No abstract

Tillage and N fertilization strategies including mineral and organic sources need to be studied in combination given their importance on the production cost that farmers face and their potential interaction on crop performance. A four-year (2010-2014) experiment based on barley monocropping was carried out in NE Spain in a typical rainfed Mediterranean area. Two tillage treatments (CT, conventional tillage; NT, notillage) and three rates of N fertilization (0; 75 kg N ha-1 , applied at top-dressing; 150 kg N ha-1 , applied at pre-sowing and at top-dressing at equal rate), with two types of fertilizers (ammonium-based mineral fertilizer and organic fertilizer with pig slurry), were compared in a randomized block design with three replications. Different soil (water and nitrate contents) and crop (above-ground biomass, grain yield, yield components and N concentration in biomass and grain) measurements were performed. Water-and nitrogen use efficiencies (WUE and NUE) as well as other N-related indexes (grain and above-ground biomass N uptake; NHI, nitrogen harvest index; NAR, apparent nitrogen recovery efficiency) were calculated. Barley above-ground biomass and grain yield were highly variable and depended on the rainfall received on each cropping season (ranging between 280 mm and 537 mm). Tillage and N fertilization treatments affected barley grain yields. No-tillage showed 1.0, 1.7 and 6.3 times greater grain yield than CT in three of the four cropping seasons as a result of the greater soil water storage until tillering. Water scarcity during the definition of the number of spikes per m 2 under CT would have compromised the compensation mechanism of the other two yield components. Pig slurry application led to the same (3 of 4 years) or higher (1 of 4 years) grain yield than an equivalent rate of mineral N fertilizer. Regardless the N origin, barley yield did not respond to the application of 150 kg N ha-1 split between pre-sowing and top-dressing compared to the 75 kg N ha-1 rate applied as top-dressing. A significant nitrate accumulation in the soil over the experimental period was observed under CT. Greater barley water use efficiency for yield (WUEy), N uptake and grain N content were found under NT than CT in three of the four cropping seasons studied. Moreover, for a given N rate, the use of organic fertilization increased significantly the WUEy as an average of CT and NT. When CT was used, a greater NHI was observed when using pig slurry compared with mineral N as an average of the four years studied. However, the use of different N fertilization treatments (rates or types) under CT or NT did not increase the NUE compared with the control. Our study demonstrates that the use of NT and the application of agronomic rates of N as pig slurry leads to greater 3 barley yield and water-and nitrogen-use efficiencies than the traditional management based on CT and mineral N fertilization.

Està subjecte a una llicència de Reconeixement-NoComercial-SenseObraDerivada 4.

14The effect of delaying sowing date and maturity class on no-till barley and soft 15 wheat performance was studied over two periods of three years each. A 3 (sowing date) 16 x 2 (maturity class) randomized complete block (RCB) design was run for 3 years with 17 barley (B-) (2006-7 to 2008-9) and soft wheat (W-) (2009-10 to 2011-12) in NE Spain. 18Sowing dates corresponded to October (D1 -the standard farming practice), November 19(D2), and December (D3). Maturity classes corresponded to early (-EC) and medium (-20 MC). Crop above-ground biomass, grain yield and yield components were analyzed. The 21 water-use efficiency of the above-ground biomass and yield (WUEb and WUEy) proportions of barley and wheat being found as the climate becomes wetter. 58Conventionally, farmers in the area sow winter cereals early, just after the first fall rains, 59around mid-October (both for barley and wheat