Crop models can be evaluated based on accuracy in simulating several years' yields for one location or on accuracy in simulating long‐term mean yields for several locations. Our objective was to see how the ALMANAC (Agricultural Land Management Alternatives with Numerical Assessment Criteria) model and a new version of CERES‐Maize (Crop‐Environment Resource Synthesis) simulate grain yield of rainfed maize (Zea mays L.). We tested the models at one county in each of nine states: Minnesota, New York, Iowa, Illinois, Nebraska, Missouri, Kansas, Louisiana, and Texas (MN, NY, IA, IL, NE, MO, KS, LA, and TX). Simulated grain yields were compared with grain yields reported by the National Agricultural Statistical Service (NASS) for 1983 to 1992. In each county we chose a soil commonly used in maize production, and we used measured weather data. Mean simulated grain yield for each county was always within 5% of the mean measured grain yield for the location. Within locations, measured grain yield was regressed on simulated grain yields and tested to see if the slope was significantly different from 1.0 and if the y‐intercept was significantly different from 0.0, both at the 95% confidence level. Only at MN, NY, and NE for ALMANAC and at MN, NY, and TX for CERES was slope significantly different from 1.0 or intercept significantly different from 0.0. The CVs of simulated grain yields were similar to the those of measured yields at most sites. Also, both models were appropriate for predicting an individual year's yield for most counties. Values for plant parameters, such as heat units for development and the harvest index, and values for soil parameters describing soil water‐holding capacity offer users reasonable inputs for simulating maize grain yield over a wide range of locations.

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Globally, much weight is currently being placed on agriculture to provide food for the growing population as well as feedstock for the bioenergy industry. Unfortunately, the intensification of agricultural operations to satisfy these growing needs has been associated with a number of environmental and human health risks. A review of publications on the subject was conducted and emphasis was placed on articles focusing on agriculture, environment, and public health as well as their interactions. Supporting information was also gathered from publications of various agricultural and environmental agencies. Agricultural practices with potential negative implications on the environment and human health were identified broadly as: (a) utilization of biosolids and animal manures, (b) use of agricultural chemicals, (c) management of post-harvest residue, (d) irrigation, and (e) tillage operations. Soil, water, and air contamination by nutrients, heavy metals, pathogens, and pesticides, as well as air contamination by particulate matters, noxious gases, and pathogens were among the leading environmental impacts. Some of the human-health impacts identified included neurological and reproductive defects, cardiovascular risks, cancers and other diseases (of kidney, liver, lung, and skin), skin allergies, gastroenteritis, and methemoglobinemia. Continual awareness on the impacts of the reviewed agricultural practices on environmental quality and human health and the implementation of experimentally-backed best management practices in agricultural systems remain indispensable.

Field studies were established on the alluvial floodplain soils in Louisiana, from 2013 to 2015, to evaluate the effect of silicate slag applications on productivity of wheat (Triticum aestivum), under sufficient and high nitrogen (N) application rates. Treatments were arranged in a randomized complete block design, with four replications consisting of twelve treatments: a factorial combination of two N (101 and 145 kg N ha−1) and five silicate slag rates (0, 1, 2, 4.5, and 9 Mg ha−1), and two control plots (with and without lime). Nitrogen had a greater impact on wheat productivity than silicate slag application. Wheat grain yield reached over 7000 kg ha−1 with applications of 145 kg N, and 9 Mg silicate slag per ha for soil having Si level <20 mg kg−1. Yield increases due to N or Si were attributed to the increase in number of spike m−2 and grain number spike−1. Silicate slag application effectively raised soil pH, and availability of several plant-essential nutrients, including plant-available N (nitrate, NO3−), demonstrating the benefits of slag application are beyond increasing plant-available Si. The benefits of silicate slag application were clearly observed in wheat supplied with high N, and on soil with low plant-available Si.

Corn (Zea mays L.) has become an important crop used in rotation with cotton (Gossypium hirsutum L.) in the mid‐South region of the USA, but there has been little research on cultural practices for corn in this cropping system. The objective of this study was to determine if starter fertilizer has beneficial effects on corn growth and grain yield at different planting dates. Starter fertilizer and planting date effects were evaluated for corn in field experiments on a Commerce silt loam (fine‐silty, mixed, nonacid, thermic Aeric Fluvaquent) for 3 yr (1991 through 1993). Six hybrids were evaluated with two starter fertilizer treatments at four planting dates. Starter treatments were (i) ammonium polyphosphate (11‐37‐0 N‐P‐K) applied in‐furrow and (ii) a control with no starter fertilizer. Planting dates were mid‐March, early April, mid‐April and late April or early May. Yield response to planting date was not consistent across years; in two of three years, however, planting later than early April decreased yield. The starter fertilizer increased grain yield in two of the three years. Yield response to starter fertilizer was not consistent across years, hybrids, or planting dates. The planting date × starter interaction for yield was significant in two of three years and the hybrid × starter interaction for yield was significant in one of three years. Starter fertilizer increased early‐season plant height by 2 to 36% and increased grain yield across planting dates from 0.5 to 1.4 Mg ha−1 in 1991 and 0.4 to 1.0 Mg ha−1 in 1993. There was no yield response to starter in 1992. Application of starter fertilizer, averaged across hybrids and years, reduced harvest grain moisture 5% and days to silking by 3 to 5 d. In this mid‐South study, in‐furrow N‐P starter fertilizer increased early‐season corn plant height and grain yield and decreased the number of days to silking of corn rotated with cotton.