Effect of mulches on soil hydrothermal regimes and growth of plum in mid hill region of Himachal Pradesh

Field study with different mulches, viz. transparent polythene (TP), black polythene (BP), bicoloured polythene (BIP), field grass (GM), pine needles (PN) and unmulched control (UM) was conducted to ascertain their effects on soil hydrothermal regimes and growth of 16-year-old plum trees (cv. Santa Rosa) during December to June, 200405 and 2005–06 (two seasons). Results revealed that all mulches maintained comparatively higher soil moisture contents over unmulched control and in situ moisture conservation was more in upper 0–7.5 cm layer. Among mulches, BP closely followed by BIP conserved highest moisture being 31.8–52.8 and 9.3–20.9% higher over UM in 0–30 cm soil depth during 2004–05 and 2005–06, respectively. Other mulches also conserved higher moisture over UM and followed the order: BP>BIP>TP>PN>GM>UM. Mulches considerably influenced soil temperature and TP recorded higher temperature both at 7.5 and 15 cm depths and effectiveness of mulches in moderating temperature followed the order: TP>BP>BIP>GM>PN>UM at 07.30 h and TP>BP>BIP>UM>GM>PN at 14.30 h. Weed infestation was effectively checked and minimum weed growth was observed under BP and BIP. Plant growth expressed as annual shoot growth and fruit yield was significantly influenced by mulches and BP gave higher yield (80.62 q ha⁻¹). Both GM and PN were equally effective in increasing the yield over UM. The seasonal income under BP, BIP, TP, GM and PN was 1.16, 1.20, 1.58, 1.09 and 1.12 times higher, respectively compared to control.