000			03323nab a22004337a 4500
999			_c12815 _d12815
001			G43601
003			MX-TxCIM
005			20211006072011.0
008			210409s1993 xxu|||p|op||| 00| 0 eng d
022			_a1435-0645|1435-0645 (Online)
022	0		_a1435-0645
024	8		_ahttps://doi.org/10.2134/agronj1993.00021962008500040027x
040			_aMX-TxCIM
041	0		_aEn
043			_aUS
072		0	_aF01
072		0	_aF04
090			_aCIS-2605
100	1		_aSain, G. _95252
245	1	0	_aDeriving fertilizer recommendations with a flexible function form
260			_aMadison, WI (USA) : _bASA : _bWiley, _c1993.
340			_aPrinted
500			_aPeer review
500			_aPeer-review: Yes - Open Access: Yes|http://science.thomsonreuters.com/cgi-bin/jrnlst/jlresults.cgi?PC=MASTER&ISSN=0002-1962
520			_aGeneral fertilizer response models are useful to derive robust recommendations for farmers who face different circumstances. This paper shows that a flexible functional form such as the transcendental can be applied to develop both agronomically and economically sound recommendation tables using a set of soil test, climate, and management variables. Data from thirty‐eight experiments on wheat response to N and P in the Humid Pampa, Argentina, were used to build a general response model that incorporates the initial levels of soil test measures (NO3‐N and Bray‐1 P), rainfall from sowing to maturity, and previous crop. The economic analysis was performed for relevant nutrient/grain price ratios ro = 8.0 and rp = 18.3 for N and P, respectively. A table of fertilizer recommendations for wheat was derived for different combinations of rainfall expectations, previous crop, and soil test values. The following results were obtained: (i) the estimated model not only accounted for a significant percentage of the total variability in the dependent variable (InY), with R2 =0.56, P = 0.01, but it also gave coefficients with signs in conformity with agronomic expectations; (ii) the economic optima for N (N*) and P (P*) are compatible with the range of optima computed with per‐site economic analyses; (iii) N* and P* increased as rainfall increased; (iv) N* was lower for wheat after soybeans than for wheat after maize; (v) N* was higher for smaller values of soil N, while P* was practically unaffected by soil N; and (vi) P* was higher for smaller values of soil P, while N* was affected by soil P, with a pattern that depended on both previous crop and rainfall. Similar tables can be derived for groups of farmers under different economic circumstances (i.e., different input/output price ratios).
536			_aSocioeconomics Program
546			_aText in English
591			_aR100ECO|R93ANALY|EP|EconomicsPubs|3|SEP archives 2
595			_aCSC
650		7	_aApplication rates _91012 _2AGROVOC
650		7	_aFertilizer application _91110 _2AGROVOC
650		7	_aRainfed farming _2AGROVOC _99381
650		7	_aWheat _gAGROVOC _2 _91310
650		7	_91190 _aNitrogen fertilizers _2AGROVOC
700	1		_aJauregui, M.A. _919542
773	0		_tAgronomy Journal _n649203 _gv. 85, no. 4, p. 934-937 _dMadison, WI (USA) : ASA : Wiley, 1993. _wG444482 _x1435-0645
856	4		_uhttps://hdl.handle.net/20.500.12665/464 _yAccess only for CIMMYT Staff
942			_cJA _2ddc _n0