Lack of young farmers capable of climbing palms requires of a robot for harvesting coconut fruits. For the construction of the robot, a structure was design that could adapt easily to the trunk of the tree (inclination, height and diameter). The structure has a crankconnecting rod system that is capable of climbing the palmtree and carries at the same time a motor, a battery and a camera which all together weighs 7 kilograms. The system of artificial vision includes a camera IP that takes images to recognize the robot position. An algorithm that detectsellipses identifies the presence of coconut fruits.

Split applications of nitrogen fertilizers according to maize requirements increase N use efficiency. However, few studies have been carried out in Mexico using N fertilizer labeled with 15N to evaluate the recovery of N applied. The objective of this study was to determine the N recovery efficiency in maize using 15N, when split N fertilizers are applied at four growth stages. The experiment was carried out between 1999 and 2000 at Gomez Palacio, Durango, Mexico. Four treatments were evaluated using N rates of 300 kg·ha-1. Split application of 75 kg·ha-1, at planting,tassel initiation (V6), beginning of fast-growing ear (V12) and silking (R1) growth stages was applied. A growth stage was labeled with 15N per treatment. A randomized complete block design with three replications was used. Drymatter yield, N recovered by crop and soil were determined. Nitrogen recovery efficiency reached values of 42.7, 83.2, 35.1 and 10.0 % when labeled fertilizer was applied at planting, V6, V12, and R1 growth stages, respectively. These datasuggest that the best way to apply N fertilizer is using three split applications, from planting up to V12 stage, with a greater proportion at V6 growth stage. Maize removed 243.2 kg N·ha-1, with 114.8 kg supplied by the soil N. From the appliedN fertilizer (300 kg·ha-1), crop recovered 42.8 %, 15.6 % was recovered from soil 0-60 cm depth, and 41.7 % of the applied N was unaccounted.

The electric field (EF) application is a non-thermal technology with great potential to replace the thermal treatment in food preservation. In this work electric field were applied to inactivate the polygalacturonase (PG) enzyme in tomato juice. A 32 factorial design was conducted, where the variation sources were frequency (25, 45 and 550 Hz) and exposure time (5, 10 and 15 minutes), at 15 kV of intensity electric field; all experiments were performed for triplicate. The study was compared with a thermal treatment at 65 °C for 5, 10, and 15 minutes. EF effect was evaluated through residual activity (RA) of polygalacturonase. Significant effects were found in both, frequency and exposure time, while their interactionwas not significant; the frequency was the factor with more contribution to variance. The highest inactivation of PG was obtained at 45 Hz, and during the first 10 minutes the residual activity was lesser than with thermal treatment.

Inthis work was estimated the water soil erosion in Pichucalco watershed in Mexico by using the Universal Soil Loss Equation (USLE); Pichucalco river is a tributary of the Grijalva river. The erosion was estimated by using the map algebra technique in ArcGIS 9.3. The rainfall erosivity factor R was estimated with daily rainfall data obtained from ten weather stations for the period 1996-2005.Watershed landuse was that interpreted in satelital images RapidEye with spatial resolution of 5 m. According to FAO classification, it is concluded that actual erosion null class is of 55.47 %, light class is 24.62 %, moderate class is 18.68 %, severe class is 0.96 % and very severe class is 0.27 %. That means that in a 20 % of the watershed is urgent to implement conservation soil and water management practices, because soil is lost with values between 10 and 200 t·ha-1·year-1.These most affected areas by erosion were detected in the middle and upper parts of the basin where there is a combination of high slopes and grasses; the least water erosion affected areas are located in those soils covered with forest and rainforest and in the lower basin where the topography is almost flat, with the presence of wetlands. The soil loss in this watershed is related to the extensive livestock in hills, which is performed in the 76.2 % of the watershed.