David D. Baltensperger

LONG–TERM MANURE AND FERTILIZER APPLICATION EFFECTS ON PHOSPHORUS AND NITROGEN IN RUNOFF

Long–term manure and fertilizer applications to a soil can increase phosphorus (P) and nitrogen (N) transport nin runoff. This study was conducted to determine P and N transport in runoff following long–term (since 1953) manure and nfertilizer applications. Duplicate soil samples (32) were collected in 1998 from the top 0.1 m of selected plots of a long–term nmanure and fertilizer applications field experiment and later placed in 1 m 2 soil pans in the laboratory. Manure and fertilizer nwere mixed with 16 of the soil samples, while no treatment was applied to the other half (long–term residual effect). Simulated nrainfall was then applied to the soil during initial and wet (24 hours later) events. nManure added just before simulated rainfall resulted in significantly greater concentrations of dissolved P (DP), nbioavailable P (BAP), particulate P (PP), total P (TP), NO3–N, and NH4–N than when the last manure application was the nprevious year in 1997. Soil test P level was not a significant factor in DP loss when manure was applied just before rainfall. nWhen the last manure application was the previous year, similar concentrations of DP, BAP, PP, and TP were measured on nthe manure and no–manure treatments. Concentrations of NO3–N and NH4–N in runoff were not influenced by long–term nfertilizer application, but significantly increased with increasing N application rate when N was applied just before rainfall. nPhosphorus concentration in runoff decreased with time of runoff up to 45 minutes, after which the P concentration remained nconstant. NO3–N and total N concentrations continued to decrease for the entire runoff period. Manure and fertilizer should nnot be applied when the probability of rainfall immediately following application is great.

Importance and Effect of Nitrogen on Crop Quality and Health

Publisher Summary This chapter discusses the importance and effect of nitrogen on crop quality and health. Nitrogen is often the most limiting factor in crop production. Hence, application of fertilizer nitrogen results in higher biomass yields and protein yield and concentration in plant tissue is commonly increased. Nitrogen often affects amino acid composition of protein and in turn its nutritional quality. In cereals, abundant supply of nitrogen decreases the relative proportion of lysine and threonine, thus, reducing the biological value of the protein. Increasing nitrogen supply generally improves kernel integrity and strength, resulting in better milling properties of the grain. In oil seed crops, protein levels are increased upon nitrogen fertilization, whereas oil concentration is decreased. Effects of nitrogen fertilization on oil composition and quality are inconsistent.

Row spacing affects grain yield and other agronomic characters of proso millet

Proso millet (Panicum miliaceum L.), a short-season summer annual with excellent water-use efficiency, is well adapted to crop production systems in semi-arid environments. It is used as an emergency crop or as a rotation crop in a three-year rotation with winter wheat (Triticum aestivum L.). Row spacing and cultivar may impact the success of proso millet in the semi-arid Great Plains. Six row spacings; 15, 19, 23, 30, 38, and 46 cm, were compared in three environments; conventional tillage irrigated, conventional tillage dryland, and no-tillage dryland. These plots were evaluated at two different weed density levels: weedy (allowed all weeds to grow in the plots during the growing period) and weed-free (did not allow any weeds during the growing period). These trials were conducted in 1995 at the High Plains Agriculture Lab, Sidney, Nebraska (latitude 41°16′ North and longitude 103° 00′ West) at an elevation of 1250 m. Proso millet responded to changes in row spacing. Grain yield, tiller number, and straw weight decreased as row spacing increased while seed weight and plant height increased with row spacing. Seed weight increased with row spacing at all row spacings in the irrigated treatment while in the dryland sites, the increase was only at the narrower row spacing. The relatively light weed pressure in all but the no-till treatment reduced the effect of weeds in the response of grain yield to row spacing. Even in the no-till treatment, row spacing had little influence on weed weight. Narrow rows were superior for grain yield and weed control. In areas of limited moisture, however, 15 cm appears to be too narrow. Thus, 19 cm would appear to be a better choice of row spacing for areas where drought is likely. *Contribution of the Nebraska Agric. Exp. Stn. Journal no. 12892. Received Jan. 20, 2000.

Chapter 3 – Importance and Effect of Nitrogen on Crop Quality and Health

This chapter delineates importance and effect of nitrogen on crop quality and health. Nitrogen (N) is often the most limiting factor in crop production. Hence, application of fertilizer N results in higher biomass yields and protein yield, and concentration in plant tissue is commonly increased by. Nitrogen often affects amino acid composition of protein and in turn its nutritional quality. Increasing N supply generally improves kernel integrity and strength, resulting in better milling properties of the grain. In oil seed crops, protein levels are increased upon N fertilization, whereas oil concentration is decreased. Effects of N fertilization on oil composition and quality are inconsistent. In sugar beet production, abundant supply of N results in a reduction of sucrose concentration per unit of fresh matter and an increase in impurities. Moreover, adequate nitrogen supply to the crop must be insured to obtain optimal root yield, but excessive nitrogen supply can have several detrimental effects on sugar beet quality. Excessive nitrogen supply, especially late in the growing season, has in general two main effects on the quality of the harvested beets. Nitrogen fertilization of forages often had little impact on forage digestibility. Finally, the main beneficial effect of nitrogen fertilization of forages, on meat production per unit land, is increases in yield resulting in increased carrying capacity.

Use of shoot reduction treatments as a means of simulating hail injury to proso millet

Abstract Proso millet, Panicum miliaceum (L.), is a warm‐season annual grass well adapted for grain production in the western Great Plains of the United States, where risk of hail injury is greater than any other region of the United States. Because adjustment procedures and loss equations are not available, proso millet producers in this region have had limited access to crop hail insurance as a risk management tool. Our research was conducted to assess impact of shoot reduction treatments imposed at different crop growth stages on grain yield loss of proso millet grown under several environments. Our goal was to provide information for development of crop insurance adjustment procedures. We also wanted to determine the impact of shoot reduction on various grain yield components. Treatments consisted of a control and three levels of shoot reduction (33,66, and 100% of full stand) applied at four growth stages (emergence, 4‐leaf, boot, and heading stages). The experiments were conducted at two locations (Akron, CO and Carrington, ND) during 1996 and 1997 to assess treatment impact on relative grain yield (RGY), expressed as percent of control. A significant shoot reduction χ growth stage interaction was observed for RGY, indicating yield loss from increasing shoot reduction varied with growth stage. A linear reduction in RGY to increasing levels of shoot reduction was observed for the 4‐leaf, boot and heading growth stages, while RGY displayed a segmented linear response to increasing shoot reduction at emergence. Variation in grain yield, induced by shoot reduction treatments, was more consistently correlated with variation in seed number than seed weight.