Philippine Journal of Agricultural and Biosystems Engineering

Estimation of Crop Evapotranspiration of Satsuma (Citrus reticulata Blanco) by Normalized Difference Vegetation Index in Nueva Vizcaya, Philippines

2025-06-30T13:58:30+00:00

Evapotranspiration has a major impact on agricultural productivity particularly in maintaining soil moisture level and sustaining plant health. Crop coefficient (Kc) is an important component for evaluating crop evapotranspiration (ETc) as it incorporates crop characteristics and average effects of evaporation from the soil. This study estimated the crop evapotranspiration of Satsuma in Malabing, Kasibu, Nueva Vizcaya using Kc values from remotely sensed NDVI data. Three neighboring areas with an area of one hectare were selected for the vegetative, early fruiting, and mature fruiting stages. Satellite imagery from Landsat 9 was used in determining NDVI values which are significant in the estimation of Kc values. It was found that the computed Kc values of citrus for the vegetative stage in all the three phases (initial, mid, and late) were 0.41, 0.46, and 0.48, respectively. The Kc values for the early fruiting were 0.47 (initial), 0.45 (mid), and 0.46 (late) and for the mature fruiting stage the values were 0.65(initial), 0.58 (mid), and 0.63 (late) which follows the trend of the FAO Kc values that decrease in the mid phase. The estimated crop evapotranspiration using these Kc values shows that the highest for the vegetative stage is in the month of August and May for both early and mature fruiting stage, while the lowest ETc values were recorded in the month of January for the vegetative and December for both early and mature fruiting stage. Thus, these computed Kc values provide a site-specific value needed for the computation of crop water requirement and irrigation scheduling for citrus production in Kasibu, Nueva Vizcaya, Philippines.

Comparative Performance of Granulated Carbon and Commercial Resin as Adsorbents for the Extraction of Phytohormones from Coconut Water in Batch Adsorption Experiments

2025-06-30T07:19:33+00:00

The study evaluated coconut-shell derived granulated carbon as a cost-effective, sustainable alternative to commercial synthetic resin for extracting phytohormones from waste coconut water via batch adsorption experiments. The adsorption performances were compared in terms of the following parameters: isotherm type, adsorption capacity, effective loading, equilibration time, separation factor, and extracted phytohormones. Although commercial resin provides higher adsorption capacity of 61.8 mL/g (versus 14.6 mL waste coconut water/g adsorbent) and desirably lower effective loading of 20 g/L (versus 200 g adsorbent/L waste coconut water), granulated carbon offers faster equilibration time of 1 h (versus 3 h) and more favorable separation factor of 0.008 (versus 0.040) at a lower adsorbent cost of PHP 7/L (versus PHP 300/L waste coconut water). Both adsorbents follow Freundlich isotherm of reversible, physical adsorption, for which all obtained extracts contain gibberellic acid 3, indole-3-acetic acid, with kinetin as the most dominant phytohormone. Despite its lesser capacity, granulated carbon could potentially deliver lower processing costs for phytohormone extraction from waste coconut water especially if considering an upscale production.

Residual Assessment of Metal Transfer from Selected Agricultural Machinery to Processed Commodities

2025-06-30T13:01:13+00:00

Stainless steel, particularly grades such as AISI 304SS and 316SS, is extensively used in food processing due to its excellent corrosion resistance, durability, and ease of cleaning, which are essential for maintaining food safety and hygiene standards. However, the verification of food-grade materials has rarely been evaluated. This study investigates the potential transfer of metal residues from food-grade machines specifically a calamansi juice extractor, and coffee grinder to processed agricultural products such as calamansi juice, and coffee. An X-ray Fluorescence (XRF) analyzer was used to determine the metal composition of the processing equipment. Levels of iron (Atomic Absorption Spectrophotometry, AAS) and lead (Inductively Coupled Plasma-Optical Emission Spectroscopy, ICP-OES) in the processed products were determined. The results showed minimal presence of impurities. Levels of iron and lead in the final products remained below international safety standards, suggesting minimal contribution of processing equipment to metal residue content. By providing empirical data on the material composition of commonly used food-processing equipment, this research contributes to improving regulatory frameworks and guiding manufacturers in selecting appropriate materials. These findings support the development of safer, high-quality food-processing equipment, thereby enhancing food safety practices in the Philippine agricultural sector.

Development of a Spray Droplet Size Test Rig for Knapsack Sprayers

2025-06-30T07:19:34+00:00

The determination of spray droplet sizes is an essential aspect of selecting spraying equipment. It influences the efficacy and safety of spraying operations. This study focuses on developing a spray droplet size test rig for agricultural sprayers. The design focuses on emulating the method of test for spray droplet measurement as per the Philippine National Standards (PNS/BAFS 332:2022). The rig consists of a linear positioning system with a carriage, timing belts, spray barriers, and a water-sensitive paper platform. A stepper motor and Arduino-based software were used for the control system. The highest coefficient of variation recorded in all trials was 1.09%. The analysis for the spray droplet sizes showed a low coefficient of variation of 5.91%. All of the tests yielded the same droplet size classification of "VERY COARSE". This is the same classification in the official test report. This indicates that the developed test rig can precisely determine spray droplet sizes. It is recommended to test the rig further using other types of sprayers.

Assessing a VTOL UAV-Based Digital Imaging System for Agricultural Monitoring using Low-Cost Digital Camera

2025-06-30T13:02:16+00:00

A vertical take-off and landing unmanned aerial vehicle (VTOL-UAV) was used to assess the possibilities of a digital image-based for agricultural surveillance system. The VTOL-UAV system has advantages in terms of efficiency, adaptability, and capacity to collect data across a variety of terrains for agricultural yield estimation, crop health monitoring, and early pest identification. The developed VTOL-UAV was constructed based on Skywalker platform with wingspan and length of 1800 mm and 1300 mm, respectively. Agricultural images were collected under various field settings using a digital camera (Canon IXUS 185 at 20 MP and 8x zoom). The study took place in an agricultural field at the University Teuku Umar, Aceh, Indonesia. The technical performance, aerodynamic and stability of the VTOL-UAV system during the hover and cruise were examined. Flight plan parameters included speeds between 10 to 20 m/s, camera angle of 90 degrees vertically looking down, altitudes between 50 m to 200 m, and flight overlap between 60 to 70 % flyaway in accordance with the chart in the flight plan that was made. The findings showed that VTOL-UAV offer viability of using imagery captured by a VTOL-UAV equipped with a low-cost camera for agricultural land mapping. Operational flexibility was increased by the capacity to switch between vertical take-off and horizontal flight, particularly in areas with restricted access. The study revealed that the system has to maintain the altitude and reference ground system within the mission planning to ensure stable flight orientation, reduce vibrations and image distortions. The agricultural ortho-photograph and digital surface model are beneficial for accurate mapping, effective monitoring, and informed decision-making in agricultural applications, particularly for smallholder farm management.