Evaluasi Status Hara Makro Nitrogen, Fosfor dan Kalium di Lahan Sawah Irigasi Kabupaten Deli Serdang, Sumatera Utara

It is important to evaluate and identify the rice field soil nutrients to determine the nutrient status both qualitatively and quantitatively. The identification process is expected to be easy, cheap, fast, and applicable for farmers. The Rice Soil Test Kit (RSTK) is a technology designed to identify soil nutrient status also provide fertilizer recommendations, especially for lowland rice. This study was carried out in two areas of irrigated rice fields in Deli Serdang Regency, North Sumatera Province, specifically in Pasar Miring Village, Pagar Merbau District and Kramat Gajah Village, Galang District. This study, which was carried out in May 2023, aimed to identify the primary macronutrient status, namely nitrogen, phosphorus and potassium in irrigated rice fields with several different planting patterns. This study used field survei method and direct soil tests in the field using RSTK. The results of the study showed that the soil fertility level in the two study areas was moderate. Generally, nitrogen status was low, while phosphorus and potassium were high. Referring to the comparison of fertilizer doses between RSTK recommendations and farmers' general application at the study areas, the fertilizer application doses by farmers were not appropriate. On land with low and medium N, 4-27 kg/ha of urea fertilizer needs to be added, while for land with high and very high N, a reduction of 40-90 kg/ha is needed. SP-36 fertilizer at low, medium, and high P needs to be added at 15-65 kg/ha while KCl fertilizer can be reduced or added at 25 kg/ha depending on the straw treatment from the previous planting season.