Phytoextraction of zinc, copper, nickel and lead from a contaminated soil by different species of Brassica.

In a pot culture experiment, five different species of Brassica (Brassica juncea, Brassica campestris, Brassica carinata, Brassica napus, and Brassica nigra) were grown for screening possible accumulators of heavy metals, viz. Zn, Cu, Ni, and Pb. The plants were grown to maturity in a soil irrigated with sewage effluents for more than two decades in West Delhi, India.

Alternative soil quality indices for evaluating the effect of intensive cropping, fertilisation and manuring for 31 years in the semi-arid soils of India.

Soil quality assessment provides a tool for evaluating the sustainability of alternative soil management practices. Our objective was to develop the most sensitive soil quality index for evaluating fertilizer, farm yard manure (FYM), and crop management practices on a semiarid Inceptisol in India. Soil indicators and crop yield data from a long-term (31 years) fertilizer, manure, and crop rotation (maize, wheat, cowpea, pearl millet) study at the Indian Agricultural Research Institute (IARI) near New Delhi were used.

Neem (Azadirachta indica) seed kernel powder retards urease and nitrification activities in different soils at contrasting moisture and temperature regimes.

A laboratory experiment was conducted to examine the potentiality of a natural resource neem (Azadirachta indica) seed kernel powder (NSKP) to reduce the urease and nitrification activities in different soils (viz., normal, acid, and sodic) at contrasting moisture (1:1 soil to water and field capacity) and temperature regimes (10 degrees C and 37 degrees C). Results have revealed that application of NSKP with urea did not exhibit any urease inhibitory property in normal and sodic soils, but in acid soil it had maintained higher concentration of urea than the urea alone treated samples for two weeks after application.

Phosphatase production by microorganisms isolated from diverse types of soils.

Qualitative and quantitative nature of phosphatases produced by various fungal, bacterial, and actinomycetes isolates from diverse soils was examined. Soil fungi, particularly those belonging to the genera Aspergillus and Penicillium, were found to be most effective in producing phosphatases intra- and extracellularly. None of the 16 bacterial isolates produced acid phosphatase, but most of them did produce neutral phosphatase.

Influence of light on pectic enzymes in root exudates of Trifolium alexandrinum inoculated with Rhizobium trifolii.

An in vitro experiment was conduced under bacteriologically controlled conditions to examine the effect of light on the production of pectin methyl esterase (PME) and pectin polygalacturonase (PG) in the root exudates of Trifolium alexandrinum inoculated with an efficient strain of Rhizobium trifolii. The results revealed that PME and PG increased with an increase in the duration of light to which plants were exposed. However, both the enzymes were detected in the root exudates of nonphotosynthesizing plants.