Sprinkler Irrigated Organic Rice

Transcription

1 First International Conference Università degli Studi di Sassari Sprinkler Irrigated Organic Rice Antonino Spanu, Francesco Barracu Dipartimento di AGRARIA Sezione di Agronomia, Coltivazioni erbacee e Genetica Università degli Studi di Sassari (Italia)

2 Rice Farming in Sardinia Sardinia has two main rice producing areas, located in the center-w (Oristano) and in the S (San Gavino). Rice growing area about 3400 Ha Experimental fields of University of Sassari are located near Oristano (39 59' N; 8 40' E; 15 m asl): - Typic Eutric Haplic Fluvisol - Alluvial origin - Medium clayey texture - Neutral ph (7.3) - Low Nitrogen (0.08 %) - High Phosphorus (43.0 ppm) - High Potassium (202.0 ppm)

3 An alternative irrigation system Sprinkler Irrigation: advantages on organic farming - energy saves, as land grading is not necessary - use of tyre-weel machinery - simpler weed control - inclusion of rotations and preceeding crops - no yield loss - save of 40-50% of irrigation water

4 Sprinkler irrigation system Irrigation water is provided depending on Eto, corrected by following coefficients: - 0.4: emergence tillering - 0.8: tillering stem elongation - 1.0: stem elongation earing - 1.2: earing cereous maturation - 0.9: cereous maturation physiological maturation

5 First Trial Objective Preceeding crops Rice Cultivars Fertilization rates Sowing rates Weeds control N Kg ha -1 Viable seeds m -1 Evaluation of preceeding crops on rice growth - Trifolium alexandrinum -Trifolium subterraneum - Balilla - Eurosis Spiked chain harrow

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7 Discussion about first Trial Trifolium alexandrinum - effective competition with weeds - total biomass: 4.6 t ha -1 DM - 21% of total DM was weeds Trifolium subterraneum - low competition with weeds - total biomass: 4.0 t ha -1 DM - 40 % of total DM was weeds

8 Results about first Trial t / ha Rice yield N0 N80 N0 N80 N0 N80 N0 N80 T. Alexandrinum T. Subterraneum Balilla Eurosis

9 Two more experiments Objective Preceeding crops Rice Cultivars Fertilization rates N Kg ha -1 Weeds control Effect of T. alexandrinum on weeds control and rice yield - Trifolium alexandrinum - Balilla - Creso - Eurosis - Selenio Mechanical precision weeder Effect of alternative preceding crops on rice yield and N soil content - Trifolium alexandrinum - Spontaneous fallow - Eurosis Mechanical precision weeder

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13 Results Rice yield trial B Rice yield trial C Rice yield (t / ha) N0 N80 N160 N0 N80 N160 N0 N80 N160 N0 N80 N160 SELENIO BALILLA CRESO EUROSIS N0 N80 N160 N0 N80 N160 T. ALEX. FALLOW

14 Results

15 Conclusions 1/2 - Precession with T. alexandrinum provides a major O.M. availability than T. subterraneum or Fallow and shows a high competition vs weeds - No one of preceeding crops used provided a sufficient amount of N to avoid fertilisation; may be interesting to study the effects of other poliannual Fabaceae as Medicago sativa - Simpler mechanisation, and effective mechanical weeds control

16 Conclusions 2/2 - Save of irrigation water (used 8000 m 3 ha -1 ) - Greater yield than continuous flooding - Great percentage of whole kernels seeds viability - Further studies on sprinkler irrigation showed that aerobic conditions allow to limit absorption and bioaccumulation of heavy metals on rice, like As and Cd. - Found that on 37 cultivars, As content on rice kernels was 98% less in sprinkler irrigated than continuously flooded rice - Perform organic farming with sprinkler irrigation systems may be more healthy for Eastern countries where rice represent staple diet, or when used for children or elderly persons

17 First International Conference Università degli Studi di Sassari Sprinkler Irrigated Organic Rice Antonino Spanu, Francesco Barracu Dipartimento di AGRARIA Sezione di Agronomia, Coltivazioni erbacee e Genetica Università degli Studi di Sassari (Italia)