The use of compost is effective to improve the physical, biological and chemical structure of the soil, which makes plant growth and yield better. The purpose of study was to determine the effect of oyster mushroom baglog compost on the growth and production of several local purple sweet potato genotypes (accessions of Dolok Perdamean with purple tuber, accessions of Silimakuta with purple tuber, accessions of Sumbul with purple tuber, and accessions of Parbuluan with purple tuber) on the various doses of oyster mushroom baglog waste compost application (0, 10, 20, 30 ton/ha). This research was conducted at Jl. Idi Gang Eka Dewi, Medan Johor Subdistrict, from the end of December 2018 to June 2019. The results showed that the administration of oyster mushroom baglog compost gave a good influence on the growth and production of some local purple sweet potato genotypes. The accession of Sumbul with purple tuber had produces the highest growth plant stem length, while the Dolok Perdamean accession with purple tuber had produces the highest on B class tuber grading. The application of oyster mushroom baglog waste compost markedly improves on A class tuber grading. The best dose of oyster mushroom baglog waste compost was 30 tons/ha.

Abstrak. Biochar application as an organic soil conditioner can increase plant growth and production, especially on suboptimal lands. This research aimed to determine the response of growth and production in some local sweet potato genotypes (Accession of Cengkeh Turi with yellow tuber flesh, Accession of Cengkeh Turi with orange tuber flesh, and Accession of Tanah Seribu with orange tuber flesh) on various doses application of paddy straw biochar (0, 5, 10, 15 tons/ha) in paddy fields. A field experiment was conducted from April to August 2018 in the paddy fields of Tandem Hilir I Village, Deli Serdang. The results of this research indicated that the local sweet potato genotype had a good growth and production response in paddy field cultivation. Accession of Tanah Seribu with orange tuber flesh had a significant effect on vine length, tuber weight per sample, and harvest index, while Accession of Cengkeh Turi with orange tuber flesh significantly affects the number of tubers per sample. Paddy straw biochar application had a significant effect on the length of vine, and tuber weight per sample. The best dose of paddy straw biochar in the paddy fields is 10 tons/ha.

Growing media plays an important role as a source of nutrition for plant growth so that the growing media can affect the quality of plant growth. This research aimed to identify the morphological characters and N uptake of mint plants treated with a different composition of growing media. The research was conducted using a Non-Factorial Randomized Block Design with seven treatments of growing media composition and four replications. The treatment is top soil; top soil + biochar (3: 1, v/v), top soil + chicken manure (3: 1, v/v), top soil+oil palm empty fruit bunch (OPEFB) compost (3: 1, v/v), top soil + OPEFB compost+chicken manure (2: 1: 1, v/v/v), top soil+biochar+chicken manure (2: 1: 1, v/v/v) and top soil+biochar+compost (2: 1 : 1, v/v/v). The results showed that the composition of the top soil+OPEFB compost (3: 1, v/v) media was the best composition of growing media because it produced the sprouting age, number of shoots, length of shoots and N nutrient uptake of mint plants were higher than the composition of other growing media.

No abstract

Sweet potato is a food crop that is widely cultivated during the dry season in rice fields. Increasing sweet potato production can be done by inoculating mycorrhizae which play a role in increasing plant resistance to drought. This research was conducted to analyse the effectiveness of mycorrhizae to increase the growth and production of sweet potatoes cultivated in paddy fields with different levels of watering. Sweet potato planting began in April-July 2020 in rainfed paddy fields located in Tandem Hilir I Village, Deli Serdang Regency. The research design used was a randomized block design with 2 factors namely mycorrhizal inoculation (0 g/plant inoculum, 20 g/plant inoculum) and watering level (watered once in 10 days for 1 month, watered once in 10 days for 2 months, watered once in 10 days for 3 months, and watered once in 10 days for 4 months). The results showed that mycorrhizal inoculation treatment at a dose of 20 g/plant significantly affected the length increase of sweet potato plants. All parameters observed were not affected by the treatment watering level. The best interaction is the combination of treatment with 20 g of mycorrhizal inoculum/plant and watered once in 10 days for 3 months.