Background : Location and Extent
The City of Tagum is the capital of the province of Davao del Norte, it is geographically located between 7°13' 38" and 7° 32' 23" north latitude and 125° 43' 30" to 125° 53' 13" east longitude. It is bounded in the north by the Municipality of New Corella, in the northwest by the Municipality of Asuncion and in the northeast by the Municipality of Mawab. In the west, the Tagum-Liboganon river fringing the Municipalities of Dujali and Carmen, in the east by the Hijo River and beyond the Municipality of Maco and in the south the Davao Gulf from the natural boundary of the city where two major rivers, Tagum-Liboganon and Hijo, and other minor rivers and each tributaries drained toward Davao Gulf.
The city is strategically located at the intersection of three major road systems namely : The Philippine-Japan Friendship Highway which leads to Davao City (Davao del Sur) in the south and the Provinces of Compostela and Agusan in the north, the Davao-Mati (Davao Oriental) road and the Tagum - Kapalong road which is proposed to connect to Bukidnon in the northwest. The city is about 54 kilometers north of Davao City, 111 kilometers west of Mati, Davao Oriental and 210 kilometers south of Butuan City. This makes Tagum City as the convergence areas for developments, and processing centers of agricultural raw materials into finished products at present to the near future.
The city is composed of 23 baranggays, 9 of which are urban and 14 are rural. The total land area of 19,580 hectares (Soil and Land Resource Evaluation Survey and Statistics) Accessibility is good from the Poblacion to various Barangays of the City. Massive construction of farm-to-market road makes rural barangays accessible and the transfer of goods and agricultural products becomes convenient to the farmers to transport their product to the city proper. The means of transportation is public utility bus and jeeps to any point of destination and vice-versa while trimobiles and multi-cabs is the means of transport within the city proper.
Based on the seasonal rainfall distribution (TRRC-DOST Agromet Station of PAGASA, Twin rivers Research Center) the City of Tagum falls under the fourth type of climate in the Philippines based on Corona system of classification. Climate of the Philippines is classified as follows;
|Two pronounced seasons with maximum rain period from June to September and a dry season which lasts from three to six or seven months.
|No dry season with a very pronounced maximum rain period from December to February.
|No pronounced maximum rain period with a short dry season lasting only from one to three months.
|Rainfall more or less evenly distributed throughout the year.
The city has an average annual rainfall of 2,034.58 mm. or 169.60 mm. As monthly average, (Table 3a ). In general, a month is regarded as wet when precipitation is more than 100 mm. And moist when precipitation ranged from 60 to 100 mm (Mohr, 1933) Moist period is considered ideal for most crops, that is the reason why Tagum City is a highly recommended suitable area for agricultural production. Based on 15 year data of mean monthly rainfall, July has the lowest precipitation of 127.66 mm., while January has the highest precipitation of 204.3 mm. High precipitation which starts from November to January causes high discharge of the Tagum-Liboganon river.
Tagum City is typhoon free, high precipitation in most part of the year is probably influenced by different rainfall causing weather patterns such as northeast and southwest monsoons, intertropical convergence zone, tropical cyclones and to a lesser extent by fronts, easterly waves and local convection.
During the months of December and January a particular type of air mass known as the north east monsoon reaches Mindanao from the northeast and east direction, bringing rain to the area. The rain gradually weakens in the late February until the end of April being the transition period between the northeast monsoon and the north Pacific trade winds.
By the end of April a gradually increasing rainfall intensifies in the area can be observed as affected by north Pacific trade air stress or an easterly wave oriented north to south from the east. The movement of the easterly waves, casually combined with the northeast and east flow of the prevailing trade wind system, causes the significant increase of rainfall as the longitude increases to the east. The month of May is another transition period between the trade wind season and the southwest monsoon season prevalent during the months of July to September.
Number of Rainy Days
Based on 20 year record as shown in table 3, Tagum City averages about 11.42 rainy days in a month. PAGASA defines a rainy day as the period of 24 hours beginning from 8:00 am up to 8:00 am of the next day during which 0.1 mm of rain is recorded. The number of rainy days is somewhat correlated with the average monthly rainfall. Comparing Table 3 with Table 3a shows that January produces 15 rainy days correlating with maximum rainfall being recorded in that month which is a mean of about 204.3 mm while April gives 8 rainy days also correlating with the lowest precipitation recorded which is a mean of about 132.1 mm.
Temperature has a role in photosynthesis and respiration of plants as well as in dry and fresh production of crops. In general, the highest temperatures are observed in valleys and plains while the lowest temperature occurs in higher elevation. PAGASA defines the maximum temperature in degrees Centigrade (°C) for the day usually occurring in the early afternoon, while the minimum temperature in degrees Centigrade (°C) recorded for the day usually occurring during the early hours of the morning before sunrise. The sum of the ratio between the maximum and minimum temperature is the average temperature.
Temperature has an inverse relationship with rainfall and relative humidity. It also varies with elevation. Temperature data of Tagum City shows some variations. Table 3b shows that mean monthly maximum temperature ranges from 31.80°C to 33.94°C and the mean monthly minimum temperature (Table 3c) ranges from 21.66°C to 22.65°C. While the mean monthly average temperature ranges from 27°C to 28.10°C (Table 3d). The analysis of the data is based from the fifteen years record. The monthly average shows that the cool months occur between December to February while warm months occur between April to June (Figure 5B).
Relative humidity is defined as the amount of water vapor in the air. It is inversely related to temperature. If the temperature is high, humidity is low, meaning the air in the atmosphere is dry. If the temperature is low, humidity is high, meaning the air is moist. High temperature and low relative humidity condition may cause the plant to wilt. High relative humidity causes the formation of fog, and when it combines with the low temperature, these favor the reproduction of fungal diseases. Figure 5c shows the mean of the monthly relative humidity in Tagum City.
Results of data analysis indicates that the highest relative humidity is experienced in the month of June with 80.69% and the lowest is April with 75.53%
Presented in Table 3 as OKTAS, cloudiness is measured in tenths of the total sky coverage, that is, from 0 to 10 OKTAS. This means that 0 OKTA refers to a clear sky, 02 partly cloudy sky, 04 partly cloudy to cloudy skies, 06 cloudy skies and 08-10 overcast.
Cloudiness is also one of the factors that may affect the growth of crops. Long duration of cloud cover on daytime lessens the exposure of crops to sunlight which is necessary for photosynthetic activity. In high elevated areas areas, long duration of cloud covers is usually observed, while low land areas have usually less duration of cloud cover.
From Table 3, we can see that during northeast monsoon in January to February and during southwest monsoon in June to July, we have cloudy skies of 5 OKTAS in Tagum City. The months of April and May indicate low cloudiness of 3 OKTAS while the rest of the months indicate partly cloudy skies measuring about 4 OKTAS. The variations on the data is relatively minimal.
Wind speed is significantly important in the selection of crops and specific variety to plant. Gentle wind of about 7 meters per second (MPS) is said to be beneficial to raise crops and the supply of carbon dioxide is immediately replenished. It favors photosynthetic activity and water utilization of crops. The circulation of dry and moist air to plant leaves creates vapor pressure difference resulting in an increased transpiration.
On the other hand, high wind velocity affects plant growth physically and physiologically. It may induce breaking of stalks, branches, and damage of leaves or grain and fruits on general. Hence, it lower productivity. High winds during pollination period induces sterility. Furthermore, continued strong wind reduces the photosynthesis process and enhances the spread of pest and diseases.
Date gathered from PAGASA (Table 3) shows that December has 2 MPS wind speed and the rest of the months has an average of about 1 MPS. The data gives favorable values of wind speed which does not exceed the range of 10 MPS and over for all months of the year. On the basis of prevailing wind velocity, Tagum City is favorable to any type of annual and perennial crop production.
Evaporation measurements are done by recording the evaporation from the open and sunken evaporation pans. Monthly results of the open evaporation are shown in Table 3. It ranges from 6.37 to 8.84 millimeters. From this figure, the annual total of 90.34 and monthly average of 7.53 millimeters were computed. These data are essential for the computation of evapo-transpiration figures are essential for the design of appropriate cropping calendar and for the estimation of water balance of the different crops being grown and proposed to be grown and proposed to be grown in the area.
The most important characteristics of sunshine duration which affects plant vegetative and reproductive stage is its duration and measured in sunshine hours. Solar energy provides two essential elements for plant growth: the light required for photosynthesis and for many other functions of plant such as seed germination. Optimal thermal condition is required for normal physiological function.
The data are presented in Table 3. The length of sunshine hours when compared to the non-sunshine hours is referred to as photo-periodicity. Photo-periodism is very important with regards to the growing of crops, we refer to the relative length of daylight compared with the dark period. Some plants require a short duration of day light (and long duration of dark) while others need relatively long exposure to light and consequently, short exposure to dark periods. These plants that respond to photo-periodism are called short day and long day plants, respectively.
The most important crops of the city such as banana, coconut, rice, corn and other diversified crops are also photo-period insensitive and just require an optimum exposure to sunlight to attain full growth and production. Considering the crops being grown in Tagum City, it is concluded that photo-periodism will not be a limiting factor in the project area.
The City of Tagum is endowed with abundant water resources. The uniform distribution of rainfall and the presence of many rivers, perennial and ephemeral streams and creeks coming from the hillsides and mountain slopes of its neighboring municipalities which normally passes Tagum City assure the city of adequate water supply. The ground water reserve is abundant to meet the demand for irrigation water for agricultural uses, domestic uses, and other and industrial uses in the future. However, the need for water conservation is necessary in order to meet the increasing demand for potable water considering Tagum is an urbanizing, industrializing and growing city.
Tagum City is new and growing city, It has a considerable population density, the development of the industry is gradually growing. The surface and ground water pollution is primarily dependent on the natural factors. The pH value of water samples in the City of Tagum which has excerpted from previous study shows more on neutral to mildly alkaline (pH 7.3 - 7.7) in the coastal plain or estuarine plain. Based from the results of the laboratory analysis of water samples taken from rivers, wells and springs, Table 4, shows that the chemical elements present in the water can be rated as acceptable for irrigation and domestic use with exceptions for some wells observed from the coastal Barangays of Busaon, Liboganon, Madaum, Bincungan and San Isidro. These exceptions were observed to have high total soluble salts and unsuitable chloride ions rendering the analyzed water samples as not suitable for irrigation and for domestic use.