Current Commercial Practice Research Articles

Developmentally dependent responses of detached cucumber ( Cucumis sativus L.) fruit to exogenous ethylene

Previous studies of the postharvest physiological and developmental behavior of cucumber ( Cucumis sativus L.) fruit have examined fruit at a single developmental stage corresponding to commercial harvest maturity. The present study investigated the postharvest storage and ethylene responses of cucumber fruit at defined developmental stages based on growth and surface color parameters. Plants of a greenhouse cucumber (cv. Manar) were grown using current commercial practices. Fruit size and surface color were monitored during fruit development. Fruit were harvested at four stages of development: Immature (4–8 d after anthesis (DAA), commercial harvest maturity), Mature (10–14 DAA), Breaker (16–20 DAA) and Yellow (35–40 DAA). Fruit were stored in air or in either 10 μL L −1 ethylene or 1300 μL L −1 propylene for 12 d at 15 °C. The data indicate that cucumber fruit undergo marked changes in ethylene responses during development. Ethylene-treated Immature fruit exhibited mesocarp watersoaking and epidermal sloughing, slight degreening, and declines in mesocarp pH and firmness compared with air-stored fruit after 6 d of storage. Mature fruit behaved similarly to Immature fruit, but exhibited a lower incidence of watersoaking and greater fruit degreening. In sharp contrast, Breaker and Yellow fruit rapidly degreened and became orange due to chlorophyll degradation and β-carotene accumulation, softened, and produced ‘fruity’ aromatic compounds after 9 d of ethylene exposure. Ethylene increased respiration in fruit of all stages of development; however, ethylene production was detectable only in decaying fruit. The data indicate that the postharvest response of mini-cucumber fruit to ethylene is highly developmentally dependent, with older fruit exhibiting climacteric-like responses and younger fruit exhibiting tissue watersoaking and general fruit deterioration.

Interaction in Short Rotation Coppice willow, Salix viminalis genotype mixtures

Abstract Seven straight Salix viminalis genotypes with different levels of rust (Melampsora epitea) susceptibility were grown as mono-plots as well as being incorporated into a range of mixtures. Two 3-year harvests (2003 and 2006) were taken. Disease progress was followed on each of the individual genotypes throughout each growing season 2001–2006. In 2003 there were small but significant yield increases from the mixtures compared to the yield of individual components grown as mono-plots. These differences were not evident at the second harvest in 2006. No consistent effect of mixtures on reducing rust on the most susceptible genotype, Salix viminalis ‘77082’ were observed. In some years, e.g. 2003, at certain times during the growing season, significant reductions were observed on Salix viminalis ‘77082’ in certain 3-way mixtures compared to mono-plots. These, however, were not repeated consistently in subsequent years. It was concluded that the current commercial practice in many parts of Europe of planting mixtures as a disease control strategy will only be effective if there is sufficient genetic diversity between the Salix genotypes incorporated into the mixture.

SEED TECHNOLOGY AND SEED ENHANCEMENT

This paper reviews the uses, properties and manufacture of the main array of ‘seed enhancement technologies’ that are implemented in current commercial practice, with a particular emphasis on cultivated horticultural and ornamental species. Recent developments, as well as some of the newer technical approaches that are still in the research or at an early commercial stage, are covered. Coating technologies - pelleting, encrusting and filmcoating - are now used increasingly widely to facilitate seed planting, by altering seed shape, weight and surface texture, improving seed-soil contact, or manipulating imbibition. They are also used to deliver materials such as micronutrients and crop protection agents, including the high-dose systemic insecticides. New pellet manufacturing techniques, using rotary coaters, have provided an alternative to traditional ‘pan coating’. Hydration treatments manipulate vigour or physiological status, such as by priming, steeping, and pregermination. These treatments are used to make germination and seedling growth more rapid and synchronous in the seedbed in the open field or in protected conditions, and better tolerate environmental stresses. Both priming and coating technologies can also deliver beneficial microorganisms from seeds to crops. Organic farming market standards are stimulating the evaluation and optimization of methods to produce healthy planting material and new seed sanitation treatments as alternatives to fungicides or conventional hot water or bleach treatment while retaining seed viability in storage. Sorting on the basis of colour, X-ray analysis of internal structures or buoyant density in solvents offer the ability to remove weak or dead seeds, and hence ‘upgrade’ seedlot quality.

A Survey of Water and Fertilizer Management During Cutting Propagation

The objective of this study was to quantify water volume and nutrient content leached during propagation of herbaceous cuttings in commercial greenhouses. Nutrient concentrations in the fertigation solution, substrate, tissue, and leachate were measured between Jan. and Mar. 2006 at eight greenhouse locations in Michigan, Colorado, New Hampshire, and New Jersey. Grower management of the timing and concentration of nutrients applied to vegetatively grown calibrachoa (Calibrachoa ×hybrida) or petunia (Petunia ×hybrida) liner trays varied among the eight locations, ranging from 0.5 to 80 mg·L−1 nitrogen (N) in week 1 and from 64 to 158 mg·L−1 N in week 4. Over a 4-week crop period, applied nutrients averaged 4.9 g·m−2 N, 0.8 g·m−2 phosphorus (P), and 5.8 g·m−2 potassium (K), and leached nutrients averaged 1.1 g·m−2 N, 0.3 g·m−2 P, and 1.6 g·m−2 K. Leaching of nutrients and irrigation water was highly variable among locations. Leached water volumes ranged from 4.5 to 46.1 L·m−2 over 4 weeks and contained 0.29 to 1.81 g·m−2 N, 0.11 to 0.45 g·m−2 P, and 0.76 to 2.86 g·m−2 K. The broad range in current commercial fertigation practices, including timing of nutrient supply, concentration of applied fertilizer, and leaching volume, indicate considerable potential to improve efficiency of water and fertilization resources during propagation and reduce runoff.

Synthesis of Polyhydroxyalkanoates in Municipal Wastewater Treatment

Biologically derived polyesters known as polyhydroxyalkanoates (PHAs) represent a potentially "sustainable" replacement to fossil-fuel-based thermoplastics. However, current commercial practices that produce PHA with pure microbial cultures grown on renewable, but refined, feedstocks (i.e., glucose) under sterile conditions do not represent a sustainable commodity. Here, we report on PHA production with a mixed microbial consortium indigenous to an activated sludge process on carbon present in municipal wastewaters. Reactors operated under anaerobic/aerobic and aerobic-only mode and fed primary solids fermenter liquor maintained a mixed microbial consortium capable of synthesizing PHA at 10 to 25% (w/w), while reducing soluble COD by approximately 62 to 71%. More critically, an aerobic batch reactor seeded from the anaerobic/aerobic reactor and fed fermenter liquor achieved approximately 53% PHA (w/w). Results presented suggest that environmentally benign production of biodegradable polymers is feasible. We further used PHA-rich biomass to produce a natural fiber-reinforced thermoplastic composite that can be used to offset advanced wastewater treatment costs.

Effect of Operational Parameters on the Determination of Laboratory Extract and Associated Wort Quality Factors

Mashing for the determination of malt extract and wort quality factors is one of the most fundamental analyses performed in malting and brewing laboratories. The origins of the Congress mash method date from the late 19th century, and dissatisfaction with the method has sometimes been voiced because the operational parameters do not necessarily reflect current commercial practices. The objective of this study was to evaluate the effect of operational parameters on the laboratory determination of malt extract and associated wort quality parameters. Two current malting cultivars, displaying three modification levels, were used in combination with three levels of grind, three grist/water ratios, and two mash temperature profiles. Grind clearly had the most marked effect and impacted all analytical values. The effects were greatest on extract. Temperature profile also affected all analytical parameters, but its impact was most obvious for wort color, β-glucans, and fermentable sugars. Mash gravity had small effects on soluble protein and free amino nitrogen. Significant interactions involving modification often were observed, suggesting that observed differences were more pronounced as malt modification of samples decreased. The results of this study suggest that although the alteration of the laboratory mash parameters evaluated in this study may change the magnitude of differences between samples it is unlikely to change the overall actual rank of samples.

SOLARIZATION AND BIOFUMIGATION REDUCE PYTHIUM APHANIDERMATUM INDUCED DAMPING-OFF AND ENHANCE VEGETATIVE GROWTH OF GREENHOUSE CUCUMBER IN OMAN

Damping-off disease, caused by Pythium aphanidermatum is a major constraint in the greenhouse crop sector in Oman. Current commercial management practice relies almost exclusively on excessive chemical fungicide inputs. Under commercial conditions solarization and biofumigation (solarization following organic amendment of soil) both reduced P. aphanidermatum inoculum levels in soil relative to untreated controls. Both treatments also reduced the level of damping-off disease in greenhouse seedlings. Biofumigation and solarization both enhanced crop growth as measured by stem height and stem diameter. Effects on pathogen population levels, disease incidence and plant growth were greater during summer growing seasons than during the winter.

The effects of harvesting of the South African kelp (Ecklonia maxima) on kelp population structure, growth rate and recruitment

Ecklonia maxima is an economically important kelp in South Africa. The harvested kelp is used mainly as feed for cultured Haliotis midae (abalone) on farms all along the South African South and West Coast. The effects that different harvesting methods have on the growth of sub-canopy kelps, kelp population structure and kelp recruitment were tested in a kelp bed at Bordjies Rif near Cape Town. Two 30 × 10 m sites were set up, about 100m apart, in near monoculture stands of E. maxima. Each 30 × 10m area was subdivided into three treatments. In treatment 1 (T1) the whole ‘head’ of each kelp sporophyte that reached the surface was cut off between the bulb and the primary blade (‘lethal’ method). In treatment 2 (T2) (‘non-lethal’ method), the secondary fronds of all sporophytes that reached the surface were cut 20–30 cm from their junction with the primary blade, and removed. In the control plot, the kelp plants were not treated. Harvesting treatments were done approximately every four months, at low spring tide, from 3 March 2003 to 3 November 2003 (three treatments). The effects of harvesting on the kelps depend largely on the size of plant and the time the fronds were removed; however, no seasonal pattern could be observed. The different treatments had no effect on the growth rate, population structure or recruitment of the kelp. This means that factors other than light play an important role in the growth, structure and recruitment of the kelp beds in False Bay. Results are discussed in relation to current commercial harvesting practices.

Responses of adult broiler breeders to feeding time

Feeding time has the potential to influence the performance of adult broiler breeder flocks and is thus of great importance. A literature review is presented concerning the responses of adult broiler breeders to feeding time.It appears that there is no benefit in feeding broiler breeders later in the day with regard to egg numbers or egg weight.There is a potential improvement in shell quality that results from feeding later in the day or from splitting the daily feed allocation across more frequent feeding periods throughout the day. However, anticipated improvements in shell quality due to delayed feeding times may not be realised, particularly when birds are housed on litter floors. Furthermore, improvements in shell quality may not be translated into improvements in hatchability due to increases in shell thickness adversely affecting the water vapour conductance of the eggshell.Broiler hatching egg producers should be aware that later feeding times may delay the time of oviposition, which may demand changes in farm procedures. Furthermore, delayed feeding times may result in feeding activity coinciding with other important periods of activity, such as mating and oviposition, resulting in a reduction in fertility and an increase in the production of eggs with abnormal shells. The current commercial practice of feeding adult broiler breeders early in the day, at, or near, lights-on, is justified, as feeding at this time has positive consequences for other aspects of hatching egg production. However, afternoon feeding is not necessarily detrimental and may be an option to consider in cases where improvements in shell quality are required, although this may not be the solution for hatchability problems. If a change in feeding time is under consideration, environmental conditions, particularly the photoperiod and ambient temperature, must be taken into account, and any changes should be made gradually, as broiler breeders may be sensitive to abrupt changes in feeding time. Furthermore, changes in the feeding schedule should be accompanied by close monitoring of performance parameters, including the number of settable, abnormal and floor eggs, percentage of fertile eggs, and hatch of fertiles.

Nitrate leaching and residual soil nitrogen supply following outdoor pig farming

. Large nitrogen (N) inputs to outdoor pig farms in the UK can lead to high nitrate leaching losses and accumulation of surplus N in soil. We investigated the residual effects of three contrasting outdoor pig systems as compared to an arable control on nitrate leaching and soil N supply for subsequent spring cereal crops grown on a sandy loam soil during 1997/98 and 1998/99 harvest seasons. Previously, the pig systems had been stocked for 2 years from October 1995 and were designated current commercial practice (CCP, 25 sows ha−1 on stubble), improved management practice (IMP, 18 sows ha−1 on undersown stubble) and best management practice (BMP, 12 sows ha−1 on established grass). Estimated soil N surpluses by the end of stocking in September 1997 were 576, 398, 265 and 27 kg ha−1 N for the CCP, IMP, BMP and continuous arable control, respectively. Nitrate leaching losses in the first winter were 235, 198, 137 and 38 kg ha−1 N from the former CCP, IMP and BMP systems and the arable control, respectively. These losses from the former pig systems were equivalent to 41–52% of the estimated soil N surpluses. Leaching losses were much smaller in the second winter at 21, 14, 23 and 19 kg ha−1 N, respectively. Cultivation timing had no effect (P>0.05) on leaching losses in year 1, but cultivation in October compared with December increased nitrate leaching by a mean of 14 kg ha−1 N across all treatments in year 2. Leaching losses over the two winters were correlated (P 0.05) for the three previous pig systems and the arable control, and cultivation timing had no effect (P>0.05) on grain yields and crop N offtake. This systems study has shown that nitrate leaching losses during the first winter after outdoor pig farming can be large, with no residual available N benefits to following cereal crops unless that first winter is much drier than average.

Control of spoilage in table grapes

Purpose of the review: Diverse means to control decay and spoilage of table grapes during storage have been described in numerous research papers that were published recently. The purpose of this review is to describe some of the major publications in this field and to point out on their advantages and shortcoming. Main findings: Studies pertaining to the control of postharvest decay of table grapes and prevention of quality losses were categorised according to the general approach used (dry, wet, physical). Of the “dry” treatments, active modified atmosphere packaging (MAP), which includes volatiles for continuous control of decay, seems to be an attractive approach. Of the methods that can be directly integrated into current commercial practices, biofumigation with the fungus Muscodor albus warrants further assessment. Wet treatments have some inherent disadvantages because they require additional handling of the grapes. However, postharvest treatments with disinfectants such as ethanol can effectively control decay during cold storage of medium duration. These wet treatments can be useful to remove visible deposits of soil and pesticides, to prolong the storage life of organic grapes, and to disinfect and retard the decay of “ready-to-eat” grape products. Advantages of ethanol are that its efficacy can be enhanced by heat, sorbates, or MAP, and that it dries faster than other wet treatments. Directions for future research: There are specific issues to be addressed for every technology to be considered. However, many of the studies published on the control of spoilage of table grapes report results using specific cultivars, storage of limited duration, or small scale experiments. Any technology further to be considered must be confirmed in large-scale, semi-commercial experiments to reveal potential pitfalls and limitations and to evaluate all aspects of fruit quality. In addition, a cost analysis of each technology is essential.

Impact of Commercial Processing on the Microbiology of Shell Eggs

Shell egg microbiology has been studied extensively, but little information is available on how modern U.S. processing conditions impact microbial populations. As regulations are being drafted for the industry, such information can be important for determining processing steps critical to product safety. Five different shell egg surface microbial populations (aerobic bacteria, yeasts and molds, Enterobacteriaceae, Escherichia coli, and Salmonella) were monitored at 12 points along the processing line (accumulator, prewash rinse, washer 1, washer 2, sanitizer, dryer, oiler, scales, two packer head lanes, rewash entrance, and rewash exit). Three commercial facilities were each visited three times, a total of 990 eggs were sampled, and 5,220 microbiological samples were subsequently analyzed. Although variations existed in concentrations of microorganisms recovered from each plant, the patterns of fluctuation for each population were similar at each plant. On average, aerobes, yeasts and molds, Enterobacteriaceae, and E. coli prevalence were reduced by 30, 20, 50, and 30%, respectively, by the end of processing. The microbial concentrations (log CFU per milliliter) in the egg rinse collected from packer head lanes were decreased by 3.3, 1.3, 1.3, and 0.5, respectively, when compared with those of rinses collected from eggs at the accumulator. Salmonella was recovered from 0 to 48% of pooled samples in the three repetitions. Higher concentrations of Salmonella were recovered from preprocessed than from in-process or ready-to-pack eggs. These data indicate that current commercial practices decrease microbial contamination of egg shell surfaces.

Screening for effects of plant extracts and active compounds of plants on dairy cattle rumen microbial fermentation in a continuous culture system

Eight dual-flow continuous culture fermenters were used to study effects of plant extracts (Experiment 1) and active compounds of plants (Experiment 2) on rumen microbial fermentation. Each experiment consisted in two replicated periods of 9 days. Fermenters were fed 95 g dry matter (DM)/day in three feedings of a 600 g/kg (DM basis) alfalfa hay and 400 g/kg concentrate (178 g/kg crude protein, CP; 325 g/kg neutral detergent fibre, NDF diet), and maintained at constant temperature (38.5 °C), pH 6.4, and solid (0.05/h) and liquid (0.10/h) dilution rates. Both experiments included a negative control with no extract (CTR) and a positive control with monensin (MON). Treatments in Experiment 1 were: Trigonella foenum graecum, Juniperus oxycedrus, Syzygium aromaticum (CLO), Anethum graveolens, Zingiber officinale, and Melaleuca alternifolia. Treatments in Experiment 2 were: benzyl salicylate, anethol, carvacrol (CAR), cinnamaldehyde (CIN), eugenol, and d-carvone. During the adaptation period (i.e., days 1 through 7), samples for ammonia N and volatile fatty acid (VFA) concentrations were collected 2 h after feeding. On days 8 and 9, samples for VFA (2 h after feeding), and large peptide (LPep), small peptide plus amino acid (SPepAA), and ammonia N concentrations (0, 2, 4, 6 and 8 h after feeding) were also collected. During the adaptation period of Experiments 1 and 2, total VFA and ammonia N concentrations were not affected by treatments. During the first 6 days of fermentation in Experiments 1 and 2, MON resulted in lower acetate and higher propionate proportions compared with CTR. However, these differences disappeared after day 6. On days 6 and 7, CLO in Experiment 1 resulted in lower acetate, and higher butyrate, proportions compared with CTR. On day 7, the proportion of acetate was lower in CIN in Experiment 2 compared with CTR. After the adaptation period, CLO resulted in lower acetate, and higher propionate, proportions compared with CTR. The LPep N concentration was higher in CLO compared with CTR, suggesting that CLO reduced peptidolytic activity of rumen microorganisms. In Experiment 2, the LPep N concentration was lower in CAR, and MON resulted in lower SPepAA N concentrations and higher ammonia N concentrations compared with CTR, suggesting that MON stimulated deamination activity of rumen microorganisms. Results indicate that ruminal microbes may adapt to additives within 7 days. However, some plant extracts modified rumen microbial fermentation patterns and may allow manipulation of ruminal fermentation under current commercial practices.

Genetic Improvement Rates of Short‐Season Soybean Increase with Plant Population

Studies with a series of historic soybean [Glycine max (L.) Merr.] cultivars have found genetic improvement rates for seed yield of about 0.5% per year since soybean was first cultivated in Canada. Work with maize (Zea mays L.) has shown seed yield differences between old and new hybrids are more pronounced under higher seeding rates. The objective of our research was to determine the effect of plant populations on the rate of genetic improvement of short‐season soybeans. Soybean cultivars released from1934 to 1996 were grown in 40‐cm‐wide rows at several seeding rates (Exp. 1, 42 cultivars grown at 25, 50, 75 seeds m−2 in 1998 and 1999; and Exp. 2, seven cultivars grown at 25, 50, 100, 150, 200 seeds m−2 in 1999 and 2000) in two fields for 2 yr at Ottawa, ON. Genetic improvement rates were based on cultivar year of release and were compared across plant populations. In Exp. 1, seed yields did not reach a plateau. In Exp. 2, a seed yield plateau was reached and genetic improvement rates generally increased with plant population. Maximum rates of genetic improvement occurred at plant populations three to four times greater than current commercial practice (40 plants m−2). A plateau for seed yield was reached at lower plant populations compared to plateaus for genetic improvement rates which were reached at higher plant populations (>80 plants m−2). Higher plant populations also resulted in earlier maturity, increased plant height, and increased lodging. Seed protein increased and seed oil decreased with higher plant populations. New soybean cultivars appear more tolerant to plant population stress than older cultivars.

Effect of drying conditions on pyrethrins content

Windrowed pyrethrum stems were air dried under a range of storage conditions to examine whether the current commercial practice of drying crop material is conducive to pyrethrins’ degradation. Crop material was stored for up to 12 days in a commercial windrow, a shed receiving indirect light or a dark, 5 °C cool-room. Analysis of pyrethrins extracted from flowers of all treatments demonstrated that pyrethrins were not degrading in windrowed crops, plant material stored in the shed or in the 5 °C cool-room. The small differences obtained in pyrethrins content among the treatments can be explained by the natural variation in pyrethrins content of pyrethrum crops. The observation that the achenes were unchanged during this drying period supported the pyrethrins analysis. These results demonstrate that pyrethrins in planta do not degrade as rapidly as extracted pyrethrins.

05/00834 Chimney emissions from small-scale burning of pellets and fuelwood — examples referring to different combustion appliances

During the last three decades, driving forces behind the development of short-rotation willow coppice (SRWC) in Sweden have been changing from a primary focus on biomass production towards emphasis on environmental applications. In most cases, current commercial SRWC practice is geared towards a combination of biomass production for energy purposes and environmental goals. The latter goals range from decreasing the impact of specific contaminants in the environment to organic waste handling in a recycling system in urban and/or agricultural areas.Where biomass production and pollutant management overlap, the science of phytoremediation has its practical application. Through phytoremediation, waste products that previously have been a burden for the society can be used as valuable resources to increase short-rotation willow biomass production.In this paper we will present the terminology and definitions of different types of phytoremediation. We also give an overview of five different cases of phytoremediation activities with a potential for large-scale implementation. Some of the types of activities are already commercially used in Sweden; others seem promising but still need further development.

Processing and material properties of Tasmanian yellow gum, Eucalyptus johnstonii

Summary Boards of native forest Tasmanian yellow gum (Eucalyptus johnstonii) were processed using current commercial best practice. Boards were evaluated before and after processing to determine parameters such as board shrinkage, appearance grade and drying degrade. Bending strength and stiffness were determined by standard tests on thirty small clear sections, while Janka hardness was measured at two points on each of ten specimens. Yellow gum boards proved prone to collapse shrinkage and distortion on drying. The results showed that the species produces much denser, stronger and harder timber than the Tasmanian oak group of eucalypts, with seasoned strength rating according to Australian Standards of strength group SD2 (compared with SD4 for the species group) and mean Janka hardness 10.9 kN (compared to 6.1 kN).

Development of short-rotation willow coppice systems for environmental purposes in Sweden

During the last three decades, driving forces behind the development of short-rotation willow coppice (SRWC) in Sweden have been changing from a primary focus on biomass production towards emphasis on environmental applications. In most cases, current commercial SRWC practice is geared towards a combination of biomass production for energy purposes and environmental goals. The latter goals range from decreasing the impact of specific contaminants in the environment to organic waste handling in a recycling system in urban and/or agricultural areas. Where biomass production and pollutant management overlap, the science of phytoremediation has its practical application. Through phytoremediation, waste products that previously have been a burden for the society can be used as valuable resources to increase short-rotation willow biomass production. In this paper we will present the terminology and definitions of different types of phytoremediation. We also give an overview of five different cases of phytoremediation activities with a potential for large-scale implementation. Some of the types of activities are already commercially used in Sweden; others seem promising but still need further development.

Non-infectious and iatrogenic diseases of salmon in commercial aquaculture.

Based on current commercial aquaculture production practices, the production cycle for Atlantic salmon (Salmo salar) extends over a 36-month period during which time the fish are first exposed to intensive freshwater rearing conditions followed by transportation to marine netpen sites for ongrowing. It is predictable that, because of the duration of the production cycle and the variety of water conditions, deleterious environmental conditions have many opportunities to affect salmon health directly and indirectly. Furthermore, diseases which are iatrogenic arise from current methods used to prevent or treat infectious diseases. Specific, more frequently encountered examples are explored, with reference to the possible roles which these diseases may have in favouring the onset of infectious diseases.

Subsurface drip irrigation in raised bed tomato production. I. Nitrogen and phosphate losses under current commercial practice

The leaching of inorganic nitrogen and phosphate was studied at field sites that utilised subsurface drip irrigation (SDI) for commercial production of processing tomatoes. Irrigation expended for the establishment of crops, at emergence, accounted for 34% of the seasonal total in a Rochester clay (site 1) and 25% in a Binabbin clay (site 2). In the period after emergence and up to crop harvests, irrigation and rainfall amounted to 88% and 105% of calculated crop evapotranspiration for site 1 and site 2, respectively. Drainage between the commencement of irrigation and crop harvests amounted to 66 mm below 2 m at site 1 and 60 mm below 0.9 m at site 2. Total irrigation caused a 2- and 5-fold depletion of soil chloride at site 1 (within 2 m) and site 2 (within 0.9 m), respectively. The drainage and chloride depletion showed that irrigation regimes at these sites were conducive to the leaching of fertiliser inputs. It was calculated that ~32 kg NO–3-N + NH+4-N/ha and 7 kg HPO2–4-P/ha was leached below 2 m during irrigation at site 1. At site 2, ~75 kg NO–3-N + NH+4-N/ha was leached below 0.9 m during irrigation.Post harvest amounts of inorganic nitrogen and phosphate at site 1 and site 2 indicated that fertiliser applications exceeded total crop uptake of both compounds. Post harvest quantities of inorganic nitrogen and phosphate at several other commercial locations (sites 3, 4, 5, 6) showed that excessive fertiliser use was not restricted to site 1 and site 2. At site 1, between an early autumn harvest and early spring, when vegetable beds were fallow, the leaching losses of post harvest amounts of both compounds below 2 m were 137 kg NO–3-N + NH+4-N/ha and 11 kg HPO2–4-P/ha. The irrigation and fertiliser management practices at all sites were similar to those reported for studies of SDI production of other vegetable and grain crops. Altogether, these results indicated that the effects of SDI combined with excessive fertiliser inputs in current commercial practice may cause the leaching of significant amounts of nitrogen and phosphate to groundwater depths.