. Soedarsono
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Journal : Forum Pasca Sarjana

Pengaruh Penggenangan Pada Berbagai Fase Pertumbuhan Kedelai (Glycine Max (L.) Merr) Terhadap Pertumbuhan dan Produksi Bangun Tampubolon; Joedojono Wiroatmodjo; Justika S Baharsjah; . Soedarsono
Forum Pasca Sarjana Vol. 12 No. 1 (1989): Forum Pascasarjana
Publisher : Forum Pasca Sarjana

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Abstract

The soybean (Glycine rnax (L.) Merr) plant is able to make morphological adaptations to flooding such as the formation of adventive roots. Long-term continuous flooding result in reductive conditions in the rhizosphere which is detrimental to plant growth. This experiment was conducted to investigate the influence of flooding at various stages of soybean development on growth and yield of the crop on Alluvial and Red Yellow Podsolic soils. Flooding invariably resulted in the reduction of the net assimilation rate and yield of soybean. Reduction depended on the time and duration of flooding. Flooding during active vegetative growth (PI), flowering-pod filling (P2), seed ripening (P3), active vegetative growth and flowering-pod filling (P4), active vegetative growth and seed ripening (PS), flowering-pod filling and seed ripening (P6), and active vegetative growth until seed ripening (P7) respectively resulted yield reductions of 20.42, 50.74, 9.43, 46.68, 30.28, 52.63 and 35.26% compared to the unflooded control. The number and dry weight of root nodules and nitrogen fixation rate were highest in the P4 and P7 treatments. Nodules were formed on the adventive roots, when the soybean plants were flooded.
Prediction of runoff, sediment yield and their quality using ANSWERS model at Batujai reservoir area, West Nusa Tenggara Gatot Irianto; Hidayat Pawitan; . Soedarsono; H. Soewardjo
Forum Pasca Sarjana Vol. 16 No. 1 (1993): Forum Pascasarjana
Publisher : Forum Pasca Sarjana

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Abstract

The possibility of ANSWERS model application for predicting runoff and sediment yield is discussed in this paper. Three types of rainfall duration (e.i. 6; 8 and 10 hours) with three amount of total rainfall of 100; 200 and 300 mm and two different systems consistink of four kinds of land use were used for simulating runoff and sediment yield. The result showed that the runoff initiation was identified at 189 minutes from the start of rainfall when the amount of rainfall total was 200 mm with 8 hour duration (about 0.0001 inch/hour). The initial sediment yield was shown to be about 0.45 kg at 188 minutes from the begining of rainfall when rainfall total w+ 300 mm with 6 hour duration. Actual runoff and maximum sediment yield were recorded about 0.0017 inchlhour and 12.000 kg respectively. The land use which were considered as potential for erosion protection were mixed gardpn and wet rice. The considered land use would reduce runoff and sediment yield about 50% than traditional land use. The type of output indicates that ANSWERS model is promising for predicting runoff and sediment yield.