Effects of Different Forms of Nitrogen Fertilizer on Yield Components and Yield Formation of Coix (Coix lacryma-jobi L.)

Purpose To study the effects of different forms of nitrogen (N) fertilizer on the yield components and yield formation of coix, providing theoretical basis for improving coix cultivation and building ideal plant type.

MethodsRenyi No.1, a main cultivar of coix in Guizhou Province, were cultured in soil potting under supply with the same application amount of N (1.6 g/plant). Five treatments, including single application of nitrate N (N₁), single application of ammonium N (N₂), single application of urea (N₃), 1 ∶ 1 combined application of nitrate and ammonium N (N₄), and no N fertilizer (CK) were set. The photosynthetic parameter, dry matter accumulation and distribution, yield components such as tillering and branching were measured, and the correlations between main yield components and yield in coix were analyzed.

ResultsStem diameter, tiller number, and grain yield of whole plant were significantly increased with N application. The SPAD value and chlorophyll a content of leaves treated with N₃ and N₄ were significantly higher than those with N₁ treatment at heading stage. Compared with N₁, N₂ and N₄ treatments, dry matter accumulation, tiller number, biological yield (fresh weight) and grain yield of whole plant were significantly increased by N₃ treatment. Grain yield of whole plant of coix was significantly positively correlated with primary shoot number, stem diameter, effective primary shoot number, tiller number and effective tiller number.

ConclusionsSingle application of urea can increase stem diameter, tiller number and dry matter accumulation in coix, which is more beneficial to increase the yield per coix.