Performance of sunflower varieties in the uplands/hillylands of Magalang-Arayat task force (Marataf) with and without soil amendments.

The results of the experiment revealed the following findings: 1) CLSUN-1 was the tallest (27.10 cm) at 30 days after planting (DAP) and 60 DAP (96.02 cm) while Improved Peredovik were the tallest at maturity (111.45 cm). Likewise, CLSUN-1 had the highest diameter of head (8.03 cm), heaviest seed weight per head (8.96 gm), heaviest 1,000 seeds weight (52.87 gm), highest percentage of filled seeds per head (59.20%), lowest percentage of empty seeds per head (40.81%), highest actual seed yield per sample area (328.1 gm), highest computed seed yield per hectare (1.47 tons), highest total N content of seeds (4.11%), highest CP [crude protein] content of seeds (25.61%), and oil content of seed (32.07%); 2) Considering soil amendments alone, plants that received 1/2 RRIF + 1398 kg MM/ha were the tallest at 30 DAP (28.69 cm) and at maturity (114.52 cm). Similarly, they also produced the biggest diameter of heads (8.67 cm), heaviest seeds weight per head (9.72 gm), highest percentage of filled seeds per head (67.62%), lowest percentage of empty seeds per head (32.38%), highest actual seed yield per sample area (350.10 gm), highest computed seed yield per hectare (1.6 tons), highest total N content of dry matter (2.36%), highest total N content of seeds (4.02%), highest CP content of seeds (25.07%), and highest oil content of seeds (33.46%); 3) Results of laboratory analysis on soil chemical and physical properties after harvest showed that growing of sunflower plants in the uplands/hillylands of MARATAF [Magalang-Arayat Task Force] without soil amendments had increased the soil OM [organic matter] by 0.56% and 64 ppm K or 28% and 64%, respectively, and; 4) Considering the cost and return analysis per hectare of sunflower seed production, the application of 1/2 RRIF + 1398 kg MM/ha had the lowest cost of operating expenses incurred compared to other combination of both inorganic and organic fertilizers.