Browse on keywords: moisture Pacific Northwest
Search results on 12/08/13
1720. Douglas, C.L., R.E. Ramig, P.E. Rasmussen and D.E. Wilkins. 1987. Residue management: small grains in the Pacific Northwest.. Crops and Soils Magazine, Aug./Sept., p.22-24.
Lack of water usually limits production in dryland cropping areas of the inland Pacific Northwest (WA, OR, ID). Precipitation is frequently insufficient during the growing season; thus, it is necessary to rely on stored soil water for cropping. Annual precipitation is unevenly distributed with approximately 65% occurring between November and March when soils may be frozen. Conventional tillage systems in the steeply rolling areas of Idaho, eastern Wash. and eastern Oregon result in high soil erosion rates which will eventually make it impossible to sustain high levels of crop production. Enough surface residue (normally 1 T/ac) must be left after fall seeding to control winter soil erosion and to sustain current production. Cereal residue management in the Pacific Northwest must begin at harvest of the previous crop. Uniform distribution of residues behind a combine eliminates chaff rows which shelter rodents and weeds, and create physical barriers to herbicide application and cereal growth. Fertilizer banding is necessary to reduce its use by shallow rooted weeds and the immobilization of certain nutrients by microorganisms. Equipment design must allow seeding and fertilizing through large amounts of surface residues.
3865. Leggett, G.E.. 1959. Relationships between wheat yield, available moisture and available nitrogen in eastern Washington dryland areas.. WA Agr. Expt. Sta. Bull. #609.
The purpose of this work is to demonstrate the relationships which exist between (1) available moisture and wheat yield and (2) available nitrogen and wheat yield. Using these relationships, it is possible to calculate the amount of fertilizer nitrogen necessary to obtain maximum wheat yield if the supply of available nitrogen in the soil and the amount of moisture available for the crop can be estimated. The results of 90 fertility experiments conducted on dryland wheat in eastern Washington during the period 1953-1957 were used to determine the relationship between wheat yield and available moisture. The results of 62 experiements were used to determine the relationship between wheat yields and available nitrogen. It is possible to calculate nitrogen fertilize recommendations from the results of soil tests for nitrate-nitrogen and available soil moisture by use of these relationships.
5632. Ramig, R.E., P.E. Rassmussen, R.R. Allmaras and C.M. Smith.. 1975. Nitrogen - sulfur relations in soft winter wheat. I. Yield response to fertilizer and residual sulfur.. Agronomy J. 67(2):219-223.
This study measured yield response of wheat to S applied with a range of N for the first crop and monitored residual S effects on yields of 3 subsequent crops. Significant N to S relationships were found. The first crop did not respond to S when N was deficient or optimal. Residual S increased straw yield in all crops and grain yield in 1 of 4 trials for the second crop, 3 of 3 trials for the third crop, and 2 of 2 trials for the fourth crop. Wheat response to residual S was influenced by N rates applied to the first wheat crop. High N and S fertilization resulted in early drought and lower yelds. Gradual release of residual S from recent organic matter apparently provided S at a rate adequate for efficient water use and maximum yield. T: Grain and straw yield response to S and N in first through fourth wheat crop following fertilization. The initial and residual effects of S on grain yield of wheat receiving optimum N.