000			02840nam a22004097a 4500
001			G74626
003			MX-TxCIM
005			20211006081059.0
008			121211s ||||f| 0 p|p||0|| |
020			_a9974-7586-0-2
040			_aMX-TxCIM
072		0	_aF01
072		0	_aP30
082	0	4	_a633.1158 _bKOH
100	1		_aMartino, D.L. _uExplorando Altos Rendimientos de Trigo; La Estanzuela (Uruguay); 20-23 Oct 1997
110	2		_aCentro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT), Mexico DF (Mexico)
245	0	0	_aRestricciones físicas de suelo para la expresión de altos rendimientos de trigo en Uruguay
260			_aLa Estanzuela (Uruguay) _bINIA|CIMMYT : _c1998
340			_aPrinted
520			_aSoil physical structure regulates the storage capacity and flow of different compounds and energy, and affects crops through four fundamental properties: mechanical impedance, and availability of water, oxygen and energy for root growth. These properties are commonly expressed as mechanical resistance to metal probes, water potential, oxygen diffusion rate, and soil temperature, respectively. The combination of climate, soil types and system of production dominant in Uruguay determine high frequency of occurrence of sub optimal levels of these variables for wheat production. The main problems that were identified are: a) low availability of thermal energy for crop emergence, which determines long seed-emergence periods; b) oxygen deficiency for germination and early deep root development; c) high mechanical impedance in the upper soil layers; d) soil water deficiency during tillering and reproductive phase. Wheat crops are able to compensate yield components to a large extent. Therefore, problems occurring early in the season do not have a large impact on productivity. However, in high-yielding environments, negative effects may occur. On the other hand, water deficiency in later crop stages would more likely impair grain yield potential. In the present work, recent experimental developments are presented, and several hypothesis for preventing and alleviating soil physical restrictions are formulated. The need to improve the currently low rain-water use efficiencies (6-10 kg ha-1 mm-1) by agricultural practices that increase soil water infiltration capacity is stressed.
546			_aSpanish
591			_a0105|AL-Wheat Program|AGRIS 0102
593			_aJose Juan Caballero
595			_aCPC
650	1	7	_aCrop management _gAGROVOC _2 _91061
650	1	0	_aResearch projects _91237
650	1	0	_aSoil chemistry and physics
650	1	0	_aSoil science
650	1	0	_aUruguay
650	1	0	_aVariety trials _92474
653	0		_aCIMMYT
653	0		_aINIA
650	1	7	_aWheat _gAGROVOC _2 _91310
650	1	0	_91313 _aYields _gAGROVOC
700	1		_aKholi, M.M.|Martino, D. _eeds.
942			_cBK
999			_c5207 _d5207