Mineral nutrition of vegetable crops: XXVI - mineral nutrition of new zealand spinach (Tetragonia expansa Murr.): absorption of macro and micronutrients

Abstract

Spinach plants were cultivated under field conditions. All manegement practice were observed. Periodically plants were harvested and analysed for N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, Mo and Zn. - The variety presented a continuous growth expressed, in dry matter, until 120 days. - The greatest demand for nutrients occurs between 93 and 106 days. - The maximum absorption of the nutrients by leaves is around the period of 93 to 106 days. - The absorption of Fe by the spinach plants is continuous until at the end of the plant life. - At 90 days the spinach leaves presented the following concentration: N- 2.54%; P- 0.21%; K- 5.64%; Ca- 1.06%; Mg- 0.83%; S- 0.35%; B- 66 ppm; Cu- 15 ppm; Fe- 364 ppm; Mn- 297 ppm; Zn- 139 ppm and Mo- 0.83 ppm. - One plant and 22,222 spinach plants (one ha.) remove the following quantities in nutrients: