Traditional Knowledge for Sustainable Management of Soils - Principles of Sustainable Soil Management in Agroecosystems - page 315

13.3.8 G reen M anurinG
Green manuring is an age-old practice prevalent since ancient times (Sofia et al.
2006). Farmers try to grow dhaincha ( Sesbania acculeata ) and sunhemp ( Crotalaria
juncea ) as green manuring crops for improving soil health. Just around flowering
(30-45 days after sowing), the crop is cut down and mixed into the soil, after which
the season's main crop is sown. These practices are more popular under irrigated
conditions. Some of the farmers do incorporate okra and potato stem in the field,
which are comparatively much better than other crops. Since these crops are termed
as cash crops, after the harvesting of pod and tuber, remaining biomass is used for
soil strengthening. So, incorporation of this green biomass after adding water in the
soil has a significant role in maintaining soil health. Green manuring is beneficial in
two ways—first, it fixes nitrogen, and second, the addition of biomass (around 5 to
10 tons/acre) greatly helps in improving the soil texture and water holding capacity.
13.3.9 B eushening in e aStern i ndia
Beushening in rainfed lowland rice is an age-old practice in the shallow submerged low-
land in most of the eastern states (Chandra 1999). Beushening is criss-cross plowing
in a standing rice crop of 30 to 45 days after seeding when water 10 to 15 cm deep
stands in the field. It helps in burying the weeds and excess rice seedlings. This is fol-
lowed by laddering and seedling redistribution. Sometimes weeding is also taken up.
The weed population decreases considerably with beushening . Through beushening , as
much as 310 g/m 2 of weeds are buried in the field as green manure. This is besides the
additional rice seedlings plowed in. The weeds and additional rice seedlings add at least
45 kg N/ha/year. However, weed control is needed for better yields under beushening .
The additional yield with beushening even in hand-weeded situations is due to root prun-
ing of the rice seedlings. Thus, in the absence of labor, at least beushening maintains
good productivity. Farmers practice to beushening suppresses weeds and adds nutrients
through green manure for the standing rice crop. Such a “green manuring” effect is ideal
in lowland rice as its decomposition does not need high energy (being anaerobic). Also,
beushening saves demand on labor, an increasingly felt constraint in modern agriculture.
13.3.10 M aghi C roppinG —l eGuMe -B aSed S equenCe C roppinG
A unique practice of legume-based sequence cropping is carried out by farmers in
the Khammam district of Andhra Pradesh. This area receives 1000-mm rainfall,
with an assured moisture supply period of 180 to 210 days. Soils are predominantly
Vertisols low in nitrogen and high in potassium. A unique practice of the green
gram-sorghum cropping system is followed here to take care of the nutrient require-
ment. The green gram is sown by early June. After 65 to 70 days, the pods are
harvested, the haulms are incorporated in the soil, and the sorghum crop is sown
during the third week of August. This is neither a kharif nor a rabi crop. Green gram
incorporation adds 35-40 kg N/ha, adequate to meet the N requirement of sorghum.
This practice has been in vogue for many years, and the physical properties of the
soils like aggregation and infiltration rate are maintained very well.