In situ rain water harvest, conservation and utilisation for establishment and early growth of sappan wood (Caesalpinia sappan L.)

Abstract

Caesalpinia sappan popularly is a leguminous perennial crop grown for its valuable timber, which exhibits medicinal properties. Though the crop is sensitive to dry spells during its initial phase of establishment, it is preferred for planting as a neglected crop in marginal lands. Hence, development of sustainable rain water harvesting and conservation measures are necessary to prolong the availability of conserved moisture. The experiment entitled, ‘In situ rain water harvest, conservation and utilization for establishment and early growth of sappan wood (Caesalpinia sappan L.)’ was conducted in split plot design at the Instructional Farm, College of Agriculture, Vellayani during 2004–05 to find out the comparative efficacy of vertical mulching, micro site enrichment, micro catchments and traditional methods of rain water harvest and conservation. The treatments consisted of combinations of twelve main plot treatments, viz., vertical mulching with coconut husk in circular trenches (M1), vertical mulching with enriched coir pith vermicompost in circular trenches (M2), vertical mulching with layering mixture in circular trenches (M3), vertical mulching with coconut husk in polythene lined circular trenches (M4), vertical mulching with enriched coir pith vermicompost in polythene lined circular trenches (M5), vertical mulching with layering mixture in polythene lined circular trenches (M6), micro site enrichment and mulching with polythene (M7), micro site enrichment and mulching with coconut husk (M8), micro catchments and mulching with coconut husk (M9), micro catchments and mulching with coir geo-textiles (M10), pitcher irrigation (M11) and drip irrigation (M12); and two sub plot treatments, viz., irrigation at 50 per cent depletion of soil moisture (S1) and life saving irrigation (S2). The treatments, (M6) followed by M7 resulted in luxuriant growth. Growth characters viz., plant height, leaf number, collar girth, number of branches, bole height, canopy height, canopy width and canopy size and root characters, viz., root length, root spread, root weight, root volume and root surface area were found to improve significantly due to the treatment effects. Sturdiness quotient and root growth potential also indicated the superiority of the treatments in the developmental physiology of the crop. Irrigation at 50 per cent depletion of soil moisture improved all the growth characters compared to life saving irrigation. M6S1 recorded the maximum stem dry matter production (SDMP) followed by M7S1, M8S1, M2S1, M6S2, M3S1 and M7S2. The reduction in SDMP in treatment combinations, viz., M6S2 and M7S2 were 45 and 37 per cent respectively when summer irrigation was avoided and moisture supply was restricted through life saving irrigation alone. The treatment combinations, M6S1 and M7S1 were found beneficial for improving crop growth potential as well. Among the various treatment combinations, crop growth potential was higher when life saving irrigation was integrated with either vertical mulching with layering mixture or microsite enrichment and mulching with polythene. Seed production potential of sappan wood was found to be influenced by the interaction effects and M6S2 and M7S2 were significant in influencing seed production. M6S2 and M7S2 increased the osmotic potential to the tune of 74.18 and 71.3 per cent respectively when compared to M12S2. The seasonal Cu, mean daily Cu and crop coefficient for M6S2 and M7S2 were found to be lower when compared to M6S1, M7S1 and other treatment combinations receiving summer irrigation at 50 per cent depletion of soil moisture. Vertical mulching with layering mixture in polythene lined circular trenches and providing life saving irrigation once in three weeks with thirty three litres of water or micro site enrichment and mulching with polythene and providing life saving irrigation once in four weeks with thirty three litres of water is found beneficial for establishment and early growth of sappan wood. The economic analysis of the system also proved the superiority of the above two treatment combinations.