SECOND FODDER INTERCROP IN BEEF AND MILK PRODUCTION, SUNFLOWER (Helianthus annuss) AND HYBRID SORGHUM (Sorghum sp.)

Provedeno je istraživanje povećanja proizvodnje krme na postojećim obradivim površinama Visokoga gospodarskoga učilišta u Križevcima, uvođenjem u plodored suncokreta (Helianthus annuss) i hibridnoga sirka (Sorghum sp., „Grazer“), kao postrnih međuusjeva. Postrna sjetva svake kulture izvršena je na četiri parcele, pojedinačne veličine oko 1000 m2. Pretkultura je bila pšenica, a predsjetvena gnojidba obavljena je gnojevkom s oko 85 m3/1 ha. Tla sa svih pokusnih parcela mogu se uvrstiti u kisela, dosta humozna tla (humus 3,88%; pH u 1M KCl 4,81), prosječno vrlo slabo opskrbljena fiziološki aktivnim fosforom (P2O5 4,39) i slabo opskrbljena kalijem (K2O 6,57 mg/100 g). Unatoč relativno nepovoljnim agroklimatskim uvjetima tijekom vegetacije (mjesečni prosjek 49 mm padavina) suncokret je dao zadovoljavajući prosječni prinos zelene mase od 410 dt/1 ha, i suhe tvari 75 dt/1 ha, s prosječnom hranidbenom vrijednošću u 1 kg suhe tvari; probavljivi protein 65 gr., NEL 4,96 MJ i NEM 4,87 MJ. Kod sirka je utvrđen prosječni prinos zelene mase od 260 dt/1 ha i suhe tvari 67 dt/1 ha, s prosječnom hranidbenom vrijednošću, probavljivog proteina 41 gr., NEL 4,79 MJ i NEM 4,60 MJ/1 kg suhe tvari. Prosječni sadržaj probavljivog proteina u suhoj tvari, na svim pokusnim parcelama, značajno je veći kod suncokreta (65 gr) u odnosu na hibridni sirak (41 gr), P0,01. Iako su kod suncokreta utvrđene više vrijednosti u ostvarenom prosječnom sadržaju NEL-a i NEM-a po 1 kg suhe tvari u odnosu na hibridni sirak, te razlike nisu značajne (P>0,05; P>0,01). Prosječno, na svim parcelama, po 1 ha ostvareno je kod suncokreta 38.400 MJ NEL-a i 37.703 MJ NEM-a, dok su kod sirka ostvareni nešto manji prinosi, i to 32.285 MJ NEL-a i 31.004 MJ NEM-a. Probavljivoga proteina ostvareno je prosječno po 1 ha, kod suncokreta 486 kg, a kod hibridnoga sirka značajno manje, 276 kg. Prema utvrđenim rezultatima provedenoga istraživanja, uzgojem suncokreta kao postrnoga usjeva i ostvarene neto energije po 1 ha izražene u NEL-u i NEM-u, postoji mogućnost proizvodnje oko 10.971 kg mlijeka (cca 3,5 MJ NEL/1 kg) i 754 kg prirasta (cca 50 MJ NEM/1 kg), dok se uzgojem sirka može proizvesti oko 9.224 kg mlijeka i 620 kg prirasta.Increase of fodder production on cultivated acreages of the College of agriculture in Križevci, by introducing sunflower (Helianthus annuss) and hybrid sorghum (Sorghum sp., „Grazer“) as the second intercrop into the crop rotation has been studied. The second sowing of each intercrop was performed on four plots, each around 1000 m2. The preceding crop was common wheat and liquid manure was used as a preceding fertilizer with around 85 m3/1ha. The soil on all investigated plots was acid humus (humus 3.88%; pH in 1 M KCl 4.81), averagely very weak poor in physiologically active phosphorus (P2O5 4,39) and in potassium (K2O 6,57 mg/100g). Despite relatively unfavourable agroclimatic conditions during the vegetation (average monthly precipitation 49mm) average yield of sunflower green mass was satisfactory and amounted to 410 dt, dry matter 75 dt/1ha with average nutrient value in 1kg of dry matter; digestible protein 65 gr., NEL 4.96 MJ and NEM 4.87 MJ. Determined average yield of hybrid sorghum green mass was 260 dt and dry matter 67 dt/1ha with average nutrient value, digestible protein 41 gr, NEL 4.79 MJ and NEM 4.60 MJ/1kg of dry matter. Average digestible protein content in dry matter of all investigated plots was significantly higher in sunflower (65 gr) than in hybrid sorghum (41 gr), P0.01. Although higher values of average NEL and NEM content in 1kg of dry matter were determined in sunflower than in hybrid sorghum, the differences were not significant (P>0.05; P>0.01). Average sunflower yields of 38.400 MJ NEL and 37.703 MJ NEM per 1 ha were achieved on all plots, while determined hybrid sorghum yields were lower, 32.285 MJ NEL and 31.004 MJ NEM. Average yield of digestible protein per 1 ha was 486 kg for sunflower and hybrid sorghum significantly less than 276 kg. Based on determined results of sunflower grown as intercrop the yield of net energy per 1 ha presented in NEL and NEM, allows an average production of 10.971 kg of milk (around 3.5 MJ NEL/1kg) and 754 kg of beef (around 50 MJ NEM /1kg) and growing hybrid sorghum as an intercrop allows an average production of 9.224 kg of milk and 620 kg of beef