The yield formation of winter wheat triticum aestivum cultivar maris huntsman growing continuously
Mueller Wilmes, U.
Landwirtschaftliche Forschung 35(1-2): 96-108
Investigations lasting 1 yr were carried out to examine the effects of continuous growing of winter wheat (cv. Maris Huntsman) on yield-formation in a 20 yr field trial in relation to the number of successive crops (1X, 2X, 14X and 20X winter wheat) and 2 levels of N application (N40 = 40 kg/ha N,N160 = 160 kg/ha N). Special attention was given to the investigation of root-formation and nutrient-uptake and to the influence of pathogenic microorganisms on root-formation of winter wheat. The grain-yield of winter wheat growing continuously did not generally decrease. The grain-yield of the 2nd and 20th winter wheat increased by 22% and 25% at N40 and by 14% and 1% at N160, respectively. The root-formation of winter wheat changed only slightly in relation to the different number of successive crops. In the 2nd and 20th winter wheat there was a change of the total root quantity of +6% and -2% at N40, and of -7% and -6% at N160 compared to the 1st winter wheat; the living root quantity showed a decrease of -12% and -4% at N40, and of -23% and -11% at N160. The content of soil nitrate increased compared to the 1st winter wheat in the 2nd and 20th winter wheat by 0.5 mg NO3/100 g soil each at N40 by 9 mg and 2 mg NO3/100 g soil at N160. N accumulation in the ear as well as in the last and penultimate internodes of winter wheat during the reproductive growing phase did not change decisively in relation to the number of successive crops. N removed by the wheat plants at harvest increased in the 2nd and 20th winter wheat by 15% and 33% at N40, by 10% and 32% at N160 compared to the 1st winter wheat. Histological investigations of the wheat root were carried out to demonstrate pathogenic microorganisms, minor pathogens as a possible cause of root-rot in wheat and barley grown continuously.