Problems and Prospects in Modeling Pearl Millet Growth and Development: A Suggested Framework for a Millet Model

Physical environment plays an important role in determining crop duration, water availability, the occurrence of pests and diseases, and thereby the ultimate yield. Knowledge of the influence of environmental factors on pearl millet growth and development will thus be helpful in devising the means to increase and stabilize pearl millet production. Simulation modeling is an effective approach to integrating various processes involved in crop growth and development. Currently no simulation mon'elforpearl millet is available in the literature, but because of the similarity in some of the growth and development processes between pearl millet and sorghum, the suitability of adapting certain subroutines of the existing sorghum model (SORGF) is examined. The difficulty in modeling the tillering habit of pearl millet is recognized. However, the effects of temperature and daylength on the duration of growth stages and tillering habit of the selected pearl millet genotypes are discussed. The total dry matter computed from the amount of light intercepted by the canopy, andpartitioning of dry matter to different plant parts are dealt with. Based on the available information, a framework for developing a pearl millet model is suggested

Newly recognized quaternary surface faulting and folding peripheral to the new madrid seismic zone, central united states, and implications for restraining bend models of intraplate seismic zones

A newly recognized thrust and nearby asymmetric anticline crop out 40 km north of Memphis, Tennessee, and they deform Eocene through Quaternary strata. These east–west-striking, south-verging structures are peripheral to the New Madrid seismic zone (NMSZ) of central North America, the source of M71 earthquakes in 1811–1812. The thrust dips ∼207 N and has 55 m of throw in Eocene strata. An angular intraformational unconformity indicates most deformation was Eocene. The anticline’s limbs dip 77 N and 227 S and fold Eocene and Pleistocene strata. Pleistocene sediments are dropped at least 4 m into a graben along the fold axis. Holocene sediment is ponded upstream from the fold axis, suggesting Holocene activity. Based on outcrops, well logs, and seismic reflection, we interpret the anticline as a fault-tip fold above a splay of the thrust fault. We interpret these thrusts in the context of a previously published sandbox model of a restraining bend uplift, which we apply here to the Reelfoot Rift fault complex. Using the eastern rift margin as the strike-slip fault of the sandbox model, the periphery of the model uplift has an east– west-striking, south-verging oblique-slip thrust where the actual thrust and anticline crop out. These results suggest that young thrust faults may be common along the periphery of the NMSZ and similar active intraplate restraining bends, that the eastern margin of the Reelfoot Rift may have been a principal strike-slip fault of the restraining bend, and that the seismic zone was active as early as Eocene

Crop Rotation and Soil Amendment Alters Sorghum Grain Quality

Soybean [Glycine max (L.) Merr.] rotation enhances grain sorghum [Sorghum bicolor (L.) Moench] yield, but infl uence on grain quality has not been measured. The objective was to determine the effect of cropping sequence (CS) and soil amendment (SA) on grain yield and quality. Sorghum grain yield and quality, soil NO3–N and water were measured in a rotation study in 2003 and 2004 on a Sharpsburg silty clay loam (fine, smectitic, mesic Typic Argiudoll). Cropping sequences were continuous sorghum, and sorghum rotated with non-nodulating and nodulating soybean. Soil amendments consisted of no amendment, manure (17–26 Mg dry matter ha−1 yr−1), and N (84 kg ha−1 yr−1). CS × SA interaction effects were found for most parameters. Rotation with non-nodulating soybean without SA increased yield by 2.6 to 2.8 Mg ha−1 over continuous sorghum without SA. Rotation without SA with nodulating soybean further increased yield by 1.7 to 1.8 Mg ha−1 over rotation with non-nodulating soybean. Grain N increased by 0.5 to 1.0, 2.5 to 5.0, and 3.3 to 4.9 g kg−1 for N application to continuous sorghum and sorghum rotated with non-nodulating and nodulating soybean, respectively. Tangential abrasive dehulling device (TADD) removal indicated that continuous sorghum without SA produced the softest grain with 43 to 44% TADD removal, and sorghum rotated with nodulating soybean with manure produced the hardest grain with 22 to 27% TADD removal. As food end-use opportunities for sorghum grain evolve, use of crop rotation and SA application will be important to produce grain with desirable quality attributes. Includes corrected Table 4