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The two species of bracken fern, Pteridium esculentumand Pteridium aquilinum, are well known to produce neoplastic lesions and thiamine deficiency when consumed by mammals, with severe consequences to health. New Zealand Pre‐European Māori are known to have consumed rhizomes of P. esculentumas food with little or no recorded consequences to health. Processing methods by Māori prior to consumption may have helped to detoxify this food. We carried out LDH toxicity tests on rhizomes that had been pre‐processed before simulated digestion to test this possibility. We tested rhizomes harvested each month of the year, different components of the rhizome, both raw and roasted rhizomes, rhizomes stored for up to 12 months, and rhizomes leached for up to 24 hours. All specimens remained equally toxic within experimental error. We carried out a detailed analysis of nutrients in bracken rhizome and compared this with kūmara, Ipomoea batatas, another important food plant for pre‐European Māori, and found that bracken rhizome has c. 70% of the caloric value of kūmara. A cost/benefit analysis of the two plants suggested that the reward for effort is greatest for kūmara by a modest amount. Analysis of historic ethnographic observations relating to bracken rhizome from AD 1769 to the 1840s provides complex and contradictory evidence of the role of bracken rhizome in the Māori economic system. Although there is clear evidence that Māori greatly favoured chewing rhizomes, this fondness may result from the presence of one or more plant secondary metabolites (PSM), such as ecdysone, which are known to be addictive. Our analysis of the evidence favours the plant being essentially a famine food, filling in the period between planting and harvest of kūmara, known as the ‘hungry gap’ between October and April in the southern hemisphere. However, it would also have provided an important source of food for travellers, as fern‐lands are widespread. Our analysis of archaeological information did not produce unequivocal direct evidence of bracken rhizome consumption. However, the presence of extreme tooth wear and a unique pattern of first molar dislocation, attributed to the use of teeth to strip starch from rhizomes, has been shown to be present at all periods of New Zealand prehistory. This is contrary to the finding of some other researchers. Les deux espèces de fougères aigles, Pteridium esculentum et Pteridium aquilinum, sont bien connues pour produire des lèsions néoplasies et carence en thiamine lorsqu'elles sont consommées par des mammifères, avec de graves conséquences pour la santé. Nouvelle‐Zélande Maoris Pré‐ Les européens sont connus pour avoir consommé des rhizomes de P. esculentum comme nourriture avec peu ou pas des enregistrements des conséquences sur la santé. Les méthodes de transformation par les Maoris avant la consommation peuvent avoir aidé à détoxifier cet aliment. Nous ont effectué des tests de toxicité de la LDH sur des rhizomes qui avaient été prétraités avant digestion simulée pour tester cette possibilité. Nous avons testé des rhizomes récoltés chaque mois de l'année, différents composants du rhizome, à la fois crus et rhizomes grillés, rhizomes stockés jusqu'à 12 mois et rhizomes lessivés jusqu'à 24 heures. Tous les specimens est resté également toxique dans les limites de l'erreur expérimentale. Nous avons effectué une analyse détaillée des nutriments dans le rhizome de fougère et nous avons comparé cela avec le kumara, Ipomoea batatas, une autre plante alimentaire importante pour les Maoris pré‐européens, et a constaté que rhizome de fougère a c. 70% de la valeur calorique du kumara. Une analyse coûts/bénéfices des deux usines a suggéré que la récompense pour l'effort est la plus grande pour le kumara d'un montant modeste. Analyse des observations ethnographiques historiques relatives à le rhizome de fougère de 1769 à 1840 fournit des preuves complexes et contradictoires du rôle de la fougère rhizome dans le système économique Maori. Bien qu'il soit clairement prouvé que les Maoris favorisaient grandement les rhizomes à mâcher, cette affection peut résulter de la présence d'un ou plusieurs métabolites secondaires végétaux (PSM), comme l'ecdysone, qui sont connus pour être addictifs. Notre analyse des preuves favorise la plante étant essentiellement un aliment de famine, remplissant le période entre la plantation et la récolte de kumara, connue sous le nom de «trou affamé» entre octobre et avril dans le sud hémisphère. Cependant, il aurait également fourni une importante source de nourriture pour les voyageurs, car les fougères sont répandu. Notre analyse des informations archéologiques n'a pas produit de preuves directes sans équivoque de fougères consommation de rhizomes. Cependant, la présence d'une usure dentaire extrême et d'un schéma unique de luxation de la première molaire, attribuée à l'utilisation des dents pour enlever l'amidon des rhizomes, a été démontrée présente à toutes les époques de la Nouvelle‐Zélande préhistoire. Ceci est contraire à la conclusion de certains autres chercheurs.

The aim of this review is to report changes in irrigated cotton water use from research projects and on-farm practice-change programs in Australia, in relation to both plant-based and irrigation engineering disciplines. At least 80% of the Australian cotton-growing area is irrigated using gravity surface-irrigation systems. This review found that, over 23 years, cotton crops utilise 6–7ML/ha of irrigation water, depending on the amount of seasonal rain received. The seasonal evapotranspiration of surface-irrigated crops averaged 729mm over this period. Over the past decade, water-use productivity by Australian cotton growers has improved by 40%. This has been achieved by both yield increases and more efficient water-management systems. The whole-farm irrigation efficiency index improved from 57% to 70%, and the crop water use index is >3kg/mm.ha, high by international standards. Yield increases over the last decade can be attributed to plant-breeding advances, the adoption of genetically modified varieties, and improved crop management. Also, there has been increased use of irrigation scheduling tools and furrow-irrigation system optimisation evaluations. This has reduced in-field deep-drainage losses. The largest loss component of the farm water balance on cotton farms is evaporation from on-farm water storages. Some farmers are changing to alternative systems such as centre pivots and lateral-move machines, and increasing numbers of these alternatives are expected. These systems can achieve considerable labour and water savings, but have significantly higher energy costs associated with water pumping and machine operation. The optimisation of interactions between water, soils, labour, carbon emissions and energy efficiency requires more research and on-farm evaluations. Standardisation of water-use efficiency measures and improved water measurement techniques for surface irrigation are important research outcomes to enable valid irrigation benchmarks to be established and compared. Water-use performance is highly variable between cotton farmers and farming fields and across regions. Therefore, site-specific measurement is important. The range in the presented datasets indicates potential for further improvement in water-use efficiency and productivity on Australian cotton farms.