Evaluation of Microbial Biomass in Agroforestry Systems Using Forage Cactus and \u3ci\u3eLeucaena leucocephala\u3c/i\u3e and \u3ci\u3eGliricidia sepium\u3c/i\u3e

Vegetation type can affect soil microbiology in agroforestry systems. Plants release different organic exudates in the rhizosphere, affecting microbial growth. This study evaluated the effect of forage cactus intercropped with different tree legumes on soil microbial biomass. The research was performed in a tropical semiarid Regosol at Caruaru Experimental Station, Agronomic Institute of Pernambuco, Northeast Brazil. Treatments included: i) Gliricidia sepium (Jacq.) Steud and forage cactus IPA-Sertânia (Nopalea cochenillifera Salm Dyck); and ii) Leucaena leucocephala [Lam.] de Wit.) and forage cactus IPA-Sertânia. Treatments were allocated in a randomized complete block design in a split-split-plot scheme, with four replications. Main plots consisted of agroforestry system, split-plot was the distance from tree rows, and split-split-plot soil depths. Organic fertilization with cattle manure was applied aiming a rate of 200 kg N ha-1. Tree legumes were planted in double rows spaced 9 x 1 x 0.5 m and cactus planted between double rows spaced by 1 x 0.25 m. Plot size measured 960 m2. Soil collection occurred in the rainy period (April 2019). Samples were collected at depths of 0-10 cm and 10-20 cm at 0, 1.5, 3.0, and 4.5 m away from legume rows. Response variables included soil basal respiration (SBR), microbial biomass C (C-mic), and metabolic quotient (qCO2). Data were subjected to analysis of variance using SAS. Means were compared by Tukey test at 5% significance. No significant difference was observed for SBR, MBC, and qCO2, with average values of 9.36, 202.98, and 0.05, and standard error 1.16, 10.90 and 0.01, respectively, in the different distances away from tree legumes. Introduction of arboreal legumes did not cause changes in microbial biomass. Microbial activity was similar in soils under forage cactus intercropped with Leucaena or Gliricidia

Mechanics of Combining Divergent Herbivores in Cultivated Pastures

Sustainable intensification of cultivated pastures is needed in ruminant production if we are to feed a growing world population expected to exceed 9 billion by 2050. Planting pastures of diverse, and therefore more productive and resilient, plant species has been proposed and researched. Despite illustrative examples from wild grasslands (Hofmann, 1989) and rangelands (Glimp, 1988), very little research and even less application of multiple herbivore species (MHS) in cultivated pastures has followed. We review the specific mechanics of divergent domesticated ruminants and theorize how these could best be combined to sustainably intensify meat, milk and fiber production from cultivated pastures around the world

Chemical Composition of Woody Species at Browsed Caatinga under Different Forage Allowance

Native rangelands are essential for Brazilian livestock production in the northeast Caatinga because they are abundant and inexpensive. Greater knowledge of nutritive values of these native plants is a needed because they fit well in prevailing edapho-climatic conditions. The chemical composition of plants, however, may differ according to ontogeny, elevation, soil, climate, plant community and human actions. Caatinga plants usually have high crude protein (CP) although some of this is fiber-bound (Santos et al., 2009). Browse can therefore become a key livestock diet component. Condensed tannins (CT) in browse can provide benefits, including anthelmintic activity greater amino acid absorption, synthesis of microbiological protein and reduction in methane emission when consumed at 20 to 50 g kg-1 dry matter (DM) (Littlefield et al., 2011; Muir, 2011). Above those levels, animals may suffer negative consequences because of the strong linkage with enzymes, metal ions and carbohydrates although browsers can neutralize CT via salivary proline (Naumann et al., 2013). The objective of this study was to estimate the chemical composition of commonly browsed Caatinga woody species in four forage allowances

Challenges to Domesticating Native Forage Legumes

If ruminant production from cultivated and natural grasslands is to depend less on petroleum-based products, forage legumes must serve as protein sources. Commercially available legumes for warm-dry climate grasslands are, however, very limited and resources available for developing such legumes are inadequate. Indeterminate flowering and dehiscent seed pods combined with the need for specialized seed harvesting equipment are major impediments (Butler and Muir 2012). Warm climates often present environmental challenges such as poor rainfall distribution, extended dry seasons, temperature extremes and aggressive grass species (Muir et al. 2011). Erosion of indigenous knowledge and replacement with inappropriate land management approaches from moist-temperate regions compound the challenges

Relationship between Field Measurements in Three \u3cem\u3eBrachiaria\u3c/em\u3e Species with Leaf Area Index and Light Interception by Indirect Methods

Brachiaria species play a strategic role in ruminant production systems in Brazil, covering an estimated pasture area of approximately 90 million hectares (Karia et al., 2006), however, these pastures are subject to different degrees of degradation due to inadequate management. In pasture management, field measurements such as canopy height, for example, are used by managers as a tool to establish parameters for the optimal point to cut the forage and for the post-grazing residue, in order to maximize production by harvesting at maximum of herbage mass accumulation, and to avoid problems associated to overgrazing, by setting ideal post-grazing height for forage regrowth. The use of the variables light interception (LI) and leaf area index (LAI) has been recommended as a tool for pasture management, based on the theory that, when the canopy reaches a light interception of 95%, the forage is near its maximum growth rate, which is called critical LAI (Brougham, 1956). The residual LAI refers to the leaf area of the post-grazed stubble. Residual LAI is used to establish the minimum leaf area necessary to ensure an efficient pasture regrowth (Lemos et al., 2014). Light interception and the LAI are difficult to measure at the farm level, due to the high cost of the equipment and technical feasibility of the process. The objective of this study was to evaluate the relationship between LI and LAI measured by two different equipment, with canopy height and soil cover in three species of Brachiaria

Pernambuco Semiarid Native Rhizobial Populations Nitrogen Fixation Potential with Native \u3cem\u3eMacroptilium\u3c/em\u3e

Nitrogen (N) is one of nature´s most abundant elements, accounting for about 78% of the atmospheric gases, but mostly as the inert N2 form. As such it is not directly available to plants, and is relatively scarce in most agroecosystems. Biological nitrogen fixation (BNF) through diazotrophic bacteria represents ca. 63% of the yearly N input in terrestrial ecosystems (Taiz and Zeiger 2004). Legumes which form effective symbiosis with the diazotrophic group of bacteria commonly known as rhizobia, are a very important source of available N. Tropical forage legumes are usually able to nodulate with a diverse population of rhizobia, and may have a relevant contribution to nitrogen availability in pastures (Santos et al. 2003). This diversity may be exploited to find more symbiotically efficient bacterial strains, thereby increasing legume effects on pastures. One way to evaluate this diversity is to isolate strains from different regions, vegetation covers or cultivation systems, and environmental conditions. This practice would potentially lead to a large number of isolates, which would increase the chance of finding some more efficient than those currently available (Chagas Junior et al, 2010). Native legumes, including several species of Macroptilium are an important forage resource in the Brazilian Northeast semiarid, contributing to the quality of ruminant diet, but they are still not well known in regards to their BNF ability. This work evaluated nodulation efficiency of Macroptilium lathyroides when inoculated with Litolic Neossol from eight municipalities of Pernambuco State semiarid

Cattle Fecal Decomposition on \u3cem\u3ePennisetum purpureum\u3c/em\u3e Schum. Pastures Managed under Different Post-Grazing Stubble Heights

Pasture management may affect cattle diet. Post-grazing stubble height is a pasture structural characteristic intrinsically linked to forage quantity and quality. Stubble height also indicates forage utilization rate, and as a result, affects nutrient pathway return (excreta or litter) and ultimately, nutrient cycling. Cattle excreta deposition affects soil chemical and physical characteristics (Carran and Theobald 2000). Slow release of nutrients from cattle dung, however, delays nutrient bioavailability for subsequent forage growth (Haynes and Williams 1993). This study evaluated how different post-grazing stubble heights on elephant grass (Pennisetum purpureum Schum.) pastures may affect cattle dung decomposition and nutrient release

Leaf Epidermal Descriptors of Forage from Caatinga, NE Brazil

In the Brazilian semi-arid region, the predominant vegetation is the Caatinga, which has a diversity of plant species, some endemic and presenting forage potential. The characterization of the plant anatomy is important for animal diet studies, using a microhistological technique (Scott and Dahl 1980) for estimating the diet botanical composition from ruminant faeces. This paper determined leaf epidermal descriptors for Caatinga species using microscopic slides

Root Decomposition of Elephant Grass Pastures Grazed at Different Management Intensities

Grazing management may alter chemical composition of plant components affecting nutrient cycling. Among pasture management tools, adjustment of stocking rate (SR) and N fertilization have potential to affect nutrient cycling in the grassland ecosystem (Dubeux et al. 2007). Excreta from grazing animal and litter are the two major pathways of nutrient return on grazed pastures (Thomas 1992). Fertilization and SR may alter these pathways by different forms. Increasing fertilization generally increases pasture net primary productivity. Stocking rate affects different pasture and animal responses. Regarding nutrient cycling, increasing SR will likely increase proportion of nutrient returned through excreta as opposed to litter, increasing as a result nutrient losses (Dubeux et al. 2006). Root system may also be affected by management intensity. Frequent defoliation and low plant nutrition level may reduce root biomass (Richards 1993) and affect its decomposition. This study evaluated the effect of different SR´s and N fertilization levels on the decomposition of elephant grass roots