Forage Legume Response to Subsoil Compaction

Abstract

Subsoil compaction affects all aspects of soil quality which may result reduction of crop development. An experiment was conducted in a phytotron using a randomized block design to evaluate the effects of different levels of subsoil compaction on forage legume crop development and mineral nutrient acquisition and translocation in an Andisol. A clay loam Andisol was used to grow the soybean, chickpea and lentil at different levels of subsoil compaction as no compaction (0 J), medium compaction (500 J) and high compaction (1000 J). Plants were also grown under same condition in surface compaction. In this experiment, the effects of soil compaction on soil physical and hydrological properties as well recorded. The bulk density of soil increased substantially with increasing compaction. Consequently the air-filled porosity and void ratio of soil decreased with increasing compaction. Compacted soil retains more water at higher matric suction. Shoot and root weights of the plants were significantly higher at 0 J than at 500 J compaction levels indicating that soil compaction hampered normal plant growth in Andisol, irrespective of crops. Furthermore, the yields of plants tended to remarkably decrease with increasing of soil compaction from 500 J to 1000 J for both surface and subsoil compaction. Although the reduction of crop yields from 500 J to 1000 J was not always statistically significant. The severity of the detrimental effect of compaction on dry matter production could be presented as chickpea lentil soybean. The results obtained in the study revealed that apart from Ca uptake by roots, compaction hampered nutrient assimilation in both shoot and root of all the crops. Similarly, the translocation of nutrients in the shoot of the plants was adversely affected by compaction. This study revealed that the effect of surface soil compaction was less severe on the forage legume crops than subsoil compaction. We confer that the morphological and physiological changes in three legume forages differed in both surface and subsoil compaction.