Manipulation of microhabitat by polyculture planting system as ecosystem stabilizer for management of pests and natural enemies in shallot (Allium ascalonicum Linn.)

Shallot (Allium ascalonicum Linn.) is one of important commodities for Indonesian people, yet its production is still limited by pest attack This research was conducted in Banyuputih Village, Wringin Subdistrict, Bondowoso Regency from July to October 2019. This study applied a Randomized Block Design (RBD) with six treatments, namely: P1 = Polyculture of shallot + lemongrass; P2 = Polyculture of shallot + celery; P3 = Polyculture of shallot + mustard; P4 = Polyculture of shallot + lemongrass + mustard; P5 = Polyculture of shallot + celery + mustard; P6 = Monoculture of shallot. Each treatment was repeated 4 times. Observation was started when plant was at the age of 30 days after planting. Data collection was done by directly observing the sample plants. Sampling was carried out using Yellow trap and pit fall trap. A total of 10 samples were collected from each plot with interval of 4 days. Observation included collecting the pest insects and natural enemies that were found, counting the number of populations of each species, and scoring towards the damage plants. The results showed that shallot planting by polyculture with different types of plants affected the population of pests and natural enemies as well as the level of diversity of insects in shallots. Planting shallots by polyculture has been proven to control pest population compared to planting shallots by monoculture. Polyculture planting with two types of plants was found to produce better outcome than polyculture planting with three types of plants with best treatment observed in P1, namely polyculture of shallot and lemongrass which resulted in the lowest pest population of 17.5.

The effect of pillen seed storage time and application of humic acid on the growth of tobacco seedlings (Nicotiana tabacum L.)

Tobacco is one of the seeds that can be stored for a specified period. Seed storage is one of the ways in maintaining the viability of the seeds to meet the needs of the next planting period. Pillen seed technology has developed where in addition to increasing the size of seeds can improve the quality of seeds. Kaolin in pillen has an Al content which is suspected if absorbed by plants will inhibit the growth of tobacco seeds. Giving humic acid is expected to be able to play a role in binding Al so that the level of Al content in the soil can be lowered so as not to cause toxins to plants. This study aimed to determine the effect of pillen seed storage and the application of humic acid on the growth of tobacco seedlings. This study used the factorial of complete randomized design (RAL) 2 × 3. The first factor of the concentration of humic acid consisted of without humic acid 0 ml / l and liquid humic acid 6 ml/l. The second factor for the shelf life of the top seeds is 3, 8, and 13 years. Humic acid concentration of 6 ml could support the growth of the tobacco seedlings.

The exploration of Bacillus spp. as antagonist agents against Xanthomonas axonopodis pv. glycines from the weed phyllosphere in soybean plantation

Bacterial pustules caused by Xanthomonas axonopodis pv. glycines (Xag) is one of the important diseases in soybean plants. Bacillus bacteria from the soybean phyllosphere have the potential to inhibit these pathogens. Weed phyllosphere in soybean plantations is also a good habitat for Bacillus life. The purpose of this study was to obtain Bacillus from the weed phyllosphere which has the potential as an antagonistic agent against Xag. The study methods included exploration, screening, and physio-biochemical identification. The results obtained 31 isolates and 22 of them were able to inhibit Xag with various inhibitory properties. Five strains of Bacillus spp. had large inhibitory effects against Xag, namely strain Bp 2(2), Jg3(3), Bg d1(1), Jg 1(3) and Jg 1(4)1. The Bacillus strain Bp2(2) had the largest inhibition zone witht 15 mm and strain Jg1(4)1 had the fastest colony growth with 68 mm. Five Bacillus spp had different growth capability based on the environmental condition and carbon source. The physio-biochemical identification results indicated that Bacillus strain Jg 3(6), Bg d 1(1), Jg 1(3), Jg 1(4)1 had the similar characteristics to B. licheniformis, while strain Bp 2(2) had the similar characteristics to B. coagulans.

Increasing corn and soybean yields by arranging the plant spacing and NPK fertilizer dosages in intercropping system

Corn and soybean are food crops which are ranked on the second and third position as the main crops with the highest yield in Indonesia. Based on data of 2012, corn and soybean harvested areas amounted 3,956 ha and 597.65 ha with the productivity of 48.99 tons/ha and 843.15 tons/ha, these areas increased up to 4,388 ha (corn) and 589.42 ha (soybeans) which lead an increase in corn and soybean production by 52.85 tons/ha and 887.54 tons/ha. However, increasing crop productivity, especially for corn and soybeans, cannot continuously use land expansion because the land area of Indonesia that is suitable for agriculture is only 94.07 million ha from 188.20 million of total land area. Thus, the solution to overcome this issue is by arranging the plant spacing and providing proper nutrients. Plant spacing in intercropping systems can minimize competition between plants to provide a well-grown of both plants. This research aimed to determine the increase in productivity of corn and soybean plants using intercropping systems through a combination of plant spacing and a combination of NPK fertilizer dosages. This study used a factorial experimental method that planted crops on the land with 2 factors with split-plot design of 4 × 3 factorial and 3 replications. The first factor is the combination of plant spacing with 4 levels, they were plant spacing of corn; 50 cm × 40 cm (J1), 75 cm × 40 cm (J2), 100 cm × 40 cm (J3), 125 cm × 40 cm (J4) and plant spacing of soybean; 40 cm × 20 cm. The second factor is 3 levels of NPK fertilizer dosages combination, they were 0% NPK fertilizer dose of the recommendation (0 g/m2) (D1), 50% NPK fertilizer dose of the recommendation (198.5 g/m2) (D2), 100% of NPK fertilizer dose of the recommendation (397 g/m2) (D3), with 3 replications. DMRT test (Duncan, Multiple Range Test) was performed with a confidence level of 95% when the results between treatments were significantly different.

Soil chemical properties of suboptimal dryland in subdistricts of Panji, Kendit, and Kapongan Situbondo Regency for development of cassava (Manihot utilissima L.) cultivation

Cassava has an important role as a potential caloric source for the community. Cassava has been known as a plant with wide range adaptability, thus it is very potential to be cultivated in areas with highly variated agro-ecological conditions such as temperate regions, marginal land, and dryland. This research aimed to study the chemical properties of suboptimal dryland in Panji, Kendit and Kapongan Subdistrict, Situbondo Regency for the development of cassava cultivation. The research was carried out by doing surveys and taking soil samples of suboptimal dryland in Subdistricts of Panji, Kendit, and Kapongan. Each subdistrict had 5 locations chosen as site obtaining soil samples. The soil samples were taken at a depth of 20 cm, each soil sample was put into a plastic clip, then was labeled and brought to the Soil Fertility Laboratory for analysis of soil chemical properties. The soil chemical properties analyzed were pH H2O, cation exchange capacity (CEC), organic carbon, total Nitrogen, available Phosphate, and available Kalium. The results showed that the organic carbon, total Nitrogen, and available Phosphate became a limiting factor which belonged to the category of very low to low, with organic carbon of 0.80-1.44%, total Nitrogen of 0.12-0.17% and available Phosphate of 15.21-15.97 ppm. Nevertheless, the soil chemical properties of suboptimal dryland are quite suitable for cassava, however other inputs are needed to the soil by fertilizing the organic matter, Nitrogen, and Phosphate.