Wood Density and Ring Width in Quercus rotundifolia Trees in Southern Portugal

Quercus rotundifolia Lam., known as holm oak or evergreen oak, occurs naturally in the western Mediterranean region, mainly as part of the agroforestry or agrosilvopastoral systems in Portugal (“montado”) and Spain (“dehesa”), and is economically important for acorn production. Less attention has been given to Q. rotundifolia wood, and its density variability is not known, namely related to tree growth. The wood density of 20 Q. rotundifolia trees was measured along the radial direction by X-ray densitometry and the factors responsible for ring width and wood density variation within and between trees were investigated at two sites located within the main species region in southern Portugal. Ring width was significantly different between sites, with an average of 1.81 mm and 1.55 mm. Wood density was very high and averaged between 888 kg/m3 and 914 kg/m3 but not significantly different between sites. Ring width and wood density showed a positive and significant correlation at both sites. Cambial age was the main source of variation for ring width and wood density, while between-tree effects accounted for a considerable proportion of wood density variation. The results are an important contribution for the species valorisation aiming at high-value wood products, also adding knowledge on the species growth of interest for tree selection and sustainable management.

Dual-Purpose Water Buffalo Production Systems in Tropical Latin America: Bases for a Sustainable Model

Tropical regions of Latin America have been incorporated into development in recent decades, with extensive cattle ranching as one of the main economic activities but without adequate planning, drastically degrading the ecosystem. In recent years, buffalo production has been incorporated into the region, with possibilities for development in profitable and sustainable models. To study this option in depth, a broad bibliographic review was carried out focusing on the ecological characteristics of tropical zones and the physiological and productive characteristics of buffaloes. We also investigated the structure and functioning of dual-purpose systems that have worked in cattle and that can be optimized with this alternative animal species. The possibility of taking sustainable advantage of abundant forage resources in the region was detected through intensive grazing models, as well as agrosilvopastoral systems, due to the gregarious qualities of buffaloes and responding to their thermoregulation needs. In this way, the productive and regenerative capacities of the dual-purpose system could be increased, as well as the quality of meat and milk, which could be marketed as differentiated products, taking advantage of their outstanding nutritional qualities. Integral management of the dual-purpose system is proposed, retaking the bases of the original model of family characters, diversified and with low investments and risks, which with specific innovations can be an effective development option for producers in the region.

Rendimiento de leche derivado de energía y proteína de vacas en pastoreo recibiendo suplementos en un sistema agrosilvopastoril

Dual purpose farms southwest of the State of Mexico produce milk and calves under subtropical agrosilvopastoral systems (ASPS). During the dry season, farmers supplement their cattle due to the low availability and quality of grasses, without considering, besides grasses, the contribution of woody species to dry matter intake, metabolizable energy (ME), and crude protein (CP) requirements of cows. The aim of this study was to determine milk produced from forage energy (MFe) and protein (MFp) of grazing cow with three types of supplement. First supplement consisted of cracked maize and commercial concentrate resulting on 14 % of CP (S14). To the S14 mixture 7 % of soybean meal was added to increase CP to 16 % (S16), and commercial concentrate of 16 % CP was used as a third supplement (SC16). Six lactating cows were allocated in a 3x3 replicated Latin Square (three cows per square), three experimental periods (EP) (three weeks per EP). There were no significant effects of supplements (P=0.80) on performance variables. Mean milk yield was 6.8 kg/cow/d. Milk from forage energy and protein were 0.8 and 6.1 kg/cow/day, respectively. Mean milk urea nitrogen (MUN) was high regardless of supplement; but nitrogen in urine (44.1 mg/dL) and feces (1.4 mg/g) were higher for SC16 (P=0.001 and 0.04, respectively). Cows obtained 90 and 10 % of their CP and metabolizable energy requirements for maintenance and production from the agrosilvopastoral system.

GEOMATIC TECHNIQUES APPLIED FOR REMOTE DETERMINATION OF THE HAY QUANTITY IN AGROSILVOPASTORAL SYSTEMS

The paper presents a descriptive model, applicable in agricultural theory and practice, for determining the quantity of alfalfa hay obtained from a land surface, using remote investigations, by geospatial methods and means. The working algorithm was tested in a rural area located in the northern part of Romania, in the Humor Depression, and the data acquisition was made with DJI Phantom 4 Pro - Unmanned Aerial Vehicle equipment. For the automated calculation of the amount of alfalfa hay harvested from a certain surface and stored as haystacks, the following steps were carried out: processing the images acquired with the drone to obtain the point clouds, determining the 3D model of the haystacks, calculating the volume of hay stored in the stacks and converting the volume in quantity of hay/surface. As a result of the measurements and calculations carried out, a quantity of hay of 11.96 tons/ha was obtained, data verified and validated by the researches from the specialized literature. Compared with the agronomic methods, the use of the geomatics techniques, to determine the quantity of hay harvested from an agricultural area, presents a series of practical and economic advantages: they exclude the manual measurements in the field and, therefore, the displacements on extended surfaces; reduce the working time; have high precision because, for the estimation of the haystacks volume, three-dimensional models are used, instead of the traditional mathematical formulas. At the same time, geospatial data is acquired through drone flying, which can be used in other types of analysis. The working algorithm can also be applied to other studied objectives or research topics.

Forage production and productive performance of Nellore heifers in agrosilvopastoral systems

Agrosilvopastoral system is a type of production that involves the soil-forage-animal interface, both of which are benefited by the system. Hence, the present study evaluated the effects of agrosilvopastoral system on the quantitative and qualitative characteristics from pasture, and the animal performance during the feeding period of Nellore heifers. The treatments included: Soil-forage-animal – 357 eucalyptus trees per hectare (LFA14x2m); Soil-forage-animal – 227 eucalyptus trees per hectare (LFA22x2m); and Soil-animal – Five native trees remaining per hectare (CON). The forage used was Brachiaria brizantha cv. BRS Piatã and having as trees planted the Eucalyptus urograndis clones H 13. Treatment effects (P <0.05) for forage accumulation and pasture height, which were lowest in LFA14x2m compared to the others. Total forage dry mass in CON treatment was significantly greater (P <0.05) compared to the other treatments, showing maximum production in March. The LFA14x2m treatment was favorable for greater forage quality, showing an effect on chemical composition (P <0.05), compared to other treatments. Whereas, in November the LFA22x2m treatment was better for neutral detergent fiber. January and March, the treatments were similar (P >0.05) for average daily gain, while in November period, LFA14x2m treatment showed the lowest value (P <0.05). The lowest weight gain by area (November) occurred in the LFA14x2m treatment (P <0.05), although in March the LFA14x2m treatment stocking rate was similar to the others. Forage production and animal performance are altered by the trees densification in agrosilvopastoral systems. The chemical composition of pasture is better in systems with a higher trees density.

Partial Grazing Exclusion as Strategy to Reduce Land Degradation in the Traditional Brazilian Faxinal System: Field Data and Farmers’ Perceptions

Land degradation is becoming a serious concern for the sustainability of traditional agrosilvopastoral systems such as the Brazilian faxinal. The IAP (Environmental Institute of the Federal State of Paraná) is favoring the partial exclusion to grazing for 10 years as strategy both to recover degraded lands and to reduce negative effects. Nevertheless, this strategy is being followed by a reduced number of owners (faxinalenses) and little is known about the effectiveness of these measures due to either lack of field data and knowledge on faxinalenses’ perceptions. We have identified one out of few farms that have followed this official strategy and, within the same farm, we have compared values of some soil properties (bulk density, porosity, water holding capacity, penetration resistance, soil organic matter and root density) from an excluded area to grazing for 10 years, with some areas that represent a gradient of grazing intensity (natural forest, secondary forest, degraded forest, grassland and a degraded area by pigs). In addition, we have interviewed some faxinalenses (one faxinal farm is owned by several farmers) in order to better understand how the risk of land degradation is perceived by them and their opinions about the usefulness of partial grazing exclusion as a strategy to improve the management of their farms. The results have shown that soil quality increases considerably as a consequence of grazing exclusion, in spite of land has been used for cropping yerba mate during the exclusion time, but faxinalenses are not mindful of these benefits and they are no longer interested in excluding other areas of their farms. They think this strategy is simply an obligation imposed by the environmental authority.

Monitoring Geomorphic Change and Catchment Sediment Production to Understand the Erosive Dynamics in a Gullied Channel by Means of High-Resolution DEMs

Gully erosion in valley bottoms is a frequent process with negative consequences in the dehesa environment. Soil loss, decrease of soil and descend in biomass are among the negative aftereffect of gully erosion processes. Studies conducted in agrosilvopastoral systems described the dynamics of gullied channels by means of fixed topographic cross sections or with low spatial resolution Digital Elevation Models (DEMs). Currently, high spatial and temporal resolution DEMs can be produced with spatially distributed information due to the development of new systems, platforms and sensors. Additionally, the rainfall and sediment discharge could also be monitored. This control allows us to relate gully erosion with catchment hydrology. The goals are (1) to quantify the sediment budgets by the spatio-temporal distribution of erosion and/or deposition in the gullied channel, (2) to interpret the geomorphic processes driving erosion and deposition and (3) to analyze the relationship between the morphological change and the catchment runoff and the sediment load. The studied area is a gullied channel located in the SW Iberian Peninsula and developed over a recent sedimentary deposit. The channel reaches an extension of 1 km in length and 2 m in depth. The methodology included the following steps: (1) flying the same study area with different time periods using a fixed-wing small Unmanned Aerial System (sUAS) to capture high-resolution aerial images and surveying Ground Control Points (GCPs) using a GNSS, (2) Structure-from-Motion photogrammetry processing using the acquired images and the GCPs to produce high-resolution DEMs for each date, (3) Applying the DEMs of difference approach to estimate topographic changes and to quantify the sediment budget and finally (4) analyzing the relationship between rainfall events, discharge, sediment load and changes in the channel previously estimated. Resulting DEMs and orthophotographs showed a Ground Sampling Distance of 0.02 m with a georeferencing Root Mean Square Error of 0.03 m. A spatially variable threshold (to differentiate actual geomorphic change from noise or errors) was produced using a Fuzzy Inference System and considering photogrammetric errors, slope and vegetation as factors. The applied method proved to be suitable to interpret the geomorphic changes for the gullied channel. For the 2016–2018 period, the gully showed a positive balance indicating accumulation of sediments coming from the hillslopes of the catchment. It is the period with the highest rainfall when numerous events generated runoff. On the contrary, for the period 2018–2019 a total soil loss of −119 m3 was estimated.