Physicochemical characteristics, functional properties, and nutritional benefits of peanut oil: a review

The legume Arachis hypogaea, commonly known as peanut or groundnut, is a very important food crop throughout the tropics and subtropics. Peanut is one of the most widely used legumes due to its nutrition and taste, and it occupies a rank of major oilseed crop in the world. It has been recognized as a functional food due to its role in a health promoting effect. Peanut oil contains a well-balanced fatty acid and antioxidant profile that provide protection against harmful substances especially free radicals. This paper gives an overview of scientific literature available on phytochemical and functional properties of peanut oil. Owing to its unique organoleptic properties associated with its cardioprotective and anti-inflammatory properties, peanut oil has found, recently, its place on the highly competitive international edible oil market.

A new modelling approach to simulate preferential flow and transport in water repellent media: parameter sensitivity, and effects on crop growth and solute leaching

A modified version of the popular agrohydrological model SWAP has been used to evaluate modelling of soil water flow and crop growth at field situations in which water repellency causes preferential flow. The parameter sensitivity in such situations has been studied. Three options to model soil water flow within SWAP are described and compared: uniform flow, the classical mobile-immobile concept, and a recent concept accounting for the dynamics of finger development resulting from unstable infiltration. Data collected from a severely water-repellent affected soil located in Australia were used to compare and evaluate the usefulness of the modelling options for the agricultural management of such soils.

The study shows that an assumption of uniform flow in a water-repellent soil profile leads to an underestimation of groundwater recharge and an overestimation of plant transpiration and crop production. The new concept of modelling taking finger dynamics into account provides greater flexibility and can more accurately model the observed effects of preferential flow compared with the classical mobile–immobile concept. The parameter analysis indicates that the most important factor defining the presence and extremity of preferential flow is the critical soil water content.

Comparison of the modelling results with the Australian field data showed that without the use of a preferential flow module, the effects of the clay amendments to the soil were insufficiently reproduced in the dry matter production results. This means that the physical characteristics of the soil alone are not sufficient to explain the measured increase in production on clay amended soils. However, modelling with the module accounting for finger dynamics indicated that the preferential flow in water repellent soils that had not been treated with clay caused water stress for the crops, which would explain the decrease in production.

Histological and global gene expression analysis of the ‘lactating’ pigeon crop

Background: Both male and female pigeons have the ability to produce a nutrient solution in their crop for the nourishment of their young. The production of the nutrient solution has been likened to lactation in mammals, and hence the product has been called pigeon ‘milk’. It has been shown that pigeon ‘milk’ is essential for growth and development of the pigeon squab, and without it they fail to thrive. Studies have investigated the nutritional value of pigeon ‘milk’ but very little else is known about what it is or how it is produced. This study aimed to gain insight into the process by studying gene expression in the ‘lactating’ crop.
Results: Macroscopic comparison of ‘lactating’ and non-’lactating’ crop reveals that the ‘lactating’ crop is enlarged and thickened with two very obvious lateral lobes that contain discrete rice-shaped pellets of pigeon ‘milk’. This was characterised histologically by an increase in the number and depth of rete pegs extending from the basal layer of the epithelium to the lamina propria, and extensive proliferation and folding of the germinal layer into the superficial epithelium. A global gene expression profile comparison between ‘lactating’ crop and non-’lactating’ crop showed that 542 genes are up-regulated in the ‘lactating’ crop, and 639 genes are down-regulated. Pathway analysis revealed that genes up-regulated in ‘lactating’ crop were involved in the proliferation of melanocytes, extracellular matrix-receptor interaction, the adherens junction and the wingless (wnt) signalling pathway. Gene ontology analysis showed that antioxidant response and microtubule transport were enriched in ‘lactating’ crop.
Conclusions: There is a hyperplastic response in the pigeon crop epithelium during ‘lactation’ that leads to localised cellular stress and expression of antioxidant protein-encoding genes. The differentiated, cornified cells that form the pigeon ‘milk’ are of keratinocyte lineage and contain triglycerides that are likely endocytosed as very low density lipoprotein (VLDL) and repackaged as triglyceride in vesicles that are transported intracellularly by microtubules. This mechanism is an interesting example of the evolution of a system with analogies to mammalian lactation, as pigeon ‘milk’ fulfils a similar function to mammalian milk, but is produced by a different mechanism.

Was monochloramine responsible for widespread lettuce crop failures at a major recycled water irrigation scheme?

In 2008, vegetable growers observed stunted lettuce plants showing signs of chlorosis and wilting. It was suspected that monochloramine in the recycled water used for irrigation, in combination with extreme environmental conditions (high irrigation water salinity and extreme heat), was responsible for these crop failures. A series of glasshouse studies was conducted to evaluate the impact of monochloramine concentration alone on iceberg lettuce seedlings, as well as in combination with high salinity and hot ambient temperatures. Monochloramine concentrations up to 9 and 15 mg L−1 Cl2 for continuous and initial irrigation only, respectively, did not affect the weight of iceberg lettuce heads (p > 0.05), while the combination of monochloramine (4–5 mg L−1 Cl2) and salinity (3,500 μS cm−1) did not significantly affect harvest measurements (p > 0.05). We therefore conclude that it is unlikely that monochloramine was responsible for the observed crop failures.

The control of rodent damage in Australian macadamia orchards by manipulation of adjacent non-crop habitats

 Habitat manipulation was used as a management strategy for the control of rodent (Rattus rattus) damage in Australian macadamia orchard systems. Large, temporally stable non-crop habitats were converted to highly modified grasslands. These sites were manipulated by removing all non-crop vegetation over 10 cm in height to a distance of approximately 20 m from the orchard. Regrowth was controlled by the application of herbicide. The total cost of the habitat manipulation was $AUD 292 per site. Manipulation resulted in a reduction in damage of 65% within the associated orchards. This reduction in rodent damage resulted in a saving of $AUD 980 per site. Therefore habitat manipulation was cost-effective and is a viable startegy for the control of rodent damage in Australian macadamia orchard systems.

Cholinesterase Research Outreach Project (CROP): measuring cholinesterase activity and pesticide use in an agricultural community

BACKGROUND: Australian farmers and their workers are exposed to a wide variety of pesticides. Organophosphate (OP) insecticides are a widely used class of pesticide used for animal husbandry practices (Naphthalophos for sheep dipping, jetting and drench), crop production for pest control (Dimethoate) and in public health (Maldison for head lice). Acute poisonings with this class of insecticide are reported among agricultural workers and children around the globe, due to the inhibition of acetylcholinesterase (AChE). Less is known about chronic exposures. Regular monitoring of erythrocyte AChE will enable farmers to identify potential exposure to organophosphate insecticides and take action to reduce exposures and improve their health and safety practices. This study aims to assess and improve the integration of AChE monitoring into routine point of care health clinics, and provide farming and non-farming people with a link between their AChE activity and their household chemical and agrichemical use. METHODS/DESIGN: The research will target individuals who work on mixed farming enterprises and routinely using OPs (n = 50) and non-farmers (n = 30). Baseline data are collected regarding demographic, health conditions and behaviours, Kessler 10 (K10) scores, chemical use and personal protection. Baseline anthropometric measures include height, weight, hip and waist circumference, body fat analysis and, biochemical analysis of fasted total serum cholesterol, triglycerides, low-density cholesterol (LDL), high-density cholesterol (HDL) and blood glucose. Analysis of erythrocyte cholinesterase (EAChE) activity is also conducted using a finger prick test. Testing of EAChE is then repeated in all participants every 3 weeks for a maximum of three times over a period 10 weeks. Participants are provided with full feedback and counselling about their EAChE activity after each reading and a detailed summary provided to all participants at the completion of the study. Data will be analysed using repeated measures within a general linear model. DISCUSSION: This work will provide an evidence base and recommendations for the integration of EAChE monitoring into Australian rural health clinics, leading to research which will further quantify pesticide exposure both on the farm and in the home, highlighting the importance of sustaining and providing a safe work and home environment for farming communities. TRIAL REGISTRATION: ACTRN12613001256763.

The production and potential of biofertilizers to improve crop yields

Extensive interactions of plant roots with soil microorganisms affect plant nutrition either directly by influencing mineral nutrient availability or indirectly through enhanced uptake efficiency via plant root growth promotion. Beneficial microbial interactions with roots may be either endophytic or associative and can be symbiotic, mutualistic, or incidental in nature. The increased understanding of the role of root – or rhizosphere –associated with microbes in the nutrition and/or yield of agricultural crops in particular has resulted in promotion of their use in agricultural production as alternatives or supplements to mineral or organic fertilizers. Despite this, there is an obvious lack of market penetration of microbial inoculants. This review specifically focuses on microbial inoculants, collectively termed biofertilizers, used to improve nutrition and yields of grain, legume, oil, tuber, and other crops. A vast number of commercial biofertilizers are available worldwide; however, the quality and efficacy of many of them are not proven or tested. In the absence of efficacious biofertilizers of good and consistent quality, the dependence on the use of mineral fertilizers is not likely to decrease. Thus the availability of high-quality biofertilizers must be priority particularly in countries where crop plant production plays a key role in the economy and food security.

Pasture height and crop direction influence reptile movement in an agricultural matrix

Tackling the global threat of habitat fragmentation on biodiversity requires knowledge of how species move within agricultural landscapes. However, the specific mechanisms influencing dispersal within such landscapes remain poorly understood. The objective of our study was to assess how matrix type (improved pasture, native pasture or crop) and structure (grass height) influence fine-scale reptile movement, as well as influences of crop sowing direction and setting-sun position. In an agricultural region of south-eastern Australia, we first released 20 individuals of an arboreal gecko (Christinus marmoratus) at set distances from trees to determine the distance at which they could perceive their tree habitat (perceptual range). We then translocated 36 individuals into six matrix environments within their perceptual range of isolated trees to examine how gecko movement was modified by the type and structure of the matrix. We also recorded crop sowing direction and setting-sun position and examined all recorded tracks using angular statistics. We found that geckos exhibited a perceptual range of 40–80m. Short matrix environments promoted direct movements towards trees, irrespective of matrix type. Furthermore, movements were significantly affected by crop sowing direction with individuals following the planted lines. Our study has three significant implications: (i) restoring mature tree spacing to 80 m apart will assist gecko movements, (ii) targeted management for low pasture height, such as by maintaining directional narrow strips of low vegetation among taller pastures, might assist movement and facilitate increased connectivity, (iii) directional sowing of crops between habitat patches presents a simple but potentially effective tool for reconnecting fragmented landscapes.