Effects Of Different Management Systems Research Articles

Effect of Different Management Systems on Soil Water Content in the Black Soil of Northeast China

Soil water content is considered to be one of the most important factors affecting crop productivity. In this study, the different management practices were investigated in the black soil of Northeast China to evaluate the efficacy of practices on soil water content. The results showed that the application of organic matter, large-scale machine and residues retention have positive effects on soil water content. Saturated water content (SWC), field water-holding capacity (WHC), and available water content (AWC) were strongly correlated with soil bulk density and soil organic matter. Our results suggested that proper management systems could improve soil water use efficiency in black soil region of Northeast China.

Assessment of different management systems in an area of Cerrado sensu stricto

This study aims to evaluate the effect of different management systems on the floristic composition and diversity of a fragment of Cerrado sensu stricto vegetation located in Brasilândia de Minas (MG), eleven years after interventions. In 1997, 30 plots were installed in the study site, in a random block design, consisting of ten treatments with three replications: 50%, 60%, 70% and 80% removal of the basal area, involving 20% reduction and increase in the De Liocourt quotient value; clear cutting and control treatment. Prior to treatment installation, an inventory was compiled of original vegetation. In 2004 and 2008 further inventories were produced. It was observed that interventions in the relevant Cerrado area led to changes in the floristic composition and diversity of local vegetation, yet these changes were also observed in undisturbed areas which had not been subjected to management plans.

Effects of different management systems on porosity of oxisols in Paraná, Brazil

Soils play a fundamental role in the production of human foods. The Oxisols in the state of Paraná are among the richest and most productive soils in Brazil, but degradation and low porosity are frequently documented, due to intensive farming involving various management strategies and the application of high-tech solutions. This study aims to investigate changes in the porosity of two Red Oxisols (Latossolos Vermelhos), denoted LVef (eutroferric) and LVdf (dystroferric) under conventional and no-tillage soil management, with a succession of annual crops of soybean, maize and wheat over a continuous period of more than 20 years. After describing the soil profiles under native forest, no-tillage management and conventional tillage using the crop profile method, deformed and non-deformed soil samples were collected from the volumes most compacted by human intervention and the physical, chemical and mineralogical properties analyzed. The various porosity classes (total pore volume, inter-aggregate porosity between channels and biological cavities) and intra-aggregate porosity (determined in 10 cm³ saturated clods subjected to a pressure of -10 kPa to obtain a pore volume with a radius (r eq), > 15 μm and < 15 μm). The results showed that the effects of no-tillage farming on porosity are more pronounced in both soil types. Porosity of the LVdf was higher than pf the LVef soil, whatever the management type. In the LVdf soil, only pores with a radius of > 15 μm were affected by farming whereas in the LVef soil, pores with a radius of < 15 μm were affected as well.

Labile and stable fractions of soil organic matter under management systems and native cerrado

Soil organic matter can be analyzed on the basis of the different fractions. Changes in the levels of organic matter, caused by land use, can be better understood by alterations in the different compartments. The aim of this study was to evaluate the effect of different management systems on the labile and stable organic matter of a dystrophic Red Latosol (Oxisol). The following properties were determined: total organic C and total N (TOC and TN), particulate organic C and particulate N (POC and PN), organic C and N mineral-associated (MOC and NM) and particulate organic C associated with aggregate classes (POCA). Eight treatments were used: seven with soil management systems and one with native Cerrado as a reference. The experiment was designed to study the dynamics of systems of tillage and crop rotation, alternating in time and space. The experimental design was a randomized block design with three replications. The soil samples were collected from five depths: 0-5, 5-10, 10-20, 20-30 and 30-40 cm. Changes in organic C by land use occurred mainly in the fraction of particulate organic matter (> 53 mm). Proper management of grazing promoted increased levels of particulate organic matter by association with larger aggregates (2-8 mm), demonstrating the importance of the formation of this aggregate class for C protection in pasture.

Estabilidade de agregados de um latossolo amarelo distrocoeso de tabuleiro costeiro sob diferentes aportes de resíduos orgânicos da cana-de-açúcar

O potencial produtivo da cana-de-açúcar decorre de fatores relacionados ao clima, ao solo e à variedade cultivada. Sistemas de manejo que proporcionem a adição de resíduos orgânicos ao solo podem provocar alterações em seus atributos físicos, favorecendo o crescimento do sistema radicular e a produtividade da canade-açúcar. O objetivo deste trabalho foi avaliar os efeitos de diferentes sistemas de manejo com cana-de-açúcar com diversos níveis de adição de resíduos orgânicos sobre a distribuição e os índices de estabilidade de agregados de um Latossolo Amarelo distrocoeso dos tabuleiros costeiros de Alagoas. Foram selecionadas áreas em talhões de produção com a cultura da cana-de-açúcar: uma área cultivada sob sistema de manejo irrigado (SMI), uma área sob sistema de manejo de fertirrigação com vinhaça (SMV) e uma área sob sistema de manejo com aplicação de vinhaça + torta de filtro (SMVT). Esses sistemas de manejo foram comparados entre si e em relação a uma testemunha-padrão, representada por um fragmento de Mata Atlântica (MN). Para avaliar a distribuição e os índices de estabilidade de agregados, amostras do solo foram coletadas ao acaso, nas áreas submetidas aos diferentes sistemas de manejo, nas profundidades de 0-0,20, 0,20-0,40 e 0,40-0,60 m, sendo retiradas num ponto situado nas entrelinhas da cana-de-açúcar. Os resultados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey a 5 %. Estudos de correlações simples foram realizados entre algumas variáveis medidas. Os resultados permitiram concluir que os diferentes sistemas de manejo promoveram alterações na distribuição de agregados do solo e a estabilização dos agregados na camada superficial dependeu do teor de matéria orgânica e da ação dos ciclos sucessivos de umedecimento e secagem do solo. Os estudos de correlações entre o carbono orgânico total e os índices de estabilidade dos agregados apresentaram correlações significativas e positivas.

Determination of the mineral composition of fresh bovine milk from the milk-producing areas located in the State of Sergipe in Brazil and evaluation employing exploratory analysis

In this work, the mineral composition of fresh bovine milk obtained from the milk-producing areas of the Brazilian State of Sergipe was examined. A dry-ashed digestion method and the ICP OES technique were used for the quantification of mineral elements ( e.g., Ca, Mg, K, Na, P, Sr and Zn) in 27 samples of milk collected from properties located in milk-producing areas around Nossa Senhora da Glória. The following ranges of values (% m/v) were obtained: 0.063 to 0.117 for Ca; 0.060 to 0.114 for P; 0.024 to 0.064 for Na; and 0.087 to 0.164 for K. The ranges of values (mg L − 1 ) for the other mineral elements were also found: 0.68 to 1.89 for Sr; 2.46 to 5.73 for Zn; and 54.2 to 109.9 for Mg. Additionally, the exploratory evaluation of the 27 milk samples was performed using principal component analysis (PCA) involving seven variables dealing with the effect of different management systems (conventional and organic) on milk composition. The results show that there are indeed differences between the mineral composition of milk from properties that use organic practices and those that use conventional management practices.

PRODUÇÃO DE MATÉRIA SECA E CONCENTRAÇÃO DE MACRONUTRIENTES EM Brachiaria decumbens SOB DIFERENTES SISTEMAS DE MANEJO NA ZONA DA MATA DE PERNAMBUCO

The cultivation of pastures for long time under different management systems can cause alterations in the dry matter production and in the macronutrients concentration in shoots of plants. In an experiment carried out at the Pernambuco Agricultural Research Institute (IPA) experiment extension, district of Itambe, Pernambuco State, Brazil, the effects of different management systems in the dry matter production and macronutrients concentration in pasture shoots were studied. The management systems consisted of a fertilized area under Brachiaria decumbens pasture consortiated with Calopogonium mucunoides, a fertilized area cultivated with B. decumbens pastures, a non-fertilized area under B. decumbens pasture, and a non-fertilized pasture of B. decumbens and native leguminous of the genus Sesbania. The plant shoots were collected at 0.15 m height, for determination of shoot dry matter production and N, P, K, Ca, and Mg concentrations. The fertilized areas with B. decumbens or with B. decumbens consortiated with C. mucunoides promoted the greatest concentrations of N, P and K in the rainy and dry seasons, and greatest shoot dry matter production in the dry season, as related to the other studied treatments. KEY-WORDS: Brachiaria; Calopogonium; Red-Yellow Argisol; coastal plain tablelands.

Adaptation of a spatially explicit individual tree-based growth and yield model and long-term comparison between reduced-impact and conventional logging in eastern Amazonia, Brazil

Timber logging is one of the main land uses in the Brazilian Amazon. Despite its recognized potential as a sustainable activity, logging is generally conducted in an unsustainable or predatory manner, with significant negative environmental impact. There is increasing pressure to adopt more sustainable practices and reduced-impact logging (RIL) is gaining acceptance as a more environmentally benign alternative to unplanned, conventional logging (CL). Comparisons of these two harvest systems have largely focused on differences in efficiency (financial) and immediate impacts on stand structure, residual timber stocks and the physical environment. Growth and yield simulation models allow long-term predictions about the response of forests to disturbance from harvesting, information that is essential to determine the effects of different management systems and to establish systems for the regulation or control of timber that are compatible with sustainable forest management. We describe the calibration of a spatially explicit individual tree-based ecological model within the SYMFOR/SIMFLORA framework for forests located near Paragominas in eastern Amazonia. Data originated from an experiment comparing RIL to CL within an area of 73.5 ha monitored over a period of 10 years. We evaluated biological realism and accuracy of the model, concluding that forest dynamics are adequately represented. This model was used to evaluate long-term effects of RIL and CL on the forest. Our results suggest that total and commercial volume recovery following RIL are faster than following CL; it takes 10 and 30–40 years to recover total and commercial volume under RIL while under CL it takes 35–40 and over 60 years, respectively. Despite benefits from RIL, as currently practiced this logging system does not result in long-term sustained timber yields, reinforcing results from previous studies indicating that RIL must be combined with appropriate systems for yield regulation. In the absence of silvicultural treatments, the model suggests that successive RIL harvests at current intensities will produce stands dominated by pioneer species groups, with few trees belonging to the emergent species group, and an increased proportion of defective trees in commercial size classes. These changes in stand composition present challenges to the long-term financial viability of RIL as currently applied in the Amazon region.

Efeito sazonal e de sistemas de manejo com pastagens de <em> Brachiaria decumbens </em> Stapf sobre as características químicas num Argissolo Vermelho Amarelo

Seasonal effect and of management systems with pastures of Brachiaria decumbens Stapf in the chemical properties in a Yellow Red Argisol. In experiment carried out in the experimental station of the Institute from Pernambuco of Agricultural Research (IPA), municipal district of Itambé, Pernambuco State, the effects of different management systems with pastures of Brachiaria decumbens in the chemical properties of a Yellow Red Argisol were studied. The management systems consisted of a fertilized area and under pastures of Brachiaria decumbens in consortium with Calopogonium mucunoides; a fertilized area and cultivated with pastures Brachiaria decumbens; an area not fertilized and under pastures of Brachiaria decumbens, and an area not fertilized and under pastures of Brachiaria decumbens and leguminouses native of the gender Sesbania. Samples were collected of each area at 0,0-0,15 m and 0,15-0,30 m depths, in the rainy and dry stations, to determine the alterations in the pH in water, contents of calcium, magnesium, potassium and exchangeable aluminum, phosphorus and matter organic total of the soil. The soils cultivated under fertilized pasture of Brachiaria decumbens presented the best chemical conditions, with the largest phosphorus values and CTC, and the smallest values of exchangeable aluminum. In general there was not expressive effect of the season in the chemical conditions of the soil of the studied areas.

Modificações na matriz de um Argissolo Amarelo Coeso sob diferentes sistemas de manejo com cana-de-açúcar

Os sistemas de manejo com cana-de-açúcar em solos de tabuleiros costeiros podem causar alterações importantes na matriz do solo. Foram estudados os efeitos de diferentes sistemas de manejo com cana-de-açúcar na organização da matriz de um Argissolo Amarelo Coeso, na usina Triunfo, Estado de Alagoas. Os sistemas de manejo consistiram de uma área não irrigada, uma área irrigada, uma com aplicação de vinhaça e uma sob floresta nativa como condição original. Amostras foram retiradas de cada área a 0-0,2, 0,2-0,4 e 0,4-0,8 m de profundidade para determinar as alterações na estrutura do solo, no sistema de poros e no arranjamento de partículas dos solos cultivados com cana-de-açúcar, em relação ao solo da mata. Os solos cultivados apresentaram associação da porosidade natural com poros aplanados e um arranjamento mais compacto das partículas na matriz solo. Nos agregados dos solos cultivados constatou-se um aspecto maciço e orientação de partículas de argila, em relação ao solo da mata.

Matéria orgânica e propriedades físicas de um Argissolo Amarelo Coeso sob sistemas de manejo com cana-de-açúcar

O cultivo contínuo da cana-de-açúcar por longo tempo sob diferentes manejos em solos de tabuleiros costeiros pode causar alterações na matéria orgânica e nas propriedades físicas do solo. Estudaram-se os efeitos de diferentes sistemas de manejo com cana-de-açúcar nas propriedades de um Argissolo Amarelo Coeso, na usina Triunfo, Estado de Alagoas. Os sistemas de manejo consistiram de uma área não irrigada, uma área irrigada, uma com aplicação de vinhaça e outra sob floresta nativa, sob condição original. Amostras foram retiradas de cada área a 0-0,2, 0,2-0,4 e 0,4-0,8 m de profundidade para determinar as alterações nos limites de consistência, parâmetros de compactação, estabilidade de agregados e frações físicas da matéria orgânica do solo. O cultivo da cana-de-açúcar sob os sistemas sequeiro e irrigado promoveu redução mais expressiva no limite de plasticidade, umidade ótima de compactação e diâmetro médio ponderado dos agregados, em relação ao solo sob mata nativa, devido à maior redução nos teores de carbono orgânico total e matéria orgânica particulada do solo. O sistema de manejo com aplicação de vinhaça promoveu menor degradação nas propriedades físicas e químicas do solo, em relação ao solo sob mata nativa.

Soil springtails (Hexapoda: Collembola), symphylans and pauropods (Arthropoda: Myriapoda) under different management systems in agroecosystems of the subhumid Pampa (Argentina)

The Pampa region is the most important agricultural area in Argentina. Although intensive agricultural activity is leading to important levels of soil degradation, studies on the impact on soil fauna are scarce. Despite the environmental importance of collembolans, symphylans and pauropods in soil, information on the influence of land management on their population densities is poor, particularly in Neotropical agroecosystems. The aim of this study was to investigate the effects of different management systems on the density of collembolans, symphylans and pauropods. Population abundance of these arthropods was examined in a natural site and a cattle raising, a mixed and an agricultural management system on a Typic Hapludoll soil in La Colacha, Córdoba, Argentina. All the sites studied had the same land use history until approximately 50 years before sampling and have the same soil type. Total abundance of the studied groups varied in the different management systems. Our results suggest that conventional agricultural management tends to reduce the density of collembolans and pauropods. Our data do not support our hypothesis that the cattle raising management system constitutes an intermediate situation between the natural site and the high-input management systems. We conclude that the reduction of collembolan and pauropod densities in high-input management systems is largely explained by the mechanical and chemical perturbations produced by conventional agricultural management practices and by particular abiotic soil conditions present in the intensively managed sites that are unfavourable for these organisms. Surprisingly, symphylans were more abundant in the mixed management site. The implications of our findings on soil ecosystem functioning are discussed.

Atributos físicos de um Neossolo Quartzarênico e um Latossolo Vermelho sob diferentes sistemas de manejo

O objetivo deste estudo foi avaliar o efeito de diferentes sistemas de manejo, nos atributos físicos de um Neossolo Quartzarênico e de um Latossolo Vermelho. Foram avaliados a densidade do solo, o volume total de poros e a resistência mecânica à penetração. Todos os sistemas de manejo e uso do solo promoveram aumento na densidade, diminuição do volume total de poros e variação da resistência do solo à penetração. No Neossolo Quartzarênico houve diminuição da macroporosidade.

Sistemas de manejo na absorção de nitrogênio pelo milho em um Latossolo Vermelho no Cerrado

O objetivo deste trabalho foi avaliar o efeito de diferentes sistemas de manejo na absorção de nitrogênio pelo milho em um Latossolo Vermelho no Cerrado. O nitrogênio total (Ntotal), derivado do fertilizante mineral (Ndfm) e do solo (Ndsolo), foi determinado, além da eficiência de recuperação do nitrogênio fertilizante (ERNF) pelo milho. Os tratamentos foram compostos de oito sistemas de manejo do solo, constituídos de diferentes implementos e épocas de incorporação de restos culturais. O plano de amostragem foi realizado por amostragem aleatória simples. O solo foi a principal fonte de N para as plantas. Sob os sistemas plantio direto ou cultivo mínimo, com escarificação, a cultura do milho apresentou maiores teores de N nos grãos (Ntotal, Ndfm e Ndsolo), assim como maiores ERNF do que no sistema com duplo revolvimento anual com arado de aivecas. O modo de ação dos arados de discos e de aivecas, bem como a época de incorporação dos restos culturais, pré-plantio e pós-colheita, não causaram diferenças nas quantidades de N (Ntotal e Ndfm) nos grãos de milho, embora tenham apresentado diferenças nas dinâmicas de absorção destes conforme a época de aplicação.

09. The effect of different management systems on levels of resistant bacteria isolated on pig and poultry farms

09. The effect of different management systems on levels of resistant bacteria isolated on pig and poultry farms

Evaluation of symbiotic dinitrogen inputs of herbaceous legumes into tropical cover-crop systems

Reliable estimates of symbiotically fixed N2 in herbaceous legumes are important in order to determine their role in maintaining or improving N levels in tropical low-external-input farming systems. We have studied the effects of different management systems on the suitability of two non-N2-fixing reference crops, imperata [Imperata cylindrica (L.) Rauescel] and maize (Zea mays L.), for estimating N2 fixation in mucuna [Mucuna pruriens (L.) DC var. utilis (Wright) Bruck] and lablab [Lablab purpureus (L.) Sweet] in the field. The total-N-difference (TND) method of estimating N2 fixation was compared to the 15N-isotope-dilution (ID) technique. The two methods did not differ with respect to estimates of N2 fixation under in situ mulch (IM) systems. In contrast, under live-mulch (LM) systems the TND method underestimated N2 fixed in mucuna by 29% and in lablab by 40% compared to estimates made with the ID method. Irrespective of the treatment, estimates of N derived from fixation in both herbaceous legumes were not influenced by either of the reference plants. Using the ID technique, the proportion of N2 derived from fixation in mucuna and lablab at 12 weeks varied from 52% to 90% depending on whether the treatments were N fertilized, inoculated or uninoculated, cover-crop systems. In view of the nature of cover-crop systems in the derived savanna of West and Central Africa, where imperata is usually present as a weed or maize is grown in IM or LM systems, imperata or maize could be used to estimate N2 fixation and N contributions of the legumes to soil fertility and subsequent crop improvements.

Fractal Analysis of Temporal Yield Variability of Crop Sequences: Implications for Site‐Specific Management

AbstractCharacterizing spatial and temporal variability is important in site‐specific or long‐term studies to evaluate the effects of different management systems on crop performance. Long‐term experiments offer unique possibilities to study the effects of management practices on crops and soils over time. The objective of this study was to characterize temporal grain yield variability of seven crop sequences using fractal analysis and to determine whether temporal or spatial variability dominated the grain yield variability. Three crops of corn (Zea mays L.), soybean [Glycine max (L.) Merr.], and sorghum [Sorghum bicolor (L.) Moench] were studied from 1975 to 1995 in various sequences. Semivariograms were estimated for the standardized crop yield. The slopes of the regression lines of log semivariogram vs. log lag (year) were used to estimate and compare fractal dimensions, which are indications of variability patterns. The intercepts of the log‐log lines, which indicate extent of yield variability, were also compared between crop sequences. A small D‐value indicates dominance of long‐term variation, while a large D‐value (near 2) indicates dominance of short‐term (year‐to‐year) variation. Corn had significantly less temporal yield variability than soybean or sorghum. Continuous corn had less yield variability than corn following soybean. Soybean had the greatest yield variability, regardless of crop sequence. Temporal variability was much more dominant than spatial variability in this study. Temporal variability may greatly influence how spatial variability is expressed in a given field. Yield maps, which are used as an indication of past management in site‐specific cases, may not be useful in making future management decisions when temporal variability is great. In a less productive year, spatial variability of any nutrient may not make much difference in crop yield of a given field.

Humus quantity and quality of an entic Haplustoll under different soil‐crop management systems

Abstract The effects of different management systems on the level and composition of humified organic matter in an entic Haplustoll from the semiarid Pampean region were studied. The systems were: TPc, wheat‐mixed pasture; TV, wheat (Triticum aestivum), oat (Avena sativa), corn (Zea mays) and triticale grasses; TP, wheat‐cattle grazing; and V, virgin, non cultivated. Humic acids were extracted, fractionated, and analyzed for their organic carbon (OC) content, elemental composition, and E4:E6 spectral ratios. The infrared (IR), electron spin resonance (ESR). and 13C‐NMR spectra were registered on these humic acids. The TP rotation showed the lowest humic acid‐carbon to fulvic acid‐carbon (HA‐C:FA‐C) ratio. The lower O:C ratio of humic acids from the cropped soils indicates a higher level of oxidation than that of the virgin one. The comparison of the different methodologies allowed us to conclude that crop rotations and conservation tillage were adequate to mantain the level and composition of the soil organic matter and humus which affected the soil fertility and level of productivity

Effect of grassland management on the amounts of soil organic N and C.

The effects of different management systems on soil organic N and C contents were studied on a sandy and loamy soil given various amounts of N fertilizers under rotational grazing, in the Netherlands. Differences in total soil N and C between grazed and mown fields were also investigated. On the loamy soil grazed plots N accumulated at 245 kg/ha per year, irrespective of the rate of applied N. Four years after the experiment was initiated both soil N and C contents were considerably higher under grazing than under mowing. The C/N ratio of soil organic matter was higher without N fertilizer application, especially in the top 5 cm. The amount of N returned to the soil by grazing was 71% and 57% in the sandy and the loamy soil, resp. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Effect of Management Systems on the Growth of Lambs and Development of Internal Parasitism. II. Field Trials Involving Medication with National Formulary and Purified Grades of Phenothiazine

Observations were made for the second grazing season (April through September of 1960) on the effects of management systems, including medication, on the development of internal parasitism in lambs. The systems included drylot confinement (Band 1), transfer of animals to clean pastures at biweekly intervals (Band 2), and rotation among separate, contaminated pastures at approximately biweekly intervals (Bands 3 and 4). Purified phenothiazine (average particle size 6.9 A) was used for all medication involving animals in Bands 1, 2, and 4. A National Formulary (N.F.) grade product (average particle size 7.0 A) was used for Band 3. All bands had free access to a 1:9 phenothiazinemineral mixture, and therapeutic doses for the most part were given in accordance with a predetermined plan. Antemortem data, including hematocrit determinations and parasite egg counts, were obtained from 20 lambs of each band; worm counts were obtained at necropsy from 10 lambs of each band. Bands 1 and 2 did not develop clinical parasitism. The average minimum hematocrit levels for the two bands were 33.0 and 33.1%, respectively. Bands 3 and 4 developed haemonchosis despite the treatment regimens employed. The packed red-cell volumes (PCV) remained below 30% in Band 3 during the entire posttreatment phase. The PCV in Band 4 dropped below those in Band 3 during July and early August but markedly improved following therapeutic treatment. The necropsied lambs of Band 3 (N.F. phenothiazine) had more worms, especially Haemonchus contortus, than those of Band 4 (purified phenothiazine), even though doses of N.F. phenothiazine were increased to 50 g, or double those of the purified product. Under the conditions of these experiments, purified phenothiazine was superior to an N.F. grade product of comparable particle size for the control of Haemonchus infections in lambs. A study of the effects of different management systems on the development of internal parasitism in lambs was initiated at Beltsville, Maryland, in 1959. In the first year (Lindahl et al., 1963) the average levels of parasitism acquired by the lambs were related directly to the degree of exposure to infective larvae. Also, clinical haemonchosis in lambs was not controlled satisfactorily by medication with N.F. phenothiazine. Limited evidence indicated, moreover, that the ineffectiveness of phenothiazine may have been due to a tolerance of the parasite for the drug. Phenothiazine resistance had been reported by Drudge Received for publication 20 September 1967. * Animal Disease and Parasite Research Division, ARS, Beltsville, Maryland. t Animal Husbandry Research Division, ARS, Beltsville, Maryland. tPresent Address: Division of Research Grants, NIH, Bethesda, Maryland. $ Present Address: Animal Disease and Parasite Research Division, ARS, University Park, New Mexico. ? Present Address: Food and Drug Administration, BSSE, DTE, Washington, D. C. II Biometrical Services, ARS, Beltsville, Maryland. et al. (1957a, b), Leland et al. (1957), and Levine and Garrigus (1961). A relationship between the purity of phenothi zine and its efficacy against gastrointestinal nematodes was noted by Douglas et al. (1959) and Baker et al. (1959). Therefore, it seemed desirable to compare the efficiency of N.F. and purified phenothiazine products of comparable particle size in controlling haemonchosis in lambs as a phase of long-term investigations at Beltsville, Maryland. Studies conducted in 1960, the 2nd year of the project, were designed to make this comparison. MATERIALS AND METHODS The general plan was similar to that followed during the 1st year, 1959, and involved three basic management systems, namely: drylot confinement (Band 1), transfer of animals to clean pastures at biweekly intervals (Band 2), and grazing of animals on contaminated pastures (Lindahl et al., 1963). However, in the present study two bands of lambs were included in the system involving contaminated pastures to permit comparative evaluations of N.F. (Band 3) and purified phenothiazine products (Band 4) under similar conditions. During the pretrial period, all lambs were creepfed with pellets containing 65% alfalfa meal, 30% ground barley, and 5% soybean oil meal.