Fitra Syawal Harahap’s research while affiliated with University of Science and Technology, Jayapura and other places

Rubber plants (Hevea brasiliensis) will experience a decrease in production as plants age and the nutrient content in the soil decreases. This study aims to find out the chemical properties of soil on plantations of rubber crops that are converted into palm and coconut crops. The research was conducted from Februari 2023 to Agustus 2024 at the palm coconut plantation of PTPN III Aek Nabara North Garden in Labuhanbatu district and analyzed in the Land Laboratory of the Faculty of Agriculture of the University of Northern Sumatra. The methods used are observation methods, field sampling, and analysis in the laboratory to obtain quantitative data. Observation parameters include soil pH, C-organic, Total Nitrogen, Available P, Cation Interchange Capacity, and Base Fulness. The results of the survey showed that the level of soil fertility at the site of the research was included in the low category. The main limiting factor that causes the low fertility of the soil is the low content of organic material in the soil. In order to improve the fertility status of the ground at the research site for further planting, it is necessary to make efforts such as irrigation and fertilization, as well as the addition of organic materials, to make the availability of nutrients for plants more affordable. Keywords: replanting area, rubber plants, conversion, soil fertility, quantitative data

The Bilah Sub-Watershed area includes areas that have somewhat critical or semi-critical land so that land use is the result of human efforts in managing the available resources to meet their various needs. This often results in land use not being in accordance with its capabilities. This research aims to examine the chemical properties of several vegetation in Negeri Lama Seberang Village, Bilah Hilir District, Labuhanbatu Regency. The research was carried out from December to March 2024 using a survey method. Soil samples were taken at 3 points for each vegetation and different slopes at depths of 1-10 cm and 10-20 cm using a simple random method. The soil parameters measured were soil acidity (electrometry), soil organic carbon content (Walkley and Black), and soil texture (bouyoucos hydrometer). Soil analysis was carried out at the Laboratory of the Faculty of Agriculture, University of North Sumatra. The results of this research show that on a slope of 0-8% the average soil pH value is 4.61% and organic C is 1.04%, while on a slope of 8-15% the average soil pH value is 4.46% and C -organic 0.91%. On a slope of 0-8% the average value of the clay fraction is 20.27%, the dust fraction is 15.02% and the sand fraction is 64.41%, while on a slope of 8-15% the average value of the clay fraction is 27.48%, the dust fraction 19.87%, and sand fraction 52.63%.

The purpose of this research is to survey and mapping nutrient status of total phosphate, available phosphate, soil pH and organic carbon at paddy fields Meijan Village Balige District Toba Regency and its influence on rice production. Soil samples was analyzed at the Analytical Laboratory of PT Socfindo Indonesia North Sumatera Province. Which began in October to December 2023 The method used is Free Grid Survey semidetailed level survey and analysis of nutrient data total phospate by Acid destruction method (HClO4), available phosphate by Bray II method, soil pH by H2O extraction and organic carbon by walkley & black method and then interpret to the map nutrient status. The result of research showing that status total phosphate classified by 3 status such as, medium (81,59 ha), high (81,15 ha) and very high (27,26 ha). Available phosphate classified in 3 nutrient status such as very low (39,11 ha), low (137,40 ha) and medium (13,49 ha). Soil pH classified in 2 status such as moderately acidic (30,16 ha) and strongly acidic (159,84 ha). Organic carbon classified by 3 nutrient status such as very low (3,06 ha), low (135,84 ha) and medium (51,10 ha). Available phosphate and organik carbon affect rice production in Meijan Village Balige District Toba Regency.

Evaluation of nutrient availability needs to be carried out to determine the ability of the soil to provide nutrients for plant growth, in this case the evaluation of the nutrient content of paddy fields in three locations in the Balige area, namely Huta Namora, Huta Bulu Mejan and Baruara. This is needed as information for the management of paddy fields on the provision of fertilizers in the future, both inorganic fertilizers and organic fertilizers. The purpose of this study was to evaluate the availability of soil nutrients such as organic C, total P, available P and soil pH after rice harvest. This research is a descriptive study by comparing data from the three research locations. In its implementation, 9 sample points of observation were chosen representing the location of each area. Every 3 sample points were mixed into one point of soil samples from the three research locations showing relatively the same results so that in one location there were 3 points of soil samples which were considered as replication 1, 2 and 3 replications. Thus, there were 9 soil samples for the three research locations. Based on the results of laboratory analysis shows that the nutrient content is relatively the same, namely for organic C content with low to moderate criteria, P-total nutrient content is on average between 6.55-7.52 (%) (low to moderate), for P is available between 27,241 – 28,909 with very low criteria. The pH parameter for paddy fields is relatively the same as the neutral criterion. This information becomes quite expensive information for the management of paddy fields in the future. The suggestion is to reduce the use of inorganic fertilizers and switch to the use of biological fertilizers and organic fertilizers.

The aim of this research is to establish an infiltration rate model for land uses including smallholder rubber plantations, rice fields, and shrubs. The infiltration rate data was analyzed using the Horton equation model. Every ten minutes, the water level drops. The results of the research show that the infiltration rate model on smallholder rubber plantation land is is f = 7.2 + (10 – 7.2) e 2.64t , whereas on small oil palm plantation land it is It is f = 7.98 + (10 – 7.98) e −2.68 t on smallholder latex plantation land; f = 9.13 + (10 – 9.13) e −5.20 t on rice fields; and f = 4 + (10 – 4) e −2.96 t on bush land. In smallholder rubber plantations, the infiltration rate is classified as moderate at 2.06 cm/hour; in rice fields and smallholder plantations, it is relatively slow, namely 0.87 cm/hour and 1.87 cm/hour, respectively. The infiltration rate in bush land is relatively fast, namely 6.56 cm/hour. With an infiltration rate of 1.87 cm/hour on smallholder oil palm plantations and 0.87 cm/hour.

Penelitian ini bertujuan untuk menentukan dosis abu sekam padi dan dosis pupuk kandang serta interaksi dosis yang optimal untuk pertumbuhan dan hasil bayam. Penelitian ini dilakukan di Mas Graha Village, Kabupaten Labuhanbatu yang berada pada ketinggian 26 meter diatas permukaan laut pada bulan agustus sampai bulan desember 2020. Penelitian menggunakan rancangan kelompok faktorial yang terdiri dari dua faktor. Faktor pertama abu sekam padi (A) terdiri dari 4 taraf, yaitu : A0 = 0 ton/ha (kontrol), A1 = 1 ton/ha setara dengan 50 g/m2 (dosis anjuran), A2 = 1,5 ton/ha setara dengan 75 g/m2. Faktor kedua yakni pemberian kotoran kambing (K) dengan tiga taraf yaitu : K0 = 0 ton/ha (kontrol) K1 = 2 ton/ha setara dengan 200 g/m2 (dosis anjuran), K2 = 4 ton/ha setara dengan 400 g/m2, K3 = 6 ton/ha setara dengan 600 g/m2. Adapun Parameter yang diukur adalah tinggi tanaman (cm), jumlah daun (helai) , berat per Tanaman Sampel (g). Hasil penelitian menunjukkan bahwa pemberian kotoran kambing 4 ton/ha setara dengan 400 g/m2 mampu meningkatkan tinggi tanaman, jumlah daun dan berat per tanaman bayam sedangkan aplikasi 1,5 ton/ha abu sekam padi setara dengan 75 g/m2 mampu meningkatkan tinggi tanaman, jumlah daun tanaman bayam Merah.

The physical properties of the soil that need to be considered are the problems of degradation and soil structure due to management functions. In addition, on cultivated land that is not eroded, organic material is lost quickly.This research was carried out through 2 stages of activities, namely field activities and analysis activities. Stages of field activities were carried out at the Kebun Sinar Pandawa Palm Oil Plantation PT. Sinar Pandawa, Labuhanabtu, North Sumatra Province with a height of 28 meters. The method used in this research is a free grid measurement method at a semi-detailed survey level (observation frequency of 1 sample per 500 meters). Carrying out soil sampling at up to 5 sampling points with a distance of 100 meters in the field using a random method, spread over a predetermined area based on the base map. Land Use Research Results withSoil texture at PT. Sinar Pandawa, Labuhanbatu Regency, Sandy Clay, The Bulk Density value shows low, soil porosity is still high, the soil color looks relatively dark, and the soil water content is still relatively normal.

The mainstay commodity that can be expected to increase the income and dignity of plantation farmers and Indonesian transmigrants is Palm Oil (Elaeis Guinensis Jacq). Oil palm Soil microbes have an important role in the soil ecosystem which is responsible for the nutrient cycle to maintain soil fertility and structure, especially the biological properties of the soil. This research was carried out through 2 stages of activities, namely field activities and analysis activities. Stages of field activities were carried out at the Kebun Sinar Pandawa Palm Oil Plantation PT. Sinar Pandawa, Labuhanabtu, North Sumatra Province with a height of 28 meters. The method used in this research is a free grid measurement method at a semi-detailed survey level (observation frequency of 1 sample per 500 meters). Carrying out soil sampling at up to 5 sampling points with a distance of 100 meters in the field using a random method, spread over a predetermined area based on the base map. Research Results Land use with different vegetation produces different biological and chemical soil properties. Soil organic C was positively correlated with total microbial population, total fungal population, and respiration. The highest correlation between biological and chemical soil properties was obtained from the total microbial population with a total P of 0.714. The highest correlation was obtained from the correlation between organic C and total N levels, namely 0.947.

p> There will be widespread damage to the land as a result of land degradation, particularly to forest land. Changes in land use from extremely durable vegetation to escalated agrarian land make the dirt all the more handily disintegrated. One of the deciding variables of disintegration is soil disintegration and soil cover vegetation. Soil erodiability is the typical measure of soil lost every year per unit of the file, while the land cover is helpful for safeguarding the dirt from the danger of harm by disintegration and further developing soil conditions. The exploration was done from October 2022 to June 2023. In January 2013, field sampling was carried out. The technique utilized in this study was the review strategy and the purposive examining technique. Choose three points of observation. Then, in the laboratory, data analysis and field observation. Assessment of soil erodibility is completed by taking soil tests, deciding soil structure, soil porousness in the field, and deciding soil surface and natural matter for examination in the research center. Distinguishing proof of disintegration by taking documentation of kinds of disintegration that alludes to references and realities tracked down in the field. To decide the worth of erodibility (soil aversion to disintegration) utilizing a nomograph (soil erosibility). Results of the Study Soil erodibility on oil palm land in the Urung Kompas Village was low to medium, ranging from 0.17 to 0.26. The research site on oil palm land in the Urung Kompas subdistrict has five types of erosion: trench erosion, splash erosion, sheet erosion, furrow erosion, and landslides. </p