Abstract
The objective was to evaluate the effect of intervals of irrigation frequency (water deficit) in the development of cover crops. The experiment was conducted in a greenhouse at the experimental campus of the Federal University of Piauí (UFPI) in Bom Jesus-PI in the period between June to August 2011, on soil classified as Typic Dystrophic - Lad. The experimental design was randomized blocks in factorial scheme 5 x 4, with factors consisting of 5 cover crops (Brachiaria brizantha cv. Piata; Mucuna aterrima; Pennisetum glaucum cv. ADR-500; P. glaucum cv. ADR 8010; Brachiaria brizantha cv. Marandu), and 4 intervals of irrigation frequency (2, 4, 6 and 8 days), with 4 replications. Cover crops were significantly affected in their development, with reductions in biomass above 50% when subjected to the interval of irrigation frequency to 8 days. The P. glaucum cv. ADR-500 has potential to overcome the water deficit conditions during the off season in the Cerrado of Piauí. Key words: Brachiaria, Pennisetum glaucum cv. ADR-500, no-tillage.
Highlights
The Southern Piauí has been occupied largely by the soybean crop, with 439 million hectares in 2011 to 2012 harvest, an increase of 14.4% compared to the previous harvest
Cover crops were significantly affected in their development, with reductions in biomass above 50% when subjected to the interval of irrigation frequency to 8 days
There was a significant interaction between cover crops and intervals of irrigation frequency for number of leaves (NL), dry biomass of dry leaves (DBDL), dry biomass of green leaves (DBGL), stem biomass (SB), dry biomass of roots (DBR), total biomass (TB), root volume (RV) and total Chlorophyll (TC) (Table 1)
Summary
The Southern Piauí has been occupied largely by the soybean crop, with 439 million hectares in 2011 to 2012 harvest, an increase of 14.4% compared to the previous harvest. Soil management used predominantly in Southern Piauí by soybean producers have been the conventional tillage with the use of soil disturbance by plowing and harrowing before crop sowing. This practice provides loss of soil fertility and reduces the quality of the physical, chemical and biological attributes (Correia and Durigan, 2008), mainly by causing erosion (Bertol et al, 2004) and reduction in the accumulation of organic matter (Costa et al, 2004). The presence of biomass on the soil surface reduces the kinetic energy of the drops of rain and breakdown of particles responsible for the initial process of erosion, whereas the dry weight root of these species decompression assist in the ground through the formation of tubules in the natural soil profile (Silva and Rosolem, 2001b; Gonçalves et al, 2006, Reinert et al, 2008), in addition to increasing chemical and biological fertility through increased organic matter and biodiversity of the system (Carneiro et al, 2009)
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