Agronomic Manipulations can Sustain Yield and
Improve Quality and Water Use Efficiency
 

H. Ibrahim Ali¹, M. Ismail Razi^2, M. Manan Mokhtaruddin³ and M. Saud Halimi³

¹ Department of Research and Development, The Gum Arabic Company Limited, Khartoum, Sudan
e-mail: mofdal@gac-arabicgum.com

² Crop Science Department, Faculty of Agriculture, UPM, Serdang, Malaysia

³ Department of Land Management, Faculty of Agriculture, UPM, Serdang, Malaysia

Abstract

This paper highlights the effect of addition of rice straw compost at 30% on yield, fruit quality and water use of tomato grown under protected environment, using soilless (coconut coir dust and peat, 3:2) and soil mixture (top soil, sand and peat, 2:1:2) media in combination with water regimes  varied by either withholding or using partial rootzone drying (PRD) technique.  The addition of rice straw compost significantly increased plant dry biomass, fruit diameter, yield and water use efficiency (WUE) in both media, whereas the water deficit significantly decreased these parameters in most of the treatments. The addition of rice straw compost, however, had opposite effects on the total organic matter content in the two media. The total organic matter significantly increased in the soil mixture, while it significantly decreased in the soilless medium. The results indicated that the moisture stress did not affect most of these parameters in soilless medium. Media drying decreased leaf water potential, stomatal conductance, as well as, plant dry biomass, in addition to increasing proline accumulations, with slight differences between the different growth media. Fruit quality indices were significantly increased by water regimes in both media.  PRD significantly reduced leaf expansion, plant leaf area and stomatal conductance in both media, but severity was more with the soil mixture. Proline and sugars, namely fructose, glucose and sucrose, were dramatically increased in the leaf especially with soil mixture. There was a significant reduction in total dry matter and shoot dry weight with PRD, but with no significant difference in dry root weight the root to shoot ratio increased significantly.

WUE increased significantly with PRD in both media. The use of soilless media resulted in a significant increase in all biological parameters. Yield was also affected with PRD in both media; there was significant interaction between the two media and irrigation regime. However, there was no significant reduction in marketable yield due to PRD in soilless media. This suggests that PRD application could be effective in soilless media. PRD significantly improved fruit carbohydrates and other fruit quality indices.