ISSN:
1432-2137
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mathematics
Notes:
- 3-N profiles, to evaluate GOSSYM's potential as a management tool under irrigated growing conditions in the desert part of the U.S. Cotton Belt, and to address questions about the way GOSSYM simulates NO- 3-N movement through the soil profile in relation to irrigation water management (which in turn affects prediction of plant growth and development). We compared measured profiles of NO- 3-N with GOSSYM-simulated profiles. Soil profile samples were obtained from an existing N-management field study, a split-plot within a randomized complete block design. Mainplots were upland and pima cotton (G. hirsutum L.) cv. DPL 5415 and G. barbadense L. cv. Pima S-7, respectively). Subplots were a check (0 fertilizer N) and three other N-management strategies. The cotton was grown on a Casa Grande sandy loam [fine-loamy, mixed, hyperthermic Typic Natrargid (reclaimed)] near Maricopa, AZ, in 1994 and 1995. Fertilizer N rates ranged from 0 to 350 kg ha-1 in 1994 and 0 to 392 kg ha-1 in 1995. Soil samples taken to a depth of 120 cm in 30-cm increments were analyzed for NO- 3-N . Comparisons of simulated and actual NO- 3-N profiles revealed tendencies in GOSSYM to overestimate NO- 3-N leaching out of the effective rooting zone, resulting in simulated N stresses midseason. When GOSSYM simulated an N stress, between 50 and 75% of the simulated soil NO- 3-N values were greater than the measured values, yet the simulated N stress still occurred. This indicates possible limitations in GOSSYM's ability to adequately predict N uptake by plants. The dynamic soil N portion of the model needs further refinement, particularly for cotton production under irrigated desert conditions.
Type of Medium:
Electronic Resource
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