Traditional Knowledge for Sustainable Management of Soils - Principles of Sustainable Soil Management in Agroecosystems - page 317

nonleguminous tree but fixes atmospheric N through Frankia to the tune of 150 kg/ha
(Sharma et al. 2002). Dhyani (1998) reported a 2.2-fold increase in the yield of car-
damom under an alder canopy.
The alder trees vary in population in the arable lands. The N contribution through
leaf litter varies with the population of the alder trees. A population of 60/ha adds
about 48 kg/ha, which goes up to 113 kg/ha if the population is 166 (Rathore et al.
2010). These trees are pollarded at 2-2.5 m above ground level. The twigs and stems
are used for fuel. The leaves are left on the field and burnt along with the stubbles of
the earlier crop to add nutrients to the soil and also to oxidize Fe 2 to Fe 3+ (an ir revers-
ible reaction), thus reducing possible Fe 2+ toxicity in the oxisols. Then different crops
are grown as a mixture by the farmer. By the time the crops come to maturity, a full
canopy develops so that next season, the cycle is repeated.
13.3.12.2 Khejri in Northwest India
Khejri ( Prosopis cineraria ) is common tree in arid regions of northwest India (west-
ern Rajasthan, Haryana, Gujarat, dry region of Deccan Plateau). It is largely limited
to rainfall below 500 m. Khejri is a moderate-sized evergreen leguminous thorny
tree. It partly sheds leaves from mid-October to mid-February. Thus, consider-
able leaf litter accumulates under the trees, and light will not be limiting for crops
that grow under the canopy. Agarwal et al. (1975) reported that khejri can fix up to
250 kg N/ha.
In the farmers' fields under a khejri canopy, the yield of barley was 999 kg/
ha, compared to 537 kg/ha away from the canopy in the Hisar district of Haryana
under rainfed conditions (Kumar et al. 1998). Such yield increases under khe-
jri were reported in the case of chickpea, pearl millet, mung bean, and cluster
bean. Therefore, khejri is considered as the kamadhenu (well-wisher) of the arid-
zone farmer, providing sustainability to crop production. The above two examples
indicate that traditional agroforestry systems in India are helpful in soil fertility
management.
13.3.12.3 Aquilaria and Bamboo in Meghalaya
Areca nut ( Areca catechu ), bamboo ( Bambusa sp.), banana ( Musa paradisiacal
Linn.), black pepper ( Piper nigrum Linn.), and canes ( Calamus sp.) are cultivated
with Aquilaria ( Aquilaria agallocha Roxb.) in Meghalaya. It is a common practice in
all parts of this hill state. Areca nut ( A. catechu Linn.) is considered as the economi-
cally important tree species of the Indian peninsula and northeast. Black pepper
( P. nigrum Linn.), ginger ( Zingiber officinale Rosc.), maize ( Zea mays Linn.), and
turmeric ( Curcuma domestica Valeton) are cultivated in the interspaces. Farming
practice based on bamboo-areca nut-betel is prominent in some isolated pockets of
Meghalaya. In this system, areca nut ( A. catechu Linn.), bamboo species ( Bambusa
tulda Roxb., Bambusa pallida Munro, Bambusa balcooa Roxb., Dendrocalamus
hamiltonii Nees., Neohouzeaua dulloa A. Camus, Melocana baccifera Kurz.), and
Piper betel Linn. are cultivated together (Jeeva et al. 2006). All these systems are
based on internal recycling of residues and litter, which supports the soil with exter-
nal inputs.