Comparison of Soil Quality in Mono-culture Forest (Pinus caribaea), Natural Forest and Analog Forest Ecosystems: A Study in Mirahawaththa Sri Lanka

Soil quality is a reflection of the ability of a soil body to perform functions which are essential to people and the environment. Soil quality definitions emphasise several features, chemical, physical and biological. However, the concept of soil quality is based on the premise that any of these features can be used to evaluate the degradation or improvement of soil ecosystem functions. Some soil quality concepts (soil structure, organic matter content (OM) and microbial as well as microbial activity) are commonly used to evaluate sustainable land management in agroecosystems. This study examined the soil quality of the three different ecosystems (Analog forest (AF), Natural forest (NF), and Monoculture forest (MF)). The study was undertaken in Belipola, Mirahawaththa, Welimada. Six soil samples were collected for each soil test (The samples were collected in zig-zag across the site). Apparent density, soil pH, soil organic matter (Walkley and Black Method), and microbial diversity (Dilution method) was evaluated. Six plots (unit area 1 m2) of each ecosystem was measured to detect the Earthworm presence indicators and observed the earthworm casts and counting. The result by apparent density in NF show the lowest value (1.09) and the highest value (1.34) in MF. The AF apparent density value was 1.22. soil pH resulted in AF-6.5, NF-6.2, and MF-5.9. Also, the result of Organic matter content in NF-3.9%, AF-3.1, and MF-1.2 was detected. Analysis of soil microbial diversity of three ecosystems was shown AF (range 137 to 296), NF (range 130 to 335), and MF (range 12 to 21) numbers of colonies in Petri dishes. Numbers of earthworm casts per square meters in AF (range 5 to 13), MF (0), and NF (range 10 to 15) were recorded. In conclusion, the soil quality of AF most close to the NF ecosystem compares with the MF system. We have revealed that there is a large potential to restore the soil into becoming more analogous to the natural forest to enhance the soil quality through AF technology.Keywords: Analog forest, Microbial diversity, Monoculture forest, Natural fores

Time Course Variation of Some Latex Physiological Parameters Associated with Yield of Rubber (Hevea brasiliensis) Grown in Eastern Province of Sri Lanka

Rubber cultivation in Eastern Province, is predominantly in the intermediate zone of whichclimatic conditions are considered to be sub-optimal for growing rubber. Due to low level ofatmospheric RH%, latex flow tends to cease early after tapping in these areas. Turgidity oflatex vessels associated with the water content of latex vessels decreases with the sunrisewhen evapotranspiration increases. Hence, time of commencing tapping greatly influences onthe latex yield. Therefore, the present study was aimed to identify the best time of the day forlatex harvesting through an assessment on latex physiological parameters. In order to identify the best time for tapping, variations in several physiological parameterstogether with latex yield were assessed at different time intervals, i.e., 04:00, 05:00, 06:00,07:00 and 08:00 in two smallholder sites in the eastern Province. Latex volume, dry rubbercontent (DRC%), initial flow rate (IFR) and plugging index (PI) were analysed along with theenvironmental factors at the time of tapping. Latex volume per day (LVPD) was highly associated with the overall latex yield hence hadbecome the prime factor concerned. The highest LVPD was recorded between 05:00 to 06:00hrs. Dry rubber content of latex had increased after 06:00 h and that could be attributed to thewater status of the trees which was governed by evapotranspiration. During 05:00-06:00 hrstime period, RH% was almost 100% and temperature was around 23° C. When tappingcommenced after 06:00 h, the overall yield declined. There was a tendency of increasing theplugging index (PI) with the delay of tapping. Therefore, the study concluded that high yieldscould be obtained in this agro-ecological region if tapping is performed before 06:00 h. Keywords: Hevea, Intermediate zone, Rubber, Sub-optimal climatic conditions, Tapping tim

Soil structural quality and soil organic matter Can the level of soil organic matter be taken as an indicator in assessing soil structural quality?

SIGLEAvailable from British Library Document Supply Centre- DSC:DXN063890 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Deterioration of soil quality with continuous plantation of teak (Tectona grandis)

A study was carried out at Rathmale teak Plantation, Thalawa to investigate the cause for the poor growth of teak saplings in a selected area. The study hypothesized that the poor growth and development of second rotation teak is a result of poor physical and chemical properties of the soil that gradually developed after the conversion of natural forest to plantation. Three sites, poorly grown teak plants, normally grown teak plants, natural forest land were selected. Soil samples from top and sub layer were analysed for pH, Electrical conductivity (EC), Nitrogen, Phosphorus, Potassium, CEC, Soil organic matter (SOM), Texture and Bulk density (BD). Bulk density, SOM and EC were Session I – Forest and Natural Resource Management Significantly different between site one and site two. Higher BD, lower SOM and EC are key components of the soil quality and the changes may have led to the poor growth of Teak in site one. It was therefore clearly evident that the change in soil quality as a result of the conversion of natural forest to teak plantation is linked with the poor growth of teak saplings in the area under investigation

Investigation of Solubility of Eppawala Rock Phosphate Using Jeevamrutham

Phosphorus is one of the most essential nutrients for plant growth. It is usually supplied by phosphorus fertiliser. Rock Phosphate (RP) is the main source to produce phosphorus fertiliser. Sri Lanka has a good quality Apatite mineral deposit at Eppawala, which can be utilised as a source for phosphorus fertiliser after increasing its capacity for water solubility. Hazardous acids are commonly used in order to produce more soluble forms of phosphate fertiliser. However; it is not an economically feasible and environmentally friendly method in a country like Sri Lanka. Hence, use of biological process, as using microbes to increase the water solubility of RP is recommended. Jeevamrutham is an Indian traditional organic fertiliser that contains a mixture of microorganisms. This study investigates the suitability of Jeevamrutham which contains natural inoculums to increase the solubility of Eppawala RP. Five undisturbed forests (Sinharaja and Badagamuwa conservation forests, Nonperial Pine, Girandurukotte Teak, and Diyathalawa Turpentine plantations) were selected in order to obtain the soil samples (n=30) using simple random sampling as bio inoculums to prepare Jeevamrutham. Available phosphorus content of selected soil samples with (5 replicates of each) were determined using the Vandomolybdate method. Five different Jeevamrutham were prepared using the selected soil conditions. High-grade Eppawala rock phosphate (HERP) were treated by prepared Jeevamrutham. Available phosphorus content of each of the samples were determined using the Vandomolybdate method within 2 months in 7 days intervals. Randomised complete block design was used as an experimental design and data was analysed by using Two-way ANOVA and Turkey pairwise comparison tests. The results revealed that the all selected soil samples, which act as bio inoculum were contained higher available phosphorus than 1 ppm. Available phosphorus percentage was increased until 6 weeks for alltreatments and then it had reduced gradually. Highest available phosphorus percentage was recorded in Pinus soil+Jeevamrutham treated HERP with 0.83% by mass after 6 weeks of treating. Teak soil+Jeevamrutham treated HERP showed high phosphorus percentage over a long period of time due to nature of the contained microorganisms. Thus, bio inoculum which grows in the Jeevamrutham supports to increase the water solubility of phosphorus in HERP.Keywords: Available phosphorus, Jeevamrutham, HERP, Microorganism