The use of straw mulch as a strategy to prevent extreme soil erosion ratesudin citrus orchard. A Rainfall simulation approach

摘要

Not only the Sahel (Haregeweyn et al., 2013), the deforested land (Borelli et al., 2013) the chinese Plateau areudaffected by intense soil erosion rates (Zhao et al., 2013). Soil erosion affect agriculture land (Cerdà et al., 2009),udand citrus orchards are being seeing as one of the crops with the highest erosion rates due to the managementsudthat avoid the catch crops, weeds or litter. Example of the research carried out on citrus orchards is found in theudMediterranean (Cerdà and Jurgensen, 2008; 2009; Cerdà et al., 2009a; 2009b; Cerdà et al., 2011; 2012) and inudChina (Wu et al., 1997; Xu et al., 2010; Wang et al., 2011; Wu et al., 2011; Liu et al., 2011; Lü et al., 2011; Xu etudal., 2012), and they confirm the non sustainable soil losses measured. The land management in citrus plantationsudresults in soil degradation too (Lu et al., 1997; Lü et al., 2012; Xu et al., 2012). The use of cover crops to reduceudthe soil losses (Lavigne et al., 2012; Le Bellec et al., 2012) and the use of residues such as dried citrus peel hasudbeen found successful. There is a need to find new plants or residues to protect the soils on citrus orchards.udAgriculture produces a high amount of residues. The pruning can contribute with a valuable source of nutrientsudand a good soil protection. The leaves of the trees, and some parts of the plants, once harvest can contribute toudreduce the soil losses. Due to the mechanization of the agriculture, and the reduction of the draft animals (mainlyudhorses, mules, donkeys and oxen) the straw is being a residue instead of a resource. The Valencia region is theudlargest producer of citrus in Europe, and the largest exporter in the world. This citrus production region is locatedudin the eastern cost of Spain where we can find the rice production area of the l’Albufera Lagoon paddy fields,udthe third largest production region in Spain. This means, a rice production region surrounded by the huge citrusudproduction region. There, the rice straw is not used in the paddy fields after harvesting and the straw is being asuda residue that damages the air quality when burnt, the water quality due to the decomposition and the methaneudproduction, and is not accepted in the field by the farmers. This is a new problem as few years ago the rice strawudwas use for animal feeding. Many attempts were developed in the last decade to remove and use the straw to avoidudfires and water pollution (Iranzo et al., 2004; Silvestre et al., 2013).udOur goal is to test if a residue such as the rice straw can be transformed as a resource: soil erosion control. Strawudhas been seen as a very efficient to reduce the water losses in agriculture land (García Moreno et al., 2013), theudsoil losses in fire affected land (Robichaud et al., 2013a; 2013b; Fernandez and Vega, 2014), and soil propertiesud(García Orenes et al., 2009; 2010; Jordán et al., 2010; García Orenes 2012).udRainfall simulations under 55 mm h-1 rainfall intensity during one hour on 0,25 m2 plots were carried out on plotsudpaired plots: bare and covered with straw. The plots covered with straw had different straw mulch cover: from 10udto 100 % cover and from 0,005 g m2 to 300 g m2. The results show a positive effect of the straw cover that showudan exponential relation between the straw cover and weight with the sediment yield.udAcknowledgementsudThe research projects GL2008-02879/BTE, LEDDRA 243857 and RECARE supported this research.