Soybean (Glycine max. L. Merr.) irrigation scheduling in different weather conditions and planting date | Osnovni elementi navodnjavanja soje (Glycine max. (L.) Merr.) ovisno o klimatskim uvjetima i rokovima sjetve

English. Soybean (Glycine max. L. Merr.) is one of the most important oilseeds that has found wide application in human nutrition, livestock production, and soil enrichment with nitrogen. The increasing occurrence of climatic extremes, the absence of precipitation or irregular distribution of precipitation during the growing season, coupled with an above-average high air temperatures are causing the most important abiotic stress; i.e. drought, resulting in soybean yield reduction. This paper aims to analyse the need for soybean irrigation in the area of Orahovica in average and dry years, depending on sowing dates, and to schedule irrigation of soybean (irrigation rate, net irrigation rate, and irrigation flow rate). In average years, a negative water balance of 160.8 mm occurs, and in dry years a negative water balance of 291.7 mm occurs. In post-sowing, the negative water balance in average years is 152.1 mm, and in dry years 277.2 mm. The irrigation rate for soybeans is 40 mm. The net irrigation flow rate in the average year is 0.39 l sec ha-1, and the gross water flow rate depending on the number of operating hours’ ranges from H20 = 0.67 l sec ha-1 to H8 = 1.7 l sec ha-1. In dry years, the net water flow rate is 0.47 l sec ha-1, and the gross water flow rate, depending on the number of operating hours, ranges from H20 = 0.80 l sec ha-1 to H8 = 2.02 l sec ha-1.

Croatian. Soja (Glycine max. (L.) Merr.) je jedna od najznačajnijih uljarica koja je našla široku primjenu u ishrani ljudi, proizvodnji hrane za stoku te obogaćivanju tla dušikom. Obzirom na sve učestaliju pojavu klimatskih ekstrema, izostanak oborina ili nepravilan raspored oborina tijekom razdoblja vegetacije te nadprosječno visoke temperature zraka, zabilježeno je sniženje prinosa soje uslijed jednog od najvažnijih abiotskih stresova, odnosno suše. Cilj rada je analizirati potrebu za navodnjavanjem soje na području Orahovice u klimatski prosječnim i sušnim godinama ovisno o rokovima sjetve te odrediti osnovne elemente navodnjavanja soje (obrok, normu i hidromodul). U klimatski prosječnim godinama javlja se negativna vodna bilanca od 160,8 mm, a u sušnim godinama negativna vodna bilanca iznosi 291,7 mm. U postrnoj sjetvi negativna vodna bilanca u klimatski prosječnim godinama je 152,1 mm, a u sušnim godinama 277,2 mm. Obrok navodnjavanja za soju je 40 mm. Neto hidromodul navodnjavanja u klimatski prosječnoj godini je 0,39 l s ha-1, a bruto hidromodul ovisno o broju radnih sati je u rasponu od H20 = 0,67 l s ha-1 do H8 = 1,7 l s ha-1. U sušnim godinama neto hidromodul je 0,47 l s ha-1, a bruto hidromodul ovisno o broju radnih sati je u rasponu od H20 = 0,80 l s ha-1 do H8 = 2,02 l s ha-1.