Effect of nutrient management on soil organic carbon sequestration, fertility, and productivity under rice-wheat cropping system in semi-reclaimed sodic soils of North India.

The ever shrinking agricultural land availability and the swelling demand of food for the growing population fetch our attention towards utilizing partially reclaimed sodic soils for cultivation. In the present investigation, we compared six treatments, like control (T1), existing farmers' practice (T2), balanced inorganic fertilization (T3) and combined application of green gram (Vigna radiate) with inorganic NPK (T4), green manure (Sesbania aculeate) with inorganic NPK (T5), and farmyard manure with inorganic NPK (T6), to study the influence of nutrient management on soil organic carbon sequestration and soil fertility under long-term rice-wheat cropping system along with its productivity in gypsum-amended partially reclaimed sodic soils of semi-arid sub-tropical Indian climate. On an average, combined application of organics along with fertilizer NPK (T4, T5, and T6) decreased soil pH, ESP, and BD by 3.5, 13.0, and 6.7% than FP (T2) and 3.7, 12.5, and 6.7%, than balanced inorganic fertilizer application (T3), respectively, in surface (0-20 cm). These treatments (T4, T5, and T6) also increased 14.1% N and 19.5% P availability in soil over the usual farmers' practice (FP) with an additional saving of 44.4 and 27.3% fertilizer N and P, respectively. Long-term (6 years) incorporation of organics (T4, T5, and T6) sequestered 1.5 and 2.0 times higher soil organic carbon as compared to the balanced inorganic (T3) and FP (T2) treatments, respectively. The allocation of soil organic carbon into active and passive pools determines its relative susceptibility towards oxidation. The lower active to passive ratio (1.63) in FYM-treated plots along with its potentiality of higher soil organic carbon (SOC) sequestration compared to the initial stock proved its acceptability for long-term sustenance under intensive cropping even in partially reclaimed sodic soils. Among all the treatments, T4 yielded the maximum from second year onwards. Moreover, after 6 years of continuous cultivation, the observed EWY (2011-2012) was found to be 41.9 and 33.1% higher in T4 as compared to FP (T2) and T3, respectively. Thus, for maintaining higher yield coupled with improved SOC sequestration and nutrient availability, T4 followed by T6 treatments would be the suitable options for long-term intensive rice-wheat system in partially reclaimed sodic soils of northern India.

Municipal waste compost as an alternative to cattle manure for supplying potassium to lowland rice.

The importance of the use of potassium in agriculture is increasing in South Asia for making most productive use of the nutrient in terms of economic returns. Nutrient supply traditionally by cattle manure is constrained by its insufficient availability. Municipal waste compost may be an alternative source of nutrient supplements. Field experiments were conducted at the Experimental Farm of Calcutta University, West Bengal, India during the wet seasons of 1997, 1998 and 1999 on flooded lowland rice. Potassium fractions in municipal waste compost and cattle manure were determined by sequential extraction and also the potassium uptake by rice to compare the effectiveness of municipal waste compost with traditional manure. Potassium was significantly bound to the organic matter in municipal waste compost. Potassium uptake by rice grain and straw increased significantly with the combined application of organics and fertilizers and it was higher in grain than in straw. Water-soluble and non-exchangeable potassium contents of municipal waste compost and cattle manure were highly correlated with the uptake of potassium by straw and grain. Exchangeable and residual potassium were also significantly correlated with the uptake of potassium by straw and grain of rice. Much higher uptake of K in rice straw and rain resulted from applying the manures in conjunction with fertilizers than when applied singly.

Prevalence of canine demodicosis in Orissa (India).

Examination of the records of 12 hospitals from the five districts of Orissa showed that 50,987 dogs were presented for treatment during the period of 5 years covering 1987-1988 to 1991-1992. Demodicosis was detected in 1697 (3%) cases. There was no difference in the occurrence of the disease in male (51%) and female (49%) dogs. The disease was recorded in 60%, 23% and 17% of dogs up to 1 year, 1-2 years and above 2 years of age respectively, suggesting that young dogs up to 1 year of age are more susceptible. Further study revealed that Tibetan apso are more susceptible (47%) than Doberman (23%), Alsatian (18%) and mongrels (12%). A total of 912 dogs with natural dermatitis were examined during the 5-year period and 35% of the dogs were found to have demodicosis. Out of these, 208 dogs (65%) had localised lesions and 111 (35%) had generalised lesions. The study revealed that dogs up to 1 year of age are more frequently affected (60%) than dogs of 1-2 years (23%) and above 2 years of age (17%). There was no difference between the susceptibility of male (49%) and female (51%) dogs. The prevalence was high in Tibetan apso (41%) as compared to Doberman (26%), Alsatian (16%) and mongrels (17%).