Carbon Sink Capacity and Agronomic Productivity of Soils of Semiarid Regions of India - Principles of Sustainable Soil Management in Agroecosystems - page 448

TABLE 16.10
Impact of Mulch-cum-Manuring with Gliricidia on the Productivity
of Castor

Castor Equivalent
(kg ha -1 )

Net Income
(Rs. ha -1 ) Treatments

T1: No FYM and no fertilizers 328 2035

T2: FYM at 5 t ha -1 + 40:30:0 kg NPK ha -1 691 5493

T3: T2 + Gliricidia 984 8307

Source: Srinivasarao, Ch. et al., Carbon sequestration strategies under rainfed production
systems of India, Central Research Institute for Dryland Agriculture, Hyderabad
(ICAR), India, 2009.

ha -1 of Gliricidia along with 10-20 kg N ha -1 . Sharma et al. (2004) reported that
the two INM treatments, 2 Mg Gliricidia loppings + 20 kg N and 4 Mg compost +
20 kg N, were the most effective in increasing the sorghum grain yield by 85% and
78% over control, respectively. However, the highest amount of SOC concentration
(0.74%) was observed in 100% organic treatment (4 Mg compost + 2 Mg Gliricidia
loppings). Some of these options of managing nutrients by using farm-based organics
can be a component of organic farming. Based on a long-term experiment, Sharma et
al. (2002) reported that the conjunctive use of urea and organics such as loppings of
Leucaena and Gliricidia (1:1 ratio on N equivalent) increased sorghum grain yield
to 1.69 and 1.72 Mg ha -1 , respectively, and thus revealed that a minimum of 50% N
requirement of sorghum can be easily met from farm-based organic sources. This
research information can be used to supplement fertilizer N up to 50% by using
green loppings of Gliricidia maculata and Leucaena leucocephala and will be use-
ful while planning for the cultivation of organic produce. Furthermore, the SOC con-
centration was significantly increased by application of CRs such as sorghum stover
and Gliricidia at the rate of 2 Mg ha -1 under minimum-tillage and CT systems for
rainfed sorghum-castor rotations on Alfisols. Sharma and colleagues also reported
that an increase in N levels from 0 to 90 kg N ha -1 significantly improved the SOC
level in these soils over a period of 8 years.

16.11 ENHANCED NUE WITH MANURING
Efficiency of applied nutrients can be substantially improved by using an INM strat-
egy. The data from a 32-year-long manurial trial at Bangalore under rainfed condi-
tions showed that partial factor productivity (PFP) can be sustained only with INM
involving organic manures. In contrast, application of chemical fertilizers alone
reduced PFP gradually in finger millet ( Figure 16.13 ) (Srinivasarao 2011). Therefore,
using INM is essential to sustainability of agricultural production on degraded soils
with low SOM and multinutrient deficiencies.