This study aims to analyze the differences in the production of rubber planting in swamp land and land in North Sumatra. Rubber plants are one of the mainstay commodities in North Sumatra Province along with oil palm plantations. It's just that lately many rubber farmers are converting rubber land to oil palm land. This causes the production and price of rubber commodities to fluctuate. One way to prevent this is to plant rubber in swampy soil. This research uses descriptive qualitative research. Collecting data by observation, interviews, document analysis, literature study, especially using previous research data. The results of this study indicate that there has been a decline in rubber production during the last ten years due to the conversion of rubber land to oil palm land whose main consideration is economic motives, both the increasing price of palm oil and decreasing rubber prices. It's just that, at the same time, rubber plantations have started in swamps that were previously untouched. However, the results are not quite satisfactory compared to rubber plants in dry land. Further research is needed on the factors that influence it and solutions to these problems

This research was carried out at the PTPN III Sarang Giting plantation, Afdeling II, which is located in Sarang Giting Village, Dolok Masihul District, Serdang Bedagai Regency, North Sumatra Province. Venue Altitude 30m above sea level (asl) and flat land topography.    The purpose of this study was to determine the effect of stem circumference and production of rubber plants (Hevea brasiliensis Muell. Arg) on ​​potassium (KCl) combined with agricultural lime (CaCO3) and magnesium (MgSO4) and their effect on the dynamics of soil K levels. This study used a factorial randomized block design (RBD) with 3 (three) factors studied, namely the agricultural lime application factor (C), which consisted of C0 = control and C1 = 1500g/tree/year. The second treatment factor was giving magnesium (M) which consisted of M0 = control, M1 = 1500g/tree/year, M2 = 3000g/tree/year, and M3 = 4500g/tree/year. The third treatment factor was the provision of potassium (K) consisting of K0 = control, K1 = 500g/tree/year, K2 = 1000g/tree/year, and K3 = 1500g/tree/year. The results showed that the administration of potassium combined with the application of agricultural lime and magnesium had a significant effect on the growth parameters of stem circumference. Potassium application combined with agricultural lime and kiserite also had a significant effect on the dynamics of K levels in the soil. However, it did not significantly affect the production of liquid latex

This study aims to analyze the conversion of rubber land to oil palm and its effect on production in North Sumatra. Today many rubber farmers are turning their land into oil palm plantations. So that the famous commodity from North Sumatra, namely, palm oil, is no longer rubber. Whereas previously the rubber plant (Hevea brasiliensis) as a plantation plant that was integrated with the culture of the people of North Sumatra Province had environmentally friendly properties. This study uses descriptive qualitative research methods. Data were collected by observation, interviews, literature study, and document analysis. The results show that smallholder rubber plantations have been the mainstay of the economy of North Sumatra Province since a century ago. Although there has been a change from Rubber Land to Palm Oil Land, currently North Sumatra accounts for 33% of the total national natural rubber production. North Sumatra is the second largest natural rubber producer after South Sumatra.

This study aims to analyse the effect of three types of organic fertilizers on the vegetative growth several varieties of soybeans. This study used a factorial randomized block design with two treatment factors, namely organic fertilizers and varieties. The first factor is: organic fertilizer from 3 levels, namely: K1 (1.5 kg of compost), K2 (1.5 kg of goat manure), and K3 (1.5 kg of chicken manure). The second factor is: soybean plant varieties consist of 4 levels, namely: V1 (Dena 1), V2 (Devon 1), V3 (Anjasmoro) and V4 (Derap 1). The parameters observed were plant height, number of branches, number of leaves, amount of chlorophyll, leaf area, and flowering age. The results of our research is organic fertilizers have a significant effect and are able to increase the growth of soybean plants except for leaf area and flowering age. Types of varieties had a significant effect and were able to increase plant height, number of branches, leaf area, and flowering age, but had no significant effect on the parameters of the number of leaves and the amount of chlorophyll. Moreover, there isn't interaction effect between the two treatments for all parameters.