Abstract:This trial was aimed to evaluate the performance of sweet potato cultivars on biochar application. The treatments were carried out using a Split-plot Design with three replications. The cultivars were placed on main plots and biochar doses were on sub-plots. The thirteen cultivars consisted of seven varieties and six accessions from Tribhuwana Tunggadewi University and Brawijaya University collections. The applied biochar doses were B 0 (0 t/ha) and B 1 (5 t/ha). The experimental unit measuring of 5 m x 0.6 m consisted of single row and planted with a spacing of 25 cm in row or 20 cuttings/row. The storage root weight, % dry matter, storage root dry weight, dry weight of biomass, harvest index and yield estimation were determined. The results showed that the sweet potato cultivars gave a significant response to the biochar application on fresh storage root weight, storage root dry weight, biomass dry weight, harvest index and storage root yields, but no interaction between cultivars and biochar doses. Storage root yield ranged from 8 to 21 t/ha without biochar and from 10 to 23 t/ha with 5 t biochar /ha, except for Beta 1 and Boko. The use of 5 t biochar /ha increased storage root yields that ranged from 8 to 45%. Keywords: biochar from tobacco industry waste, sweet potato, storage root fresh weightTo cite this article: Indawan, E., Lestari, S.U. and Thiasari, N. 2018. Sweet potato response to biochar application on sub-optimal dry land.

Sweet potato is a dual-purpose crop, which could produce both food and feed. The vine pruning prior to storage root harvesting was intended to increase the quantity and quality of fresh forage for animal feed. This study aims to evaluate whether periodic pruning can affect the storage root yield and its starch content. This experiment employed split-plot design with two factors and three replications. The first factor as main plot was vine pruning which consisted of four distinct pruning times (four times, three times, twice and once). The second factor as sub-plot was cultivars which consisted of six dual-purpose cultivars and two controls. The storage root yields, vine yields, starch yields and the reduction in storage root yields were observed. The results showed that the vine pruning decreased the storage root yields, with small increases the vine yields. The percentage of the reduction in storage root yields were 4-58%, while the decrease vine yields are relatively inconsistent. The starch yield of the cultivars with one pruning time were in the range of 2.34-6.67 ton ha^-1. On the contrary, the three times pruning or more since 80 days after transplanted can reduce the starch yields for more than 50%. The slight increase in vines yield due to pruning was followed by the decrease in storage root yields and starch content of the sweet potato.

Abstract:The occurrence of pollution in mangrove land is due to changes in physical, chemical and biological properties of water because of the increasing human activities that produce problems due to residential and industrial wastes and other related activities, or due to seawater tide. The existence and presence of residential and industrial wastes in soil sediments can disturb the environment that in turn will threaten mangroves growth. This study was aimed to reveal the presence of heavy metals in sediment shown by environmental changes of water polluted by residential and industrial wastes. The study was conducted in field plots located at five watershed areas of Andil, Porangan, Kacar, Gombal and Krondo in Tambak Lekok Village of Pasuruan District, East Java. Field exploration and observation was started from waterfront and riverside vegetations. The exploration was made 300 m toward inland, perpendicular to the edge of the waters. The sediment samples of mangrove stands were collected at three points for each plot. The thickness of the collected sediment samples was ± 10 cm from the surface. Sediment samples were analyzed for heavy metals (Pb, Cr, Zn and Cu) and texture. The results showed that the Pb severely polluted the Gombal watershed with a concentration of 7.24mg/kg. The lowest Pb concentration of 7.24 mg/kg was observed for Andil watershed. Except for Andil watershed, Cu heavily polluted all the watersheds studied.

The study was aimed to gasp inventory an expired plant mangrove species characteristic respectively collection specimen land us function BTEX and heavy metal at growth environment. The study held from April through November 2007. Design with two classes, Rank I : survey activities and explored in land for quantity and identification, Rank II : Analysis totality solid matter petroleum level BTEX and heavy metal situ by research in location. The results of mangrove identification (main component, supporting component, and associated mangrove) showed there are 11 families and 25 species. BTEX parameter from soil sample was detected benzene intensive contamination on Andil river (16.30 ppm), Porangan river (81.30 ppm), Gombal river (56.90 ppm), Kacar river (36.90 ppm) but it was not detected on Krondo river. Toluene intensive contamination Porangan river (824 ppm) and Kacar river (896 ppm). BTEX parameter from water sample was detected benzene intensive contamination on Andil river (24.30 ppm), Porangan river (8.13 ppm), Gombal river (20.30 ppm), Kacar river (8.13 ppm), Krondo river (8.13 ppm), and Toluene contaminate slightly. Ethylbenzene and xilene were not detected by gas chromatography. Soil medium showed that contamination mainly Pb on Gombal river (5.98 mg/Kg), Kacar river (7.24 mg/Kg) and Krondo river (6.43 mg/Kg), where are Andil river and Porangan river were only slightly contaminated. The metal occurred on Cu for all, except Andil river (6.22 mg/Kg), whereas Zn and Cr did not contaminate, while Ag and Cd were not detected. Water medium was not contaminated by Pb, Cd, Cr, and Zn, furthermore Ag and Cu were not detected.

The experiment was conducted to evaluate the effect of different pruning intervals on nutrient composition and yield of vines from seven sweet potato cultivars. Treatments were arranged in a split-plot design with three replications. The pruning intervals were 80, 90, 120, and 150 days after planting as the main-plots and the trimming volume of sweet potato vine was 25%. Seven sweet potato cultivars (Kuningan Putih, Beta 2, Kuningan Merah, BIS OP-61, 73 OP-5, BIS OP-61-♀-29 and BIS OP-61-OP-22) were in the sub-plots and allocated at random. Results showed that increasing the pruning intervals increased dry matter, organic matter, and crude fiber significantly. However, ash and crude protein were decreased as the trimming intervals increased. Eter Extract was unaffected by trimming intervals.