Floor Litter Research Articles

Soil macrofauna and litter nutrients in three tropical tree plantations on a disturbed site in Puerto Rico

Tree plantations are increasingly common in tropical landscapes due to their multiple uses. Plantations vary in structure and composition, and these variations may alter soil fauna communities. Recent studies have demonstrated the important role of soil fauna in the regulation of plant litter decomposition in the tropics. However, little is known about how plantation species affect soil fauna populations, which may in turn affect the biogeochemistry of the plantation system. We measured soil macroinvertebrate abundance and biomass in 9-year-old N 2-fixing Leucaena leucocephala, Casuarina equisetifolia, and non-N 2-fixing Eucalyptus robusta plantations on a degraded site in Puerto Rico. Nutrient concentrations and standing stocks of forest floor litter were also determined to examine the relationship between litter chemistry and soil macroinvertebrates. Leucaena plantations had significantly higher abundances and biomass of millipede species than Casuarina and Eucalyptus. Earthworm biomass did not differ among plantation treatments. Nitrogen, P, and K concentrations were generally higher in Leucaena litter, which resulted in higher standing stocks of these nutrients in fragmented, moderately decomposed litter (Oe horizon). Millipede biomass was highly correlated to N concentration and C/N ratio in the Oi litter horizon. These results suggest that plantation species differ in their influence on soil fauna, and the biomass and abundance of soil fauna can be regulated through careful selection of plantation species in degraded tropical lands.

Composting of de-inking paper sludge with poultry manure at three nitrogen levels using mechanical turning: behavior of physico-chemical parameters

De-inking paper sludge (DPS) is rich in carbon (C) but poor in nitrogen (N). Thus, it has a high C:N ratio which limits the composting process. Accordingly, the goal of this study was to investigate the effect of three N treatments on DPS composting. Compost piles of 100 m 3 were formed by mixing raw DPS with poultry manure and chicken broiler floor litter, giving on average 0.6%, 0.7% and 0.9% total N. The changes in physico-chemical parameters, total weight and fiber losses, and maturity of composting piles of DPS were monitored during 24 weeks. The compost piles had a neutral to alkaline pH throughout the study. Inorganic N decreased whereas organic N increased over time for all treatments. These changes in magnitude were different among N treatments resulting in a final total N content of 0.9% for the 0.6% N treatment whereas final total N contents of 0.7% and 0.9% N were measured for the 0.7% and 0.9% N treatments. The total weight, cellulose and hemicellulose losses were higher in 0.6% N treatment giving the lowest C:N ratio after 24 weeks of composting. However, none of the 24 week-old composts of DPS were mature based on their final C:N ratio and colorimetric test of maturity. Except for copper, their final total trace element contents meet most known standards or guidelines for organic soil conditioners. Overall, 0.6% N treatment was the best to enhance DPS composting using mechanical turning, but a period of more than 24 weeks was required to reach compost maturity.

The effects of management on soil and plant carbon sequestration in slash pine plantations

Summary Intensively managed pine plantations in the south‐eastern United States can play an important role in global carbon sequestration both through accumulation of carbon in wood used in long‐lasting products as well as through increased soil carbon storage. Fertilization and understorey‐elimination are two commonly used intensive management practices in the south‐eastern United States that have the potential to increase carbon storage in vegetation and affect soil carbon. In this study, we assessed the effects of these practices on carbon accumulation in vegetation biomass and in the soil of 17‐year‐old slash pine Pinus elliottii plantations in the flatwoods of northern Florida, USA. Three treatments, fertilization, understorey‐elimination, and fertilization plus understorey‐elimination, were evaluated and compared with an untreated control. All three treatments increased above‐ground biomass accumulation compared with the untreated control; understorey‐elimination also increased biomass of the forest floor litter, with or without fertilization. Although understorey‐elimination increased above‐ground production, as a result of reduced below‐ground production total net primary production was decreased in plots from which the understorey was eliminated. Soil carbon storage was lower in plots where the understorey was eliminated, with or without fertilization. This appeared to be the result of reduced fine root growth and mortality but also may have reflected reduced litterfall inputs early in the rotation. Our results indicate that intensive management of pine plantations on sandy flatwoods soils can increase carbon sequestration, but these increases will be the result of increased carbon accumulation in biomass and its long‐term uses rather than through increased soil carbon.

The efficiency of a multi-soil-layering system on domestic wastewater treatment during the ninth and tenth years of operation

A multi-soil-layering (MSL) wastewater treatment system has been operating at Matsue City, Japan, since July 1990. This study investigates the efficiency of the MSL treatment system during the ninth and tenth years of operation. The MSL system consists of soil mixed with forest floor litter, pelletized jute and iron particles in the ratio of 60:10:15:15 by weight, respectively. The soil mixture is arranged within a 1.75×2.5×1.2 m 3 durable plastic box as blocks thus forming an alternating brick layer-like pattern with zeolite inter-layers. Household wastewater was pre-treated using the traditional Japanese septic tank system (Tandoku Johkasou) with integral aeration facility, before being gravitationally discharged continuously into the MSL system. The flow rate of pre-treated wastewater into the MSL system varied from 1.2 to 113.4 l h −1 as a function of household water consumption. The results indicate that during the period of investigation, the MSL system was still effective at removing biochemical oxygen demand (BOD 5) and total phosphorus (TP). The removal rates of BOD 5 and TP were up to 91.0±4.5 and 89.0±4.4%, respectively, in the ninth year and 95.2±3.8 and 82.9±11.9%, respectively, in the tenth year of operation. Total nitrogen (TN) removal was significantly dependent on aeration of the MSL system, quality of pre-treated wastewater and temperature. Although the continuous aeration of the MSL system for 24 h d −1, which was equivalent to 2.8×10 4 l m −3 d −1, was effective in facilitating the removal of BOD 5 and TP, it was inappropriate for TN removal. However, after aeration was stopped, TN removal improved considerably, increasing to 89%.

Diet, Reproduction, and Density of the Leptodactylid Litter Frog Zachaenus parvulus in an Atlantic Rain Forest of Southeastern Brazil

Amphibians and reptiles are important constituents of leaf litter communities in tropical forests (Fauth et al., 1989; Allmon, 1991; Vitt and Caldwell, 1994). Forest floor leaf-litter frogs forage for arthropods (Toft, 1980a,b), and three general guilds can be recognized depending on the proportions of different kinds of prey: ant specialists, non-ant specialists, and generalists (Toft, 1980a). In general, leptodactylid frogs are considered non-ant specialists eating predominantly soft-bodied, mobile arthropods, mainly orthopterans and spiders (Toft, 1980a,b, 1995). Zachaenus parvulus is a small leptodactylid frog, which occurs among the floor litter of the Atlantic rain forest of eastern Brazil (Duellman and Trueb, 1986; Rocha et al., 1998). Information on the species is restricted to data on reproduction (Lutz, 1944) and defense tactics (Sazima, 1978; Rocha et al., 1998), with almost nothing known about other aspects of its biology. In the Atlantic rain-forest leaf-litter anuran community that we studied, Z. parvulus is the second most abundant species (after the brachycephalid Psyllophryne didactyla). Herein, we report an investigation of some aspects of the ecology of Zachaenus parvulus providing information on its diet, reproduction, and density at Ilha Grande, Brazil. The study site was in the Atlantic rain forest at Ilha Grande (23?10'558S; 44?12'499'W), an island in southern Estado do Rio de Janeiro, southeastern Brazil (Fig. 1), at an elevation of approximately 240 m. Rainfall is seasonal, with mean annual rainfall of 2240 mm and monthly averages ranging from 87 mm (July) to 293 mm (January; Bittencourt, 1998). Mean air temperature is 22.5?C, with February being the hottest month (25.7?C) and July the coldest (19.6?C; Bittencourt, 1998). Ilha Grande is covered by Atlantic rain forest with different levels of succession resulting from disturbances caused by human activities through the last centuries (Araujo and Oliveira, 1988). The study area consists of a remnant of undisturbed Atlantic rain forest with trees reaching 30 m, covered by bromeliads and vines, and with a relatively deep leaf-litter layer (80-150 mm). From August 1996 to November 1997 frogs were

A Novel Delivery of Oxytetracycline in Turkey Breeder Hens

A novel product (SQ12) for subcutaneous (SQ) injectable delivery of oxytetracycline (OTC) has been developed for use in livestock. SQ12 employs microfluidic spheres encasing OTC crystals, which allows for longer release of the OTC compared with other injectable antibiotics. The objectives of the study were to determine serum and tissue levels of SQ12 in turkey breeder hens to 14 days postinjection and to evaluate effects of SQ12 on reproductive status. Thirty photostimulated hens were housed in litter floor pens and provided with 14.5 hr of light per day in a curtain-sided facility. Six hens served as untreated controls. Twelve hens per treatment group received SQ injections in the neck with SQ12 at 11.4 (L dose group) or 22.7 mg/kg (H dose group) to assess low and high doses, respectively. Serum samples were obtained from each hen at predose and 6, 12, 24, 48, 72, 96, 168, 240, and 336 hr postinjection. All hens were euthanatized at 14 and 15 days postinjection. One-half of the hens in each treatment group were sampled (liver, lung, kidneys, and breast muscle) for tissue residue levels of OTC. The control group had no detectable OTC in serum or tissues at any sample collection time. There were no detectable serum levels of OTC in either treatment group prior to injection. The average serum concentrations of the L and H dose groups showed similar depletion curves although the H dose group was 42% higher at maximum concentration than the L group. Average tissue concentration of OTC for all tissues sampled from the H dose group was twice that of the L dose group. All tissue levels were below the OTC residue tolerance limit. SQ12 provided an extended source of OTC in serum of turkey breeder hens with no effect on reproductive status. SQ12 may provide for a novel treatment of bacterial infection in turkey breeder hens with longer lasting serum levels compared with other single injectable OTC products.

New records of mites (Acari: Cheyletidae) from stored products with description of a new species in Greece

Five species of cheyletid mites, Acaropsis sollers Kuzin, Cheletomorpha lepidopterorum (Shaw), Cheyletus aversor Rohdendorf, Cheyletus trouessarti Oudemans and Cheyletus trux Rohdendorf, are reported for the first time from Greece. A new species, Chelacheles hellenicus, collected on floor litter in a flour mill at Votanikos, Athens, Attiki Co., is illustrated and described.

Estimates of forest floor litter frog communities: A comparison of two methods

Estimates of forest floor litter frog communities: A comparison of two methods

Estimates of forest floor litter frog communities: A comparison of two methods

AbstractEstimates of forest leaf litter frog density, mass, richness and diversity given by the widely used 8 m × 8 m large plot method (LPM) were compared with estimates obtained by a newly proposed method (small 2 m × 1 m plots with leaf removal; SPLR). The study site was an undisturbed area of the Atlantic Rainforest of Ilha Grande, an island located in the south of Rio de Janeiro State, Brazil. Twenty‐four LPM (totalling 1536 m2 of forest floor) and 90 SPLR (totalling 180 m2 of forest floor) were performed. The estimates obtained by the two methods differed markedly, indicating that even using a much smaller sampling area (11.7% of that of LPM), SPLR gave frog density estimates six times higher, and frog mass estimates approximately 2.5 times higher than estimates provided by LPM. The species richness and diversity obtained by the two methods were similar, despite the fact that the total area sampled with SPLR was much smaller. These data suggest that LPM may underestimate the abundance and biomass of leaf litter frogs in a given area.

Effects of clear-cutting on decomposition rates of litter and forest floor in forests of British Columbia

The rate of mass loss of three standard substrates (pine needle litter, aspen leaf litter, and forest floor material) was measured in forests and adjacent clearcuts at 21 sites throughout British Columbia, to test the hypotheses that (i) rates of mass loss are greater in clearcuts than in forests and (ii) clear-cutting would stimulate decomposition most in colder zones. Mass loss ranged from 53 to 75% after four years in pine needles, 49 to 70% after 3 years in aspen leaves, and 11 to 20% after 4 years in forest floor material. Mass loss from pine needles was significantly slower in clearcuts throughout the 4-year incubation. Aspen leaf litter and forest floor material lost mass at similar rates in forests and clearcuts. The effect of clear-cutting did not vary between relatively cold and warm sites. The effect of clear-cutting was not related to the size of the clearcuts, which ranged from 1 to 97 ha.

Soil organic matter formation and sequestration across a forested floodplain chronosequence

Successional changes in soil organic matter formation and carbon sequestration across a forested floodplain chronosequence were studied at the Savannah river site, National Environmental Research Park, SC, US. Four floodplain sites were selected for study, three of which are in various stages of recovery from impact due to thermal effluent discharge. The fourth is a minimally disturbed reference site. Forest floor organic matter increases rapidly during early secondary succession, with a maximum of 657 g/m 2 and decreasing to 338 g/m 2 during the later seral stages. Carbon content in the forest floor also reflected this pattern, with levels greatest during early succession and declining thereafter. Changes in carbon pools of the forest floor are primarily driven by changing levels of forest floor biomass in the various stages of succession, rather than element concentrations. The composition of the forest floor from the various stages differed markedly. The percent herbaceous material declined during succession from 74% in an early stage to <1% in the latest seral stage. Conversely, the amount of woody foliage increased from 6.7 to more than 70% in late succession. Measures of the degree of transformation of forest floor litter to soil organic matter using the lignocellulose index (LCI) did not differ between stages of succession. Percent lignin and percent cellulose of the forest floor were similar between stages and ranged from 13.8–16.3, and 30.4–32.5%, respectively. Carbon content of the mineral soil increased with successional stage of the floodplain chronosequence. Soil carbon content ranged from 15.6 kg/m 2 per 0.7 m in the earliest stage of succession to 55.9 kg/m 2 in late succession. Regression analyses indicated that it may take over 50 years for carbon levels to reach 75% of that of the reference site. The evidence also suggests that soil structure was disrupted by the disturbance, producing a greater proportion of microaggregates in early seral stages. The formation of soil macroaggregate structure, which may facilitate the accrual of carbon, appears to be occurring slowly.

Spring ephemeral herbs and nitrogen cycling in a northern hardwood forest: an experimental test of the vernal dam hypothesis

In the late 1970s R.N. Muller and F.H. Bormann posited their "vernal dam" hypothesis, stating that spring-ephemeral herbs in deciduous forests serve as a temporary sink for N when overstory trees are dormant, and then release this N later, in the summer, when the trees are active. This hypothesis has gained wide acceptance, yet two of its critical assumptions have never been experimentally tested: (1) that N taken up by spring ephemerals would otherwise be lost from the ecosystem, and (2) that N from senesced ephemeral tissues contributes to increased rates of summertime N mineralization. To test these assumptions, I quantified patterns of N cycling and loss from a set of paired plots, half of which served as controls and from half of which all spring-ephemeral plants were removed. There were no significant differences in NO3- leaching between plots with and without spring ephemeral vegetation. These results are consistent with the relatively low rates of N uptake by the dominant spring ephemeral, Allium tricoccum, and its apparent preference for NH4+, which is far less mobile in soil than NO3-. In addition, based on sequential sampling, I found that soil microorganisms took up 8 times as much N during the spring than did spring-ephemeral herbs (microbial uptake=3.19 vs. plant uptake=0.41 g N m-2), suggesting that microbial immobilization of N is the dominant sink for N during this season. Removal of spring ephemeral vegetation also had no effect on summertime rates of net N mineralization. Furthermore, the addition of spring ephemeral litter to soil+forest floor microcosms did not significantly increase rates of N mineralization in a laboratory incubation. Instead, this experiment demonstrated the overwhelming influence of forest floor litter in controlling the release of mineral N from these soils. Overall, neither assumption of the vernal dam hypothesis holds true in this ecosystem, where patterns of N cycling and loss appear to be dominated by microbial decomposition of forest floor material and soil organic matter.

Effects of altered water regimes on forest root systems

How ecosystems adapt to climate changes depends in part on how individual trees allocate resources to their components. A review of research using tree seedlings provides some support for the hypothesis that some tree species respond to exposure to drought with increases in root∶shoot ratios but little change in total root biomass. Limited research on mature trees over moderately long time periods (2–10 yr), has given mixed results with some studies also providing evidence for increases in root: shoot ratios. The Throughfall Displacement Experiment (TDE) was designed to simulate both an increase and a decrease of 33% in water inputs to a mature deciduous forest over a number of years. Belowground research on TDE was designed to examine four hypothesized responses to long‐term decreases in water availability; (1) increases in fine‐root biomass, (2) increases in fine root∶foliage ratio, (3) altered rates of fine‐root turnover (FRT), and (4) depth of rooting. Minirhizotron root elongation data from 1994 to 1998 were examined to evaluate the first three hypotheses. Differences across treatments in net fine‐root production (using minirhizotron root elongation observations as indices of biomass production) were small and not significant. Periods of lower root production in the dry treatment were compensated for by higher growth during favorable periods. Although not statistically significant, both the highest production (20 to 60% higher) and mortality (18 to 34% higher) rates were found in the wet treatment, resulting in the highest index of FRT. After 5 yr, a clear picture of stand fine‐root‐system response to drought exposure has yet to emerge in this forest ecosystem. Our results provide little support for either an increase in net fine‐root production or a shift towards an increasing root∶shoot ratio with long‐term drought exposure. One possible explanation for higher FRT rates in the wet treatment could be a positive relationship between FRT and nitrogen and other nutrient availability, as treatments have apparently resulted in increased immobilization of nutrients in the forest floor litter under drier conditions. Such hypotheses point to the continued need to study the interactions of water stress, nutrient availability and carbon‐fixation efficiency in future long‐term studies.

Effects of the Trichothecene Mycotoxin Diacetoxyscirpenol on Feed Consumption, Body Weight, and Oral Lesions of Broiler Breeders

Three experiments were conducted to determine the effects of 4,15-diacetoxyscirpenol (DAS) on BW, feed consumption, and oral lesions of broiler breeders. In Experiment 1, caged broiler breeder hens were fed 0, 5, 10, or 20 mg DAS/kg diet from 24 to 25 wk of age. There were dose-related decreases in BW and feed consumption indicating feed refusal, as well as dose-related increases in the extent of mouth lesions. The areas of the mouth most sensitive to DAS were associated with the salivary glands and the tip of the tongue.In Experiment 2, individually caged male and female broiler breeders were fed a basal diet containing 0, 5, 10, or 20 mg DAS/kg from 25 to 27 wk of age. There were dose-related decreases in BW and feed consumption for the female broiler breeders, whereas there was a decrease in feed consumption for the male broiler breeders at the 10 and 20 mg DAS/kg levels.In Experiment 3, male broiler breeders were fed 0 or 10 mg DAS/kg diet from 23 to 25 wk of age on a litter floor. For this experiment the daily intake of feed was restricted, and the feed consumption rate was measured. There was an increased amount of unconsumed feed at 23 wk of age due to the presence of DAS.In summary, the experiments provided evidence that DAS caused decreased BW and feed consumption as well as cytotoxic injury including oral lesions in broiler breeders.

Risk factors for Marek’s disease and mortality in White Leghorns in Norway

A prospective longitudinal field study was conducted in the period from January 1994 to January 1996 to analyse the relationship between some selected risk factors in the growing and laying periods and (1) the flock-level occurrence of Marek’s disease (MD) during the period from 16 to 32 weeks of age and (2) the cumulative mortality during the same period. A total of 171 layer flocks in 102 egg-production farms were included in the statistical analyses. A logistic regression (with strain of layer and vaccination program against MD as fixed effects) of flock-level MD-status during the first 16 weeks of the laying period was conducted. Of the risk factors investigated, “multi-age management” and “housing system” were significantly associated at the rearing farm, and “number of hens in each cage” at the egg-production farm. Flocks kept in single-age facilities had a lower risk of MD than flocks housed in farms with multi-age management. The odds of MD were larger for flocks housed on a litter floor in the rearing farms compared to flocks housed in battery cages. At the egg-production stage, flocks kept in battery cages housing more than three hens were at greater risk of MD than those held in cages for three hens or less. A weighted least-squares regression (with strain of layer and flock-level MD-status as fixed effects) of cumulative mortality during the period from 16 to 32 weeks of age was also run. The same risk factors (with the same directions of effects) and “size of the rearing farm” were included in the final model of mortality. Chicks reared in medium-sized farms were at higher risk of dying than those coming from either small or large rearing farms. Our results confirm the importance of preventing chicks from being exposed to MD-virus during the rearing period, to reduce the risk of MD-outbreaks (and thereby, mortality losses) during the early stage of the egg-laying period.

Soil CO2evolution and root respiration in 11 year-old loblolly pine (Pinus taeda) plantations as affected by moisture and nutrient availability

We measured soil CO2evolution rates with (Sff) and without (Sms) the forest floor litter and root respiration monthly in 11-year-old loblolly pine (Pinus taeda L.) plantations during the fourth year of fertilization and irrigation treatments. Values of Sffranged from less than 1 µmol·m-2·s-1during the winter to greater than 5 µmol·m-2·s-1in late spring. Average Sffwas significantly greater in unfertilized relative to the fertilized stands; however, there was no difference in average Smsamong treatments. Soil temperature and the mass of the forest floor (litter) explained most of the difference in Sffamong treatments. Soil temperature and volumetric water content accounted for 70% of the seasonal variation in Sff. Annual carbon efflux from the soil averaged 14.1 Mg·ha-1per year for all treatments. Most of the evolved carbon was derived from root respiration (50-73%). Net ecosystem productivity was -1.1 and 6.9 Mg C·ha-1per year for the unfertilized and fertilized stands, respectively. At age 11, the unfertilized stands were functioning as a net carbon source, while fertilized stands were a strong carbon sink. It was concluded that fertilization could decrease the time for a young pine plantation to change from a carbon source to a carbon sink.

Effects of clear-cutting on decomposition rates of litter and forest floor in forests of British Columbia

Effects of clear-cutting on decomposition rates of litter and forest floor in forests of British Columbia

Soil CO&lt;sub&gt;2&lt;/sub&gt; evolution and root respiration in 11 year-old loblolly pine (&lt;i&gt;Pinus taeda&lt;/i&gt;) plantations as affected by moisture and nutrient availability

We measured soil CO2 evolution rates with (Sff) and without (Sms) the forest floor litter and root respiration monthly in 11-year-old loblolly pine (Pinus taeda L.) plantations during the fourth ye...

Some hydrological effects of changing forest cover from eucalypts to Pinus radiata

A study of the hydrological effects of clearing a catchment covered by native, dry sclerophyl eucalypt forest, and replanting it with a Pinus radiata plantation was undertaken. The purpose of this study was to examine the effects of vegetation species change and growth rates on streamflow. The water balance of the two forests was observed for a 27-year period; 11 years before and 16 years after the forest conversion. Data on precipitation, canopy interception, forest floor interception and water yield, combined with analysis of the rate of vegetative growth and development of the forest floor litter, enabled investigation of the effects of forest conversion on the water balance components for the whole period (1967–1993). The age of a P. radiata plantation during the first 16 years of its growth greatly affected the streamflow and other water balance components. For the first 4 years after forest conversion, the rates of evapotranspiration and streamflow changed completely. Transpiration and the evaporation of intercepted rainfall ceased after the forest was cleared. The changes in the first 4 years were followed by a further transformation of the whole evapotranspiration process as the pine plantation developed. A trend of increasing evapotranspiration and canopy and forest floor interception losses as the plantation grew, with decreases in runoff, was followed by an equilibrium situation in which streamflow, and the evapotranspiration from soil water storage were smaller than for the native forest.

The demand for straw and feathers as litter substrates by laying hens

Consumer demand theory has been applied to investigate behavioural demands and environmental requirements of farm animals. Recent research with laying hens has shown that the demand for various floor litters (peat, sand, wood-shavings) is inelastic. Other types of litter (e.g., straw and feathers) are available to laying hens in some housing systems. This study aimed to determine the importance of straw and feathers to laying hens by measuring demand functions for these items. In 1 h sessions individual birds ( n=6) were given the opportunity every second day to work on fixed ratio (FR) schedules (FR5 to FR200) for access to either straw or feathers. The number of responses made and reinforcers delivered was recorded. All birds worked to gain access to straw but only three worked for feathers. None of the hens dustbathed consistently in either litter. The mean elasticities of the demand were significantly different from zero and were −0.48 (s.e. 0.04; p<0.001) for straw and −0.45 (s.e. 0.05; p<0.001) for feathers. The results imply that even if a substrate does not stimulate dustbathing, caged laying hens have a high demand for a litter substrate.