Physiological response of autumn planted sugarcane to soil moisture depletion and planting geometry on different soils under arid conditions

A field experiment was conducted on autumn planted sugarcane cv. hsf 240 at two locations,i.e.,research area at rakh bibi campus gomal university,dara ismail khan on silty clay soil and main line lower land reclamation research station,chak no 37 tda (thal development authority) bhakkar,pakistan on sandy loam soil during 2003-04 and 2004-05. the experiment was laid out according to a randomized complete block design (rcbd) with a split plot arrangement having four replications. there were four available soil moisture depletion levels (asmdl) including asmdl1 -20%,asmdl 2 -40%,asmdl 3 - 60% and asmdl 4 -80%,which were kept in main plots and four planting patterns viz. g 1 -60 cm,g 2 -75 cm spaced single row planting patterns and g 3 -30/90,g 4 -30/120 cm spaced paired row strip planting pattern,assigned to the sub plots having net subplot size of 24 m 2. analysis of pooled data of both locations showed that leaf area index (lai),leaf area duration (lad),crop growth rate (cgr) and net assimilation rate (nar) were significantly affected by asmdl and were maximum at 40% asmd level followed by 60%,20% and the minimum at 80% asmd level during both years. whereas lad,cgr and nar were also significantly affected and were maximum in 30/90cm spaced paired row strip planting pattern followed by 75 cm and 60cm and minimum in 30/120cm spaced paired row strip planting pattern during both years. treatments interactive effects of asmd levels and planting patterns on lad,cgr and nar were significantly different except lai and were maximum in 40% asmdl x 30/90cm spaced paired row strip planting pattern and minimum in 80% asmdl x 30/120 cm spaced paired row strip planting pattern during both years. therefore it was concluded that under arid conditions on silty clay and sandy loam soils sugar cane crop gave best physiological performance by irrigation at 40% asmd level and sowing in 30/90 cm spaced paired row strip planting pattern.