This is our second in a series of blog posts on improving nitrogen (N) use efficiency in California small grains. This post focuses on the use of N-rich reference zones to assess in-season N status and make management decisions based on crop need. Our goal is to help growers and consultants learn how to use N-rich zones to improve small grain N fertilizer use efficiency and reduce negative environmental outcomes. To demonstrate what we know about this practice across the small grain growing regions of the state, our team has helped growers establish N-rich zones in their fields across a wide range of soil and climatic conditions. These demonstration sites are in the Sacramento Valley, Delta Region, San Joaquin Valley, and the...

After almost 6 weeks without a substantial rainstorm, there is finally some precipitation starting to appear in the 10-day forecast for the Sacramento Valley. The lack of rain thus far has made it difficult to proceed with N fertilizer topdress applications in non-irrigated wheat fields this season. In addition, the warmer than normal temperatures have increased the rate of crop development such that many fall planted wheat crops are further along than would normally be the case at this time of year. Figures 1 and 2 below represent the cumulative rainfall since 10/1/2017 and the cumulative growing degree days (GDD) for wheat since 11/21/17, when we planted our experimental trials in Davis (each is compared to a 10-year...

Recent UCCE research has illustrated the value of in-season applications of nitrogen (N) fertilizer, particularly applications made at the early vegetative growth stages. This is typically the stage of growth when N demand from the crop is increasing rapidly, the soil is beginning to warm up, and microbial metabolism and associated mineralization/transformations of the various forms of N are increasing. Over a wide range of California conditions and across multiple seasons, applications of N fertilizer at this stage of growth have been shown to