Rotational grazing increases purple prairie clover frequency in the rangeland plant communities under semi-arid environment

Purple prairie clover (PPC, Dalea purpurea Vent.) is a grazing tolerant perennial legume with good nutritional quality and is widely distributed across North America. Deferred rotational grazing (DR) and continuous grazing (CG) are the most widespread grazing systems on North American grasslands. We conducted a 10-year grazing study to assess the effects of environmental factors and grazing on the frequency of PPC in plant communities. The results showed that the frequency of PPC decreased and then increased with increasing precipitation under CG (P<0.05), while there was no significant change under DR (P>0.05). Meanwhile, PPC frequency increased with temperature under DR (P<0.05), but did not change under CG (P>0.05). Both grazing systems and the number of grazing years had a significant effect on PPC frequency (P<0.05), and there is no interaction between those two factors (P>0.05). We found that from 2011 to 2020, the growth rate of PPC population is 18.24% and 11.69% per year under DR and CG grazing, respectively. Moreover, after 10 years of grazing, the PPC increase in DR was 22.86% higher than that of CG. Thus, selecting the DR grazing system can increase PPC and is an effective practice for coping with environmental changes.

Intensity of land use by pasture as result of pedogeoclimatic characteristics and anthropogenic management

In the world, the most significant change in the ecosystems structure is the conversion from natural land surface into cultivated systems. In 2018, 26.8% of the Brazilian territory was occupied by agricultural activities, from which 73% is pasture. Considering that the management adopted in Brazilian pastures is incipient and leads to degradation, there is a need to characterize the state of the pastures to diagnose the intensity of this use on the soil. However, the diagnosis of large areas using satellites with more detailed resolution is limited by cloud coverage and low temporal resolution. In this sense, the present work aims to diagnose the intensity of land use by pastures (ILUP) in large areas based on the mosaic of images from Landsat 8 (LS8), Landsat 7 (LS7), Sentinel-2 (S2), and MODIS. The methodology consists of harmonizing the NDVI from LS7 and S2 satellites with LS8. For MODIS, the harmonization was carried out based on ILUP obtained previously from NDVI LS8. The methodology was applied at the Doce river basin (DRB). The combination of different sensors allowed to overcome the cloud coverage limitation. DRB has 61.3% of its area occupied by pastures and 78.2% of them have some degree of degradation. ILUP was dependent on DRB’s pedological and climatic characteristics. This dependence is enhanced due to pasture management in the basin, mainly characterized by continuous grazing, which commonly leads to overgrazing scenarios. The areas with great rainfall seasonality and associated with Acrisols/Cambisols are the most susceptible to degradation.

Effect of Grazing Management and Land Cover Types on Mineral-Associated Organic Carbon and Particulate Organic Carbon in a Semi-arid Rangelands in Kenya

BackgroundEnhancing soil organic carbon storage in areas under extensive livestock grazing has become a challenge in most arid and semi-arid rangelands in Sub-Saharan Africa. In Kenya for instance, continuous unplanned grazing in community lands has led to overgrazing and degradation of the rangelands. For decades, livestock production has shaped the landscape through various management practices. Grazing can be used to increase soil organic carbon (SOC) content but intensive use of land can lead to its depletion. This study was set out to elucidate the effect of two types of grazing management under varying land cover types on mineral-associated organic carbon (MAOC) and particulate organic carbon (POC) in the soil. The study was carried out in two ranches, Mpala Research Centre (controlled grazing) and Ilmotiok Community Group Ranch (continuous grazing). The experimental design was a completely randomized block design in split-plot arrangement with three replicates. The main plots were the grazing practices; (controlled grazing and continuous grazing); and sub-plots were the land cover types: (bare ground, patches of grasses, and mosaics of trees). These treatments were randomly selected and replicated three times. Three topographical positions (mid-slope, foot slope and bottom land) were used as a blocking factor.ResultsThe interaction had no significant effect on MAOC fraction in any soil depth interval. Controlled grazed zones significantly recorded higher organic carbon content (POC= 0.887% CC SD=0.49) compared to zones under continuous grazing (POC = 0.718% CC SD=0.3). Mosaic of trees (POC =1.15% CC, SD = 0.22) recorded the highest concentration of carbon followed by patches of grass (POC = 0.87% CC, SD= 0.37) and bare ground (POC = 0.38% CC SD = 0.12) had the least.ConclusionThis study shows that grazing practices as well as land cover types have a significant effect on POC but not on MAOC. Mosaic of trees under controlled grazing has higher POC whereas bareground under continuous grazing had the least POC. Destocking should be done under continuous grazed zones to reduce further loss of POC and MAOC and allow vegetation recovery.

Influence of integrated crop-livestock-forest on morphological composition and nutritional value of Marandu palisadegrass under continuous grazing

This study characterizes the changes in leaf mass, morphological composition and nutritional value of leaf blades of palisadegrass (Urochloa brizantha cv. Marandu) under continuous grazing in the first year of implementation of pasture and after second year of the eucalyptus planting in an Integrated Crop-Livestock System and Integrated Crop-Livestock-Forest, which were tested in the four seasons. The experimental design was in random blocks, with three treatments: Crop-Livestock System (ICL) and Integrated Crop-Livestock-Forest with two eucalyptus tree densities (ICLF-1L, 196 eucalyptus trees ha-1 and ICLF-3L, 448 eucalyptus trees ha-1) and four replicates. Sixty castrated Nellore cattle with initial weight of 235.43 ± 25.46 kg and mean age of 16 ± 2.81 months were used during the growing phase under continuous grazing. The agronomic variables were: total dry mass of forage, leaves, stem and dead material; leaf: stem and live: senescent material ratios; and accumulation rate. The leaf: stem and live: senescent material relation did not obtain any difference between the evaluated systems. Dry matter, crude protein, fiber fractions and digestibility of leaf blades were evaluated. Dry mass of the forage (6775 kg ha-1), stem (2175 kg ha-1), senescent material (3175 kg ha-1) and dry matter content (28.6%) were greater in the ICL, whereas crude protein (11.3%) was greater in the ICLFs. On the other hand, accumulation rate and dry mass of leaf blades did not change between systems. Thus, until the first year of grazing, tree systems have advantages, because the forage production (accumulation rate) and leaf mass are similar to those of plants in full sun, besides showing higher nutritional value.

Herd dynamics, production and marketing constraints in the commercialization of cattle across Nguni Cattle Project beneficiaries in Eastern Cape, South Africa

This paper examines the challenges restricting the commercialization of cattle across Nguni Cattle Project beneficiaries in South Africa. Data were collected from one hundred and twenty (120) Nguni cattle beneficiaries using a structured questionnaire across six district municipalities of the Eastern Cape Province. Results revealed that majority of Nguni cattle beneficiaries were males, were above 60 years old, and have received formal training in livestock farming. Most of the beneficiaries reared cattle with other livestock species, with 45% owned non-descript breeds, 33% Nguni and 22% other breeds such as Bonsmara and Brahman. About 79.2% of the beneficiaries practised continuous grazing while 52.5% give their cattle supplements, with most commonly (48%) using rivers as the source of water. Most beneficiaries (38.4%) reported diseases as main production constraints, followed by stock theft (27.5%) and feed shortages (22.5%). Furthermore, results showed that 80.8% of beneficiaries market one to 10 cattle per year, 64.8% adult cattle (2+ years old) and 35.2% weaners (8 months to 1 year). Most beneficiaries (78.7%) used private marketing channels to sell their animals, while 4.3% used abattoirs. Factors identified as the main market constraints included low cattle numbers (41.7%), inability to meet formal market standards (25%) and inadequate government support. There was a strong association between formal livestock training and cattle marketing attributes as well as production constraints. In conclusion, more emphasis should be given to improve cattle production and commercialization through provision of more cattle, livestock trainings and market services to communal farmers.