Studies on Analysis and Application of Intensive Planting Techniques in Small Land Agriculture : I. Effect of plant type, sowing time and planting density on growth and yield in maize-kidney bean intercropping

摘要

The field experiment based on the results of field surveys (1978-1979) was made to determine the effect of plant type, sowing time and planting density on growth and yield in maize-kidney bean intercropping in 1979, from a viewpoint of analysis and application of conventional intensive culture in small land. Applied planting pattern was hill space intercropping of in-row planting and the obtained results were as follows: 1. Growth: The overlapping period of growth duration of maize and kidney bean in intercropping was longer in the planting with pole type bean than with the dwarf type bean, and also it was longer in late sowing than in early sowing of beans. Maize showed a tendency of increasing plant height at high planting density after tasseling irresepective of planting patterns. Plant height of pole type bean was shorter at intercropping than single cropping and this tendency was remarkable at later sowing with high planting density (Table 2). The dwarf type tended to be taller in plant height at intercropping in later sowing, especially in high planting density, but no difference in plant height was observed at early sowing (Fig. 2) Weed prostration was remarkably surpressed at high planting density of intercropping. The weed growth was coincident with the patterns of light transmission (relative light intensity) in the plant community (Fig. 3). 2. Yield: Grain yield per plant of maize was low at higher planting density irrespective of planting patterns. This higher yield in intercropping could be obtained at the planting with dwarf type bean than the planting with pole type bean. On the other hand, yield per area was higher at high planting density of any planting patterns but this incremental rate by intercropping was small (Fig. 4, Fig. 5, Fig. 6). The intercropping bean yield was particularly low at early sowing of pole type bean and also at late sowing of dwarf type bean. 3. Evaluation of land utlization in intercropping culture by relative yield totals (RYT) showed higher effect compared with single cropping, and maximum of RYT was found at late sowing with pole type in high planting density and early sowing with dwarf type bean in low planting density (Fig. 10).