Increasing degree of soil compaction affects the growth and yield of sweetpotato cultivars

kamote1Ariel B. Bolledo*, Sergio M. Abit, Beatriz C. Jadina, 2011 *(


Influence of soil physical factors like soil compaction has been known to affect root growth and tuberous root development of sweetpotato.  This physical factor is often left-out in the evaluation of newly released cultivars of sweetpotato.  A pot experiment was conducted to evaluate the growth and yield responses of sweetpotato cultivars to various levels of soil compaction and to determine the degree of soil compaction that would result in optimum growth of various sweetpotato cultivars.  A 4 x 3 factorial experiment with 4 sweetpotato varieties (PSB SP-16, PSB SP-17, PSB SP-25 and Ciete Flores) as factor A under 3 levels of compaction (1.1, 1.3 and 1.5 g cm-3 bulk density) as factor B was conducted.  Results showed that depth of tuberous root formation and number of marketable tuberous roots decreased with the increasing degree of soil compaction.  Other growth and yield parameters were not significantly affected by the treatments applied.  Interaction effect of sweetpotato cultivars and levels of soil bulk density was significant on depth of tuberous root formation and number of marketable tuberous roots.  Observation on the nature of formation, penetration, distribution and direction of tuberous root development showed that those at lower degree of compaction (1.1 g cm-3), tuberous roots were evenly distributed and were able to penetrate vertically and formed at deeper parts of the soil layer.   However, the tuberous roots in compacted soils (1.3 to 1.5 g cm-3) were formed at shallower depths andwere not able to penetrate deeply.

Keywords: Compaction, Bulk Density, Sweetpotato cultivars, Tuberous root formation,

Physical and chemical characteristics of soils from the landslide areas of Abuyog, Leyte

DSC09705Jorge P. Cabelin* and Beatriz C. Jadina, 2013 *(


The steep and unstable topography of Abuyog, Leyte and recent landslide occurrences in the area particularly in Canmarating and Tadoc justifies the need for soil characterization of the landslide areas of the place. This research was conducted to determine the physical and chemical properties of soils from the landslide areas in Abuyog,  Leyte and relate these to landslide occurrences.  Two landslide cuts from different sites were evaluated using representative soil profiles which were examined in the field and sampled for the analysis of physical properties including particle size distribution, bulk density, particle density, total soil wet density, porosity, field capacity and water holding capacity, hydraulic conductivity, Atterberg limit and some chemical properties including pH, organic matter content, cation exchange capacity, and exchangeable sodium content.

Soils from the two landslide areas in Abuyog, Leyte generally have clayey texture, low bulk density, high total soil wet density, average particle density, porosity, moderately high saturated hydraulic conductivity, high liquid limit, and plastic index with very strongly to moderately acidic pH, high organic matter in surface and low at subsurface layers, moderate CEC and exchangeable Na.

Keywords: landslide, physical, chemical, plastic limit, Atterberg limit

Effects of charred and uncharred poultry litter on organic waste decomposition

compostAriel B. Bolledo* and Pearl Aphrodite B. Carnice, 2012 *(


Composting is a sustainable way of returning nutrients back in the soil. A laboratory composting study using a soda bottle was conducted to determine the effect of uncharred and charred poultry litter on the decomposition of compost. Organic waste materials consist of Arachis pintoi, wood chips, paper strips, banana peelings and goat manure were placed in a soda bottle for composting with soil mixed with uncharred and charred poultry litter. There were three treatments (control or no poultry litter application, applied with poultry litter and charred poultry litter) replicated three times arranged in completely randomized design (CRD). Results showed that highest microbial respiration was attained in compost without poultry litter and with the highest percent of weight loss. This implies that, poultry litter component did affect the activity of microorganisms in the decomposition process. Organic wastes amended with charred poultry litter have the lowest microbial respiration and percent weight loss. Microbial respiration was not significantly affected with the use of charred poultry litter compared with the uncharred poultry litter.

Keywords: Composting, Organic Waste, Poultry litter

Coco char and Poultry litter char effects on Attenuation of Amoeba in a Saturated Sandy Soil

   amoebaAriel B. Bolledo*, 2012 *(



The use of biochar has been shown to affect the transport of pathogenic microorganisms. A transport experiment was conducted to determine the effect of biochar application in soil contaminated with amoeba in relation to its transport in sandy soil and to evaluate the effect of coco char and poultry litter char to the attenuation of amoeba.Poultry litter char and charred coconut shells were used as two different sources of biochar and were incorporated at 10 % (w/w) soil-biochar mixture in a polyvinyl chloride (PVC) column (15 cm height and 2.5 cm diameter). There were three treatments and three replicates. One treatment is applied with coco char and the other was with poultry litter char. Control treatment was with no biochar application. Two hundred fifty amoebas were used in the transport experiment and were leached for 15 minutes. Results showed that 30 % of the total amoeba was leached in the saturated column without biochar compared to the less 8-14 % of the total amoeba in the biochar amended columns. Coco char is more effective in attenuating amoeba with 6% advantage over the poultry litter char. Spatial distribution of amoeba in the soil column showed that the number of amoeba accumulated in shallower depths (2-6 cm) in biochar amended columns compared to columns without biochar. Amoeba in coco char amended column accumulated in 2-4 cm only compared to poultry litter char at 4-6 cm. It is shown that incorporation of biochar effectively attenuated the transport of amoeba in a saturated sandy soil. This is where coco char is superior to poultry litter char in terms of attenuation capacity.

keywords: attenuation, amoeba, sandy soil, coco char, poultry char

Nutrient status of selected degraded upland soils in Samar island

IMG_4925Leo Jude D. Villasica* and Victor B. Asio, 2013 *(


Due to the low productivity of degraded uplands, this study focused on the evaluation of the nutrient status of two degraded upland soils in Samar island namely, Brgy. Tulay, Sta. Rita, Western Samar and Brgy. Naparaan, Salcedo Eastern Samar. Soil monitoring plots were established in the farmer’s field planted to various crops. The soil nutrient status was evaluated by periodic sampling and analysis of the soil pH, OM, total N, available P, exchangeable bases, readily mineralizable C and N, plant nutrient concentration and microbial activity by soil respiration.

Results revealed that the nutrient status of the degraded uplands in Sta. Rita and Salcedo are low. In general, the low nutrient status is more severe in the Salcedo site than in the Sta. Rita site which is related to the more weathered nature of the former than the latter. Moreover, both sites have strongly acidic soil which is low in OM, total N, available P, and exchangeable bases contents. The low nutrient status of the soil is reflected by the low leaf concentration of the nutrients (N, P, K, Ca). Also, the low nutrient status is observable from the low respiration rate and low levels of readily mineralizable C and N. Considerable variations in nutrient status is observable under different vegetation covers.

Keywords: nutrient status, degraded uplands, vegetation cover, Samar Island