Gulzar Ahmad

Influence of nitrogen and sulfur fertilization on quality of canola (Brassica napus L.) under rainfed conditions

Field experiments were conducted at Cereal Crops Research Institute, Pirsabak, Nowshera, Pakistan, during winter 2003∼2004 and 2004∼2005 to evaluate the effect of nitrogen and sulfur levels and methods of nitrogen application on canola (Brassica napus L. cv. Bulbul-98) under rainfed conditions. Four levels of S (0, 10, 20, and 30 kg/ha) and three levels of N (40, 60, and 80 kg/ha) and a control treatment with both nutrients at zero level were included in the experiments. Sulfur levels were applied at sowing while N levels were applied by three methods (100% soil application, 90% soil+10% foliar application, and 80% soil +20% foliar application). The experiments were laid out in randomized complete block (RCB) design having four replications. Oil content increased significantly up to 20 kg S/ha but further increase in S level did not enhance oil content. Glucosinolate content increased from 13.6 to 24.6 μmol/g as S rate was increased from 0 to 30 kg/ha. Protein content increased from 22.4% to 23.2% as S rate was increased from 0 to 20 kg/ha. Oil content responded negatively to the increasing N levels. The highest N level resulted in the highest values for protein (23.5%) and glucosinolate (19.9 μmol/g) contents. Methods of N application had no significant impact on any parameters under study.

EFFECT OF NITROGEN AND SULFUR FERTILIZATION ON YIELD COMPONENTS, SEED AND OIL YIELDS OF CANOLA

Field experiments were conducted to evaluate the effects of nitrogen (N) and sulfur (S) levels and their methods of application on canola. Branches plant−1, pods plant−1 and biological yield significantly increased with increase in nitrogen level and no significant increase in seed pod−1 and seed and oil yields occurred beyond 120 kg N ha−1. However, thousand seed weight consistently decreased with increasing level of nitrogen. Pods plant−1 and biological yield continually increased with increase in sulfur level. Alternatively, significant increase in branches plant−1, seed pod−1, seed weight, seed and oil yields was noted with increase in sulfur level up to 40 kg ha−1. Applications of sulfur and nitrogen in split significantly decreased seed yield as compared to sole applications. It is concluded that sulfur and nitrogen application as sole at the rate of 40 and 120 kg ha−1, respectively performed better than the rest of their levels and method of application.

QUALITY PARAMETERS OF CANOLA AS AFFECTED BY NITROGEN AND SULFUR FERTILIZATION

Field experiments were conducted at Cereal Crops Research Institute Pirsabak Nowshera, Pakistan, for two years (2003–2004 and 2004–2005) to evaluate the effects of nitrogen (N) and sulfur (S) levels and their methods of application on quality parameters of canola (Brassica napus L. cv. ‘Bulbul-98’). Four levels of S (0, 20, 40, and 60 kg ha−1) and three levels of N (80, 120, and 160 kg ha−1) and a control treatment (with both nutrients at zero level) were applied as a sole dose at sowing, in two split applications (half each at sowing and leaf rosette stages) and three split applications (one third each at sowing, leaf rosette stage, and early flowering). Large increases in oil and protein concentrations were measured at 40 kg S ha−1 while no further significant increase was observed at 60 kg S ha−1. However, increasing level of S consistently increased glucosinolate concentrations to the highest level of 60 kg S ha−1. Nitrogen significantly increased protein concentrations up to the maximum level of 160 kg N ha−1 while glucosinolate concentrations were increased up to 120 kg N ha−1. However, oil concentrations showed negative trend to increasing level of N.