Utility in Wastelands and Problematic Soils
In the various agro-climatic zones of the country, large areas are affected by salinity,
alkalinity, acidity and water logging. Neem tree is found growing on sand, loam and clay
textured soils, but dry areas - saline and alkaline as well as black cotton soils are ideally
suitedl9. Neem tree is known to increase the soil fertility and water holding capacity, as it has
a unique property of calcium mining, which changes the acidic soils into neutral 20 The tree
has been employed for afforestation of dry localities for reforesting bare ravines and for
checking soil erosion and also as windbreaks. Neem cover in northeastern region of .he
country (Tripura) improved the nutrient availability and water-retention capacity of the
undulating and eroded soils.
Azadirachta indica was classified as
moderately tolerant to alkali soils and
sensitive to soil salinity21. In Gujarat2 under
saline conditions, among eucalyptus, A.
nilotica, leucaena, and neem, it showed the
best performance both in growth parameters
and survival. About 50,000 trees of neem
were planted in the plains of Arafat (Saudi
Arabia) to provide shade to the 2-3 million
muslim pilgrims visiting Mecca. This
plantation is irrigated with saline water and
the plants seem to be tolerant to the ill effects
of saline waters because the earliest
plantings represent more than nine years old
healthy plants now.
To grow neem on alkali soils, a technique has been developed at Central Soil Salinity
Research Institute, Karnal. For planting the tree on highly alkaline soil, the method described
is leveling and bunding the land and applying gypsum over the whole surface @ 10-12 t/ha
(depending on the soil pH) in June/July. A rice-wheat / berseem rotation is then followed for
4-5 years and subsequently neem can be planted. With this technique, prior to planting
neem, the land provided food and fodder. Bose and Bandoyopadhyal5 reported that neem
performance on alkali soils was comparatively better (Table 7). On the basis of a recent
review, Singh et al26 have recommended Azadirachta indica with intercrop for management
of salt-affected soils.