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Although most vegetables are grown using conventional tillage (CT) practices, no-tillage (NT) is becoming more prominent in vegetable production due to growers gaining more understanding of the economic and ecological benefits associated with the NT production system. Nitrogen (N) fertility management in NT systems is important to maximize yield productivity, but there is little available information on N fertilizer recommendations for vegetable crops grown in this production system. Therefore, two field studies were conducted at a grower location in southern Illinois to determine the effect of N application rates in NT zucchini squash and cucumber production following the herbicide burn-down of a wheat cover crop in early spring. Results indicated that the maximum total squash fruit yield was achieved when 30 to 120 lb N/acre was sidedress applied [or a range of 125 to 210 lb total N (pre-plant, soil, and applied N)/acre]. Although squash plant growth was maximized when 180 lb N/acre was sidedressed (or a range of 264 to 273 lb total N/acre), the overall yield was less compared to the 30 to 120 lb N/acre rates. Cucumber results indicated that maximum total fruit yield was achieved again at 30 to 120 lb N/acre sidedress rates (or a total N rate range of 114 to 208 lb/acre). Cucumber plant growth was maximized at a sidedress application of 120 to 180 lb N/acre, although yield decreased at the 180 lb N/acre sidedress rate (or 260 to 270 lb total N/acre). It appears that if cucurbit vegetables have high amounts of N available in the soil through over application of N fertilizer, the excess N will be used for plant vegetative growth rather than for fruit production. These studies indicated that when too much N is applied in both NT cucumbers and zucchini squash, these high N rates will stimulate vegetative growth (as indicated by high plant vigor and leaf chlorophyll content) while reducing fruit yields.

Hard Red Winter (HRW) and Soft Red Winter (HRW) wheat classes (Triticum aestivum L.) and oat (Avena sativa L.) are commonly established as a source of winter and spring forage for cattle grazing in many regions of Texas and the U.S. Southern Great Plains. Small grains used in these grazed systems offer the flexibility of management for season long forage production or production of both forage and grain (dual-purpose). Many commercially available and experimental cultivars are continually evaluated on their ability to produce grain, but little yield data is available on wheat and oats under dual-purpose management systems. In forage production systems, soil fertility management is also an integral component in meeting specific yield goals that producers depend upon to sustain adequate animal performance. Current nitrogen (N) recommendations in Texas are based on heavy, moderate, and light levels of grazing. To address these issues, two-year studies were initiated at three locations in Central Texas. The objectives of these studies were; (1) to evaluate thirty wheat and ten oat cultivars based on forage production and grain yield to identify those best suited to dual-purpose management; (2) to determine winter wheat forage yield potential at varying levels of N fertility; and (3) to evaluate five minimally invasive and non-destructive methods of quantifying forage yield. Results from dual-purpose cultivar evaluations included significant differences in forage yield, nutritive value, and grain yield between cultivars and species. Overall, oat produced less forage than either class of wheat, but Mg content was generally higher in oat. For grain production, SRW performed better under irrigation, but in dryland situations both wheat classes performed equally. We also found that pre-plant N fertilizer significantly reduced stand establishment in dry environments. The 67 kg ha-1 pre-plant N and the 45 kg ha-1 top-dress rates produced the highest forage yield. Nutritive value generally increased as N application rate increased, even when no yield increase was observed. Hand clipping and canopy height both correlated very well with full plot harvest and visual ratings and NDVI had moderate relationships with full plot harvest. The relationship between ground cover and dry matter yield was variable and only weakly correlated.

Modern genetics have improved maize hybrids to better tolerate stress, use nutrients more efficiently and potentially yield higher. Management practices, such as narrow row technology and high plant population density (PPD) may further improve yields in modern maize under irrigated, non-limiting conditions. High PPD (74, 99, 124, 148 K seeds ha-1) were tested in narrow rows with up to four nitrogen (N) rates in three locations over two years in Kentucky with a modern maize hybrid in irrigated, non-limiting conditions. Results indicate that optimal seeding rates were 99,000 to 124,000 seeds ha-1, providing maximum yield and highest partial return, likely due to increasing seed number ha-1 and greater canopy closure, although seed size declined and pollination was more asynchronous as PPD increased. Excess N did not overcome silking delay or the decline in kernel mass associated with higher PPD, indicating 252 kg N ha-1 was adequate for high yields at any population, although data indicates better utilization of supplied N at higher populations. Implications can be used to implement better management techniques in high-yielding maize to supplement use of improved genetics.

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