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.

Assessing the influence of cereal-legume mixtures on the productivity of degraded pastures in the Kostanay region of northern Kazakhstan

This study presents the results of some options to restore pastures with low productivity in the arid steppes of the Kostanay region of northern Kazakhstan, describing the effects associated with grass-legume mixtures. The effects of grass-legume mixtures, contribution to the preservation and maintenance of pasture forage crops, and the productivity of pastures were discussed. Mixtures of grasses and legumes were selected that are promising crops for arid regions.The plant density and its condition were determined based on test plots of adjacent rows of 0.5 m each, followed by counting. The plant height was determined before the yield of green mass by measuring 25 plants of each species. The yield of green mass in the maturity phase of the grass was determined by mowing and weighing the green mass in the plots, followed by the analysis of the species composition in the grass mixture and drying until air dry. The density of plants, the height of the plants, and the safety of the forage plants according to the sowing method were the data collected. In addition, the effect of grass mixtures on the productivity of forage crops to improve pastures was compared. According to these results, the highest productivity under experimental conditions was found in the wheat grassalfalfa-bromegrass variant. This information can contribute to the improvement of the state of the pastures since it is complete and inexpensive food for farm animals.

Assessing the Wall-To-Wall Spatial and Qualitative Dynamics of the Brazilian Pasturelands, between 2010 and 2018, Based on the Analysis of the Landsat Data Archive

The Brazilian livestock is predominantly extensive, with approximately 90% of the production being sustained on pasture, which occupies around 20% of the territory. In the current climate change scenario and where cropland is becoming a limited resource, there is a growing need for a more efficient land use and occupation. It is estimated that more than half of the Brazilian pastures have some level of degradation; however there is still no mapping of the quality of pastures on a national scale. In this study, we mapped and evaluated the spatio-temporal dynamics of pasture quality in Brazil, between 2010 and 2018, considering three classes of degradation: Absent (D0), Intermediate (D1), and Severe (D2). There was no variation in the total area occupied by pastures in the evaluated period, in spite of the accentuated spatial dynamics, with a retraction in the center-south and expansion to the north, over areas of ​​native vegetation. The percentage of non-degraded pastures increased ~12%, due to the recovery of degraded areas and the emergence of new pasture areas as a result of the prevailing spatial dynamics. However, about 44 Mha of the pasture area is currently severely degraded. The dynamics in pasture quality were not homogeneous in property size classes. We observed that in the approximately 2.68 million properties with livestock activity, the proportion with quality gains was twice as low in small properties compared to large ones, and the proportion with losses was three times greater, showing an increase in inequality between properties with more and less resources (large and small, respectively). The areas occupied by pastures in Brazil present an unique opportunity to increase livestock production and make available areas for agriculture, without the need for new deforestation in the coming decades.

Changes in Soil-Borne Communities of Arbuscular Mycorrhizal Fungi during Natural Regrowth of Abandoned Cattle Pastures Are Indicative of Ecosystem Restoration

Natural restoration of ecosystems includes the restoration of plant-microbial associations; however, few studies had documented those changes in tropical ecosystems. With the aim to contribute to understand soil microbial changes in a natural regrowth succession of degraded pastures that were left for natural restoration, we studied changes in arbuscular mycorrhizal (AM) fungal communities. Arbuscular mycorrhizal fungi (AMF) establish a mutualistic symbiosis with plants, improving plant nutrition. Amplification of the small subunit rRNA with specific primers and subsequent Illumina sequencing were used to search soil-borne AM fungal communities in four successional natural regrowth stages in two landscapes (hill and mountain) with soil differences, located in the Andean-Amazonian transition. Molecular results corroborated the results obtained previously by spores-dependent approaches. More abundance and virtual taxa of AMF exist in the soil of degraded pastures and early natural regrowth stages than in old-growth or mature forest soils. Although changes in AM fungal communities occurred similarly over the natural regrowth chronosequence, differences in soil texture between landscapes was an important soil feature differentiating AM fungal community composition and richness. Changes in soil-borne AM fungal communities reflect some signals of environmental restoration that had not been described before, such as the reduction of Glomus dominance and the increase of Paraglomus representativeness in the AM fungal community during the natural regrowth chronosequence.

METHOD FOR RESTORING DEGRADED PASTURES IN THE SEMI-DESERT ZONE OF ASTRAKHAN REGION

Since ancient times, steppe pastures have been a source of balanced and cheapest animal feed, as well as insurance in bad weather, all year round. Thus, it is an ecological and economic potential that should be used effectively supporting and strengthening with the aim of moderate use of biological resources for the future generation.

Growth and development of the wild-growing subshrub Salsola orientalis SG Gmel. in culture under conditions of the Central Asian desert

In terms of life form Salsola orientalis S.G. Gmel. is a semi-shrub; its height reaches 40–60 cm; in terms of ecology, it is a haloxerophyte, extremely resistant to salt stress, air, and soil droughts. Salsola orientalis is a highly nutritious forage plant containing up to 20% protein in the budding phase. High resistance to environmental stress and good forage value allow us to consider it as a promising plant – its introduction into culture allowed restoring the forage productivity of degraded pastures in the Central Asian desert. The features of growth and development of Salsola orientalis were studied for ecological and biological characteristics and the possibility of introducing it into culture. It was found that the laboratory germination of seeds of the wild-growing half-shrub Salsola orientalis was quite high – 20–60%; field germination was very low – 0.1–1.7%. The survival rate of seedlings in young plants depends on environmental conditions and plant density. Under conditions of the Central Asian desert the plants basically die in the first year, especially in the germination phase; in the second year we registered insignificant losses; in subsequent years the number of plants stabilized. Salsola orientalis was found to be a fast growing plant, forming a normal half-shrub in the first year of life. The high ecological stability of Salsola orientalis in combination with its deeply penetrating and powerfully developed root system ensures vigorous and rapid growth. Under conditions of the Central Asian desert Salsola orientalis yields 1.3–1.7 t/ha of dry fodder mass, which is 4–5 times higher than the fodder productivity of natural desert pastures.

Ecological restoration of fodder productivity of degraded pastures in the foothill desert zone of Central Asia

Irrational, ecologically unregulated economic activity in the vast deserts of Central Asia has led to biodiversity depletion, decrease in the fodder productivity of natural pastures and, as a result, deterioration in the fodder base of grassland farming. Forage production of these degraded pastures requires ecological restoration. To enrich the species composition and to increase the fodder productivity of degraded pastures we conducted strip sowing of black saxaul. Restorative succession on degraded pastures led to the formation of a long-term halophytic shrub-ephemeral pasture community consisting of two layers: upper (I) layer represented by black saxaul and lower (II) layer composed of ephemeroids, ephemerals and annual saltwort. Ephemerals are short-growing fodder plants (March–April); Haloxylon aphyllum refers to long-growing (226–242 days) fodder plants, which sprout in the period from late March to early December. Annual salsolas Salsola carinata and Halocharis hispida develop well under the crown of Haloxylon aphyllum. Here they are much larger than between the crowns. The shrub-ephemeral pasture community is dominated by annual grasses and Poa bulbosa. They are mainly concentrated on the outer border of the undercrown ring and are characterized by lush development. In the halophytic semi-shrub-ephemeroid pasture community, the total yield of forage mass of ephemera was 0.90 t/ha; the total yield of forage mass of annual saltwort was 0.14 t/ha; the total yield of forage mass of Haloxylon aphyllum was 0.89 t/ha; the total yield of forage mass was 1.93 t/ha.

Cover crop increases soybean yield cropped after degraded pasture in sandy soil

ABSTRACT Soybean cropping has been growing in recent years in environments with sandy soils and with climatic risk, but yield is low, especially in the early years. The objective of this study was to evaluate the effect of cover crops and nitrogen management in a sandy soil previously under degraded pastures on soybean yield. The study was conducted in Western São Paulo state, Brazil. The experimental design was randomized blocks, with four replicates, and the treatments were: black oats; black oats + 50 kg ha-1 of N in black oats; black oats + 50 kg ha-1 of N in soybean; black oats + lupine; black oats + lupine + 50 kg ha-1 of N in soybean; lupine; fallow; fallow + 50 kg ha-1 of N in soybean. Nitrogen concentration of the microbial biomass was higher with oats + N in soybean applied at the beginning of flowering (R1). The number of nodules in soybean roots increased by 2.3 times with oats and oats + N in soybean as compared to fallow. Soybean yield was higher in treatments with oats + N in oats (2,130 kg ha-1), oats (2,038 kg ha-1) and oats + N in soybean (1,872 kg ha-1). In the absence of cover crops, N fertilization in soybean increased yield by 19% (262 kg ha-1) compared to fallow. Black oats are the best option to increase soybean yield. However, in the absence of cover crops, nitrogen fertilization in soybean is necessary.