Kauri (Agathis australis), which is one of the world's largest and longest‐living conifer species, is under threat from a root and collar dieback disease caused by the oomycete pathogen Phytophthora agathidicida. The noted incidence of kauri dieback has increased in the past decade, and even trees >1000 years old are not immune. This disease has profound effects on both forest ecosystems and human society, particularly indigenous Māori, for whom kauri is a taonga or treasure of immense significance. This review brings together existing scientific knowledge about the pathogen and the devastating disease it causes, as well as highlighting important knowledge gaps and potential approaches for disease management. The life cycle of P. agathidicida is similar to those of other soilborne Phytophthora pathogens, with roles for vegetative hyphae, zoospores and oospores in the disease. However, there is comparatively little known about many aspects of the biology of P. agathidicida, such as its host range and disease latency, or about the impact on the disease of abiotic and biotic factors such as soil health and co‐occurring Phytophthora species. This review discusses current and emerging tools and strategies for surveillance, diagnostics and management, including a consideration of genomic resources, and the role these play in understanding the pathogen and how it causes this deadly disease. Key aspects of indigenous Māori knowledge, which include rich ecological and historical knowledge of kauri forests and a holistic approach to forest health, are highlighted.

Ammonia volatilization from granular urea applied at l o g Nm-' to pasture was investigated using an enclosure method. Misting 0,4 or 16 mm of water on to the soil at field capacity within 3 h of urea application resulted in total NH, losses of 2.81, 0.92 and 0.18 g N m-' respectively. Further delaying the watering reduced this effect until at 48 h, volatilization was lowered from 3.33 to only 3.09gNm-' with 16mm of water. Hydrolysis and NH, loss were rapid. Similar trends occurred at a lower initial soil moisture content.14% of the urea remained after 30 days) and volatilization, while gradual, accounted for 33% of applied urea-N after 30 days. Addition of 16 mm of water 48 and 96 h after urea application was followed by a period of rapid hydrolysis and volatilization, resulting in a total loss of 2.59 and 2.40 g N m-' respectively. Repeated addition of 2 mm of water produced bursts of hydrolysis and NH, loss until completion of hydrolysis when additional water had no effect. A total loss after 30 days of 3.94 g N m-* occurred in this 2 mm treatment.

Ammonia (NH,) volatilisation from various nitrogenous (N) fertilisers broadcast at different times of year on to pasture at a rate of 3 g/m? N (30 kg/ha N) was measured by an enclosure method. The average percent losses ofNH,-N were: urea, 11.9; diammonium phosphate, 5.3; ammonium sulphate, 1.0; and calcium ammonium nitrate, 0.8. Loss from sulphur-impregnated urea was equal to, or slightly less than that from urea. The loss was positively related to the maximum soil surface pH produced by each of the fertilisers. No seasonal pattern was observed, except that NH, loss tended to be lower in August-September. The loss from urea increased from 13 to 33% of N applied as the application rate increased from 3 to 20 g/rn? N (30-200 kg/ha N).

This article describes countercurrent fermentation to anaerobically convert corn stover and pig manure to mixed carboxylic acids using a mixed culture of mesophilic microorganisms. Corn stover was pretreated with lime to increase digestibility. The Continuum Particle Distribution Model (CPDM) was used to simulate continuous fermentors based on data collected from batch experiments. This model saves considerable time in determining optimum operating conditions. For 80% corn stover/20% pig manure, the highest total carboxylic acid productivity was 1.81 g/(L of liquid. d) at a concentration of 21.4 g total acid/L. The highest total acid selectivity, yield, and conversion were 0.714 g total acid/g volatile solids (VS) digested, 0.550 g total acid/g VS fed, and 0.770 g VS digested/g VS fed, respectively, at a concentration of 16.0 g total acid/L. CPDM predicted the acid concentration and conversion within 13.4 and 11.6%, respectively.