Effects of Spacing and Lopping on a Mesquite (Prosopis juliflora)–Karnal Grass (Leptochloa fusca) Agroforestry System on an Alkaline Soil

Abstract

The effects of spacing and lopping on a mesquite (Prosopis juliflora) and Karnal grass (Leptochloa fusca) agroforestry system on an alkaline soil at Karnal in India was examined over a three year period from planting. There were no significant differences in the height and diameter of the mesquite or in the number of branches at different spacings, but growth was significantly improved by lopping. The oven dried biomass obtained from lopped branches over a 40 month period was greatest at a 2 × 2 m spacing. The green forage yield of Karnal grass was greatest under mesquite spaced 4 × 4 m apart and was markedly improved under lopped mesquite. The inorganic composition of the Karnal grass, including trace elements, made it a valuable fodder in an area with an adverse alkaline soil environment. The calcium and potassium content of the grass increased and the sodium content decreased in successive cuttings. Mesquite and Karnal grass grown together reduced soil pH and EC and improved the organic carbon and available nitrogen content of the soil.