pieces of 2.0cm in length and served to trained taste panelists in coded aluminum foil for sensory evaluation. A five-point category scale was used for the evaluation. There were no significant differences among the fuel types on the qualities of the smoked pork sausages. The fuel types imparted a desirable brownish colour and a moderate ‘smoky' flavour in the sausages resulting in a pleasant taste and these qualities were found to persist after freezing for fourteen days. The alternative fuel exhibited different characteristics during the smoking process. The SBR was found to burn faster than all the other fuels and therefore, would be needed in relatively larger quantities than any of the fuel types for meaningful economic use. The CC had the tendency to flame easily, burn quite fast and requires occasional sprinkling with water to enhance smouldering and smoke production. The moistened GP were observed to produce the best smoke comparable to standard fuels like hardwoods. These alternative fuels therefore, have some potential for use in smoking pork sausages without marked deviations from the conventional products smoked with sawdust. They could, therefore, serve as substitutes or supplementary fuel to the use of sawdust. Keywords: smoking, fuel, organoleptic, pork, sausages African Journal of Food, Agriculture, Nutrition and Development Vol. 9 (2) 2009: pp. 691-699

Haematology and serum biochemistry of broiler finisher birds fed biodegraded groundnut pods

Haematology and serum biochemistry of broiler finisher birds fed biodegraded groundnut pods

Farmers’ Perceptions of Quality of Groundnut: Vis-à-vis Farmers’ Characteristics

Groundnut is an important oil seed crop of India. In spite of its high nutritive value, 80% of the total production is utilized for oil extraction. It has great potential for diversification to food uses. Maintenance of quality is one of the major concerns for diversification. Apart from visual characters, such as pod shape, size, color, cleanliness, etc., aflatoxin contamination in kernels is considered as an important criterion for judging the quality of groundnut. Aflatoxins are the toxic substances produced by strains of fungi belonging to Aspergillus flavus and A. parasiticus. Aflatoxin contamination has led to human and cattle health concerns, significantly influencing groundnut trade worldwide. Aflatoxin contamination in groundnut pods has been reported to be more prevalent in Junagadh district compared to other groundnut growing districts of India. Hence, the study was undertaken to assess the perceptions of farmers on quality of groundnut in Junagadh district of Gujarat State, India. The results indicated that majority of farmers had low perception of quality and there were significant differences between the perceptions of big farmers and small farmers. The characteristics of farmers: knowledge of aflatoxin management practices, innovativeness, and market orientation significantly influenced the perceptions. Based on the results suggestions are made to formulate strategies to increase the knowledge level of farmers on aflatoxin management practices of groundnut through appropriate extension approaches. Mass awareness campaigns to educate farmers and consumers on the ill effects of consumption of aflatoxin contaminated produce, providing incentive price to farmers, building of consumer demands for aflatoxin free and good quality groundnuts are needed.

Cost effectiveness of selected post harvest pod handling techniques against damage, mouldiness and aflatoxin contamination of shelled groundnut in Ghana

Some post harvest pod handling methods were evaluated at Ejura and at KNUST, Kumasi to determine the costs and effectiveness of the methods in minimising post harvest damage, mouldiness and aflatoxin (AF) contamination of shelled groundnut. The study was conducted in 2002 (dry season) and repeated in 2003 (wet season). Four treatments were imposed on pods from 180 m2 plots at harvest. The treatments were (i) inverted windrowing (1wk) followed by drying of the pods on mats (3wk) (ii) random windrowing (1wk) followed by drying of the pods on mats (3wk) (iii) stripping and drying of pods on mats (4wk) and (iv) storage of pods without drying (control). Costs involved in carrying out the treatments were estimated. Fungi associated with the kernels and AF levels were also determined at harvest and at 4 weeks. In both seasons, Aspergillus niger was the most common fungus associated with kernels at harvest and after the 4 wk pod handling periods. Aspergillus flavus was also encountered at both periods. When pods were dried for 4 wk, the amounts of damaged/mouldy ones that were rejected were low (2.7-13.1%; av. 8.6 %) compared with undried pods where 18.9-25.94% (av. 22.08%) were rejected. Aflatoxins were not detected in kernels at harvest and generally, dried pods had lower levels of AFs (0 - 0.7µg/kg) than the undried control pods (7278.1µg/kg). Visibly healthy pods sorted from the dried lots had kernel AF levels of 0.2 - 0.6µg/kg which were similar to the 0 - 0.7µg/kg levels associated with the unsorted lots. Sorting, however, cost an extra ¢31,354/100 kg lot (¢8,200 = $ US1), making the practice uneconomical for well dried pods. Total cost of pod drying up to 4 wk was the same for the random and the inverted windrowed crops (¢89,980/100 kg pod) but was ¢95,440 when pods were dried on mats immediately after stripping. When pods were not dried, cost of handling was ¢69,600/100 kg pods but due to the high AF contamination (7278.1µg/kg), kernels from such pods constitute total loss. Thus, both windrow and mat drying of groundnut pods are cost effective in controlling damage/mouldiness and AF contamination but costs are lower when windrowed. Journal of Science and Technology(Ghana) Vol. 27 (1) 2007: pp. 17-27

Crop productivity and soil properties as affected by polyethylene film mulch and land configurations in groundnut (Arachis hypogaea L.)

Field experiments were conducted at Regional Research Station, Tamil Nadu Agricultural University, Vridhachalam, India, during autumn 1999 and winter 2000 using groundnut to examine the effect of different colours of polyethylene film mulch on crop yield and soil properties. The results of the experiment conducted with different colours of polyethylene film mulch (black, transparent white and non-mulched control) and three land configurations (flat bed, ridges and furrows and broad bed and furrows) indicated that irrespective of the colours, polyethylene film mulch significantly increased the soil micro-organisms at all stages of observation during both seasons except for bacterial population, which was significantly higher under non-mulched control during the winter season. The soil physical properties such as rate of water loss/day, soil bulk density, percentage of pore space and hydraulic conductivity were also favourably influenced by the polyethylene film mulch. The data on soil available nitrogen, phosphorus and potassium (NPK), showed that effect of polyethylene film mulch was significant at 30 DAS and not during later stages during both the seasons. Similarly the evolution of carbon dioxide (CO2) (soil respiration) was also significantly improved by polyethylene film mulch. The effect of land configuration was not significant for most of the parameters observed except for bulk density and pore space during winter seasons. With regard to yield parameters and yield, in both the seasons, white polyethylene film mulch out yielded other treatments in terms of groundnut pod yield. However the performance of white polyethylene film mulch was comparable with black polyethylene film mulch during winter 2001 – 2002 seasons. Among the land configurations, the results of yield components and yield were in favour of flat bed during both the seasons of study.

Structure and Physical Characteristics of Shell of Groundnut Pod, with Reference to Longevity of Seed-In-Shell

Structure and Physical Characteristics of Shell of Groundnut Pod, with Reference to Longevity of Seed-In-Shell

Effects of chlorpyrifos and quinalphos on dehydrogenase activities and reduction of Fe3+ in the soils of two semi-arid fields of tropical India

Abstract The impact of seed dressing and standing crop treatment (SC) with chlorpyrifos [O,O-diethyl O-(3,5,6-trichloro pyridyl) phosphorothioate] and quinalphos [O,O-diethyl O-quinoxalin-2-yl phosphorothioate] on the oxidative capability of the soils of two semi-arid regions of tropical India were studied by monitoring their dehydrogenase activities (DHA) and capacities for reduction of iron (Fe3+) for three consecutive crop seasons. In the sandy loam, the metabolites of quinalphos inhibited both reduction of Fe3+ and DHA whereas chlorpyrifos was found stimulatory. The metabolites of chlorpyrifos namely 3,5,6-trichloro-2-pyridinol (TCP) and 3,5,6-trichloro-2-methoxy pyridine (TMP) stimulated DHA but were significantly inhibitory to reduction of Fe3+. The stimulatory effect of TCP and TMP suggested their utilization as substrates by soil microbes. In the loamy sand, chlorpyrifos and quinalphos inhibited the overall DHA within a field but stimulated DHA of the rhizospheric microbes. Standing crop treatments with quinalphos and chlorpyrifos caused prolonged inhibitory effects on reduction of Fe3+ while seed treatments caused fluxes of shorter durations. The inhibitory effects on reduction of Fe3+ were more prolonged with chlopyrifos than with quinalphos. Pesticide treatments at the recommended doses increased the yield of groundnut (Arachis hypogaea L.) pods that had no residual pesticides. Adverse effects of agronomic importance on DHA and reduction of Fe3+ were not observed during this study.

A microplot study on Ditylenchus africanus population densities and damage symptoms on groundnut in relation to commercial yields

AbstractOptimum kernel quality is important at all levels of groundnut production and utilisation because of its value as a direct or processed food. Kernel quality can be reduced by many factors but in South Africa the groundnut pod nematode, Ditylenchus africanus, is responsible for severe losses in groundnut crops. The objective of this study was to evaluate in microplots the effect of D. africanus on groundnut yield in terms of commercial grading principles. Differential initial population densities (Pi) of between zero to 7000 and zero to 20000 nematodes per plant were inoculated, respectively, in two separate trials over two consecutive seasons. Significant non-linear relationships were recorded between Pi and nematode densities at harvest (Pf), between Pi and downgrading of kernels (% unsound, blemished and soiled (UBS)) and between % UBS and income earned per tonne. No relationships were found between initial or final nematode population densities and kernel fresh weight. Sufficient evidence was provided that damage by D. africanus on groundnut could be expressed in terms of commercial yield grading stipulations. Therefore, it is possible to estimate the effect of this nematode in monetary terms and to consider control measures in terms of financial gains or losses.