Combine harvesters are an important cause of fires worldwide. The purpose of this work has been to investigate the critical points associated with the risk of fire, identified through a survey distributed to combine owners in Aragon (Spain). Information was collected on the technical characteristics of the machines and, when appropriate, on the characteristics of the generated fires (crop, use of straw chopper, point in which the fire was originated, etc.). Based on the survey data, relationships between the characteristics of the machine and the ignition of a fire were analyzed, and the points of the harvester in which the fire originated were investigated. A statistically significant relationship of fire risk was only found with the number of hectares harvested, in such a way that the risk would be especially high for machines with more than 6000 accumulated ha. 32% of the fires were originated in the engine zone, compared with 31% in the cutting bar and 18% in the bearings and belts. The study was completed with on-site temperature measurements carried out on nine machines in 2018 and 2019, in which temperatures above 250 • C were recorded in the exhaust manifold and in the cutting bar. These temperatures exceeded the ignition thresholds obtained in the flammability studies conducted for wheat residues collected from the harvesters.Agronomy 2019, 9, 877 2 of 13 can be analyzed for the different regions. In the case of Aragon, there were 226 and 357 forest fires in 2018 and 2019, which affected a total surface of 215 and 1291 ha, respectively. The second most important cause of those fires, after negligence, was associated with agricultural machinery (including harvesters), which accounted for 8.8% of the fires that occurred in 2018 and 9.2% of those that took place in 2019.The possible causes of fire ignition in agricultural machines and specifically in harvesters are very varied. Quick [5] lists a number of potential points in which fire can start: engine and flue gas outlets, transmissions, bearings, brakes, electrical short-circuits, impact of mowing heads with stones or other elements, and introduction of foreign bodies into the machine. Of all of them, the most common cause is the accumulation of combustible material in points with high temperatures located near the engine. The surface temperatures of these elements can reach 500 • C [5], exceeding the ignition temperatures of the crop residues, which vary depending on the thickness of the sample, but which are generally above 200 • C in the case of wheat straw [6]. As for the spread of the fire, field conditions can favor or hinder the process, which would be influenced by four main factors: relative humidity, ambient temperature, wind speed, type and condition of the crop [5,7].Despite the importance of the consequences of agricultural and forest fires, there are hardly any studies focused on the causes of fires in combine harvesters. So far, the most important studies have been those carried out in the USA by Shutske et al. [8,9], in which the authors ...

Sheep farming makes an important socio-economic contribution to Spain’s rural areas by sustaining farming and employment in less favored regions, but it is a low-profit sector because of high operating and regulatory costs. One possible solution would be to raise for slaughter lambs from dairy sheep that are not required as replacements. However, the early weaning of these lambs and their artificial rearing generally lead to reduced growth rates and high mortalities. In the work presented herein, three housing systems (slat + heating plate, slat + infrared lamp, and deep-litter + infrared lamp) were tested on 763 lambs over an eight-month period in a farm located in Ejea de los Caballeros (Zaragoza, Spain), with a view to reducing mortality during the period of artificial lactation. The effect of the environmental parameters of the lamb housing on the development of the lambs was evaluated by monitoring environmental (temperature, relative humidity, CO2 and NH3) and productive parameters (weight, average daily gain, and deaths). The results suggested that the combination of deep litter with straw bedding and infrared lamp heating would be the most favorable option, as it led to the highest average daily gain and the lowest percentage of deaths. From the study of the relationship of the initial weight with deaths, a prediction curve was obtained, defining the maximum prices to be paid per lamb as a function of their initial weight to guarantee the profitability of the raising process. This may be regarded as a valuable guidance for Spanish sheep farmers, as it can reduce their economic uncertainty.