Extensive Grazing Systems Research Articles

Productivity of lactating goats under three grazing systems in the tropics of Mexico

Although goat production in Southeast Mexico rely on native vegetation, information regarding the potential of this grazing system for milk production is scarce. The objective of this study was to evaluate the productivity of lactating goats under three grazing systems: a grass monoculture system (GMS), an intensive silvopastoral system (ISPS) and a native vegetation system (NVS). Thirty Creole female goats (weight 41.7 ± 3.8 kg) from 2.5 to 3 years old and 60 days postpartum were randomly assigned to the three grazing systems. The availability and chemical composition of forage, milk production and composition, blood urea, body condition and live weight were assessed. In the NVS, goats consumed more than 60 different plant types, but their diet consisted mainly of 13 identified plant species. Although forage availability was lower for the NVS, the edible plants of this system had higher crude protein and lower fiber compared to the GMS and the ISPS. Consequently, milk yield in the NVS was similar (P > 0.05) to the other systems and, compared with the GMS, had a higher content of protein, fat, lactose and minerals (P < 0.0001). Edible plants from the NVS also had a higher content of tannins, which probably helped to modulate rumen NH3-N, as reflected in the lower blood urea concentration in that system (P < 0.01). Due to its higher forage availability, the GMS showed the highest milk production per unit area, followed by the ISPS and NVS. It is concluded that NVS, the most biodiverse and extensive grazing system, supplies good quality forage to support high quality milk production similar to ISPS. In addition, it is associated with a low ecological impact.

A field study on the efficacy of ivermectin via subcutaneous route against chewing lice (Bovicola caprae) infestation in naturally infested goats.

Caprine pediculosis is an ectoparasitic disease of great concern among goat farmers in India. It may be caused by either sucking lice or chewing lice; the latter one results in severe skin lesions, leading to production loss. This study evaluated the effectiveness of the macrocytic lactone drug, ivermectin, administered via subcutaneous injection, against chewing lice Bovicola (Damalinia) caprae infestation in naturally infested goats. The study was conducted on 20 goats with severe B. caprae infestation. Animals of group A (n = 10) were treated using a single dose of ivermectin (200 µg/kg body weight) subcutaneously and animals of group B (n = 10) underwent placebo therapy using normal saline. The animals were examined on days 0, 3, 7, 14, 21, 28, 42 and 56 for lice counts. There was 100% elimination of lice in all animals of group A and effective protection from re-infection remained at least for 21 days. Considerable improvement in haematological parameters was also observed by day 21. Based on this study, ivermectin injected via a subcutaneous route can be used effectively for the therapeutic and prophylactic management of chewing lice infestation in goats maintained under an extensive grazing system.

Performance of stocker cattle grazing bales in winter and supplemented with wheat-based dried distillers grains plus solubles or barley grain in western Canada

ABSTRACT Backgrounding calves during winter months in western Canada requires additional supplementation due to the cold climatic conditions. The objectives of this study were to determine the effects of supplementing either wheat dried distillers grains plus solubles (DDGS) or barley grain in an alternative backgrounding program on steer performance and DMI when winter bale grazing in a 2-yr study. Each year, 54 crossbred steers (BW, 219.5 ± 5.3 kg) from a similar annual cohort were stratified by BW and randomly allocated to 1 of 3 replicated (n = 3) supplement treatments [3 kg/d of (1) 100% barley grain (BARL); (2) 100% wheat DDGS (WDDGS); or (3) 50% barley + 50% wheat DDGS (50:50)] during winter grazing of grass–legume bales [CP = 7.1, ADF = 44.6, TDN = 48.0 (% DM)]. Supplement strategy did not affect (P = 0.95) DMI of round bale hay. Crude protein intake was 25 and 67% greater (P = 0.01) for WDDGS steers compared with 50:50 and BARL steers, respectively. Total digestible nutrient intake was similar (P = 0.73; 6.4 kg/d) among supplement strategies. Steers fed WDDGS tended (P = 0.07) to have 5 and 11% greater ADG (0.97 kg/d), and 4 and 10% greater total gain (103 kg), than the 50:50 (99 kg) and BARL (94 kg) steers, respectively. The study results suggest a tendency for greater performance of beef steers supplemented with wheat DDGS compared with barley grain when managed in an extensive winter bale grazing system.

Improved management to limit milk production losses resulting from the transition to once-a-day milking in dairy sheep

There has been increasing interest in once-a-day milking (ODM) in recent years. Despite the loss in milk production due to the reduction in milking frequency, ODM has several advantages for farm management, particularly labour savings. It has already been demonstrated that adapting management can compensate for the reduction in milk production, especially on dairy cow farms based on extensive grazing systems. The objective of this study was therefore to investigate the impact of management adaptations associated with a switch to ODM in a diverse range of dairy ewe farms in the ‘Rayon de Roquefort’, France, at the farm level. For that purpose, a model was developed to evaluate the ability of three flock management adaptations to compensate for losses due to the transition to ODM: (i) increasing the flock size, (ii) increasing the milking period and (iii) increasing grazing in the ewes’ diet. The model results show that depending on the farm, a transition to ODM on the first day of milking reduces the milk yield of the whole flock by 18–19% and causes an 8–16% decrease in household income. When the transition occurs around the turnout date, the impact on the performance of the flock is reduced, but so is the time spent on routine work. In the short term, it is possible to make adaptions to limit losses both in milk production and in household income by lengthening the milking period and/or by making better use of pasture. Conversely, increasing the number of milked ewes does not compensate for the loss of income. For each farm, a scenario was designed to provide a satisfactory trade-off between household income, milk delivery and routine workload. However, although the management adaptations are the same, their modalities of implementation depend on the farm concerned, which have different amounts of leeway. For the diverse range of farms tested, ODM represents a good compromise between flexible workload management and the performance of dairy sheep farms. ODM, during the whole or part of the milking period, is a useful farm management tool to manage both labour and grazing during strategic periods.

Spatiotemporal dynamics of cattle behavior and resource selection patterns on East African rangelands: evidence from GPS-tracking

ABSTRACTCharacterizing cattle behavior is crucial to inferring fine-scale resource selection patterns and improving rangeland management. However, our understanding of cattle behavior and resource selection on the extensive African rangelands suffers from a lack of quantitative, continuous and inter-seasonal monitoring of cattle movement. Based on integration of GPS-tracking and field observations, this study links cattle behavioral types with statistical parameters of movement, analyzes spatiotemporal dynamics of behavior and predicts resource selection patterns in Borana Zone of southern Ethiopia. We find that different cattle behavioral types were associated with distinct ranges of movement velocity. Distribution of identified cattle behavior varied substantially within the day and along the distance gradient from camp locations. Vegetation greenness, topography, study site, herding strategy and season were dominant factors influencing foraging areas selection by cattle. Research findings suggested that extensive herding through camp relocation can promote forage uptake while reducing energy spent on traveling. Future modeling of cattle resource selection needs to be based on longer-term GPS-tracking data and incorporate additional social, environmental, institutional and cultural factors to better interpret the complexity associated with cattle behavior in extensive grazing systems.

Caffeine supplementation of ewes during lambing may increase lamb survival

Perinatal mortality of lambs is on average 20% of lambs born in extensive Australian grazing systems, constituting a substantial production loss and welfare concern. Hypoxia resulting from prolonged or difficult births contributes to lower rates of lamb survival, and caffeine may reduce the effects of hypoxia. This study evaluated whether oral supplementation of grazing ewes with caffeine could improve lamb survival. Pregnant Merino ewes (n=492) which had been naturally mated to Merino rams in February/March were allocated to three replicates of control (no caffeine) or caffeine treatments. Caffeine was fed daily in troughs in each paddock at a rate of 1.6 g/ewe per day (estimated at 20 mg/kg live weight) from the day before the first lamb was born, for 14 days, with lambing continuing for 6 weeks. Intake was facilitated using 320 g/day per ewe of barley grain with molasses, which was fed to both treatments. The proportion of lambs born alive during the period of supplementation did not differ (P>0.05) between treatments. The proportion mortality of lambs to 1 day of age was lower (P=0.029) in the caffeine (0.01) compared with the control (0.16) treatment for lambs born during the 1st week of supplementation, but not in later weeks. This difference in mortality for lambs born in the 1st week of supplementation was maintained to marking age (caffeine 0.09; control 0.30; P=0.027). Extreme weather during the 2nd week of supplementation may have prevented any reduction in mortality due to caffeine in that week. Feeding caffeine to a naturally lambing flock of grazing ewes may be a highly effective and commercially practical method of increasing lamb survival, but further research is needed to confirm these results, and caffeine be regulated for use.

Practical implications of mineral and vitamin imbalance in grazing sheep

Rapid progress in research on mineral functions in biological systems over the past 20 years has provided new and unexplored implications for health and production in grazing livestock. The strong interaction among calcium (Ca), magnesium (Mg), phosphorus (P), sodium (Na), potassium (K) and vitamin D influences the absorption, utilisation and status of these nutrients, particularly Ca and Mg. An imbalanced intake of Ca, Mg, P, Na, K and vitamin D is common in ruminants grazing pastures and vegetative crops. The interaction may modify susceptibility to clinical hypocalcaemia, hypomagnesaemia and pregnancy toxaemia, or to subclinical and chronic deficiencies of Ca, Mg and Na. However, hypocalcaemia is also associated with endocrine failure. Whether this failure is susceptible to nutritional modulation or even whether supplements of Ca, Mg, Na and vitamin D reduce or exacerbate the risk of metabolic disease in sheep is unclear. Selenium, manganese, zinc, copper, sulfur, vitamin E and vitamin A play synergistic roles in the antioxidant defence mechanism and modulate the consequences of oxidative stress. In extensive grazing systems combined low intakes of these antioxidants are not unusual, particularly in seasonally dry environments and at a time coinciding with the increased oxidative stress that naturally occurs through the reproductive cycle. This oxidative stress is accentuated by heat stress and parasite infection. Oxidative stress in the short-term influences growth, reproduction, offspring survival and health. Long-term, oxidative damage to embryo DNA and changes in RNA expression, may influence lifetime performance of offspring. The high cost of providing mineral supplements to grazing sheep is a deterrence to addressing the implications of multiple mineral deficiencies. New herbaceous and shrub options to increase the botanical and nutritional diversity within pasture and crop-grazing systems may allow livestock to select a heterogeneous diet providing a more balanced mineral intake.

Parasite prevalence among equidae in the backland of the State of Pernambuco, Brazil

The present study aimed to assess the prevalence of gastrointestinal and lung parasites in equidae reared in the backland of the state of Pernambuco, Brazil and also evaluate the influence of equidae species, rearing system, age group, and anthelmintic administration schedule the infection level. 185 fecal samples were randomly collected in cities in the backland of Pernambuco. After collection, the material was submitted to a qualitative coproparasitological analyses and number of eggs and larvae of parasites. The horses were found to have lower EPG count than the donkeys. Regarding the rearing system, equidae reared in pasture had higher EPG counts than those confined in pens. Moreover, foals under one year old have lower EPG count than those between one and two years old. No difference was found in EPG count among de equidae that received anthelmintic at different frequencies, while the horses and donkeys had a higher amount of Cyathostominae than of other nematodes researched. It is concluded that, in the backland of Pernambuco, most equidae had light to moderate parasite loads, with a predominance of the Cyathostominae e Strongylinae subfamilies, with no horses, donkeys, or mules infected by Dictyocaulus arnfieldi. In addition, the donkeys had higher parasite loads than the horses and the extensive grazing system presents a greater risk of infections by nematodes.

Modeling Herding Decision Making in the Extensive Grazing System in Southern Ethiopia

The practice of extensive herding through camp relocation allows pastoralists to track greener pastures while redistributing grazing pressure throughout the landscape, but the lack of intensive and continuous monitoring data on large-scale livestock movement results in limited understanding of this important practice. This article takes an integrated approach to understanding pastoral mobility and modeling extensive herding. The analysis is based on Global Positioning System (GPS) tracking of fifty-eight cows, as well as surveys, participatory mapping, and interviews with pastoralists in five study sites in southern Ethiopia. Linear mixed-effect models are used to examine the community- and household-level determinants of extensive herding. The findings suggest that resource conditions, resource users, and socioeconomic context play significant roles in affecting the practice of extensive herding. Compared to household herd size, community-level factors largely determine the feasibility of extensive herding. Future pastoral policymaking needs to facilitate the creation and maintenance of favorable herding context to encourage large-scale mobility as an adaptation strategy in the arid and semiarid environment.

Technical efficiency and the impact of grassland use right leasing on livestock grazing on the Qinghai-Tibetan Plateau

This paper reviews changes in grassland property rights and measures the efficiency of livestock grazing on China’s Qinghai-Tibetan Plateau, where there is an extensive nomadic grazing system. A cross sectional data set from a field survey of 197 livestock grazing households is used to develop a stochastic translog distance function and technical inefficiency model; variables for livestock intensity and property rights are incorporated. The overall average technical efficiency of the extensive livestock grazing is estimated to be 0.62, lower than the value of 0.67 found for households who rent-in grassland. The results indicate that renting-in grassland improves the technical efficiency of livestock grazing significantly. Both household size and livestock intensity have an effect on technical efficiency, especially the dummy variable of whether the summer pasture is near the winter pasture. This may indicate that grassland fragmentation would be not ideal for extensive livestock production on the Qinghai-Tibetan Plateau.

Hygienic Practices and Bacteriological Quality of Cow Raw Milk from Selected Smallholder Dairy Farms of Mersa Town, North Wollo, Ethiopia

The present cross sectional study was conducted to assess hygienic practices and determination of bacterial load of milk when directly milked from the udder and from the collecting bucket at the farm level in selected smallholder of Mersa town; from November 2016 to May 2017. A total of 120 respondents were interviewed and 60 milk samples were collected for laboratory analysis to assess bacterial load. Aerobic mesophilic bacterial counts (AMBC) and coliform counts (CC) were conducted on milk samples. Results showed that, majority of small-dairy holders were males, managing their cattle in unclean environments and practicing extensive grazing system on communal grazing area. The mean aerobic mesophilic bacterial counts of raw milk samples analyzed were 5.81 log10 cfu/ml (udder), 8.01 log10 cfu/ml (bucket) The mean coliform counts were 3.7 log10 cfu/ml (udder), 5.15 log10 cfu/ml (bucket) and the increment of both counts at the milk bucket was observed statistically significant (P=0.000) and there was no significant variation between kebeles (P=0.921) for aerobic mesophilic bacterial counts and (P=0.715) for coliform count. According to international standards of raw milk quality, both of the above counts found to have values above the upper limits. Milk produced by the selected small-holder dairy cow owners in Mersa town were of poor quality and can be a potential source of milk-borne infections.

Nitrate supplementation has marginal effects on enteric methane production from Bos indicus steers fed Flinders grass (Iseilema spp.) hay, but elevates blood methaemoglobin concentrations

This experiment has quantified the methane abatement potential of nitrate in the context of extensively managed cattle. The experimental protocol consisted of two, 4 × 4 Latin square design using eight rumen fistulated Bos indicus steers fed Flinders grass (Iseilema spp.) hay ad libitum. The treatments were Control (nil nitrogen supplement), urea (32.5 g/day urea) and two levels of calcium nitrate: CaN1 and CaN2 (to provide 4.6 g and 7.9 g NO3/kg DM equivalent to ~0.46% and 0.80% of DM, respectively). Complete supplement intake was ensured by dosing any supplement that had not been voluntarily consumed, through the rumen fistula, 1 h after feeding. Enteric methane production was measured using open circuit respiration chambers. Methane yield (g/kg DM intake) from the CaN2 treatment tended to be lower (P &lt; 0.07) than either the Control or urea treatments. There were no significant differences in methane yield between Control, urea or CaN1 treatments. Mean blood methaemoglobin concentrations were significantly (P &lt; 0.001) higher for CaN2 animals compared with the Control, urea or CaN1 treatments. In addition, a significant time effect after dosing (P &lt; 0.001) and a significant interaction between treatment and time after dosing (P &lt; 0.001) was apparent. Overall mean total volatile fatty acid concentration was 74.0 ± 1.53 mM with no significant treatment effect, but a significant effect for both time of sampling (3 h vs 6 h) within days and among 7 sampling days. The inclusion of calcium nitrate as a non-protein-N source significantly reduced the molar proportions of butyrate (P &lt; 0.001), iso-butyrate (P &lt; 0.05) and iso-valerate (P &lt; 0.001) compared with the Control. The provision of nitrate supplements, providing both a NPN and an alternative sink for H that would otherwise support enteric methanogenesis, has some potential. In extensive grazing systems effective methane abatement strategies are required. The elevated concentration of MetHb using CaN2 suggests that the strategy of replacing urea with nitrate in supplements fed to extensively managed cattle in the northern rangelands may be inappropriate where supplement intake cannot be controlled on an individual animal basis and forage quality is seasonally variable.

Animal energetics in extensive grazing systems: Rationality and results of research models to improve energy efficiency of beef cow-calf grazing Campos systems1

Animal energetics in extensive grazing systems: Rationality and results of research models to improve energy efficiency of beef cow-calf grazing Campos systems1

The effects of low-input grazing systems and milk pasteurisation on the chemical composition, microbial communities, and sensory properties of uncooked pressed cheeses

The objective of this work was to determine whether the effects of farming systems on the cheese sensory properties are reduced when the milk used to make cheese is pasteurised. The milk of cows reared under two grazing systems (extensive and semi-extensive) was processed into raw and pasteurised milk cheeses. These grazing systems were mainly differentiable by the milk fatty acid (FA) composition and, to a lesser extent, by their levels of lactic acid bacteria, which were higher in milk from the extensive grazing system. In cheese, the different FA composition persisted and affected the texture of the cheese regardless of the milk treatment. The effects of each grazing system were indistinguishable in several cheese characteristics (proteolysis, texture, and aroma) after pasteurisation. In contrast, among pasteurised milk cheeses, those resulting from an extensive system had greyer rinds, while no difference in rind colour was observed among raw milk cheeses.

Dorper sheep utilizing feed resources efficiently: a Mediterranean case study

The aim of the study was to determine the effect varying feeding systems would have on meat quality and production. The study looked at 45 Dorper lambs which were subjected to three different feeding protocols representing three alternate production systems: extensive grazing system (Group G), an intensive feedlot system being fed concentrate + alfalfa hay (Group C), and a semi-intensive production system comprising grazing + concentrate (Group GC). The lambs were slaughtered 62 days after weaning at approximately four months of age and meat quality factors such as pH, colour, shear force, cooking and water loss, as well as carcass characteristics; back fat thickness, muscle depth, muscle width, and muscle area were measured instrumentally on the longissimus dorsi muscle. A new measuring index was used to assess feed cost against weight gain to determine performance for profitability. In calculating cost kg-1 live weight gain, the extensive grass-fed production was significantly lower, approximately 70% less than the intensive feedlot system. Very little significant effect on meat quality was seen among the three systems. Slaughter weight had a significant effect on hot carcass weight, cold carcass weight, and drip loss. The lean carcass trait of the Dorper breed was a major positive attribute, but minor benefits gained in meat quality with the feedlot production system did not justify the substantial additional cost of production. Dorper sheep can be considered efficient feed converters on pasture, and thus a suitable breed for lamb meat production in countries like Turkey, where feed costs are the main contributor to farm outgoing.

Variation in the sensory profile of South African Dorper lamb from extensive grazing systems

Descriptive sensory analysis was used to determine the variation in the sensory profiles of extensively produced South African Dorper lamb. The Longissimus thoracis et lumborum and subcutaneous fat of lambs from seven different farms in South Africa were assessed by rating its sensory attributes, determining proximate composition and measuring pH, thaw loss, cooking loss and Warner-Bratzler shear force. Discriminant analysis grouped treatments in terms of sensory and physical characteristics. The Northern Cape farms [except for Hantam Karoo/Calvinia (HK/CAL)] clustered closely with less discrimination and were rated highest (P≤0.05) in lamb-like characteristics, tenderness and juiciness. Mutton-like, sheep wool and herbaceous attributes were prominent for HK/CAL, while Rûens (RU) and Free State (FS) received high ratings for mutton-like, oily and barnyard/kraal attributes. These groupings are likely owing to dietary differences between the regions. The results suggest the possibility of region of origin classification for South African lamb such as Karoo lamb with herbaceous attributes related to a fragrant Karoo plant diet.

Guardian dogs protect sheep by guarding sheep, not by establishing territories and excluding predators

Guardian animals have been a common non-lethal method for reducing predator impacts on livestock for centuries in Europe. But elsewhere, livestock producers sometimes doubt whether such methods work or are compatible with modern livestock husbandry practices in extensive grazing systems. In this study we evaluate the hypothesis that guardian dogs primarily ‘work’ by establishing and defending territories from which canid predators are excluded. Eight maremmas and six free-ranging wild dogs of different sexes were fitted with GPS collars and monitored for 7 months on a large sheep property in north Queensland, Australia. Wild dog incursions into the territories of adjacent wild dogs and maremmas were recorded. Wild dog territories never overlapped and their home ranges infrequently overlapped. In contrast, 713 hourly locations from 120 wild dog incursions into maremma territories were recorded, mostly from three wild dogs. These three wild dogs spent a mean of 2.5–5.9 h inside maremma territories during incursions. At this location, maremmas worked by guarding sheep and prohibiting fine-scale interaction between wild dogs and sheep, not by establishing a territory respected by wild dogs. We conclude that shepherding behaviour and boisterous vocalisations of guardian dogs combined with the flocking behaviour of sheep circumvents attacks on sheep but does not prevent nor discourage wild dogs from foraging in close proximity. Certain husbandry practices and the behaviour of sheep at parturition may incur greater predation risk.

Changing year-round habitat use of extensively grazing cattle, sheep and pigs in East-Central Europe between 1940 and 2014: Consequences for conservation and policy

Many habitats in Europe have been managed by grazing for thousands of years. However, extensive grazing systems are becoming increasingly rare in the region, and there is a lack of understanding of the functioning of these systems.We carried out 147 structured interviews in 38 landscapes throughout the Carpathian Basin, with 3–5 informants/landscape. The number of actively grazing cattle, sheep and pigs, their year-round habitat use and the proportion of herds actively tended were documented for four characteristic historical periods (before, during and after socialist cooperatives and after EU Accession).The numbers of grazing cattle and sheep had decreased substantially by 2010 (by 71% and 49%, respectively), while pig grazing almost disappeared by the 1970s. Cattle primarily grazed habitats with taller vegetation. Sheep grazed dry pastures and stubbles, while pigs were driven into marshes and forests. In general, the importance of dry and wet grasslands increased, while the significance of marshes, stubble fields, vegetation along linear elements, second growth on hay meadows, wood-pastures and forests decreased over time. Approximately half of the grazed habitats were not typical pasture grasslands, and functioned as supplementary pastures during droughts, autumn and winter. The number of habitat types grazed per month per site dropped, and herding decreased substantially, in particular in the case of cattle and pigs.Contributing factors of the economic and social changes of the examined period included the collapse of the communist-era legal framework, the intensification of livestock husbandry, EU Common Agricultural Policy (CAP) regulations, and the rise of a nature conservation ethic.We conclude that agricultural policies should take into account the full spectrum of habitat types necessary for the effective operation of extensive grazing systems. We argue that conservation-oriented extensive grazing should use the traditional wisdom of herders but adapted to the present situations.

ORGANIC CARBON AND TOTAL NITROGEN IN THE DENSIMETRIC FRACTIONS OF ORGANIC MATTER UNDER DIFFERENT SOIL MANAGEMENT

ABSTRACT: The evaluation of land use and management by the measurement of soil organic matter and its fractions has gained attention since it helps in the understanding of the dynamics of their contribution to soil productivity, especially in tropical environments. This study was conducted in the municipality of Colorado do Oeste, state of Rondônia, Brazil and its aim was to determinethe quantity of organic carbon and total nitrogen in the light and heavy fractions of organic matter in the surface layers of a typic hapludalf under different land use systems: Native Forest: open evergreen forest, reference environment; Agroforestry System 1: teak (Tectona grandis LF) and kudzu (Pueraria montana); Agroforestry System 2: coffee (Coffea canephora), marandu palisade grass (Brachiaria brizantha cv. Marandu), "pinho cuiabano" (Parkia multijuga), teak and kudzu.; Agroforestry System 3: teak and cocoa (Theobroma cacao); Silvopasture System: teak, cocoa and marandu palisade grass; and Extensive Grazing System: marandu palisade grass. The experimental design was a randomized block in split-split plots (use systems versus soil layers of 0-0.05 and 0.05-0.10 m) with three replications. The results showed that relative to Native Forest, the Agroforestry System 2 had equal- and greater amounts of organic carbon and total nitrogen respectively (light and heavy fractions) in the soil organic matter, with the light fraction being responsible for storage of approximately 45% and 70% of the organic carbon and total nitrogen, respectively. Therefore, the light densimetric fraction proved to be useful in the early identification of the general decline of the soil organic matter in the land use systems evaluated.

INFLUENCE OF TIME MANAGEMENT IN MODELING OF CURVE RESISTANCE TO THE PENETRATION OF A LATOSOL UNDER DIFFERENT USES AND MANAGEMENT OF PASTURES AND NATIVE WOODLAND

ABSTRACT The soil resistance to penetration study helps in understanding the state of soil compaction, indicating how best to manage it. The present study aimed to verify the influence of time management in modeling curves of resistance to penetration in Oxisol under different uses and management of pastures and woodland in field conditions, using the stepwise procedure. The study was conducted in the Cerrado region. Five (5) systems of uses and management of pastures and native woodland were evaluated: ILPF: crop-livestock-forest integration; ILP: crop-livestock integration; P: Area in the extensive grazing system; MN: native woodland; PIQ: rotated picket. The experiments were assessed for the years 2012/13 and 2013/14. To obtain the models, an analysis with four independent variables was performed: Gravimetric moisture (X1), bulk density (X2), total porosity (X3) and organic matter (X4) and the dependent variable, soil resistance to penetration (Y). The multiple regression analysis by STEPWISE with F of 0.15 was used. The equation that best estimated the resistance to penetration was RP = 14.68 to 0.26 for Native Woodland in layers from 0.20 - 0.40 m with R2 indices of 0.97 in year 1. For year 2, the equation that estimated the resistance to penetration was obtained in the PIQ treatment, PR = - 15.94 - 0.29 PT + 15.87 DS + 0.05 MO. with R2 of 0.94.