Rice is the most important Kharif crop of Punjab. With the increase in production of rice there is concomitant increase in the production of residue (rice straw), which is approximately 18.75 MT. About 80 percent of the rice residue it burnt in the fields, particularly after harvesting rice by combine harvesters.

Rice-wheat is a major crop rotation in the Indo-Gangetic region. Tillage is one of the major crop production operations and is an important contributor to the total cost of production. It is a common observation that direct tilling of any crop into combine-harvested rice stubbles from a reasonable rice yield is not possible without any prior burning or removal of straw.

Harvesting a crop generates a huge amount of crop residue. Uttar Pradesh tops the list of the Crop Residue Producing States followed by Punjab, Madhya Pradesh and so on. A large part of this crop residue is burnt in the open fields since the farmers do not have any worthwhile use of this waste. Burning of residues give rise to emissions of aerosols, major gases and trace gases.

A diagnostic survey was conducted in rice-wheat and maize-wheat blocks of Bulandshahr district for identification of tillage and other related soil physical constraints in farmers' fields.

A decision support system was developed for reclamation and management of alkali soils. The decision support system identified different reclamation and management techniques as land levelling, gypsum requirement and its addition, cultivation of tolerant crops, cultural practices, afforestation, groundwater recharge, groundwater use and surface drainage.

An evaluation of response of one disturbed, one rehabilitated and one mature forest soil in lower subtropic China to simulated acid rain (SAR) were studied using a controlled laboratory leaching experiment. Land use change is one of the important factors in controlling soil response to acid deposition.

The report by K.Van Oost et al., "The impact of agricultural soil erosion on the global carbon cycle" (26 October 2007, p. 626) raises two serious concerns. First, the eroded soil is severely depleted of its soil organic matter (SOM) pool, which is preferentially removed by surface runoff because it has low density and is concentrated in the surface layer. Second, the process of soil erosion by water entails three distinct stages : (i) detachment, (ii) transport/redistribution, and (iii) deposition. (Letters)

Perhaps genetic engineering could help to increase the efficiency with which crops absorb nitrate from soil (5 January, p 28). However, the claim by Arcadia Biosciences that this will substantially cut agricultural emissions of the greenhouse gas nitrous oxide appears Utopian rather than Arcadian. (Letters)

Farming contributes more to global warming than all the world's cars, trains, ships and planes put together. And the single biggest problem with farming is not carbon but nitrogen. From the maize fields of Kansas to the emerald rice paddies of China, today's bountiful harvests depend on generous applications of nitrogen fertiliser. Although only a tiny proportion escapes into the atmosphere as nitrous oxide, it is an extremely potent greenhouse gas. It's a vexing problem, but Eric Rey believes he has some of the answers, in the form of crops genetically modified to require less fertiliser.

In view of the environmental problems generated by large-scale production of fly ash, increasing attention is now being paid to the recycling of fly ash as a good source of nutrients. Because
availability of many nutrients is very low in fly ash, available ranges of such nutrients must be improved to increase the effectiveness of fly ash as a soil amendment. In our experiment, we assessed the possibility of increasing total nitrogen, total phosphorus, total potassium and micronutrients in fly ash through