NUTRIENT MANAGEMENT FOR SUNFLOWER PRODUCTION

Fertilizer \n\t\t\tmanagement is an important part for sunflower production and one \n\t\t\tmust know how input affects the crop and soil traits. Determination \n\t\t\tof optimum fertilizer rates is important because of increasing \n\t\t\teconomic and environmental concerns. This study was therefore \n\t\t\tconducted to determine optimum fertilizer and manure requirement for \n\t\t\tsunflower production. In this regard, three field experiments were \n\t\t\tconducted at Students Farm, Sindh Agriculture University, Tandojam, \n\t\t\tPakistan, located at 25o25 60N 68o31 60E, altitude 19.5 m asl. In \n\t\t\tall the experiments sunflower variety HO-1 was sown in rows (75 cm \n\t\t\tspacing). The experiment-1, was meant to evaluate NPK, Zn and B \n\t\t\trequirements for sunflower production. The treatments consisted: \n\t\t\tFactor-A=Seasons (Spring and Autumn), Factor-B NPK Levels (0-0-0 NPK \n\t\t\tkg ha-1, 60-30-30 NPK kg ha-1 (N as broadcast), 90-45-45 NPK kg ha-1 \n\t\t\t(N as broadcast), 120-60-60 NPK kg ha-1 kg ha-1 (N as broadcast), \n\t\t\t60-30-30 NPK kg ha-1 (N as fertigation), 90-45-45 NPK kg ha-1 (N as \n\t\t\tfertigation) and 120-60-60 NPK kg ha-1 (N as fertigation) and \n\t\t\tFactor-C (zinc and boron levels (0-0, 10.0-1.5, 10.0-2.0, 15.0-1.5, \n\t\t\t15.0.2.0, 20.0-1.5 and 20.0-2.0 Zn+B kg ha-1). The results recorded \n\t\t\ttaller plants (207.2 cm), maximum stem girth (12.2 cm), better head \n\t\t\tdiameter (23.0 cm), more seeds head-1 (696.4), heavier seeds weight \n\t\t\thead-1 (49.0 g), bolder seed index (71.2 g), maximum seed yield \n\t\t\t(2743.0 kg ha-1) and higher dry matter (11666.7 kg ha-1), higher \n\t\t\tN-uptake (70.2 kg ha-1), P-uptake (19.1 kg ha-1), K-uptake (93.9 kg \n\t\t\tha-1), Zn-uptake (335.8 g ha-1) and B-uptake (199.2 g ha-1) under \n\t\t\tapplication of 90-45- 45 NPK x 15-1.5 Zn-B kg ha-1 (N applied as \n\t\t\tfertigation). Similarly, higher values of physiological traits at \n\t\t\tflowering phase i.e dry matter (1353.0 g m-2), leaf area index \n\t\t\t(5.7), leaf area duration (55.6 days), crop growth rate (8.7 g m-2 \n\t\t\tday-1) and net assimilation rate (24.3 g m-2 day-1) were also noted \n\t\t\tfor the same treatement. However, oil content in this Interactive \n\t\t\teffect showed non-significant differences. The regression \n\t\t\tcoefficient (b) revealed that a unit increase in various traits \n\t\t\tresulted in corresponding increase of sunflower seed yield by head \n\t\t\tdiameter (101.2 kg ha-1) seeds head-1 (6.2 kg ha-1), seed weight \n\t\t\thead-1 (55.2 kg ha-1), seed index (58.2 kg ha-1), dry matter (0.3 kg \n\t\t\tha-1), leaf area index (1108.3 kg ha-1), leaf area duration (113.4 \n\t\t\tkg ha-1), crop growth rate (378.4 kg ha-1), net assimilation rate \n\t\t\t(213.7 kg ha-1), nitrogen uptake (27.4 kg ha-1), phosphorus uptake \n\t\t\t(131.8 kg ha-1), potassium uptake (32.4 kg ha-1), zinc uptake (6.5 \n\t\t\tkg ha-1) and boron uptake (10.9 kg ha-1). However, a unit increase \n\t\t\tin seed oil content resulted corresponding decrease in seed yield by \n\t\t\t1339.2 kg ha-1. \n\t\t\tThe experiment-2, involved Integrated use of organic manures and \n\t\t\tinorganic fertilizers nutrients for sunflower production The \n\t\t\ttreatments consisted: no manure, cattle manure (5, 10 and 15 tons \n\t\t\tha-1) and poultry manure (5, 10 and 15 tons ha-1) with 90-45- 45 NPK \n\t\t\t+ 15 Zn + 1.5 B (kg ha-1). The results of the study showed that the \n\t\t\tincorporation of fertilizers and manures significantly enhanced all \n\t\t\tthe crop parameters. The taller plants (232.3, 231.2 cm), more stem \n\t\t\tgirth (13.9, 13.9 cm), maximum head diameter (27.1 and 26.5 cm), \n\t\t\thigher number of seeds head-1 (801.9 and 797.9), heavier seed weight \n\t\t\thead-1 (66.6 and 65.9 g) bolder seed index (83.2 and 83.0), superior \n\t\t\tseed yield (3681.8 and 3643.2 kg ha-1) and higher dry matter at \n\t\t\tharvest (12859.3 and 12845.0 kg ha-1), higher Nuptake (80.7 and 82.2 \n\t\t\tkg ha-1), P-uptake (24.2 and 24.5 kg ha-1), K-uptake (114.2 and \n\t\t\t114.0 kg ha-1), Zn-uptake (531.9 and 530.4 g ha-1) and B-uptake \n\t\t\t(320.4 and 314.9 g ha-1), higher dry matter (2075.0 and 2066.7 g \n\t\t\tm-2), maximum leaf area index (7.2 and 7.2), greater leaf area \n\t\t\tduration (67.4 and 67.3 days), more crop growth rate (10.3 and 10.2 \n\t\t\tg m- 2 day-1) and superior net assimilation rate (30.7 and 30.7 g \n\t\t\tm-2day-1) were recorded under cattle manure 10 t ha-1 + 90-45-45 NPK \n\t\t\t+ 15-1.5 Zn-B kg ha-1 and poultry manure 5 t ha-1 + 90-45-45 NPK + \n\t\t\t15-1.5 Zn-B kg ha-1, respectively, where N was applied as \n\t\t\tfertigation. Whereas, seed oil content showed inverse relationship \n\t\t\tunder higher applications of inorganic fertilizers and manures. It \n\t\t\twas observed that application of poultry manure at 5 tha-1 or cattle \n\t\t\tmanure at 10 t ha-1 with 90-45-45 NPK + 15-1.5 Zn-B kg ha-1 \n\t\t\tsignificantly enhanced all these traits and beyond these treatments \n\t\t\tno significant differences were exhibited even at higher levels of \n\t\t\tmanures and were economically optimum levels for achieving \n\t\t\tsatisfactory crop parameters. The regression coefficient indicates \n\t\t\tthat a unit increase in various traits resulted in corresponding \n\t\t\tincrease of sunflower seed yield by head diameter (150.0 kg ha-1) \n\t\t\tseeds head-1 (6.5 kg ha-1), seed weight head-1 (53.1 kg ha-1), seed \n\t\t\tindex (62.8 kg ha-1), dry matter (0.4 kg ha-1), leaf area index \n\t\t\t(1027.5 kg ha-1), leaf area duration (116.0 kg ha-1), crop growth \n\t\t\trate (469.9 kg ha-1), net assimilation rate (218.3 kg ha-1), \n\t\t\tnitrogen uptake (36.1 kg ha-1), phosphorus uptake (172.1 kg ha-1), \n\t\t\tpotassium uptake (40.4 kg ha-1), zinc uptake (5.9 kg ha-1) and boron \n\t\t\t(9.5 kg ha-1). However, a unit increase in oil content resulted \n\t\t\tcorresponding decrease in seed yield by (1546.3 kg ha-1). \n\t\t\tThe experiment-3 entitled residual effect of organic manures and \n\t\t\tsupplemental inorganic fertilizers on sunflower production revealed \n\t\t\tprolonged maturity (99.3 and 99.33 days), taller plants (258.1 and \n\t\t\t256.9 cm), more stem girth (16.2 and 16.2 cm), maximum head diameter \n\t\t\t(31.1 and 31.0 cm), higher number of seeds head-1 (888.1 and 884.2), \n\t\t\theavier seed weight head-1 (80.1 and 79.7 g) bolder seed index (90.9 \n\t\t\tand 92.0 g), superior seed yield (4420.2 and 4450.4 kg ha-1) and \n\t\t\thigher dry matter (14395.9 and 14381.2 kg ha-1), higher N-uptake \n\t\t\t(100.9 and 100.3 kg ha-1), P-uptake (33.9 and 33.7 kg ha-1), \n\t\t\tK-uptake (159.1 and 158.8, kg ha-1), Zn-uptake (603.0 and 605.1g \n\t\t\tha-1), B-uptake (361.0 and 364.7 g ha-1), maximum leaf area index \n\t\t\t(7.9 and 7.9), greater leaf area duration (76.0 and 75.8, days), \n\t\t\thigher dry matter (2808.7 and 2740.4 g m-2), more crop growth rate \n\t\t\t(12.1 and 12.0 g m-2 day-1) and superior net assimilation rate (36.9 \n\t\t\tand 36.0 g m-2day-1) were recorded under residual cattle manure 10 t \n\t\t\tha-1 + 90-45-45 NPK + 15-1.5 Zn-B kg ha-1 and residual poultry \n\t\t\tmanure 5 t ha-1 + 90-45-45 NPK + 15-1.5 Zn-B kg ha-1 respectively \n\t\t\twhere N applied as fertigation and beyond these treatments no \n\t\t\tsignificant increase in all the crop traits was noted. The \n\t\t\tregression coefficients indicate a unit increase in various traits \n\t\t\tresulted in corresponding increase of sunflower seed yield by head \n\t\t\tdiameter (157.2 kg ha-1) seeds head-1 (7.3 kg ha-1), seed weight \n\t\t\thead-1 (53.7 kg ha-1), seed index (67.9 kg ha-1), dry matter (0.4 kg \n\t\t\tha-1), leaf area index (1064.0 kg ha-1), leaf area duration (111.2 \n\t\t\tkg ha-1), crop growth rate (456.8 kg ha-1), net assimilation rate \n\t\t\t(195.3 kg ha-1), nitrogen uptake (36.0 kg ha-1), phosphorus uptake \n\t\t\t(143.0 kg ha-1), potassium uptake (33.3 kg ha-1), zinc uptake (6.5 \n\t\t\tkg ha-1) and boron (10.3 kg ha-1), however, a unit increase in oil \n\t\t\tcontent resulted in corresponding decrease in seed yield by 2037.6 \n\t\t\tkg ha-1. \n\t\t\tIt is concluded that the fertilizers and manures enhanced all the \n\t\t\tcrop traits, nutrient uptake and improved soil fertility. The \n\t\t\tapplication of NPK (90-45-45 kg ha-1, N applied as fertigation) + \n\t\t\tZn+B (15+1.5 kg ha-1) with 10 t ha-1 of cattle or 5 t ha-1 poultry \n\t\t\tmanure for their residual effect in the subsequent crop were \n\t\t\tsuperior and optimum fertilizer and manure doses for sunflower \n\t\t\tproduction without degrading fertility of soil. It is suggested that \n\t\t\tany source of well decomposed organic manures could be incorporated \n\t\t\tin the field to enrich the soil fertility on long term basis and \n\t\t\thigher sunflower production. Thus, it is recommended that sunflower \n\t\t\tcrop should be fertilized with incorporation of NPK (90-45-45 kg \n\t\t\tha-1, N as fertigation) + Zn+B (15+1.5 kg ha-1) with 10 t ha-1 \n\t\t\tcattle or 5 t ha-1 poultry manures for satisfactory yield and \n\t\t\tmaintenance of soil fertility.