Quality and Nitrogen Use Efficiency of Sunflower Grown at Different Nitrogen Levels Under Mediterranean Conditions

Abstract

A two-year field experiment (during 1998 and 1999) was carried out in a Mediterranean environment to study the effects of different nitrogen (N) fertilizer rates on N uptake, N remobilization, N use efficiency, and yield performance of sunflowers grown in Southern Italy. Two sunflower genotypes (one commercial standard line and one selected genotype) and three N fertilization levels (0, 50, and 100 kg ha −1 as ammonium nitrate) were compared in this experiment. N uptake (N content × biomass dry weight) of the leaves and stems, hand-held chlorophyll meter (SPAD readings), and leaf area index (LAI) were measured at flowering time; yield and its components, percentage of oil content, and plant N uptake were determined at physiological maturity. Nitrogen use efficiency parameters and N remobilization were also calculated. The results indicated a significant difference in yield, percentage of oil content, total N uptake, and N use efficiency parameters between the years, indicating greater limits imposed by the environment on sunflower potential. In the year with irregular rainfall (1998), higher N uptake at the flowering stage was found, thus determining higher N translocated, whereas in the year with normal rainfall distribution (1999), a higher total N uptake at the maturity phase was recorded. The intermediate N fertilization treatment (50 kg N ha −1 ) showed a better utilization of applied N, reducing the possibility of pollution. In fact, in both years, yield, LAI, total N uptake, and N use efficiency were statistically unaffected by the two N fertilization treatments. The differences between sunflower genotypes in yield performance and N use efficiency were observed during 1999, when the climate did not limit sunflower growth. In contrast, during 1998 N fertilization rates showed a significant response to the N fertilizer treatments in yield and in most measured parameters. Finally, the significant correlation between N uptake and N use efficiency parameters with yield indicate the importance of N nutrition in sunflowers grown in Mediterranean 336 Montemurro and De Giorgioconditions, whereas the negative correlation between yield and oil content confirms that higher seed production is associated with lower oil content.

Oil Content and Saturated Fatty Acids in Sunflower as a Function of Planting Date, Nitrogen Rate, and Hybrid

“…At Newton, oil content in the 67, 134, and 202 kg N ha −1 rates were equal (324 g kg −1 ), but lower than that at the 0 kg N ha −1 rate (341 g kg −1 ) (data not shown). This result is consistent with previous reports indicating decrease in oil content with increasing N rates (Tonev, 2006; Montemurro and Giorgio, 2005; Valchovski, 2002; Zheljazkov et al, 2008). Also at Newton, oil content was highest in the seeds from the first planting date, and lower from the second planting date followed by the lowest oil content from the third planning date (Table 4).…”

Effect of Nitrogen on Yield and Oil Quality of Sunflower (<i>Helianthus Annuus</i> L.) Hybrids under Sub Humid Conditions of Pakistan

“…The minimum value of mean NUE (0.0 kg·kg -1 ) was observed from plots fertilized with 0 kg·N·ha -1 (N 1 ). Similar findings were also reported by [28,29].…”

Agronomic Practices at Low Environmental Impact for Durum Wheat in Mediterranean Conditions

“…The values are divided by crop management values. Contrary to the findings of other crops (Lòpez-Bellido et al, 2000;Montemurro and De Giorgio, 2005), the conservative crop management reached good productive responses. In fact, no significant difference between CONS and CONV (25.28 and 25.84 t ha −1 , respectively) was observed.…”