Intermediate Harvest Research Articles

Características físicas e físico-química da casca de mangostão em três períodos da safra

Avaliaram-se as características físicas do fruto e físico-químicas da casca do mangostão colhido em diferentes períodos da safra (início, meio e fim). As características físicas dos frutos variam significativamente (p<0,05) do início ao fim da safra, e observou-se que a média de peso dos frutos variou de 91,33 a 50,82 gramas, e a casca representa, em média, de 61,39 a 76,86% do peso total do fruto. A caracterização físico-química mostrou que a casca possui elevado teor de umidade (64,5 a 66%), fibras totais (24,9 a 29,1%), alta atividade de água (0,96 - 0,98), baixo valor energético (24,8 a 34,7 Kcal/100 g) e expressivo teor de antocianinas totais (25,9 a 63,9 mg/100 g), principalmente no período intermediário da safra.

Evolutionary responses to harvesting in ungulates

1. We investigate the evolutionary responses to harvesting in ungulates using a state-dependent, stochastic, density-dependent individual-based model of red deer Cervus elaphus (L.) females subject to different harvesting regimes. 2. The population's mean weight at first reproduction shifts towards light weights as harvesting increases, and its distribution changes from a single peak distribution under very low or high harvest rates, to a bimodal distribution under intermediate harvest rates. 3. These results suggest that, consistent with previous studies on aquatic species, harvesting-induced mortality may drive adaptive responses in ungulates by reducing the fitness benefits from adult survival and growth in favour of early and lightweight reproduction. 4. Selective harvesting for heavy animals has no additional effect on the evolutionarily stable strategy, suggesting that harvest rate is more important than the degree of selectivity in driving adaptive responses. However, selective harvesting of light females is positively associated with maturation weights even higher than those of a nonharvested population, probably due to the reduction in the fitness value of the offspring. 5. The average number of weight at maturation strategies in the population declines but the total number of strategies across all simulations increases with harvest rate, suggesting that harvesting-induced selection on weight at maturity overcomes the increase in strategy diversity expected from density-dependent release. 6. Yield initially increases with harvesting due to enhanced productivity of light females experiencing density-dependent release. However, it crashes under intense harvesting resulting in a population skewed to light, young and, therefore, less reproductive animals.

Effects of forest ownership and change on forest harvest rates, types and trends in northern Maine

Forest ownership maps from 1994, 2000 and 2004 were analyzed with land cover maps (early 1990s) and forest change detection maps derived from Landsat imagery (1991, 2000, 2004). Between 1994 and 2000, roughly 80% of the Industrial forest ownership in a northern Maine study area changed hands. Approximately 75% of these forestlands were sold to Timber Investment Management Organizations (TIMOs) and 25% to other Industrial owners. Non-Government Organizations (NGOs) and Logger/Short-term Investors (LDs) purchased smaller parcels of forestland from the Industrial and TIMO sellers, from 1994 to 2004. Landsat change detection methods indicated a general trend in landowners’ preference to harvest softwood and softwood–hardwood in the 1980s, softwood–hardwood and hardwood–softwood stands in the 1990s, and nearly a balanced proportion of four forest types between 2000 and 2004; however, these trends varied among individual landowners. Industrial ownership type harvested the highest percentage of forest in the 1980s, but not in the 1990s and early 2000s. The TIMOs and LDs harvested a higher percentage of forest in the 1990s and early 2000s, while the NGOs harvested less. The Non-Industrial Private Forest (NIPF) held more stable ownership through time and had more equal and intermediate harvest rates through time. Forest land that experienced no ownership change had significantly lower harvest rates than land that changed ownership between 1994 and 2000. Given the rates of past harvesting and current composition of forestland, the estimated average forest disturbance rotation on the 2004 Industrial ownership would be 51 years, compared to 70 years for NIPF forestlands.

Aspects of nitrogen use efficiency of cauliflower II. Productivity and nitrogen partitioning as influenced by N supply

Based on studies concerning dry matter (DM) partitioning, DM production, root growth, nitrogen (N) contents of cauliflower organs and soil nitrate availability (first part of the paper Kage et al. 2003b), an integrated simulation model for the cauliflower/soil system is constructed, parameterized and evaluated.Dry matter production of cauliflower is described and predicted using a simple light use efficiency (LUE) based approach assuming a linear decrease of light use efficiency with increasing differences between actual, NCAProt, and ‘optimal’, NCAoptProt area based leaf protein concentrations. For 2 experimental years the decline of LUE with decreasing nitrogen concentration was at 0·82 and 0·75 (g DM×m2/(MJ×g N)). Using the parameters obtained from the first experimental year shoot DM production data of cauliflower from five independent experiments with varied N supply containing intermediate harvests could be predicted with a residual mean square error (RMSE) of 72 g/m2 for intermediate harvest DM values ranging from about 50 to 900 g/m2. Nitrogen uptake and partitioning of cauliflower was simulated using functions describing an organ size dependent decline of N content. Leaf nitrate was considered explicitly as a radiation intensity dependent pool, mobilized first under N deficiency. The curd was assumed to have a sink priority for nitrogen. The model predicted shoot N uptake including data of intermediate harvest with a RMSE of 2·4 g/m2 for intermediate harvest N values ranging from about 3 to 30 g/m2. Nitrogen uptake of cauliflower at final harvest was correlated to final leaf number.A scenario simulation was carried out to quantify seasonal variation in N uptake of cauliflower cultivars under unrestricted N availability. Due to variations in the length of the vernalization phase, simulated shoot N uptake ranged from about 260 kg N/ha for spring planted crops to about 290 kg N/ha for summer planted crops of the cultivar ‘Fremont’. The cultivar ‘Linday’, which shows a more severe delay of vernalization under high temperatures, shows on average a larger shoot N uptake for summer planted crops of about 320 kg N/ha and a much larger variation of shoot N uptake.

CO 2 and ozone effects on canopy development of potato crops across Europe

This paper describes the effects of elevated CO 2 (550 and 680 μl l −1) and O 3 (60 nl l −1 O 3 as an 8 h mean), alone or in combination, on canopy development and senescence in potato ( Solanum tuberosum L. cv Bintje) across a range of European agro-climatic conditions. The assessments were made within the European CHIP project (CHanging climate and potential Impacts on Potato yield and quality) that was conducted for two growing seasons (1998 and 1999) in free air CO 2 enrichment systems (FACE) and open-top chamber facilities (OTCs) at seven European sites. A comparison of chambered and unchambered experimental plots was included to examine the effects of chamber enclosure. Phenological growth stages, plant height, leaf area index (LAI) and the number of green and yellow leaves were recorded non-destructively throughout the growing season and by a destructive intermediate harvest at maximum leaf area (MLA). In the dynamic growth analysis CO 2 and O 3 effects were studied over three developmental stages: canopy expansion, full canopy and canopy senescence. Chamber enclosures promoted potato crop development (taller plants, more leaves) during the initial growth stages and led to a faster decline of LAI and a higher number of yellow leaves. The growth in ambient plots varied between sites and seasons, as did the scale of the treatment responses. Despite the large background variation, some overall treatment effects could be detected across all sites. Both levels of increased CO 2 reduced final plant height in comparison to ambient concentrations, which indicates a premature ending of the active plant growth. At the stage of full canopy and crop senescence the average number of green leaves was significantly ( P<0.05) decreased by 680 μl l −1 CO 2 (OTC experiments) and LAI showed the same tendency ( P=0.07). As there was however no indication of a decreased leaf formation during initial growth and at full canopy, this must have been due to an earlier leaf fall. In the FACE experiments LAI had already began to decline at the stage of full canopy at 550 μl l −1 CO 2 but not in ambient CO 2 (DAE×CO 2, P<0.05). These observations strongly indicated that elevated CO 2 induced a premature senescence during full canopy. O 3 did not have an overall detrimental effect on crop development during initial growth nor at full canopy, but did induce a faster reduction of LAI during crop senescence (DAE×O 3, P<0.05). Final plant height was not affected by O 3. There were few CO 2×O 3 interactions detected. There was a suggestion ( P=0.06) that O 3 counteracted the CO 2-induced decrease of green leaves at full canopy, but on the other hand during crop senescence the decline of LAI due to elevated O 3 was faster at ambient compared to elevated CO 2 ( P<0.05). These responses of canopy development to elevated CO 2 and O 3 help to explain the treatment responses of potato yield within the CHIP project at sites across Europe.

Assessing effects of ambient ozone on injury and yield of bean with ethylenediurea (EDU): three years of plant monitoring at four sites in The Netherlands.

EDU (ethylenediurea) and non-EDU-treated bean plants (Phaseolus vulgaris L. cv. Lit) were exposed to ambient air at four rural sites in The Netherlands during the growing seasons of 1994 through 1996 to investigate the responses to ambient ozone. Ozone-induced foliar injury was observed each year and differences in injury between sites depended on year. On average, injury amounted to 27% in 1994, to 8% in 1995 and to 1% in 1996. Injury increased with increasing ozone exposure (AOT40) and the estimated AOT40 value corresponding with 5% injury was circa 3650 nl l(-1) h ozone. The highest ozone levels accumulated at each site for five consecutive days before injury exceeded the proposed short-term critical level for injury development. EDU reduced injury and its protective effect was positively related to the injury intensity in non-EDU-treated plants. Yield of green marketable pods (intermediate harvest) and mature pods (final harvest) was generally reduced in non-EDU-treated plants compared to EDU-treated plants and differences in yield reduction between harvests varied between years. The yield of mature pods was reduced in 1994 and 1996 while the yield of green pods was reduced in 1995 by ozone only. Since yield reduction was not correlated with AOT40. the EDU method was not valid to determine an ozone exposure-yield reponse relationship for bean.

Urbanization’s impact on timber harvesting in the south central United States

The impact of urbanization on timber harvesting in the south central United States was investigated. Geo-referenced Census and Forest Inventory Analysis (FIA) data were combined using a geographic information system (GIS) in order to examine the effects of various demographic and biophysical forest inventory characteristics on timber harvesting. These effects were estimated for intermediate and final harvests using a multinomial logit model. The probability for both types of harvests decreased with increasing population density, decreasing forest size, and decreasing distance to urban areas; however, the reduction in intermediate harvests was greater for each variable. Harvesting rates decreased by as much as 19% as population densities increased or distance to urban areas decreased. The results indicated that active forest management is curtailed far beyond the urban boundary. In order to model the impact of urbanization adequately, timber supply projections must also account for its impact on harvesting frequencies in surrounding areas.

Growth responses to ozone in plant species from wetlands

Ten wet grassland species were fumigated with four concentrations of ozone (charcoal-filtered air, non-filtered air and non-filtered air plus 25 or 50 nl l −1 ozone) in open-top chambers during one growing season to investigate the long-term effect of this air pollutant on various growth variables. Only Eupatorium cannabinum showed ozone-related foliar injury, while five species reacted with significantly ozone-enhanced senescence. Premature senescence was paralleled by a significant ozone-induced reduction of green leaf area in Achillea ptarmica, E. cannabinum and Plantago lanceolata. At the intermediate harvest performed after 28 days shoot weights were significantly decreased by ozone in A. ptarmica and increased in Molinia caerulea. At the final harvest performed at the end of the growing season two other species, Cirsium dissectum and E. cannabinum had a significantly reduced shoot weight due to ozone. Root biomass was determined only at the intermediate harvest. The root:shoot ratio (RSR) was significantly reduced in C. dissectum, while it increased in M. caerulea. Seven of the species developed flowers during the experiment. While no significant ozone effects on flowering date and flower numbers were detected, flower weights were significantly reduced in E. cannabinum and P. lanceolata.

POSTSTORAGE SENSORY PROFILES OF FRUIT OF FIVE APPLE CULTIVARS HARVESTED AT DIFFERENT MATURITY STAGES

ABSTRACT Apples of five cultivars (Braeburn, Fuji, Golden Delicious, Red Chief and Staymared) were harvested four times at weekly intervals. Selected and trained panelists evaluated the intensity of sensory characteristics of fruits after storage (4 months at OC in air) and shelf‐life at 20C by descriptive analysis. Sensory attributes were firmness, crispness, mealiness, juiciness, sweetness, sourness and aroma. Harvest time mainly influenced fruit texture after storage: in Staymared the juiciest and the most crisp fruits were those of the intermediate harvests, in Red Chief those of the first harvest, while in Fuji those of the last two harvests. Sensory quality of Braeburn and Golden Delicious was not affected by harvest time. The characterization of apple maturity and cultivars according to the sensory characteristics of fruits can help to identify the fruit best satisfying the consumers’ requirements.

Responses of bean ( Phaseolus vulgaris L. cv. Pros) to chronic ozone exposure at two levels of atmospheric ammonia

Plants of bean ( Phaseolus vulgaris cv. Pros) were exposed to a range of O 3 concentrations up to 70 nl litre −1 for 9 h day −1 in the presence (45 nl litre −1) and absence (21 nl litre −1) of enhanced NH 3 in 12 open-top chambers. Treatment effects on visible injury, growth and yield were assessed after 49 (intermediate harvest) and 62 days of exposure (final harvest). The proportion of leaves with visible injury at final harvest increased with increasing concentrations of O 3. Enhanced NH 3 did not cause any symptoms and did not affect injury by O 3. The estimated seasonal mean concentration corresponding with 5% injury was circa 23 nl litre −1 O 3. Biomass production and green pod yield decreased with increasing concentrations of O 3 and were generally stimulated by enhanced NH 3 at both harvests. Adverse effects of O 3 on biomass and pod yield did not depend on the NH 3 level. Relative yield response to increasing 9-h daily mean O 3 concentrations was nonlinear and yield losses of 5 and 10% were calculated to occur at seasonal daytime mean concentrations of 27 and 33 nl litre −1 O 3, respectively. Linear regression showed that the Accumulated exposures Over a Threshold of 30 (AOT30) and 40 nl litre −1 (AOT40) O 3 performed equally well. The estimated accumulated O 3 exposures corresponding with a yield loss of 5% were 1600 nl litre −1 h for AOT30 and 400 nl litre −1 h for AOT40. The results are discussed in relation to the long-term critical level that is used as a guideline to protect crops against adverse effects by O 3.

Assessing effects of ambient ozone on injury and growth of Trifolium subterraneum at four rural sites in the Netherlands with ethylenediurea (EDU)

To assess adverse effects of ambient ozone on injury and growth, EDU (ethylenediurea) and non-EDU-treated plants of subterranean clover ( Trifolium subterraneum cv. Geraldton) were exposed to ambient air at four rural sites in the Netherlands. In each of two successive experiments of eight weeks during the 1994 growing season, an intermediate harvest (cutting) was performed after four weeks of exposure. Concentrations of ambient ozone were high in Experiment 1 (June 21–August 16) and relatively low in Experiment 2 (August 23–October 18). Subterranean clover displayed characteristic ozone injury at all sites in Experiment 1 and in Experiment 2 until the intermediate harvest (September 20). The proportion of leaves injured in non-EDU-treated plants was higher than that in plants treated with the antioxidant. Both the degree of injury and the protective effect by EDU differed between sites and were not related to the measured ozone levels. The proposed short-term critical levels for injury development by ozone would not have protected clover against ozone injury in Experiment 2. The site-dependent pattern of injury in non-EDU-treated plants was similar for the various harvests and experiments and a maximal degree of 23% injury was observed after four weeks of exposure. The protective effect by EDU was related positively to the injury intensity in non-EDU-treated plants, irrespective of site, harvest and experiment. EDU caused variable effects on leaf biomass production under conditions of low ozone in Experiment 2 whereas EDU generally increased leaf biomass when the plants were exposed to the relatively high concentrations in Experiment 1. The EDU-induced increase in leaf biomass production in this experiment did not vary between sites and was on average 5–7%, depending on the harvest. The involvement of elevated concentrations of ambient ozone measured at the four sites in the Netherlands in 1994 in the observed increase of leaf biomass by EDU is discussed.

Effect of elevated CO 2 on the carbon balance of a grass-clover mixture

Experiments were carried out to investigate the effect of elevated CO 2 (780 μmol mol −1) on the C-balance and carbon release from the roots of a mixture of Dactylis glomerata and Trifolium pratense. The plants were grown for 67 days in a growth chamber with controlled watering and fertilisation, with an intermediate harvest after 41 days. Elevated CO 2 increased total net uptake of carbon (C) by about 30% by the end of regrowth. Total net C-uptake and the amount of C recovered in the second harvest were balanced at both CO 2 concentrations, and the root: shoot ratio was not affected by elevated CO 2. 13C-allocation to roots, and 13C released into the root environment were measured following pulse-labelling with was 1.6% and 13C released from roots was only 0.4%. No significant difference in these proportions was observed at elevated CO 2, but in absolute terms, plants grown at elevated CO 2 released more 13C from the roots.

Interference in Trifolium Repens--Lolium Perenne Mixtures: Short- and Long- Term Relationships

1 Intraand interspecific interactions were investigated in mixtures of Lolium perenne L. and Trifolium repens L. Species pairs were collected from pastures sown in 1979, 1970, c. 1945 and c. 1880, and sampled at five times during a single growing season. 2 In 46 of the 48 different combinations of species, harvest time and pasture age, inverse yield-density models described decreases in above-ground dry matter production per plant as species population densities (d) increased. Inverse yield-density models also described cumulative above-ground dry matter production for each species at each source pasture age. 3 Significant interactions in the yield-density models, indicated that intra and interspecific interference in each species changed with time of harvest and age of the source pasture. 4 Substitution rates, measuring the impact on a species of replacing one of its members by a member of the other species, indicated that Lolium was consistently less affected by Trifolium than by members of its own species. In addition, the impact of Trifolium on Lolium declined during the growing season and with increasing source pasture age. 5 In Trifolium, substitution rates varied widely. In the youngest pastures there was evidence that the presence of Lolium was beneficial to Trifolium, but at intermediate source pasture ages Trifolium was adversely affected by Lolium to a greater extent than by members of its own species. 6 Lolium-Trifolium mixtures used resources more effectively than their corresponding pure stands. Resource utilization was most effective at intermediate harvests and in mixtures from the youngest and oldest pastures.

Soil boron and selenium removal by three plant species

High concentrations of boron (B) and selenium (Se) naturally found in the environment are detrimental to sustainable agriculture in the western USA. Greenhouse pot experiments were conducted to study B and Se uptake in three different plant species; Brassica juncea (L.) Czern (wild brown mustard), Festuca arundinacea Schreb. L. (tall fescue), and Brassica napus (canola) were grown in soil containing naturally occurring concentrations of 3.00 mg extractable B kg−1 and 1.17 mg total Se kg−1 soil. During the growing season, four intermediate harvests were performed on wild mustard and tall fescue. Final harvest I consisted of harvesting wild mustard, canola, and clipping tall fescue. Final harvest II consisted of harvesting wild mustard, which had been planted in soil in which wild mustard was previously grown, and harvesting previously clipped tall fescue. The greatest total amount of above ground biomass and below surface biomass was produced by tall fescue. Plants were separated into shoots and roots, weighted, and plant tissues were analyzed for total B and Se. The highest concentrations of tissue B were recovered in shoots of wild mustard and canola at final harvest I, while roots from tall fescue contained the highest concentrations of B irrespective of the harvest. Tissue Se concentrations were similar in all plants species. Soils were analyzed for residual B and Se. Extractable soil B concentrations at harvest times were lowered no less than 32% and total Se no less than 24% for all three species. The planting of wild mustard, canola, or tall fescue can reduce water-extractable B and total Se in the soil.

The Declining Even Flow Effect and the Process of National Forest Planning

Abstract Recent literature (McQuillan 1986) has identified what may be a serious flaw in the planning process used by the USDA Forest Service. The problem, which McQuillan called the declining even flow effect (DEFE), can occur during repeated iterations of a planning process in cases where a timber harvest scheduling model whose objective is wealth maximization subject to nondeclining yield constraints is utilized. The DEFE creates a situation in a sequence of plans over time in which the first period harvest level declines below that attained for previous planning iterations. This paper addresses the relationship between the process used by the Forest Service to develop FORPLAN models and the DEFE. An example using Kootenai National Forest planning documents is presented to illustrate the highly constrained nature of Forest Service planning models. The effect of these constraints and other characteristics of FORPLAN models on the DEFE is examined. Two items common to nearly all forest planning models, a land base which is not entirely old-growth and constraints to assure that the 40-ac clearcut limit is not violated, caused a large reduction in the DEFE observed in a FORPLAN version of McQuillan's case study model. However, one characteristic of Forest Service planning models, the use of intermediate harvest options, which plausibly could have reduced the DEFE, did not. The major conclusion of the study is that the regulations, initial conditions, and formulation of the FORPLAN model all tend to reduce the likelihood and magnitude of the DEFE. For. Sci. 36(3):665-679.

Tall Fescue Response to Placement of Urea/Ammonium Nitrate Solution

AbstractSeveral studies have shown that cool‐season grasses may respond more to subsurface (knife) applications of fluid fertilizer than to surface applications. However, optimum depth of knife application has not been clearly identified. A field study was conducted from 1984 to 1986 to determine the effects of 5‐, 10‐, and 15‐cm knife and surface band (dribble) and broadcast applications of urea/NH4NO3 solution at 84 and 168 kg N ha−1 on forage yield and N use of tall fescue (Festuca arundinacea Schreb.), and on soil N levels. The soil is a Parsons silt loam (fine, mixed, thermic Mollic Albaqualf). In 1985 and 1986, 168 kg N ha−1 resulted in higher final forage yields than 84 kg N ha−1. Knife applications at 10 cm generally resulted in the highest forage yield, though not always significantly higher than other placements. Knife placement at 15 cm resulted in lower N uptake in early grass clippings (intermediate harvests), compared with surface and shallower knife applications. The N concentration, N uptake in the final spring harvest, and apparent fertilizer‐N recovery by the forage were usually increased by 10‐cm placement. Knife applications of N at or below 10 cm resulted in higher inorganic soil N concentrations at intermediate harvests than did surface applications.

Potential Sawtimber Availability in Northcentral Pennsylvania: the Next Three Decades

Abstract Analysis of future hardwood sawtimber availability from an 8-county region in Pennsylvania over a 30-year period shows that the volume of rotation harvests from even-aged forests could double. This is based on a model projection of the stand structure of the region's forests in combination with the assumed forest management regimes for public and private owners. Additional sawtimber could also be provided from intermediate and selection harvests. Realization of this potential output will depend on an expansion of sawtimber markets and an effective means for regenerating stands after their rotation harvest. North. J. Appl. For. 4:119-123, September 1987.

Phosphorus Uptake from Soil Layers Having Different Soil Test Phosphorus Levels1

AbstractThe effect of available P in subsoil on plant uptake of P from surface soil layers and consequently on fertilizer recommendations is largely unknown. Our objective was to determine how much P may be removed by crops from subsurface soil layers and how the subsurface P level influences crop drawdown of P from the surface layer. Soil columns were prepared that contained all four possible combinations of low or high P levels in the surface soil and low or high P levels in the subsurface layer. The soil used was a Farnum fine sandy loam (fine‐loamy, mixed, thermic Pachic Argiustoll). Phosphorus removal was monitored by growing hybrid sorghum‐sudangrass [Sorghum bicolor (L.) Moench cv. ‘Honey Chow’] 84 days with an intermediate harvest after 35 days. Compared to when both the surface and subsurface layers had low P levels, P uptake increased when either or both layers had high P levels. Root growth and morphology responded to the P level of the soil layers. For all conditions, P uptake demonstrated a high correlation (R2=0.94) to an accessibility factor defined as the product of the available P level and root length summed for both soil layers. Comparing ratios of crop P removal to the change in soil test showed that P drawdown from the surface layer was reduced when the P‐supplying capacity of the subsurface layer was high. We concluded that available P in the subsurface layer can supply P to the crop, especially if the surface layer cannot supply sufficient P to meet crop demand. These results suggest that subsoil fertility should be considered in evaluating P available to crops and in estimating crop drawdown of available P.

Quantifying Residue after an Intermediate Harvest of a Second-Growth Redwood Stand

Abstract Logging residue was examined following an intermediate harvest that removed 40 percent of the basal area of a mature second-growth coast redwood stand. Tree pieces at least 1.5 inches in diameter and 4 feet in length qualified as residue. Cable logging produced 844 cubic feet of residue per acre, 22 percent more than tractor logging--possibly because of crushing and breakage by tractors during skidding. The authors conclude that low volumes and present markets make it uneconomical to use residue for building materials or fuel.

Recent innovations in cultivation of edible molluscs in Taiwan, with special reference to the small abalone Haliotis diversicolor and the hard clam Meretrix lusoria

Annual production and culture area of small abalones and hard clams have surprisingly increased in recent years. The factors contributing to this increase, aside from heavy demand and high price, include new techniques in catching the tiny clam seed (0.5 mm in size), success in mass production of seed of both species in hatcheries, better understanding of the molluscs' biology as well as their response to environmental changes, improved management of water quality to provide the optimal growth conditions, cheap and easy supply of Gracilaria for abalone feed, use of powdered formulated feed for hard clams, application of chicken manure and rice bran to enrich the water, intermediate harvest of animals of marketable size, and control of predators. However, major constraints to further development and expansion of molluse cultivation remain, including water pollution from industrial wastes, limited area with suitable water supply, strict regulations on the use of seashore land and littoral zone, and the lack of export market. Other species of molluscs, including the oyster Crassostrea gigas, the short-necked clam Comphina veneriforms, the purple clam Soletellina diphos, the cockle anadara granosa, and the small freshwater clam Corbicula, have potential for further expansion if problems of seed supply, water pollution, control of disease, and market price are properly solved.