Weed interference in Marandu palisade grass pastures under renewal or maintenance conditions

ABSTRACT The presence of weeds as a consequence of pasture degradation is one of the main problems facing livestock worldwide. Thus, knowing the interference aspects and the appropriate time for weed management is essential for applying a particular control measure. This research aimed to study the weed interference on the morphostructural and nutritional quality of the Marandu palisade grass in conditions of renewal or maintenance of pasture. The experiments were conducted in a randomized block design, with four replicates and treatments consisted of eight growth periods of coexistence between Marandu palisade grass and weeds (0, 15, 30, 45, 60, 75, 90, and 120 days). Forage grass was characterized at the end of the experimental period, corresponding to 120 days of coexistence, and the main morphostructural and nutritional components were determined. Under the renewal or maintenance process, the weeds interfere in the morphostructural and nutritional quality of pasture areas with Marandu palisade grass. In vitro organic matter digestibility of Marandu palisade grass is negatively influenced by weeds, suggesting that control measures for renewal or maintenance areas should be adopted within 24 and 18 days of coexistence, respectively.

Alternatives for the recovery and renewal of degraded pastures

This review aimed to approach the dynamics of pasture degradation, relating its causes and forms of recovery and/or renewal. Despite being based on extensive systems, Brazilian agriculture faces serious problems related to pasture degradation. The reduction in forage productivity directly affects the production system, having negative impacts on the economy and the ecosystem. Factors such as the choice of forage species, grazing management and the use of fire are the main factors responsible for the degradation of pastures in Brazil, causing an environmental and productive imbalance. However, it is possible to stop the progress of degradation and resume system productivity using pre-defined techniques in accordance with the objective of the production system. Furthermore, pasture recovery techniques are efficient for the resumption of productivity, and environmental protection, by helping to reduce greenhouse gases. Nevertheless, more research is needed to prove and consolidate pasture recovery techniques in the environmental, economic, and social scope.

Status quo of pastures in Uzbekistan and their effective utilization

The Global research to assess the impact of climate change on soil-climatic conditions of arid lands has resulted in the following scientific findings: pasture degradation due to inefficient use of available resources; improved technologies for the condition of pasture soils and their restoration and the use of GIS monitoring; soil conditions, desertification factors and degradation processes of anthropogenesis in pasture conditions; developments for remote sensing of the Earth to determine the current state of pastures and the use of GIS technologies; and, improved technologies for adapting to climate change and combating soil degradation. Measures have been developed to restore biodiversity, increase crop productivity, and increase the fertility of these soils. This article describes the relevance of pasture land use around the world and the effectiveness of the use of a variety of water-saving technologies (Water-box) in the foothills and desert pastures.

Population dynamics of the pasture leafhopper complex (Hemiptera: Cercopidae) in brachiaria and mombasa grass

Pasture leafhoppers are considered highly important pests in forage grasses in Brazil due to their widespread occurrence. This insect is one of the most relevant pests in pasture degradation. In order for the control of spittlebugs to be efficient, it is important to know the population behavior of the species of this insect, identify the period of greatest occurrence, as well as the climatic and environmental conditions that favor the development of the pest. Thus, this study aimed to evaluate the population dynamics of spittlebugs, at a quantitative level, in Brachiaria decumbens and Panicum maximum pastures, associating the results with meteorological data from the municipality of Conceição do Araguaia, Southeast Pará. To study the population dynamics of spittlebugs, samples were taken every two weeks, in two types of pastures aged between 5 and 7 years, kept under rotational grazing, with a stocking of 1.5 animal units. The method of monitoring nymphs and adults of leafhoppers was adopted, through walking within the observation area. The level of infestation of spittlebugs in both forage species was evaluated and all results were submitted to analysis of variance by the F test. It was found that the species B. decumbens had a greater number of adults and nymphs when compared to the forage species P. maximum. The population dynamics of spittlebugs occur gradually according to climatic conditions, and the period with not-so-high temperatures (22 ºC to 34 ºC) and good rainfall provide an infestation of this insect pest in the pasture.

Remote Sensing of Pasture Degradation in the Highlands of the Kyrgyz Republic: Finer-Scale Analysis Reveals Complicating Factors

Degradation in the highland pastures of the Kyrgyz Republic, a small country in Central Asia, has been reported in several studies relying on coarse spatial resolution imagery, primarily MODIS. We used the results of land surface phenology modeling at higher spatial resolution to characterize spatial and temporal patterns of phenometrics indicative of the seasonal peak in herbaceous vegetation. In particular, we explored whether proximity to villages was associated with substantial decreases in the seasonal peak values. We found that terrain features—elevation and aspect—modulated the strength of the influence of village proximity on the phenometrics. Moreover, using contrasting hotter/drier and cooler/wetter years, we discovered that the growing season weather can interact with aspect to attenuate the negative influences of dry conditions on seasonal peak values. As these multiple contingent and interactive factors that shape the land surface phenology of the highland pastures may be blurred and obscured in coarser spatial resolution imagery, we discuss some limitations with prior and recent studies of pasture degradation.

Change of feed stocks in southern subarctic tundra of Yamal

The relevance of the research is related to the need to monitor the resource potential of the vegetation in the southern subarctic tundra. The Yamal tundra has been experiencing a high grazing pressure since 1990. As a result of the increase in the number of private farms and the number of domesticated reindeer in Yamal, pasture degradation occurs (trampling of forage mass, shredding vegetation, disappearance of lichen cover, increased soil deflation). Purpose of the research is compare the forage stocks of reindeer pastures in the southern subarctic tundra of Yamal in 2017–2018 and in the 1990s. In the course of the study, estimates of the amount and structure of forage stocks in plant communities of the southern subarctic tundra of the Yamal Peninsula was assessed in the vicinity of the Payutayakha river. The stock of aboveground phytomass was determined by the mowing method. In 2017, degraded areas of the tundra were studied, and in 2018 undisturbed and intact areas were investigated. Scientific novelty. The data obtained are compared with the estimates published for the southern subarctic tundra in the 1990s. Results. Forage stocks in degraded areas, compared to stocks in the southern subarctic tundra in the 1990s, decreased 14 times; while in on undisturbed areas they decreased 3 times. In the structure of forage stocks in 2017–2018, compared to the situation at the end of the 20th century, the proportions of shrubs, lichens and grasses has decreased; the proportion of dwarf shrubs in degraded areas increased 4 times, while in undisturbed areas it increased 6 times. The study confirms the existence of overgrazing and a shortage of forage resources on pastures in the zone of the southern subarctic tundra of Yamal.

Application of an improved vegetation index from the visible spectrum in the diagnosis of degraded pastures: Implications for development

Inadequate pasture management causes land degradation and negative impacts on the socio-economic development of agricultural regions. Given the importance for Brazil and the World of pasture-based livestock production, the recognition of pasture degradation is essential. The use of remote sensing satellite systems to detect degraded pastures increased in the recent past, because of their capability to survey large portions of Earth’s surface. A struggle nowadays is to improve detection accuracy and to implement high-resolution surveys at farmland scale using unmanned aerial vehicles (UAVs). The satellite sensors capture reflectance from the visible spectrum and near infrared bands, which allows estimating plant’s vigor vegetation indices. The NDVI is a widely accepted index, but to generate an NDVI map using a UAV a relatively high-cost multispectral sensor is required, while most UAVs are equipped with low-cost RGB cameras. In the present study, a script developed on the Google Earth Engine image-processing platform manipulated images from the Landsat 8 satellite, and compared the performances of NDVI and an improved color index that we coined “Total Brightness Quotient” of red (TBQR), green (TBQG) and blue (TBQB) bands. An efficient detection of pasture degradation using the TBQs would be a good prognosis for the surveys at farm scale where environmental authorities are progressively using UAVs and forcing landowners towards pasture restoration. When compared to NDVI, the TBQG showed a correlation of 0.965 and an accuracy of 88.63%. Thus, the TBQG proved as efficient as the NDVI in the diagnosis of degraded pastures.

ANALYSIS OF THE DEGREE OF GRASSLAND DEGRADATION USING REMOTE SENSING

The objective of this study is to adapt the calculations of the Pasture Degradation Index (GDI) to the Brazilian savannah using medium spatial resolution satellite image for the dry season. Vegetation cover is the main evaluation parameter used to calculate the GDI. The extreme ranges of the grazing class were determined by the NDVI histogram of a single date. Pasture cover was distinguished into five classes called Vegetable Pasture Cover (GVC), derived from NDVI and compared with five other classes derived from field photographs, named Green Coverage Percentage (GCP). The similarity between GVC and GVP demonstrated that GVC can be used to classify pasture cover. As a product of GVC, GDI was obtained. The GDI showed that pasture degradation in Paraíso das Águas is very serious. Extremely severe and Severe degradation occupy 9.28% and 25.22% of the study area, moderate and light degradation of pasture occupy 8.29% and 4.50%, respectively, and the non-degradation area covers 1.43 % of pastures. The results suggest the possibility of applying the GDI, originally developed for natural fields and multitemporal remote sensing data, to evaluate the conditions of the tropical savanna planted fields by means of a unique image.

Biological activity of mountain meadow subalpine soils of Central Caucasus

Indicators of biological activity (humic content and stock, Cmic content and stock, hydrolytic and redox enzymes activity) were measured for the first time in the upper horizons of mountain meadow subalpine soils of Central Caucasus (elbrus altitudinal zonality in Kabardino-Balkaria). The comparative assessment was performed for the biological characteristics together with soil density and acid-base properties for soils of natural and pasture ecosystems. The integral index of ecological and biological soil state (IIEBSS) was calculated to estimate the level of changes in biological activity. It was shown that pasture degradation leads to 30% decrease of IIEBSS compared to the undisturbed soil. The defined biological parameters of natural undisturbed mountain meadow soils could be used as diagnostic indicators for the ecological studies of ecosystems under anthropogenic load.