Productivity of high-yielding crops

Abstract

Abstract “Standard yield variety” and “high-yielding variety” of rice, winter wheat, maize, soybean, potato, beet, and sunflower were grown, and the relationship between root growth and absorption of nitrogen was studied. To estimate the role of root in nitrogen absorption, nitrogen absorption rate (ΔN, g N m−2 d−1) was parameterized into root dry weight (RW, g m−2) and specific absorption rate of nitrogen per root dry weight (SARN, ΔN RW−1). 1. Since during the vegetative growth stage, the correlation between ΔN and crop growth rate (CGR) was high, ΔN was under the control of shoot demand for nitrogen, while during the early maturing stage, ΔN was well correlated with SARN except for sunflower. Thus, ΔN at the vegetative growth stage was regulated by shoot growth (CGR), which was related to RW sometimes. Thereafter, ΔN was regulated by SARN with the progression of growth.2. Based on the cluster analysis of SARN or RW for ΔN, and correlation between ΔN and SARN or RW, crops were classified into three groups: group (I), soybean, potato, and beet; group (II), rice, winter wheat, and maize; and group (III), sunflower. During the early maturating stage, ΔN of group (I) was regulated by mainly SARN, ΔN of group (II) was regulated by both SARN and RW, and ΔN of group (III) was regulated mainly by RW.3. SARN remained high during the early maturation stage in the “high-yielding variety” of crops.