G. Singh , N. Bala , V. Kuppusamy , T. R. Rathod

Abstract

Growth and productivity of Cassia angustifolia was studied during 1997 to 2000 in presence of adult neighbours namely Acacia tortilis , Prosopis juliflora and Calligonum polygonoides. The objectives were to find out suitable combination to control sand drift and to increase overall productivity of arid area. Seedlings of above species were planted in September 1996 , whereas the C. angustifol ,ia was sown in July 1997. Growth of woody perennials , growth , phenology , biomass productivity and ischolar_main study of C. angustifolia and soil water content were the recorded observations. C. angustifolia flowered twice in a year and remains green during peak summer of May and June and therefore would be beneficial in sand drift control. It had deep penetrating ischolar_mains to gather limiting resources in this unproductive land. Production of C. angustifolia was higher (P<0.05) with C. polygonoides as compared to P. juliflora and A. tortilis. Soil water content was higher under C. polygonoides than that under other two species and suggested to be due to spreading type of canopy. Fresh weight of stem + twigs and leaves of C. angustifolia ranged from 61.9% to 66.7% and 33.3% to 38.1% , respectively with total above ground biomass production of 3.70 to 7.35 tonnes ha^-l. There was no difference between biomass of summer and autumn harvesting , though the production decreased with age of the plants. The combination of C. polygonoides and C. angustifolia was best to increase production of this dry land with additional benefits of sand drift control.

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G. Singh , Bilas Singh , V. Kuppusamy , N. Bala

Abstract

Investigations were made on soil properties and foliage nutrient compositions under four age classes of Acacia tortilis (L) Forsk plantation to determine the nutrient buildup and the impact of Acacia tortilis plantation on soil properties. The study was carried out through simple random sampling using four stands of different ages viz 4 years (Y₄) , 9 years (Y₉ ) , 12 years (Y₁₂) and 19 years (Y₁₉). Elemental concentration of
A. tortilis foliage differed significalltly (P4) and increased with increasing stand age. Mg , K , Zn , Mn and Fe showed a reverse trend that was attributed to the effect of irrigation during the first five years and increased competition for resources in older stands. Most of the soil nutrients were higher in plantation area compared to control area (Y_o). Soil organic carbon (SOC) increased with increasing age of the stand , influencing the soil pH and soil nutrient availability. Soil available nitrogen N (NH_4-N+NO_3-N) , P0_4-P , Ca , Cu , Zn and Fe increase through SOC/litter accumulation. K and Zn also showed increasing trend , though the availability was less compared to Y₀ area and was due to higher utilisation in actively growing young plantation. Extractable Mg decreased with age and was probably utiJised in stand development. Accumulation was greater in 0-15 cm soil layer compared to 15-30 em layer. The increased soil nutrients under A. tortilis plantation had direct impact on site improvement. Thus the study suggests that the species can be utilised in wasteland development and other afforestation programmes.

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