[RELATIONSHIP OF SLOPE STEEPNESS TO SOIL WATER CONTENT, SOIL PH, AND PERFORMANCES OF GERGA ORANGE AT LEBONG REGENCY]. In Lebong Regency, gerga orange is commonly grown in hilly areas and many of the crop stands were found on steep sloped land. Objective of this study was to determine the pattern of relationship of slope steepness to soil water content, soil pH, and the overall plant performances. Soil samples were collected from the area below the canopy of 300 gerga orange trees differing in the slope steepness for for soil water content (SWC) and soil pH.  The observation of plant performances were also made from the same tree as used for the soil properties observations. The analysis of regression indicated that relationship of slope steepness to both the observed soil properties and plant performances could be represented by the linear models suggesting that all the observed variables were reduced along with the increasing slope steepness.

To enable conservation of degraded land requires Map of Conservation Activity Plan (CAP). The map is established based on a model developed by the then Ministry of Environment and Forestry. One step to analyze the CAP is land unit elimination (LUE) having area of < 1 cm2. This study aimed to determine the effect of LUE on the CAP at Air Bengkulu Watershed. Maps used for input to CAP are EHL (Erosion Hazard Level), Soil Depth, Slope, Population Pressure, and the Recommended Landuse, whereas to calculate EHL requires R, K, LS, C, and P Factors. CAP Map as a result without involving LUE is compared to the CAP Map with involving LUE. The research result showed that the LUE influences on the change of the recommended of the CAP up to 77.6% of the total area of the study, either in engineering recommended or in vegetatively recommended conservation, while the rest (22.4%) were unchanged.

Precise water use systems under sustainable agriculture may only be achieved if in-situ soil water content and availability of the plant can be measured quickly. Soil water content can be determined directly using the gravimetrical method by calculating the loss of water when the soil dries out, and indirectly by measuring other variables from which soil water can be calculated. The indirect methods have some advantages when compared to the direct gravimetrical method because measured; non-destructive soil water data are available instantly. Soil dielectric properties have strong relationships with soil water content and have been used widely as indirect methods of soil water determination, but the cost of the available instrument is too expensive for small-scale farmers. Two studies were conducted in 2011 and 2015 to develop a quick, cheap method to determine in-situ soil water content and precise water use by crops. The method applied a non-linear relation between soil water content (θ, in gg -1 ) and soil electrical impedance (Z, in kΩ) as follows: θ = a.Z b where a and b are constants. Parameter Z showed a good predictor for soil water content (R ≥ ≥ ≥ ≥ 0.90) therefore can be used to determine soil water content in the field quickly. The dielectric method has been successfully used to determine the water balance in the vegetated soils, in wich changes in soil water content caused by daily rainfall as low as 10 mm was detected up to the depth of 60 cm. The method was also successfully capable of calculating the amount of water used by palm oil nursery grown in media with different levels of soil organic matter.

Taro (Colocasia esculenta L. Schott) is a plant that has an excellent economic and healthy value, as well as a great potential development of Bengkulu coastal area. That is because taro has wide adaptability, and can be consumed both as a staple food and healthy food alternative. This research was conducted to study the vegetative growth of two cultivars of taro given four different doses of nitrogen. This study applied a Randomized Complete Block Design (RCBD) with two factors. The first factor was the cultivar of taro consisted of two levels, namely Taro Satoimo (T1) and the Taro Local (T2). The second factor was the doses of nitrogen fertilizer which consisted of four levels namely: N0 = 0 kg / ha (control), N1 = 50 kg / ha (2.6 g, N2 = 100 kg / ha, and N3 = 150 kg / ha. Thus, obtained eight treatment combinations. Each treatment was repeated three times to get 24 plots. The results showed that based on increased vegetative growth, the cultivar Satoimo has a faster response than local cultivar. Satoimo has demonstrated another advantage because it produced some leaves and number new shoot. The best dose of nitrogen fertilizer on the vegetative growth of taro in the coastal area of Bengkulu is 150 kg/ha.

[GROWTH AND LETTUCE YIELD (Lactuca sativa L.) BY GIVING MANURE AND RICE HUSK ASH IN INCEPTISOL].  Increasing market demand for lettuce (Lactuca sativa L.) makes the prospect of developing lettuce very promising. Bengkulu Province is dominated by inceptisol soil types which have low soil fertility, making it less optimal for lettuce growth. Giving organic matter can increase soil fertility through improving soil physical, chemical and biological properties so that it can support the growth of lettuce. This study aims to determine the dosage of manure, the dose of rice husk ash and the optimal dose interaction for lettuce growth and yield. This research was conducted from May 2018 to July 2018 in Medan Baru, Muara Bangkahulu Subdistrict, Bengkulu City. The research design used was a Completely Randomized Design (CRD) consisting of two factors and repeated 3 times. The first factor is the dosage of cow manure with three levels, namely: 0 tons/ha, 15 tons/ha, and 30 tons/ha. The second factor is the dose of rice husk ash which consists of three levels, namely 0 tons/ha, 3 tons/ha, and 6 tons/ha. Data from the observations were analyzed statistically by Analysis of Variance (ANOVA) using the F test at the level of 5%. To determine the dosage of manure, the dose of rice husk ash and the optimal combination of doses for growth and yield of lettuce used the Polynomial Orthogonal method. The results showed that there was no interaction between cow manure and rice husk ash on the growth and yield of lettuce. The effect of cow manure has not shown the optimum dose for growth and yield of lettuce. The addition of manure doses up to 30 tons/ha was able to increase the value of plant height, number of leaves, leaf area, and fresh weighted plant weight of 0.189, 0.038, 0.931 and 0.104 respectively. Giving rice husk ash up to a dose of 6 tons/ha did not have a significant effect on all observed variables.