Rice is the primary food commodity in Indonesia. To increase the rice production, urea fertilizer has been excessively used, specifically on marginal land. However, it has no desired effect on the plant’s Nitrogen uptake due to volatilization. Previous studies suggest the use of zeolite to be mixed with urea to reduce the volatilization rate. This study aimed to determine the effect of six NP-SR (Nitrogen Phosphorus Slow Release) fertilizer compositions (without NP-SR; 20.69-0; 19.7-5; 17.27-10; 15.9-15; and 18.94-20) on soil chemical properties, nitrogen efficiency, and paddy rice yield on Ultisols at three waterlogging levels (0.5 cm, 3 cm, and 5 cm). The study was an experiment arranged in a Randomized Complete Block Design (RCBD) consisting of two factors, which were waterlogging levels and NP-SR fertilizer compositions. The results showed that waterlogging treatments significantly affected soil chemical properties in the initial vegetative and harvest phases. It can be concluded that the treatment of flooding (up to 3 cm) and fertilizer (NP-SR of 15.90-15) application could significantly reduce the volatilization rate, increase the efficiency of N fertilizer, and increase rice yield.

Genangan merupakan salah satu stress abiotik yang dapat memengaruhi hasil panen tergantung frekuensi dan luasnya genangan, serta jenis tanaman. Penelitian ini bertujuan untuk mengetahui pengaruh dan interaksi cekaman genangan dan pemberian pupuk N, P, K terhadap pertumbuhan dan hasil tanaman jewawut di Inceptisols. Penelitian dilaksanakan di greenhouse Fakultas Pertanian Universitas Jenderal Soedirman pada bulan April sampai Desember 2020. Penelitian ini menggunakan percobaan faktorial yang disusun dalam Rancangan Acak Kelompok Lengkap (RAKL) dengan dua faktor perlakuan, yaitu empat taraf dosis pupuk N, P, K (N, P, K = 25%, 50%, 75%, 100%) dan empat taraf tingkat genangan (tanpa genangan, genangan 1 – 2 cm, genangan 2 – 3 cm, genangan 4 – 5 cm) dan diulang sebanyak tiga kali. Variabel pengamatan terdiri dari tinggi tanaman, luas daun, bukaan stomata, kerapatan stomata, umur berbunga, umur panen, panjang malai, bobot malai, bobot basah tanaman, bobot kering tanaman. Terdapat interaksi antara perlakuan dosis pupuk N, P, K dengan tingkat genangan pada variabel luas daun, bukaan dan kerapatan stomata. Perlakuan tingkat genangan secara mandiri mempengaruhi variabel tinggi tanaman, bobot basah dan bobot kering tanaman, serta karakter hasil yaitu umur berbunga, umur panen, panjang dan bobot malai. Cekaman genangan menyebabkan terjadinya penurunan pada karakter pertumbuhan, fisiologis maupun karakter hasil pada tanaman jewawut. Penurunan terbesar terjadi pada karakter bobot basah tanaman (81,6%), bobot kering tanaman (80,1%), dan bobot malai (89,6%).

Shallot or red onion is one of the horticultural commodities that has good economic value as it is needed for almost every cuisine. The aims of the research were to determine 1) the effect of nitrogen slow-release zeolite-based NZEO-SR fertilizer and elemental Sulfur on the dynamics of soil main nutrients N, P, K, and S, and their uptake the red onion plants 2) the effect of slow-release N fertilizer on the growth and yield of shallots; 4). the effect of S fertilizer on the growth and yield of red onion and 5) the interaction of slowrelease N fertilizer and S soil nutrient dynamics and the growth and yield of shallots. The research was conducted in a greenhouse using Inceptisols. soil analysis was carried out in the the Land Resource Laboratory, Faculty of Agriculture, Jenderal Soedirman University, Indonesia. The design of this study was a Completely Randomized Block Design (CRBD) with two factors i.e. slow-release nitrogen fertilizer NZEO-SR and elemental sulfur. The test plant used was shallot Bauji variety. The slow release nitrogen fertilizer were applied at 0 , 100 , , 200, dan 300 kg.ha-1 , while the rates of S fertilizer were 0, 25, 50 and 75 g.ha-1. The variables observed consisted of selected soil chemical properties, available N, P, K, and S, N and S uptake, growth and yield of shallots. The results showed that the nitrogen slow release fertilizer applications increased soil available N and S, N uptake, the number of tubers, the weight of fresh shallot bulbs but decreased the soil available P. The applications of S increased soil electrical conductivity and available N and S but decreased the soil pH, available soil P, S and N uptake, and number of bulbs. The applications of S at the highest rate (75kg.ha-1) decreased the bulbs fresh and dry weight. The combination of 200 kg.ha-1 NZEO-SR and 75 kg.ha-1 S gave the best results in available soil N. The applications NZEO-SR and S generated negative interaction on the soil available P.

This study aimed to determine the land suitability for paddy plantation in Semangga subdistrict, Merauke Regency, Papua Province and to identify any treatments that needs to be taken to promote the land suitability classes. The information on land suitability is important to determine the treatment required in land preparation in order to achieve optimal production. S2wfn, 55.8% (19,495.83 hectare) as class of S3n, 7% (2,431.83 hectare) as class of S3np, 35.3% (12,349.74 hectare) as class N1n, and 0.9% (306.6 hectare) as class of N2f. The finding of land suitability classes and its dominant inhibitory factor can be used then to determine the proper land treatment planning such as fertilization, liming, and drainage system design. Survey was conducted to collect necessary data which includes climate data, nutrient content (N, P, K available), Cation Exchange Capacity (CEC), pH, and toxicity. These data are interpolated within the area of Semangga subdistrict and classified based on the criteria developed by Indonesian Soil Research Institute -Ministry of Agriculture and FAO. Overlay analysis is performed in order to determine land suitability classes and the dominant limiting factor. Criteria for determining the suitability classes was taken from the lowest class of land unit. The results showed that the area of 1% (360.09 hectare) is classified as class of