Ag Data Commons

File(s) stored somewhere else

Please note: Linked content is NOT stored on Ag Data Commons and we can't guarantee its availability, quality, security or accept any liability.


posted on 2024-02-13, 13:39 authored by Wallace W. Wilhelm, Gregory S. McMaster, Ronald W. Rickman, Betty L. Klepper

SHOOTGRO emphasizes the development and growth of the shoot apex of small-grain cereals such as winter and spring wheat (Triticum aestivum L.) and spring barley (Hordeum vulgare L.). To better incorporate the variability typical in the field, up to six cohorts, or age classes, of plants are followed using a daily time step.

Assessing the influence of nitrogen and water availability on development and growth of individual organs of winter wheat (Triticum aestivum L.) is critical in evaluating the response of wheat to environmental conditions. We constructed a simulation model (SHOOTGRO 2.0) of shoot vegetative development and growth from planting to early boot by adding nitrogen and water balances and response functions for seedling emergence, tiller and leaf appearance, leaf and internode growth, and leaf and tiller senescence to the existing wheat development and growth model, SHOOTGRO 1.0. Model inputs include daily maximum and minimum air temperature, rainfall, daily photosynthetically active radiation, soil characteristics necessary to compute soil N and water balances, and several factors describing the cultivar and soil conditions at planting. The model provides information on development and growth characteristics of up to six cohorts of plants within the canopy (cohort groupings are based on time of emergence). The cohort structure allows SHOOTGRO 2.0 to provide output on the frequency of occurrence of plants with specific features (tillers and leaves) within the canopy. The model was constructed so that only water availability limited seedling emergence. Resource availability (nitrogen and water) does not influence time of leaf appearance. Leaf and internode growth, and leaf and tiller senescence processes are limited by the interaction of N and water availability. Tiller appearance is influenced by the correspondence to: W.W. Wilhelm, USDA-ARS, Department of Agronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0934, USA. 0304-3800/93/$06.00 0 1993 - Elsevier Science Publishers B.V. All rights reserved 184 W.W. WILHELM ET AL. interaction of N, radiation and water availability. Predicted and observed dates of emergence and appearance of the first tiller had correlation coefficients of 0.98 and 0.93, respectively. However, these events were, on average, predicted 3.2 and 5.2 days later than observed. SHOOTGRO 2.0 generally under-predicted the number of culms per unit land area, partially because the simulation is limited to a maximum of 16 culms/plant. Model output shows that the simulation is sensitive to N and water inputs. The model provides a tool for predicting vegetative development and growth of the winter wheat with individual culms identified and followed from emergence through boot. SHOOTGRO 2.0 can be used in evaluating alternative crop management strategies.

Resources in this dataset:




Data contact name

McMaster, Gregory S.

Data contact email



United States Department of Agriculture


  • Not specified

ISO Topic Category

  • biota
  • farming

National Agricultural Library Thesaurus terms

grains; winter wheat; winter; spring wheat; Triticum aestivum; spring barley; Hordeum vulgare; age structure; culms; tillers; phenology; developmental stages; leaves; inflorescences; florets; seeds; chaff; models; South Africa; Italy; England; computer software; crop models; nitrogen; environmental factors; simulation models; planting; seedling emergence; growth models; air temperature; rain; photosynthetically active radiation; soil properties; cultivars; soil quality; canopy; Agricultural Research Service; agronomy; Nebraska; United States; correlation; prediction; alternative crops; crop management

OMB Bureau Code

  • 005:18 - Agricultural Research Service

OMB Program Code

  • 005:040 - National Research

Primary article PubAg Handle

Pending citation

  • No

Public Access Level

  • Public

Preferred dataset citation

Wilhelm, Wallace W.; McMaster, Gregory S.; Rickman, Ronald W.; Klepper, Betty L. (2019). SHOOTGRO. United States Department of Agriculture.