Concerns about a growing resistance to herbicides

In Mediterranean or arid climates, particularly in areas with marginal soils, crop rotations are often limited to a narrow range of hay, pasture, a handful of winter legumes, or rainy-season grasses. Arid conditions and weathered soils drove Australia's rainfed grain growers to adopt no-till strategies earlier than their counterparts in California. While beneficial from a water use perspective, successful no-till systems depend on herbicides to control weeds that were traditionally kept in check with tillage.

Dependence on herbicides alone in these systems has resulted in weeds with resistance to multiple modes of action. In Australia, there is one...

Weather patterns are highly variable across the state of California. They change from year to year and across locations. While parts of the state may be experiencing drought conditions this year (Figure 1), each location can have dramatically different weather. For growers and agronomists, location-specific weather information is essential to understand plant growth and water use. It is also important for planning field management activities such as fertilization and irrigation.

We have created a new interactive website where users can access their location-specific precipitation and temperature data:

Seeding rate is an important consideration for small grain growers at planting. There are a number of agronomic factors that help to determine the ideal seeding rate such as whether a field will be irrigated, the potential for weed pressure or lodging, the planting date, crop type, and seed germinability. In addition, there can be a large range of seed weights among different small grain varieties and from one seed lot to the next. To achieve full yield potential under irrigated conditions in California, 25 to 30 plants per square foot is a good target density for wheat. As a seeding rate this translates to approximately 1.2 million seeds per acre with a seed weight of 40 gram per thousand seeds. However, adjustments to the seeding...

As the fall planting season begins, we'd like to share recently developed case studies detailing N management actions and crop productivity outcomes in several small grain fields during the 2019-20 growing season. Growers from different parts of the state worked with UC Cooperative Extension to implement N-rich reference zones in their fields. The N-rich reference zone is a relatively small area within a field where extra N fertilizer is added at the beginning of the season. This extra fertilizer ensures that the reference zone is not N-limited between planting and the time when an in-season fertilizer decision is made. When a grower is...