Influence of the Level of Nitrogenous Fertilizer on the Yield and Dry Matter Content of Marrow Stem Kale at Various Sowing Dates

Abstract

ALTHOUGH nitrogen, appears to be the major element affecting the yield of kale¹, there is marked variation in response², which depends on the level of soil fertility³, rainfall⁴ and the dates of harvesting^4,5 and sowing, some authors finding a greater response to nitrogen when sowing occurs after early June². It is also known that higher rates of nitrogen reduce the dry matter content^4,5 and increase the number of lodged and rotted plants in marrow stem kale, especially with very late harvesting⁵. In 1962, 1963 and 1964 the effects of nitrogen level and plant population on the yield and dry matter content of Cannells marrow stem kale were investigated in respect of varied dates of sowing and two dates of cutting (Table 1). Five levels of nitrogen were used: (a) no nitrogen, 1963 and 1964; (b) 2 cwt. nitro-chalk (21 per cent nitrogen) per acre, late sowing 1964; (c) 4 cwt. nitro-chalk/ acre, 1962, 1963 and 1964; (d) 6 cwt. nitro-chalk/acre, early sowing 1964; (e) 8 cwt. nitro-chalk/ acre, 1962, 1963 and 1964. All nitrogen was broadcast immediately after drilling and each treatment received a basal dressing of 5 cwt./acre of a 20 per cent phosphorus pentoxide compound, 20 per cent potassium monoxide compound which contained no nitrogen. Graded seed was precision drilled at 1 and 2 in. spacings in rows 8, 16 (1962) and 24 in. apart.