Various efforts has been done to narrow the gap between national soybean production and import, including through intensification in production center of soybean, extensification and diversification based on resources potential. The expanding of soybean planting areas in Indonesia is currently directed at many sub-optimal lands, one of which is rainfed areas. The main problems of planting in rainfed areas are the availability of water and lack of farmers interest to cultivate soybean due to its lower profit compared to food crops. Due to those reasons, most of the rainfed areas in Lampung have not been utilized to cultivate soybean after the rice harvest.

Soybean productivity in Lampung was relatively low, i.e. 1.16 t/ha and it was even lower than the average of national soybean productivity of 1.57 t/ha. Research results on soybean cultivation in some rainfed areas could reach 1.4-2.4 t/ha depend on improved soybean varieties used and production inputs given. The potential yield of some improved soybean varieties released by Ministry of Agriculture through Indonesian Legume and Tuber Crops Research Institute (Iletri)has already reaching >2.5 t/ha.

Iletri has set up soybean cultivation technology package in rainfed areas named Biodetas. Previously, in 2017, the application of Biodetas in Tompobulu Sub-district, South Sulawesi Province was able to produce 2.1-3.2 t/ha soybean seeds. Components of Biodetas in South Sulawesi Province included the use of (1) biofertilizers, (2) lower dosage of Nitrogen-Phosphorus-Potassium (NPK) fertilizer, (3) foliar fertilizer, and (4) organic fertilizer. In order to be immediately adopted and developed at the farmers level, Biodetas needs to be disseminated more broadly with a regard to the agroecological and specific location of soybean cultivation.

Specific Biodetas as soybean cultivation technology package in rainfed area with acidic soil

Rainfed areas in Lampung has specific condition of acidic soil. Mostly of them have characteristics of poor macro and micro biotic nutrient as well as high Al saturation level therefore they require a large number of organic and chemical fertilizers to obtain high soybean yield. Therefore, the application of soybean cultivation technology package of Biodetas in rainfed area was developed adapting to acidic soil condition in East Lampung Regency (specific location) so that it experienced a slight modification by adding dolomite (Table 1).

Table 1. Soybean cultivation technology packages of Biodetas in rainfed areas in non-acidic and acidic soils, Iletri, 2017-2018

Technology components	Soybean cultivation technology packages of
	Recommended Biodetas* (in non-acidic soil) – Tompobulu Sub-district, South Sulawesi 2017	Specific Biodetas (in acidic soil) – Raman Utara Sub-district, Lampung 2018
Land preparation	Without land preparation; straws are cut 1-3 cm above the ground, spread as mulch	With land preparation; straws are cut 1-3 cm above the ground, spread as mulch
Drainage channels	Made every 3-4 m; width and depth of channels of about 30 cm	Made every 3-4 m; width and depth of channels of about 30 cm
Pre-grown herbicide	Apply 2-3 days before planting	Apply 20-21 days after planting
Seed preparation	good quality seeds; growth viability >80%	good quality seeds; growth viability >80%
Planting	2-3 seeds/hole	1-3 seeds/hole
Varieties	Anjasmoro	Anjasmoro
Planting time	4-7 days after rice harvesting	4-7 days after rice harvesting
Planting method	Use manual dibbling tool	Use manual dibbling tool
Plant spacing	40 cm x 15 cm	40 cm x 20 cm
Seed treatment	Agrisoy200 g/50 kg of seed/ha	Agrisoy200 g/50 kg of seed/ha
NPK fertilizer	200 kg/ha Phonska + 50 kg/ha SP36	200 kg/ha Phonska + 50 kg/ha SP36
Dolomite	–	500 kg/ha
foliar fertilizer	Sprayed at 20 and 40 days after planting	–
Organic fertilizer	1000 kg/ha as a cover for planting holes	1000 kg/ha as a cover for planting holes
Pests and diseases controlling	IPM, sprayed with chemical pesticides when the threshold is reached	IPM, sprayed with chemical pesticides when the threshold is reached
Irrigation	Once at around 20 days after planting	Depend on rainfall
Harvesting	At physiological mature stage	At physiological mature stage
Post harvesting	Thresher	Thresher

The application of specific Biodetas in rainfed area with acidic soil in Raman Utara Sub-district, Lampung was also adjusted to the commonly of farmers’ practises for soybean cultivation because according to the cooperating farmers, do the commonly soybean cultivation practises give them a satisfaction and confidence. Therefore, there were three treatments for the introduction of specific Biodetas, particularly at the stage of land preparation and planting method, namely: (1) P1 = With land preparation and planting using manual dibbling tool, (2) P2 = With land preparation and planting using simple planting tool as can be seen in Figure 1; and (3) P3 = Without land preparation and planting using simple planting tool.

The model of technology transfer conducted in Raman Utara is called as farmers participatory model. Farmers are actively participatory involved in the research process from beginning to end so that the scientific research process is enriched and its success can be improved. By this bottom-up planning model, the technological innovations that are produced ultimately match the needs of farmers and specific location agroecosystems due to the effective communication is occured during the learning process.

Soybean yield and production cost

The range of yield obtained was 1.36-1.73 t/ha. The yield was still below the potential yield of Anjasmoro variety of 2.03-2.25 t/ha. The treatment P3 produced the highest yield of 1,72 t/ha or reaches about 76-85% of the potential yield of Anjasmoro.

The input costs for production materials for three treatments were the same, due to the amount of production materials provided i.e. soybean seed, fertilizers (bio, inorganic, and organic), as well as chemical pesticides and others were adjusted to the need of production materials as recommended soybean cultivation technology package of Biodetas in rainfed area. The aplication of dolomite for specific Biodetas technology package in acidic soil increased production cost by IDR 625,000/ha when compared to recommended Biodetas technology package that was previously applied in South Sulawesi.

The difference in production cost for labors input, particularly for land preparation and planting purposes, where P1 treatment required the highest labors cost, 2.2 % higher than P2 treatment and 9.3% higher than P3. Without land preparation, farmers could reduce labors cost by 66.7%; and by planting using simple planting tool, farmers could reduce labors cost by 33.3%. Other labors cost that vary were the costs of processing and yield transportation due to they were highly depend on soybean yield obtained by farmers. In the yield processing stage, threshing cost that must be spent by farmers was IDR 700,000/t of soybeans; while the yield transportation cost incurred by farmers to transport the harvest from the land to the seed breeder as yield collector was IDR 50,000/t of soybeans.

Farming income and feasibility

With the price of IDR 9,000/kg, the highest total revenue received by farmers was obtained by P3 treatment, which was respectively 126.8% and 123.5% higher than P1 and P2 treatments (Table 2).The lowest total benefit was P1 treatment, while the highest was P3. The combination of P1 treatment with common farmers’ practises increased the benefits of P2 and P3 respectively by 115.7% and 225.0% compared to P1.

Table 2. Farming income and financial feasibility of soybean farming with specific Biodetas. Raman Utara Sub-district, East Lampung Regency, Lampung, planting season of May-August 2018

Components	Treatments of
	P1	P2	P3
Production cost (IDR)
a. Producton materials	3.790.000	3.790.000	3.790.000
b. Labors	4.279.500	4.103.500	3.525.500
Total production cost (IDR)	8.069.500	7.893.500	7.315.500
Total production (kg)*	1.362	1.398	1.727
Net production (kg)**	1.226	1.258	1.554
Total revenue (IDR)***	11.034.000	11.322.000	13.986.000
Total benefit (IDR)	2.964.500	3.428.500	6.670.500
Marginal B/C ratio	–	3,64	4,92
Notes: * Total production at 15% seed moisture content ** Net production after reducing losses during threshing by 10% *** Total revenue is the result of net production multiplied by the selling price of soybean received by farmers from seed breeder of CV. Krame Tani in August 2018 i.e. IDR 9,000/kg

Evaluation of technological feasibility used parameter of marginal B/C ratio. With marginal B/C ratio of respectively 3.64 and 4.92, which meant that every IDR 1,000 addition to the production cost is able to increase the benefit by respectively IDR 3,640 and IDR 4,920, the specific Biodetas in acidic soil adjusting to the common farmers’ practices in soybean cultivation were feasible to be applied. However, the most financially feasible for further application in East Lampung Regency is specific Biodetas combined with the common farmers practises i.e. without land preparation and planting using simple planting tool. By implementing this, the farmers could receive the multiplied benefit of soybean farming of around 5 times from the amount of additional capital they invested.

Dian A. A. Elisabeth / A. A. Rahmianna/ Arief Harsono

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