Effect of Crop Rotation and Fertilization on the Quantitative Relationship Between Spring Wheat Yield and Moisture Use in Southwestern Saskatchewan

Abstract

this has resulted in substantially greater moisture use efficiency in recent years likely due to better, more timely crop management and the improved cereal varieties now used. When y was related to AvSpSM and GSP ( I May to 31 July) analyzed as separate variables, the relationship was only improved in terms of coefficient of determination (R2) value when a quadratic model was used. However, the latter did not predict the 1985 and 1986 yields as well as the y vs. MU relationship did. For fallow-seeded wheat, the relative effect of GSP on yield variability was about 5.4 times as great as that of AvSpSM; for stubble-seeded wheat it was only 1.5 times as great. GSP was equally important in affecting yields of wheat grown on fallow or stubble. The grain-filling period was confirmed as the most important for the occurrence of precipitation for both fallow-and stubble-seeded wheat, but precipitation at or near seeding time was almost as important for stubble-seeded wheat since this ensures the establishment of an adequate plant stand.

Temperature and precipitation effects on durum wheat grown in southern Saskatchewan for fifty years

“…These results appear to agree with those of Campbell et al (1988); they found that the period from shot-blade to soft-dough stage was the most important time for precipitation in an 18-yr (1967-1984) field study of spring wheat grown on fallow at Swift Current. The important period for MaxDT also peaks near the first week of July, but extends into early August.…”

Stubble height effects on microclimate, yield and water use efficiency of spring wheat grown in a semiarid climate on the Canadian prairies

“…Thus, in all years conditions were adequate for plant emergence and growth of wheat and above average for grain production. Precipitation during the months of May, June and July are particularily important to yield in the semiarid prairies (Campbell et al 1988) and in all years precipitation in these months were average to above average.…”

Regression model for predicting yield of hard red spring wheat grown on stubble in the semiarid prairie

“…2c), but performed less well in estimating yields for F-W-(W) (r 2 = 0.38 * , RMSE = 366) or Cont W (r 2 = 0.42 * , RMSE = 335) each receiving P but no N (data not shown). Thus, our model will perform best in cases where nutrient inputs are balanced with respect to both N and P. We did not include data for 1970 in our prediction of the rotation data because, although this was a year with above average GSP, 70% of the GSP came between June 10-18th (Campbell et al 1988). Most of this precipitation was likely lost via leaching.…”

“…This ongoing study, which was conducted at SPARC, is described elsewhere (Campbell et al 1983;Campbell et al 1988); thus, only a brief description is presented. The study, which involves 12 wheat-based rotations initiated in 1967, uses conventional tillage management and compares crop types, fertilizer treatments, and cropping intensities.…”

“…Apparent water used by the crop (WU) was taken as available soil water in spring plus precipitation from 1 May to 31 July (Bole and Pittman 1980;Campbell et al 1988). Degree days (DD) were calculated as the sum of the mean [(maximum + minimum)/2] daily air temperatures minus 5°C for the period 1 May to 31 August.…”