China mission report, 8-17 March 2009 : conservation agriculture and in particular DMCs (Direct-sowing mulch-based cropping systems): an urgent issue and a major challenge for Franco-Chinese scientific research for sustainable development

Tour of Shanghai region and Chongming Island --- Jiao Tong University (Franco-Chinese ARCUS project). Tour of Southeast Yunnan. Route Kunming -- Wenshan - Mengzi - Kunming - YAAS University. Seen on Chongming Island and areas around Shanghai (Qingpu) : - In the field: Agroforestry work (Dr. Chunjiang Liu), very intensive cropping system. Rice/wheat with tillage, burnt straw, massive use of chemical fertilizers including N (> 240--300 kg/ha/year) on slightly alkaline, hydromorphic alluvial soils with a varying water table. - Jiao Tong University: Multi-disciplinary complex with state-of-the-art equipment and top level scientists. Proposals: ? Improve agroforestry DMC systems to be "as fully ecological as possible". - Convert the existing rice/wheat system into a DMC with management of straw combined with live perennial legume covers planted in the wheat and controlled by irrigation water in the rice - Rapid reduction of chemical inputs to quickly achieve organic rice/wheat production with clean soil and water without productivity loss. - DMC rice/wheat systems set up on farms and on the University campus to serve Franco-Chinese PhD trainings on major biology topics at the heart of DMC operations (carbon sequestration, pertinent global biological indicators, microbial ecology tools, ecology engineering x ecosystem services including phytoremediation, optimization of "genotypes x environments x soil and crop management mode" relationships). Seen in southeast Yunnan (Wenshan) - Mediterranean red soil (fersiallitic) on upland peneplains and on low mountains +/-- leached, active degradation under heavy tillage; mountains farmed from top to bottom, manure carried up on people's backs, 1000 m²/worker. On the plains, irrigated rice farming on the lowest lying zones during the hot season, potato on straw beds (rice straw). Vertisol +/-- saline bordering on red soil on the large upland plains planted with fruit trees (grape vines, Eriobotrya japonica, Punica granatum, Morus alba, various fruit trees) as in the Mengzi region. - On extremely steep slopes + maize intercropped with sweet potato in the hot season (on these soils, rapid fall of organic matter). - On the plain, very intensive system on tilled soil + plastic over vast surface areas, irrigated by small hill reservoirs; maize, pepper, tobacco crops in the hot season (tropical climate), wheat + strong diversification of market garden produce in the cold season. - 5 - Proposals - Enormous work to do with fertility regenerating DMCs, intensive sustainable agriculture with minimal chemical inputs, on both mountain and plain agriculture. ?- Very intensive, very diverse DMCs to be built: On the plains: - DMC on live plant covers (multiple agrosystemic services) with buried drip irrigation (+/- 20 cm) sustaining very diverse associated crops ("mini-forests"). - Under irrigated trellis fruit crops, install plant covers that do not require maintenance and provide extensive ecosystemic services. - On rice paddy fields, beyond the rice-potato system, build very productive DMCs with little chemical inputs, including N towards increasingly biological, ecological DMCs. In the mountains: - Urgent priority: stop tillage; focus instead on protecting soil with cover crops. - Build very intensive DMCs on live and dead covers based on maize + sweet potato (traditional system), maize associated with biodiversity combinations that provide at no cost enormous ecosystemic services which economize inputs and protect the environment (maize + Stylosanthes, maize + Desmodium (uncinatum + intortum) maize + (Finger millet + Cajanus), maize + soya, maize + (oat + vetch); soya + (oat + vetch) etc... and these same crops on perennial legume covers. - As in Chongming-Shanghai, YAAS University has excellent laboratory equipement and young, highly skilled, highly motivated, multi-disciplinary teams. The same major scientific themes cited in the case of Chongming-Shanghai centered on soil biology could be the focus