Nitrogen Slow-Release Zeolite-Based Fertilizer on Rice Plants at Inceptisol Soil

Nitrogen (N) is the main element needed by plants for growth. Nitrogen increases plant growth and production (Pan Set al., 2022). Nitrogen functions are a major component informing proteins, nucleic acids, chlorophyll, and other organic compounds. Nitrogen also gives a green appearance to leaves as a component of chlorophyll, supports growth, increases plant height and the number of leaves, increases leaf size, increases seed size, and increases protein composition in seeds (Sumiyanah & Iman Sungkawa, 2018).

One of the problems of rice cultivation today is using fertilizer chemistry continuously with high doses, causing negative effects on the environment and reducing fertilization efficiency (Abdulrahman et al., 2008). The dosage of N fertilizer at the farm level is currently relatively high, reaching 400-600 kg urea/ha, especially in intensive rice fields in Java, which is above the national recommendation of 200-260 kg urea/ha (Triadiati et al., 2012).

Nikmah (2019) argues that the application of nitrogen (N) fertilizers in rice cultivation in Indonesia every year has increased. However, the ability of rice plants to absorb N is still low, around 30% -50%. The rest (50-70%) will be lost to the environment through evaporation and surface runoff (Coskun et al., 2017 Kharisun & Budiono, M.N, 2015). Even according to Oliveira et al. (1997), loss of N can reach 94% when urea is applied to soil covered with straw. N loss is caused by dispersion (Sommer et al., 2004), volatility NH3 (Li et al., 2017), and washed away by surface runoff (Cai et al., 2002). The evaporation of gas from paddy fields is thought to be one of the contributors to the greenhouse effect (IPPC, 2013; Ye Yuan, 2019). Some gas emissions from fertilizing paddy soil are N2O (Wu et al., 2017) and CH4 (Shang et al., 2013). Nitrogen is a plant macronutrient that is very important for plant growth and production, and inmost soils, monoculture cereals such as rice are deficient (Omara et al., 2019).

One of the things needed for nitrogen fertilizers is fertilization technology with low solubility but can provide sufficient nutrients for plants. Nitrogen technology Slow-release fertilizer is a fertilizer technology with low nutrient solubility and can provide nutrients gradually over along period. The low nutrient release will enable nutrient absorption with high efficiency and nutrient loss due to the washing. Fertilizer NZEO-SR-Plus is a slow-release nitrogen fertilizer that uses natural zeolite as the main ingredient and is enriched with Si and humic acid, rice husk and clay minerals (montmorillonite) as binders and nano-zeolite coating and humic materials. The presence of nano-zeolite coating and humic materials can increase the soil'sphysical, chemical and biological fertility, especially on marginal soils. The coating is a layer applied to the surface (Ngguna et al., 2020).

Humic acid can stimulate and activate physiological and biological processes in living organisms in the soil, which makes humic acid act as a soil conditioner. The humic acid given to the urea fertilizer acts as a coating which helps protect the nitrogen elements from possible evaporation and dissolves with surface runoff. This is shown when N fertilizers such as urea are given humic acid, properties volatile (volatile) of urea fertilizer appear to be reduced. NH2 from urea fertilizer changes into ammonium ion (NH4+).

Zeolite is an aluminosilicate mineral in three-dimensional crystals with a nano-sized pore channel structure resulting in avery large surface area. In NZEO SR Plus fertilizer, zeolite will bind NH4+, released from the hydrolysis of N fertilizers such as urea. NH4+ ions are adsorbed on the negatively charged lattice in the nano-sized, making them inaccessible to microbes. The adsorbed ions can be released slowly and controlled through the cation exchange mechanism. According to Suwardi (2020), applying nitrogen fertilizer without adding zeolite facilitates high N leaching and volatilization, making it unavailable to plants (Suwardi, 2000). N fertilizer based on zeolite can work as a slow-release fertilizer (Kharisun et al. 2017). Using nitrogen fertilizers released in a controlled manner using zeolite can increase nitrogen uptake efficiency and reduce the loss of nitrogen gas through ammonia evaporation and denitrification (Cabezas et al., 2005; Achmed O.H. et al., 2010; Palanivel Pet al. 2015). Slowrelease N fertilizer based on zeolite and humic acid is expected to overcome the efficiency of nitrogen fertilizers and can increase sub-optimal soil fertility. This study aims to determine the effect of slow-release fertilizer (NZEO-SRPlus) on the growth and production of IR64 rice plants and determine the best dose for I.R. 64 rice plants in soil inceptisol, Karangsari, Cirebon.