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To compare the growth performance of koi carp, Cyprinus carpio var. koi, produced in concrete tanks (2.13 · 0.91 · 1.22 m; capacity: 2,000 l each) and earthen ponds (9.1 · 6.10 · 1.07 m; capacity: 59650 l each), fish larvae (stocking size: 0.12 ± 0.008 g) were cultured for 11 weeks and individual weight gain, survival rate and number of marketable fish produced were compared among four management regimes for each culture system: (1) live zooplankton fed to fish larvae in ponds (PLF) and tanks (TLF); (2) application of poultry manure in ponds (PPM) and tanks (TPM); (3) application of cow manure in ponds (PCD) and tanks (TCD); and (4) a control treatment for ponds (PC) and tanks (TC), where a commercial feed was applied. There were three replicates for each treatment. Weight gain of koi carp was highest in the PLF treatment, followed in decreasing order by TLF, PPM, PCD, TPM, TCD, PC and TC treatments (P < 0.05). There was a significant difference in the survival of koi carp among the treatments, ranging from 67.83% in TC to 95.50% in PLF. The number of marketable fish produced was highest in the PLF treatment, followed in decreasing order by TLF, PPM and PCD treatments. However, none of the fish produced in the TPM, TCD, PC and TC treatments attained marketable size. Significantly higher (P < 0.05) values of pH and dissolved oxygen (for water samples collected weekly at 9 A.M.) were obtained in the live food and control treatments (for both tanks and ponds), compared to the manured treatments. The concentration of total alkalinity, BOD, PO 4 -P, NO 3 -N and specific conductivity were significantly higher (P < 0.05) in PPM and PCD, compared to other treatments. NO 2 -N and NH 4 -N values were significantly higher (P < 0.05) in TPM and TCD, than other treatments. The results suggest that introduction of live zooplankton into culture 2006 units result in higher growth of koi carp larvae compared to manure based systems. Earthen ponds appeared to be better alternative to concrete tanks for manure application through maintenance of better water quality due to their higher assimilatory capacity and greater abundance of plankton which resulted in better growth of cultured fish.

Crop diversification is considered as a pathway to promote agricultural development. The present paper examines the subtleties of crop diversification in Odisha, an eastern state in India through spatial trends across 30 districts and determinants of crop diversification. The analysis carried out from 1993-94 to 2012-13 indicates sluggishness and unevenness in crop diversification. The coastal districts lack diversification while several of the districts falling in the southern part of the state tend to be more diversified. The analysis reveals that greater use of high-yielding crop varieties and access to irrigation have influenced crop concentration, whereas rural roads and income have led to crop diversification.

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