This study aimed to classify the types of sweet potato based on the ratio of total dry matter of roots to vine (R/V) in order to make the option available in integrating the crop-livestock systems. Seventeen sweet potato cultivars were planted in Randomized Complete Block Design with three replications applied at two locations, Malang and Blitar. Each cultivar planted in plot measures 2.5 m x 5 m in Malang and 3.0 m x 5 m in Blitar, and each consists of four rows with a spacing of 25 cm in rows. All cultivars gave a dose of 250 kg NPK fertilizer (15-15-15)/ha twice, one-third of dose given at planting and the remainder in a month after planting. Plants were harvested at four months after planting. Fresh weight and dry weight of storage root, fresh weight and dry weight of vines, harvest index, and the ratio R/V are determined. There was different performance of 17 cultivars planted at two locations. Cultivars planted in Malang were classified into four types, namely forage, which consists of three cultivars among 17 cultivars, low dual-purpose (3 cultivars), high dual-purpose (7 cultivars), and low root production (4 cultivars); while cultivars planted in Blitar turned into the forage type.

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.

Phytoremediation has been intensively studied due its costs effectiveness and environmentally sound. Studies of heavy metal pollution phytoremediation has been done in develop countries, but still limited in Indonesia. This study aims to explore the potential of wild plant species Eleusine indica L. and Sonchus arvensis L. as an agent of phytoremediation on Cd-contaminated soil. This study was done descriptively in Pujon, Malang, Indonesia, to test the ability of two species of wild plants E. indica and S. arvensis in absorbing Cd. Along this research, plant growth and the concentration of Cd in roots, stems and leaves, was monitored. Plant growth was measured every week for three months. The plant roots, stems, and leaves collected separately, then analyzed its Cd levels. The results showed that both of two species of wild plants grew well on soil contaminated Cd. Plant roots can accumulate higher Cd than the stem part. In addition, E indica has the ability to accumulate Cd higher than S. arvensis, i.e. 57.11% and 35.84%, respectively.

The base-population of the controlled cross breeding is one of the important factors to develop a new improved cultivar. Since the incompatible nature of sweet potato remains a barrier for genetic improvement, therefore it requires a lot of crossed pairs. This study aimed to determine the level of incompatibility among crossing line between high yielding and micronutrient content cultivars. The field experiment conducted at Brawijaya University Research Station, Jatikerto-Malang, during February to August 2015. The North Carolina Design II was applied to sixty pairs controlled cross breeding and their sixty reciprocal pairs of six cultivars for micronutrient content enrichment with ten high yielding cultivars. The observations were made to the cross flowers number, capsules, fruit sets, and seeds number. The level of incompatibility between crossed pairs was determined by the level of fruit set. The result showed that most pairs were compatible (fruit set > 20%) and only few were incompatible (fruit set < 10%). Among six parents with micronutrient content enrichment, two of them, have a high compatibility as as female parents, to all the high yielding cultivars, i.e. BIS OP-61 and Cangkuang. Positioning as a female parent can improve the effectiveness of its selection scheme.

Heavy metal pollution in agricultural land threatens soil and food quality. Soil pollution could be remediate using biochar, but the effectiveness of biochar on soil quality improvement is determined by types of feedstock and pyrolysis temperature. This study was aimed to explore the effect of different types of biochar on soil properties. Biochar from rice husk and tobacco waste was applied to soil contaminated with lead and mercury. This study was conducted at Sumber Brantas, Malang East Java, and used a completely randomized design with three replicates. Heavy metals content was measured using AAS. The results of measurements were analyzed using analysis of variance at 5% and 1% significance levels. The initial analysis of the soil properties at the research site showed that the soil nutrient status was low, i.e. N (0.2 %), K (0.50 cmol + /kg), and CEC (5.9 me/100g) respectively, but soil pH was neutral (6.8). The research site also has crossed the threshold of heavy metal content for Hg (0.5 ppm), Pb (25.22 ppm), Cd (1.96 ppm), and As (0.78 ppm). Biochar added had a positive influence on soil characteristics improvement. It could increase the content of organic C, i.e. 35.12% and 31.81% and CEC (cation exchange capacity), i.e.30.56 me/100g and 28.13 me/100 g for rice husk biochar and tobacco waste biochar, respectively. However, N, P, and K contents were low i.e. N ( 0.33 and 0.30 %); P 2 O 5 (148.79 and 152 ppm); K (1.58 and 2.11 mg/100g) for rice husk biochar and tobacco waste biochar, respectively. Keywords: biochar, heavy metal, remediationTo cite this article: Hamzah, A., Hapsari, R.I. and Priyadarshini, R. 2017. The influence of rice husk and tobacco waste biochars on soil quality.