A Metric Encoding for Bounded Model Checking (extended version)

In Bounded Model Checking both the system model and the checked property are translated into a Boolean formula to be analyzed by a SAT-solver. We introduce a new encoding technique which is particularly optimized for managing quantitative future and past metric temporal operators, typically found in properties of hard real time systems. The encoding is simple and intuitive in principle, but it is made more complex by the presence, typical of the Bounded Model Checking technique, of backward and forward loops used to represent an ultimately periodic infinite domain by a finite structure. We report and comment on the new encoding technique and on an extensive set of experiments carried out to assess its feasibility and effectiveness

Does Winter Wheat Yield Response to Fungicide Application Depend on Nitrogen Management?

Nitrogen and fungicide are among the more important management tools to increase wheat (Triticum aestivum L.) grain yield in Kansas. However, there is limited information on whether hard red winter wheat grain yield is impacted by the interaction of nitrogen rates and foliar fungicide application. Thus, our objective was to evaluate the effects of different N rates with or without a fungicide application at Feekes 10.5 on grain yield of two winter wheat genotypes with contrasting disease resistances to leaf and stripe rust. Eleven field experiments were established across Kansas using a factorial structure of two fungicide management options (either no fungicide or 13 fl oz of Nexicor per acre), five N rates (0, 30, 60, 90, and 120 pounds of N per acre), and two genotypes (Larry and Zenda) in a split-split plot design during the 2021–2022 growing season. There was a significant interaction between genotype and environment where Larry out-yielded Zenda in anywhere from 3.1 to 15 bu/a. There was a significant interaction between N rate and environment, likely due to the initial soil NO3-N and yield potential, as grain yield ranged from less than 34 to more than 81 bu/a. Increases in fractions of canopy cover in response to N fertilization and fungicide application explained about 29% and 15% of the increases in grain yield, respectively. There was a slightly greater crop yield response to foliar fungicide application as the N supply increased, from a nearly null difference at low N supply to as much as 5.9% for total N supply greater than 160.7 lb of N/a. In dry conditions with minimal disease incidence, winter wheat response to N availability differed in each environment, but there was only a marginal response to foliar fungicide

Wheat Variety-Specific Response to Seeding Rate Under Intensive Management Conditions in Western Kansas in 2020–2021

Wheat response to seeding rate is variable and depends on resource availability during the growing season (e.g., fertility, moisture, and temperature). Our objective was to evaluate winter wheat population and grain yield responses to seeding rate and its interaction with variety in a highly-managed production system where manageable stresses were limited. This study was established to evaluate the response of the wheat varieties Joe, WB-Grainfield, Langin, and LCS Revere to five seeding rates ranging from 200,000 to 1,000,000 seeds per acre. The site was managed by growers that consistently win state and national wheat yield contests near Leoti, KS. The trial was established on September 25, 2020, after a long summer fallow in sorghum residue, approximately 10 days after a 0.3-in. rainfall event, ensuring good stand establishment. The fall was dry, but spring conditions were favorable for high yields with cool temperatures and about 11 inches of precipitation. There were significant effects of seeding rate and variety on stand count, but the interaction was weak (P = 0.12). Main effects suggested that the stand count increased with increases in the seeding rate (from 252,265 to 521,347 plants per acre), with the 800,000 and 1,000,000 seeds/a rates attaining the highest stands. However, we note that final populations were closer to the target population at lower seeding rates as compared to higher seeding rates. Grain yield also depended primarily on variety and on seeding rate, with no interaction between both effects. Grain yield ranged between 97 and 101.3 bushels per acre for the seeding rates ranging between 600,000 and 1,000,000, and from 89.9 to 93.3 bu/a for lower seeding rates. Langin was the highest yielding variety (102 bu/a), followed by LCS Revere and WB-Grainfield (94.7–97.5 bu/a), and lastly by Joe (90.3 bu/a). These results suggest that wheat grain yield responses to seeding rate were not dependent on variety, with optimum seeding rates as low as 600,000 seeds/a. We note that increasing seeding rates beyond 600,000 seeds/a led to numerical but not statistical increases in yield

Wheat Yield Response to Nitrogen Rate Depends on Foliar Fungicide Application

Nitrogen (N) and fungicide are among the most important factors impacting wheat yields in Kansas. However, there is limited information on whether foliar fungicides interact with N rates in wheat yield determination. Thus, our objectives were to evaluate wheat yield as impacted by different N rates with or without the use of foliar fungicide. One field experiment was established using a factorial structure of five N rates (0, 30, 60, 90, and 120 pounds of N per acre) by two fungicide management practices (either absent or 13 fluid ounces per acre of Nexicor) in a split-plot design near Hutchinson, KS, during the 2020–2021 wheat growing season. The variety Larry was planted at 90 pounds of seed per acre, N was the whole plot and fungicide was the subplot. There was a significant interaction between N and fungicide on winter wheat grain yield, where the benefit of fungicide was greater with higher N rates. In the absence of fungicide, wheat yields ranged from 51.1 bushels per acre in the zero N rate, to 68.5 bu/a in the highest N rate. Meanwhile, grain yield ranged from 57.3 bu/a when no N was applied, to 83.8 bu/a in the highest N rate. Despite higher yields when fungicides were applied, grain yield within fungicide treatment plateaued at the 90 pounds of N per acre rate. This experiment provided initial empirical evidence for the interaction between N management and fungicide. More field experiments are expected to validate this in future years

Previous Crop Impacts on Wheat Variety Performance in Central Kansas During the 2021–2022 Growing Season

The effect of a previous crop and its residue left on the field before the next crop is a consequence of soil water usage and residue quality. We evaluated the grain yield of forty winter wheat varieties, as well as soil bulk density, soil water content, and previous crop’s residue C:N ratio in three neighboring fields near Solomon, KS. Wherein these three fields, winter wheat was no-tilled following a previous crop of either 1) soybean; 2) cover crop mix (legume and cereal); or 3) winter wheat. The mix of cover crops consisted of pearl millet, sorghum sudan, and sunn hemp. Soil samples were taken in October during winter wheat sowing. Four replications of soil measurements for bulk density and water content were taken from the 0- to 16-in. depth at 8-in. intervals. Six replications of 10.8-ft2 quadrats of residue biomass were sampled and evaluated for total nitrogen (N) and carbon (C). There were no significant differences in winter wheat grain yield among the varieties nor among the sites, although yield following soybeans was slightly lower than yield following wheat or cover crops (41 vs. 46 bu/a). Soil bulk density and residue C:N ratio were the lowest when following soybean (i.e., greater soil porosity and faster residue decay), although soil water content was also the lowest. Soil water content at sowing was the greatest when following winter wheat, likely as there were no actively growing summer crops to use precipitation water prior to wheat sowing. Soil water content increased at deeper layers (0–8 in. compared to 8–16 in.) when winter wheat was sown following a cover crop mix or a previous winter wheat crop, but it decreased when following soybean. Preliminary results from this on-farm experiment suggest that winter wheat variety performance was similar across previous crops despite measured differences in residue and soil characteristics. These results may help farmers to decide the benefits of each crop residue based on their cropping system needs