Suntoro

Study of Soil Degradation Status at Jatipurno District, Keduang Sub-Watersheds, Wonogiri Regency, Central Java

This study is aimed to evaluate soil degradation based on Standard Criteria of Soil Degradation for Biomass Production under Indonesian Government Regulation No. 150 in 2000. Conducted at Jatipurno District, Keduang Sub-Watersheds, between October and December 2016, at seven selected land units, each land unit is represented by four sample points. The selection of sampling area is according to Stratified Purposive Sampling method. The evaluation of soil degradation is carried out by determining the threshold value and key factors of soil characteristics based on the Standard Criteria of Soil (matching process), which lead to degradation. The results showed that the entire soil at Jatipurno District is slightly degraded. The most extensive soil degradation 2,869.31 ha area (69.60%) is caused by a low colloid fraction, high bulk density, low total porosity and low soil permeability. The soil degradation mostly caused by low soil permeability which the number is under critical threshold < 0.7 cm hour -1 in the entire land units. Implementing providing organic matter to the soil, planting variations of cover crops, on land plots (low, medium, high cover crops), land management by crop rotation and intercropping, minimum tillage in accordance with the rules of environmental conservation, can be done to minimize the soil degradation.

The Effects of Rice Husk Ash and Dolomite on Soybean Yield at Latosol Soil

The aim of this research is to evaluate the effects ofrice husk ash and dolomite application on soybean yield at latosol soil. This research was conducted at a plastic house from September to December 2016. This research employed Factorial Randomized Complete Design with two factors and three replications. The first factor is the dosage of rice husk ash, consisted of four levels (0 (control), 3.75 ton ha -1 , 7.5 ton ha -1 and 15 ton ha -1 ), and the second factor is the dosage of dolomite consisted of three levels (0 (control), 250 and 500 kg ha -1 , respectively). The results found that the application of 15 tons ha -1 rice husk significantly affected the number of full pods and total pods, but did not affect the number of the empty pods. The application of 3.75 tons ha -1 husk ash increased the seed weight and weight of 20 dry seeds. It was also found that the higher the rice husk ash dose applied, the more root nodules produced.

PEMETAAN POTENSI EMISI GRK METANA: SEBAGAI STRATEGI MITIGASI EMISI DAN MENJAGA PRODUKTIVITAS LAHAN PADI SAWAH ORGANIK DI KABUPATEN SRAGEN

Tujuan umum penelitian ini adalah memetakan potensi produksi emisi metana pada lahan sawah organik di Desa Sukorejo dan Jetis, Kecamatan Sambirejo, Sragen, yang dapat digunakan untuk memitigasi emisi metana dan meningkatkan produktivitas lahan. Secara garis besar pelaksanaan penelitian dibagi menjadi 4 tahap ; (1) karakterisasi tanah dan lahan, pengungkapan secara mendalam karakter obyek lahan pada setiap satuan penggunaan lahan sawah, (2) pengukuran potensi produksi emisi metana, dengan metode inkubasi sampel tanah di laboratorium, sampel gas yang dihasilkan dianalisis menggunakan kromatografi gas yang dilengkapi dengan flame ionization detector (FID) untuk menetapkan flux CH 4 , (3) analisa data, taraf perbedaan nilai potensi produksi metana diketahui dengan analisis beda nyata Uji T, dan penentuan faktor yang paling berperan terhadap besarnya potensi emisi metana dengan analisis stepwise regression, dan (4) rekomendasi, pemilihan rekomendasi didasarkan pada praktek budidaya pertanian yang efektif meningkatkan C organik dan menekan produksi emisi metana tanpa mengurangi produktivitas tanaman. Hasil penelitian menunjukkan bahwa ; (1) potensi produksi metana (CH 4 ) berbeda nyata antar satuan penggunaan lahan (SPL) sawah di Desa Sukorejo dan Jetis, (2) iklim, varietas tanaman dan cara budidaya di daerah penelitian tidak signifikan mempengaruhi besarnya potensi produksi metana, dan (3) faktor yang berpengaruh signifikan terhadap besarnya potensi produksi metana di tanah sawah adalah potensial redoks (Eh). Hubungan Eh dengan besarnya potensi produksi metana berkorelasi negatif, artinya penurunan Eh akan menyebabkan peningkatan produksi metana. Mitigasi emisi GRK metana yang dapat dilakukan berdasarkan penelitian ini, bahwa potensial redoks adalah faktor utama penentu potensi produksi metana di dalam tanah sawah, maka alternatif yang memungkinkan adalah dengan pengelolaan air irigasi, yang dalam periode tertentu tanaman padi tidak diairi atau tidak digenangi, atau apabila kondisi air berlebih dilakukan drainase. Usaha ini dilakukan dengan tujuan kondisi tanah tidak terlalu reduktif atau potensial redoks tidak akan turun secara drastis, sehingga akan dapat menghambat aktivitas mikrobia methanogen dalam memproduksi metana.

REKAYASA FORMULA PUPUK SUPER ORGANIK DALAM PENERAPANNYA PADA BUDIDAYA TANAMAN SAYURAN BAYAM (Amarantus sp)

The decline of soil organic matter in the low of soil productivity. To increase soil of productivity and returns back bearing capacity of the plant, then the business can be done for example by encouraging re-use of organic fertilizers. The study titled “Engineering super organic fertilizer formula in vegetable cultivation on spinach ( Amaranthus sp) aims to a). getting a super-organic fertilizer formula, the most good, b). knowing the influence of various super organic fertilizer formula on growth and yield of vegetable Amaranthus sp. The experiment was conducted from April to November 2010. Five kinds of super-organic fertilizer, which is an engineering formula fertilizer that s made from a mixture of manure, sawdust, dolomite, rock phosphate, molasses and starch in the form of granules, making it easier in applying and provide with the same dose. As ground control does not super plus organic fertilizer. Research using Randomized Complete Block Design (RAKL) single factor. The observed variables are observed 1. Independent variables: a. Without organic fertilizer and b. The use of super-organic fertilizer formula 2. Dependent variables include soil chemical properties (properties which are used as a determinant of soil fertility), which consist of: soil pH, soil organic matter content (organic C), cation exchange capacity (KPK), Burnout base (KB), and P is available, and growth spinach plants. The results showed that: super organic fertilizer formula is best P5G2 (mixture of manure, rock phosphate and dolomite with starch adhesive), proved its influence on growth and yield of spinach, either on plant fresh weight, dry weight, root volume and uptake of N gave the highest yield compared with other treatments.

Potential Emission Of N2O from Various Types of Soil with Organic Material Addition

N2O is one of the greenhouse gases generated by agricultural activities which is currently highlighted. Amount of N2O is the least amount in the atmosphere, but it has a global warming potential 310 times compared to the global warming potential by CO2, and has a very long half-life time in the atmosphere is about 120-150 years old. Organic fertilization is considered one trigger for N2O emissions, but the other organic materials are needed by the soil as soil-forming material. Intensive research is needed to determine the effect of the organic material to N2O on various aspects including soil type, because Indonesia is rich in soil. Indonesia has 10 of the 12 soil types that exist throughout the world (Soil Taxonomy). This study aims to determine the N2O emissions in different types of soil which were variations of the addition of organic matter. This research was conducted with an experimental method using a completely randomized design.The main observation is the variable potential N2O emissions which analyzed by Soil Incubation method. The results showed variations of provision does not affect the potential of organic materials N2O emissions for 30 days. Soil types of the most releases N2O respectively are Alfisols, then Inseptisols and most minor releases N2O is Andisols.