<p>The eruption of Merapi mountain has primary and secondary hazard and may damage to the land. In detail, the hazards are land degradation is a loss of some or many of germplasm and changes in plant biodiversity. The others hazard including loss of water catchment areas, the destruction of forests, and even the closing of the water source, as well as the loss of water channels. The burried of soil and soil formation inhibition were caused by the repeated eruptions of Merapi, beside the loss of roads access to agricultural land and loss of land ownerships boundaries by the eruption and cool lava. Materials of eruption are sand and pyroclastic materials, as well as the nature of cementation require special techniques and technology to use the land as new farmland. Land restoration efforts can be done with the land management by reforestation on government-owned land for water catchment function, agroforestry forage grass based, grazing field on land owned by the village and residents, with the use of organic materials in the eruption sandy soil ameliorant.</p>

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<p>Nowadays the innovations in organic agriculture systems continue to be developed to achieve a sustainable agriculture system. In Indonesia with high rainfall, nutrient loss is still a major problem. The application of zeolite and manure as a soil amendment is expected to increase nutrients available in soil and cation exchange capacity of the soil in the long term. The results on the first planting season showed a significant increase in chemical soil fertility. The objective of this study is to research the effect of residue zeolite and manure on soil chemical fertility and yields of the second planting season. This study used a complete randomized block design. The factors were a dose of zeolite (Z1: 2.5 tons ha ^-1; Z2: 5 tons ha^-1) and kind of manure (P1: quail manure; P2: cow manure), with three replications. The result showed that zeolite treatment of 5 tons ha^-1 and cow manure increased the total N soil by 27.78% and 45.4% compared to the control. The treatment of quail manure increased soil organic matter 78.78% compared to the control. The treatment of cow manure increased the green bean yield 28.76% compared to the control.</p>

<p>Soil degradation mostly occurs on land where a lack of surface coverage results in soil-aggregate destruction due to heavy rainfall. Turfgrass is an ornamental plant and covers the soil surface and, thus, potentially improves soil-aggregate stability. This study determined the potential of some summer grasses to improve soil-aggregate stability and was a pilot experiment using six turfgrass species: <em>Paspalum vaginatum</em>; middle-leaf <em>Zoysia sp.</em>; <em>Cynodon dactylon</em>; coarse-leaf <em>Zoysia sp.;</em> <em>Axonopus compressus</em>; <em>Zoysia matrella</em>. Turfgrasses were planted using stolons in a 0.6 m² plot unit with 5 cm x 5 cm space. Lawn maintenance included irrigation, fertilizing, and weeding. Soil characteristics were observed six months after planting and showed that turfgrass increased the soil-aggregate index from 42.3% to 83.0% in control, and carbon particles measuring 6.4 μm from 28.3% to 63.0%.</p>

Mujiyo M., Sunarminto B.H., Hanudin E., Widada J., Syamsiyah J. (2017): Methane production potential of soil profile in organic paddy field. Soil & Water Res., 12: 212−219.The use of organic fertilizers in the organic paddy/rice field can increase methane (CH 4 ) production, which leads to environmental problems. In this study, we aimed to determine the CH 4 production potential (CH 4 -PP) by a soil profile from samples using flood incubation. Soil properties (chemical, physical, and biological) were analyzed from soil samples of three different paddy farming systems (organic, semi-organic, and conventional), whilst soil from teak forest was used as the control. A significant relationship was determined between soil properties and CH 4 -PP. The average amount of CH 4 -PP in the organic rice field profile was the highest among all the samples (1.36 µg CH 4 /kg soil/day). However, the CH 4 oxidation potential (CH 4 -OP) is high as well, as this was a chance of mitigation options should focus on increasing the methanotrophic activity which might reduce CH 4 emissions to the atmosphere. The factor most influencing CH 4 -PP is soil C-organic (C org ). C org and CH 4 -PP of the top soil of organic rice fields were 2.09% and 1.81 µg CH 4 /kg soil/day, respectively. As a consequence, here the mitigation options require more efforts than in the other farming systems. Soil with various amounts of C org reached a maximum point of CH 4 -PP at various time after incubation (20, 15, and 10 days for the highest, medium, and the lowest amounts of C org , respectively). A high amount of C org provided enough C substrate for producing a higher amount of CH 4 and reaching its longer peak production than the low amount of C org . These findings also provide guidance that mitigation option reduces CH 4 emissions from organic rice fields and leads to drainage every10-20 days before reaching the maximum CH 4 -PP.

One effort that can be done to improve soil fertility and crop yields is fertilization. Fertilization using a mixed source fertilizer (MSF) is an option to overcome the impact of inorganic fertilizer use and organic fertilizer drawbacks. This study aims to evaluate the effects of MSF application on the chemical properties of Inceptisol and rice yields. A field experiment was conducted using a completely randomized block design (RCBD) with two factors and three replications. The first factor was the three formulas of MSF (F1, F2, F3) and the second factor was MSF doses (0, 2.5, 5, 7.5, 10 Mg ha-1). The results show that there is no significant difference on the total soil N, available soil P, plant height and total number of tillers of rice plants applied with the three MSF formulas. The increased MSF doses applied significantly improve the soil chemical properties of Inceptisol and rice yields. The application of 10 Mg ha-1 MSF increases total- N (57.89%), available-P (29.13%), exchangeable-Ca and -Mg (117% and 250%, respectively), plant height (40%) and total number of tillers (43.2%) in comparison to those without MSF application. There are interaction effects between formulas and doses of MSF on the amount of exchangeable-K, organic-C content, and CEC of the soil and rice yields. The application of 10 Mg ha-1 MSF F3 results in better effects on the amount of exchangeable-K, organic-C content and CEC of the soil, and number of productive tillers and rice yields than the application of other MSF formulas. The MSF can be used as an alternatif fertilizer that can improve Inceptisol productivity.

<p>Arrowroot  able  to  be  alternative  food  because  it  has  high  enough  carbohydrate  content.  The  increase  of productivity of arrowroot can be reached by using plant spacing and fertilization. This study aims to determine the effect of plant spacing and fertilization, also their interaction on growth and yield of arrowroot (Maranta arundinacea L.). This research was held from March to November 2016 in the experimental land, Faculty of Agriculture, Sebelas Maret University. This research arranged in Completely Randomized Block Design (CRBD) consisted of 2 factors; dosage of N,P,K fertilizer (with 3 levels) and plant spacing (with 2 levels). Each treatment was repeated 4 times. The data obtained analyzed with analysis of variance and followed with Duncan Multiple Range Test at 5% level if any significant influences. The results showed that the interaction between plant spacing of 30x40 cm and urea, Sp36 and KCl 300Kg-1ha significantly increased the number of tillers and diameter of arrowroot respectively. The use of plant spacing 30x40 cm tends to increase growth and better yield. The use of 300 Kg-1ha Urea, SP36 and KCl fertilizer significantly increased plant height, while 150  Kg/ha urea,  SP36 and  KCl fertilizer significantly increased the number of tuber crops.</p>

Entisols is soil that newly formed and has diverse fertility, and potential for shallot cultivation.. The center of shallot production is mostly carried out in coastal areas which have a limiting factor high soil salinity. High salinity will cause nutrient uptake and plant growth disrupted. Soil amendments such as zeolite and gypsum potential option to overcome tha impact of high salinity. This study was completely randomized design (CRD) two factors, shallot cultivar (Brebes cultivar = V1, Purbalingga cultivar = V2, Pemalang cultivar = V3), and soil amendment (gypsum = G, zeolite = Z, without amendments= K. Each pot countaned of 15 kg of entisols and irrigated by 1 liter saline water of 2 mS / cm every day. Results shallot that amendment application can significantly improve pH, EC, SAR. Application of gypsum (25 Mg ha-1) and zeolite (15 Mg ha-1) showed the higher effect on purbalingga cultivars (V2). Interaction amendments and cultivars did not significantly affect on plant height and diameter of the bulbs. Gypsum 25 Mg ha-1 (G) significantly increased wet weight and fresh weight of bulb in purbalingga cultivars.