Biomass/productivity and nutrient retention in some Dalbergia sissoo Roxb. plantations of Punjab, India

Abstract

The biomass and nutrient distribution in Dalbergia sissoo Roxb. Plantations of different ages (25-33 years) has been studied at six sites at Nara, Chaksadhu, Dhirowal, Kharkan, Dharamkot and Kamalpur of Hoshiarpur, Feerozpur and Amritsar Forest Division of Punjab. The biomass ranged from 83.56 kg tree-1 to 1516 kg tree-1 and from 85.42 to 1226.94 t ha-1 in all these sites. Productivity ranged from 2.59 t ha-1 yr-1 (at 33 yrs) to 9.28 t ha-1 yr-1 (at 25 yrs). The contribution of individual tree components to total biomass varied as: leaf 0.65 to 3.86%; twig 1.62 to 5.64%, branch 10 to 24.88%, bark 8.49 to 12.27%, root 14.98 to 20.58% and bole 42.98 to 58.76%. The percent contributions of all tree components in all the sites were in the order of bole > root > branch > bark > twig > leaf. Prediction models have been worked out by using allometric regressions. Among prediction variables tried D2H were found the most reliable parameters for prediction of biomass. The amount of various nutrients varied from N-691.12 to 2087.24 kg ha-1 P-26.33 to 98.05 kg ha-1, K-470.2 to 1305.4 kg ha-1, Ca-725.05 to 3306.38 kg ha-1 and Mg – 58.33 to 141.20 kg ha-1, respectively. The percentage contribution of different nutrients to total nutrients were as; N (24.57 to 42.41%), P (1.28 to 2.1%), K (16.69 to 31.95%), Ca (28.25 to 54.79%) and Mg (1.51 to 4.27%), respectively. Nutrient losses through complete harvesting have also been discussed and some suggestions have been made to replenish the nutrient loss and improve the site productivity.