Long-term 4R nitrogen management in dryland wheat-fallow systems

Yost, Matt A. , Cartee, Ray , Davis, Brad , Cardon, Grant , Creech, Earl , Rasmussen, Phil

2024-07-01 SOIL SCIENCE SOCIETY OF AMERICA JOURNAL 2024   88(卷), 4(期), (1297-1308页)

查看原文

  • JCR分区:

    影响因子:

  • Several short-term studies have investigated 4R (right source, rate, time, and place) N management for dryland wheat (Triticum aestivum L.) production and profitability, but few long-term studies exist in the United States or abroad. This study evaluated long-term impacts of several aspects of 4R N management on dryland hard red wheat yield, protein, and return to N. Experiments were conducted at Nephi and Blue Creek, UT, during 1995-2007. Fourteen N treatments evaluated performance of starter fertilizer, fall applications of anhydrous ammonia (AA) with and without nitrapyrin (AA-Nitrapyrin and AA, respectively), and several split applications in the fall and spring. Across years, winter wheat required N to increase yield, protein, and returns at both sites. Applying 56 kg N ha-1 as AA in the fall usually produced the best return to N compared to other N treatments. Starter N (6 kg N ha-1) at fall planting rarely increased yield, protein, or returns at either site. Across both sites, nitrapyrin increased mean annual yield by 0.6 Mg ha-1 and mean return to N by $150 ha-1. Spring application of N was rarely required and only increased yield in 13% of the years. Results indicate that nitrapryin is often needed with fall AA applications to optimize yield and returns and that starter N or extra N in the spring are rarely economical in dryland wheat in Utah and possibly the greater Intermountain West. Further, N rate had the most influence among 4Rs on wheat production and should be the focus of future efforts to improve 4R stewardship. Few long-term studies have compared various 4R (right source, rate, time, and place) nitrogen aspects for dryland wheat-fallow systems. Across 13 years, fall fertilizer N was needed to optimize production and economics in dryland wheat-fallow system. Starter N and spring N applications rarely improved wheat yield, protein, or return to N. Nitrapyrin added to anhydrous ammonia increased mean annual yield by 0.6 Mg ha-1 and mean return to N by $150 ha-1. N rate had the most influence among 4Rs on wheat production and should be focus of future 4R stewardship efforts.

    关键词