Response of ratooning grain sorghum to nitrogen fertilizer and insecticides

Touchton, J.T. and Martin, P.B. (1981) Response of ratooning grain sorghum to nitrogen fertilizer and insecticides. Agronomy Journal, 73 (2). pp. 298-300.

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In field trials, grain sorghum cv. DeKalb 54 was sown on 15 April 1977 and 27 March 1978 at 280 000 plants/ha and harvested on 15 Aug and 24 July, resp. Stems were cut c. 12 cm above the soil surface, plots were given N at 8 rates from 0 to 157 kg/ha and insecticides were or were not applied to the 2nd (ratoon) crop at flowering and before heading. Late harvest and early frost resulted in the 1977 ratoon crop not reaching full maturity until after a killing frost. In 1977, leaf N content increased with increasing N rate from c. 1.83 to 2.81%, av. grain yield was 2.2. and 1.4 t/ha with and without insecticides and did not respond to >112 kg/N. 100-grain wt. was 1.6 g compared with 2.7 g in the sown crop. In 1978, leaf N content was 1.4-2.0% and did not increase with N rates >67 kg/ha. Grain yield increased from 2.7 to 3.4 t/ha with up to 67 kg/N, decreased at the highest rates and was little affected by N rate in the absence of insecticides when it was c. 1.9 t/ha. 100 grain wt. was 2.91 g and 2.22 g without and with insecticides, resp. Total grain yields from both harvests with the opt. N rates and insecticides were 8.7 and 9.8 t/ha in 1977 and 1978, resp. It was concluded that added N was important in hastening maturity and increasing yield and that the ratoon crop was more sensitive to insect damage than was the 1st crop

Item Type: Article
Author Affiliation: Department of Agronomy, University of Georgia, Agricultural Experiment Station, Experiment, GA 30212, USA
Subjects: Plant Protection
Divisions: Sorghum
Depositing User: Ms K Syamalamba
Date Deposited: 07 Feb 2013 08:45
Last Modified: 07 Feb 2013 08:45

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