Ailanthus excelsa L. based agroforestry systems to arrest land
degradation in North-West India
Different Ailanthus excelsa based agroforestry systems (Bund/boundary,
scattered trees in the existing farming systems) are practiced by the
farmers in dry parts of north-west India. However, modern/improved A.
excelsa based agroforestry systems are not popular among the farmers.
Therefore, in this study improved A. excelsa based agroforestry systems
with different tree densities were developed and assessed during initial
years of establishment in nutrient poor, light textured soils to enhance
soil fertility and productivity. In the present study, the yields of
agricultural crops were not influenced by A. excesla trees, irrespective
of crop or tree geometry/density. This might be due to young age of A.
excelsa trees. However, soil fertility status in terms of organic
matter, available P and K improved under agroforestry systems as
compared to sole cropping. Growth performance of A. excelsa under
different tree densities and in association with crops was statistically
at par. Maximum girth (47.10 cm) at breast height was recorded under 10
x 20 m spacing with cluster bean-wheat sequence, but it was at par with
other treatments. Maximum carbon sequestration (9.64 t ha-1 year-1) was
recorded in A. excelsa + cluster bean – wheat agroforestry system with
200 trees/ha. Cluster bean – wheat crop sequence sequestered more
carbon as compared to pearl millet- Indian mustard. A. excelsa based
agroforestry systems fetched higher net returns as compared to sole
cropping. Two years experimentation showed maximum benefits under
agroforestry with 10 x 5 spacing under both the crop sequences.