DAIRY DEREGULATION AND LOW-INPUT DAIRY PRODUCTION: A BIOECONOMIC EVALUATION

Deregulation of the Australian dairy industry could affect the utilization of resources by milk producers and the profitability of dairy production. In this study we examine the feed mix that dairy producers use, both pastures and supplements, under partial and total deregulation. We are particularly interested in the interaction of pasture utilization and farm profitability. The results of this research demonstrate that profitable low-input dairy is constrained by the most limiting resource, feed supplied by pasture, and that the interactions between economic and biological processes are critical to farm profitability.Agricultural and Food Policy, Production Economics,

DYNAMICS OF OPTIMAL INTERACTIONS BETWEEN PASTURE PRODUCTION AND MILK YIELDS OF AUSTRALIAN DAIRY FARMS

Deregulation of the Australian dairy industry could effect the utilization of resources by milk producers. In this study we examine the feed input mix dairy producers use, both pastures and supplements, prior to and after deregulation. We are particularly interested in the interaction of pasture utilization and farm profitability.dairy production, pasture utilization, deregulation, Land Economics/Use, Livestock Production/Industries,

IRRIGATION DISTRICT ADOPTION OF WATER CONSERVING RATE STRUCTURES

A binary choice model was used to identify the attributes that influence irrigation district adoption of conservation rate structures. Using principles of rate design and irrigation district administration as a framework, measures of irrigation district rate structure objectives and physical and economic conditions were developed. The factors investigated characterize the constraints under which districts operate, value and cost of water, quantity of water delivered and revenue risk for districts. Rate structure adoption was predicted with over 75% accuracy. Both significant and non-significant factors are key to understanding rate choice. Districts were more likely to adopt conservation rate pricing when the cost of water to farmers was greater, higher value crops were grown and in areas with warmer and longer growing seasons. These conditions may be interpreted as reflecting the presence of greater opportunity costs in allocating water between low and higher valued uses. Conservation rate pricing was less likely to be adopted by districts where the proportion of alfalfa to total acreage was higher and with higher per acre deliveries of water. Somewhat surprisingly, annual variation in water deliveries (which should increase the risk of revenue shortfalls) and size of the district (larger districts being more sophisticated) have little bearing on the type of rate structure adopted.Environmental Economics and Policy, Land Economics/Use, Resource /Energy Economics and Policy,

EMERGING AGRICULTURAL WATER CONSERVATION PRICE INCENTIVES

Recent Bureau of Reclamation policies encourage or require irrigation districts to adopt price conservation incentives. Using unpublished survey results and new district-level information, we examine the rate structures and incentives of district water pricing. Our findings reveal that the majority of districts use fixed charges independent of the quantity of water delivered and that most conservation rate structures recently implemented are designed so that the first tier quantity allocation satisfies most crop water needs. Although other district management objectives may be satisfied, price incentives are diminished or nonexistent. The question of whether conservation is being achieved is tautological and depends on how each district defines conservation.Resource /Energy Economics and Policy,

EVALUATING THE EFFECTIVENESS OF CONSERVATION WATER-PRICING PROGRAMS: REPLY

Resource /Energy Economics and Policy,

EVALUATING THE EFFECTIVENESS OF CONSERVATION WATER-PRICING PROGRAMS

Charging farmers increasing block prices for irrigation deliveries is advocated as a means of encouraging agricultural water conservation in the West. We formulated a model of a hypothetical irrigated river basin to investigate the hyrdro-economic circumstances in which such pricing leads to water conservation. Our results indicate that increasing delivery prices may encourage irrigators to make adjustments with countervailing impacts on consumptive water use and conservation. Whether these countervailing impacts combine to conserve water or increase its consumptive use must be resolved empirically. An alternative resolution of this ambiguity is to assess water prices in terms of consumptive use.Resource /Energy Economics and Policy,

Excess noise in GaAs and AlGaAs avalanche photodiodes with GaSb absorption regions—composite structures grown using interfacial misfit arrays

Interfacial misfit arrays were embedded within two avalanche photodiode (APD) structures. This allowed GaSb absorption layers to be combined with wide-bandgap multiplication regions, consisting of GaAs and Al0.8Ga0.2As, respectively. The GaAs APD represents the simplest case. The Al0.8Ga0.2As APD shows reduced dark currents of 5.07 μAcm−2 at 90% of the breakdown voltage, and values for effective below 0.2. Random-path-length modeled excess noise is compared with experimental data, for both samples. The designs could be developed further, allowing operation to be extended to longer wavelengths, using other established absorber materials which are lattice matched to GaSb

An apoplastic peptide signal activates salicylic acid signalling in maize

Control of plant pathogen resistance or susceptibility largely depends on the promotion of either cell survival or cell death. In this context, papain-like cysteine proteases (PLCPs) regulate plant defence to drive cell death and protection against biotrophic pathogens. In maize (Zea mays), PLCPs are crucial in the orchestration of salicylic acid (SA)-dependent defence signalling. Despite this central role in immunity, it remains unknown how PLCPs are activated, and which downstream signals they induce to trigger plant immunity. Here, we present the discovery of an immune signalling peptide, Zea mays immune signalling peptide 1 (Zip1). A mass spectrometry approach identified the Zip1 peptide being produced after salicylic acid (SA) treatment. In vitro studies using recombinant proteins demonstrate that PLCPs are required to release bioactive Zip1 from its propeptide precursor (PROZIP1). Strikingly, Zip1 treatment strongly elicits SA accumulation in maize leaves. Moreover, RNAseq based transcriptome analyses revealed that Zip1 and SA treatments induce highly overlapping transcriptional changes. Consequently, Zip1 promotes the infection of the necrotrophic pathogen Botrytis cinerea in maize, while it reduces virulence of the biotrophic fungus Ustilago maydis. Together, Zip1 represents the previously missing signal that is released by PLCPs to activate SA defence signalling