Tambang batubara di Indonesia umumnya melakukan kegiatannya dengan teknik penambangan terbuka. Permasalahan utama yang timbul di wilayah bekas tambang batubara adalah perubahan lingkungan yang berdampak pada perubahan fisik, kimiawi, dan biologi tanah serta menurunnya produktivitas tanah akibat lahan menjadi tanah tandus atau gundul. Tujuan penelitian adalah untuk mengetahui tanaman yang sesuai pada lahan pasca tambang batubara yang diberi pupuk organik dan kapur. Penelitian ini dilakukan selama bulan Januari sampai dengan September 2019 bertempat di persemaian Politeknik Pertanian Negeri Samarinda dengan sampel tanah berasal dari lokasi bekas tambang batubara Desa Berambai Kecamatan Samarinda Utara. Penelitian menggunakan Rancangan Acak Lengkap (RAL) 2 faktor dengan 15 ulangan. Faktor pertama yaitu: JP (Jarak pagar), JM (Jambu mete), dan LG (Lamtoro gung). sedangkan faktor kedua yaitu: Po (Tanah bekas tambang batu bara), P1 (Tanah bekas tambang batu bara yang diberi kapur dolomit sebanyak 3,8 g/polybag), P2 (Tanah bekas tambang batu bara yang diberi pupuk organik sebanyak 150 g/polybag), dan P3 (Tanah bekas tambang batu bara yang diberi kapur sebanyak 3,8 g/polybag dan pupuk organik sebanyak 150 g/polybag). Hasil penelitian menunjukkan bahwa tanah bekas tambang batubara dapat diperbaiki kesuburannya dengan memberikan kapur dan pupuk organik serta perlakuan media tanam P3 memberikan pengaruh nyata terhadap tinggi tanaman lamtoro gung.

The process of palm oil bunches in the factory produces abundant wastes, both solid and liquid wastes, whereas the processing of 1 ton palm oil bunches will produce 21-23% empty bunches and 0.4-0.7 tons liquid wastes. However, it is the biggest problem that must be faced by the palm oil industries and it creates environmental pollution due to it contains pollutant, and some solutions are required to overcome these problems. Composting technique is the right solution for the problems by turning the wastes into organic fertilizer (compost). Naturally, it takes longer time for the organic wastes to decompose into organic fertilizer so that an activator is required to accelerate the decomposition by adding MOL or local microorganism, which is made from the wastes of shrimp heads, fish bones, and banana humps, and according to the preliminary research, they are very effective to accelerate the composting and fermenting process. Objectives of the research were: 1) analyzing physical properties of the compost (color, odor, shape, texture, temperature, and the day when the compost is ready to be used), 2) analyzing the nutrient content of the compost based on the treatments that include C/N Ratio, phosphor, nitrogen, calcium, potassium, sulfur, magnesium, and pH, 3) finding out quality of the compost resulted from the research by comparing it with the compost standard based on the standard of SNI 19-7030-2004, and 4) measuring the best vegetative growth of chili after being treated. Results of the research showed that 1) the compost is well-done at the 37th day as marked by the physical properties, for instance, loose texture, crushed-shape, brownish black, odorless, and the temperature is stable close to room temperature, 2) Compared to standard of SNI 19-7030-2004, the resulted compost has met the standard for pH H2O, N, P, and K, but it has not met the standard for C Organic and C/N ratio, 3) The growth of chili, the plant height and leaf width, did not show significant difference by the treatment of P0, P1, P2, and P3, but it showed significant difference on number of leaves, leaf length, and diameter. However, P3 is the best treatment based on average value of the increase plant height of 11.40 cm, number of leaves is about 10.75, leaf width of 2.35 cm, leaf length of 0.50 cm, and stem diameter of 3.99 mm.

This study is motivated by how the work environment influences the performance of harvest employees with the limitation of problems in work environment activities that will affect the performance of harvest employees on oil palm plantations at PT. Dewata Sawit Nusantara. It should be understood that the expected performance of an employee is not easy because it is influenced by various compensation factors, motivation, work environment and many other factors. This study aims to determine whether the work environment influences the performance of harvest employees at PT. Dewata Sawit Nusantara. The data analysis method used was a simple linear regression statistical analysis and uses a hypothesis test to analyze the closeness of the relationship of individual variables, while testing the instrument using a validity and reliability test. Statistical test results showed that the relationship between work environment and employee performance was positive (unidirectional). Based on the results of hypothesis testing obtained a significant value of 5% then H1 was accepted or Ho was rejected. This means that the work environment influenced the performance of harvest employees at PT. Dewata Sawit Nusantara.

This research is motivated by the failure of tomato harvest one of which is a pest attack for that program will be carried out to identify pest attacks so that crop failure can be avoided. This expert system will be implemented with the certainty factor method can provide accurate results obtained from calculations based on the weight of the symptoms chosen by the user, able to provide answers to problems that are not certain of truth such as problems diagnosing disease risk, and with this method, the expert illustrates the confidence of an expert with giving the weight of confidence in accordance with relevant expert knowledge. so that researchers increasingly believe that this expert system will be easily accessible and used by the community. From the explanation above for that, the writer makes a system, namely expert system for diagnosing oil palm plant diseases using the certainty factor method which is intended to assist the work of farmers in providing information and conclusions from pests suffered on oil palm plants.