Sub-bituminous coal [SC] activation with dolomite is the future technology in utilizing coal as an alternative organic material [Humic Substance]. This study aims to study the effect of SC activated with dolomite in improving the chemical properties of Ultisols and palm oil growth at the main-nursery stage [Elaeis guineensis Jacq.] In Dharmasraya. The experimental design was in Randomized Completely Block Design with three replications consisting of 6 treatments : A = 150g SC planting hole−1; B = 300g SC planting hole−1; C = 450g SC planting hole−1; D = 150g SC + 10% [15g] dolomite planting hole−1; E = 300g + 10% [30g] dolomite planting hole−1 and F = 450g SC + 10% [45g] dolomite planting hole−1. The results showed that the effect of activation on SC differs from those treatments without activation with dolomite. Effect of 450g SC activated with dolomite planting hole−1 is significant on the chemical properties of Ultisols, such as increasing in pH, available P, organic C, total N, CEC [Cation exchange capacity], and K, Ca, Exch-Mg, by 0.44 units, 1.33 ppm P, 0.44% C, 0.04% N, 0.25, 0.27, and 0.29 cmolckg−1, compared to 450g SC without activator and an increase in palm oil growth on height [12.33cm], stem diameter [0.84cm] and N, P, and K nutrient concentration from leaf of plant [0.014% N, 0.004% P, 0.002% K], compared to 450g SC without activator.

A research was carried out at glass house and at Soil Laboratory of Faculty of Agriculture, Andalas University Padang. The experiment was aimed to determine the interaction between humic material from compost and P fertilizer on some chemical properties of Oxisol, nutrient uptake and corn production. This experiment consisted of 2 factors (4 x 4) with three replications which were allocated in completely randomized design (CRD). The first factor was humic material having 4 doses (0, 400, 800, and 1200 ppm) and the 2nd factor was P fertilizer having 4 doses (100%, 75%, 50%, and 25% of recomendation (R)). The result showed that there was : 1) Interaction between humic materials and P fertilizer for the quality the corn seeds. Application of 800 ppm humic material improved the quality of the seeds even though at low level of P fertilizer. 2) Then, it also increased availability of P by 23.03 ppm, N total by 0.09 %, and decreased Al-exch by 0.53 me (100 g) -1 and Fe-exch by 25.62 ppm compared to threatment without application of humic material. Likewise, nutrients (N and P) uptake by plant also increased by 0.28 and 0.03 %, respectively. 3) Application of P fertilizer at 75 % R increased soil P availability by 3.77 ppm, N and P content of plant by 0.43 % and 0.06 %, and seed weight by 13.20 g and decreased Fe-exch by 21.16 ppm, compared to 25 % R of P fertilizer.

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Last researchers reported that Tithonia diversifolia (Mexican sunflower) could replace 25% to 50% of N and K of commercial fertilizer applied in chili production on the first and second planting time in the Ultisols of West Sumatra. A Continuation field experiments was conducted to find out the the appropriate NK cobination sources should be added on the third season to get the higest yield of maize. The treatments were the combination of NK T. diversifolia + NK commercial fertilizer which is maize needed. There were 9 treatmens such as A(0%+0%); B(0%+0%); C(50%+25%); D (50%+25%); E(25%+75%); F(25%+75%); G(50%%+50%); H(50%%+50%); and Control (0+100%). The results showed that integrated use 50% NK from tithonia with 25% NK from commercial fertilizer is the appropriate NK combination to get the higest yield (5ton ha -1 )of maize on the third season in Ultisols, if on the first season for chili planting time have reseived as 50% + 50% and on the second season for chili planting as much 25%+75% NK from titonia and NK from commercial fertilizer.

A research aiming to evaluate external factors affecting fertility process on manggo trees had been conducted in Lima Puluh Kota Regency, as one of production central for manggos in West Sumatra.  In the first year, the activity of the research was aimed to identification on earlier and later flowering plants.  External factors being identified were soil nutrients and soil chemical characteristics, as well as temperature and relative humidity around canopies of the trees.  The results showed that there was an interaction among the external factors  on the characteristics of both groups of the manggo trees.  Earlier flowering plants had higher  temperature around the canopies, but lower relative humidity than those later flowering plants.  Some other external factors such as light intensity as well as the duration of day and night period will be identified on the following research.Key Words: Manggos tree, canopy temperature and humidity, earlier flowering plants, later flowering plants