Effect of solar radiation on the growth and productivity of crops of different height and maturity under cropping system

Date

10-1979

Abstract

Two sorghum row spacings (75 cm /rl/ and 100 cm /r2/), and 2 cropping systems: monoculture (short sorghum /Sgs/ and tall sorghum /Sgt/, early /Sye/ and late /Sy1/ soybean, and early /Mge/ and late /Mggl/ mung bean) and intercropping (Sgs + Sye, Sgs + Syl, Sgs + Mge+ Sgs+ Mgl+ Sgt+ Sye, Sgt+ Mge, and Sgt+ Mgl) were used in wet and dry season experiments with sorghum as the main crop. A split plot design with four replications were used. Sorghum row spacing served as main plots and cropping systems as subplots.

Narrow row spacings in both seasons increased the grain yield (GY) and total dry matter (TDM) of sorghum and soybean and remained the same for mung bean. The highest GY and TDM yield of short, sorghum, soybean and mung bean were from monoculture, and from SgtMgl combination in the wet season and SgtMge in the dry season. The TDM was the predominant factor affecting GY of sorghum, soybean and mung bean crop combinations; increase in TDM was due to narrow row spacings. In estimating the TDM of the crops, the left area index (LAI) was found more important than the leaf area duration (LAD).

Varying the intercropping combination with height and maturity resulted in a decrease of certain yield components of the crops, decreasing the GY and TDM compared with monoculture. But the total grain yield of the crops in the intercropping system was comparatively economically higher than that of the crops in monoculture, Although the GY of each intercropping system crop was relatively lower than that in monoculture.

Percentage of light intercepted at 50 days after seeding (DAS) in the wet season was more important in the determination of GY and TDM of sorghum and soybean instead of 30DAS; but this was not applicable for mung bean. During the dry season 30 and 50 DAS were both important for all crops. Narrower row spacings and closer cropping canopy increased the percentage of light intercepted.

As indicators of photosynthetic capacity, increased LAI and Lad decreased leaf area ratio (LAR) and relative leaf growth rate (RLGR) of the crops. For photosynthetic efficiency, the net assimilation rate (NAR) and crop growth rate (CGR) increased in the early stage and decreased in the later stage; but the relative growth stage (RGR) decreased throughout the growth stages.

Therefore, with the decrease of all indicators, the TDM of each crop in the intercropping system decreased compared with that of crops in monoculture. Subsequently, TDM increased as NAR, RGR, and CGR decreased.

In general, CGR greatly affected TDM of the crops showing that this could be a good indicator of TDM production. The NAR and RGR of sorghum did not show a highly significant correlation with TDM but showed a significant correlation with TDM in soybean and mung bean. Thus, the NAR and CGR could not be used to predict TDM of sorghum under such cropping system.

Document Type

Dissertation

Degree

Doctor of Philosophy in Agronomy

College

Graduate School (GS)

Adviser/Committee Chair

Dr. Romeo U. Quintana

Co-adviser

Dr. Pretonio S. Ongkingco

Committee Member

Dr. Arturo C. Alferez, Dr. Igmidio T. Corpuz

Language

English

LC Subject

Plants, Effect of solar radiation on, Solar radiation Physiological effect

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 996 1979 A42 M44

Notes

Doctor of Philosophy (Agronomy)

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