Effect of Corn, Sugarbeets, and Fallow on Zinc Availability to Subsequent Crops
Field observations indicated that Zn deficiency of beans (Phaseolus 
vulgaris L.) was sometimes more severe than expected when 
grown on fallowed soil that was low to marginal in available Zn. 
The objectives of this study were to determine the effects of fallow, 
sugarbeets (Beta vulgaris L.), and corn (Zea mays L.) on Zn availability 
to subsequent crops grown on a Portneuf silt loam (Durixerollic 
Calciorthids, coarse silty, mixed, mesic). The sugarbeet and 
corn plant tops and sugarbeet roots were removed, and 11.2 kg Zn 
ha-1 was applied on one-half of each plot before fall plowing 25-cm 
deep. Beans, sweet corn, or potatoes (Solanum tuberosum L.) were 
planted the following spring. Whole plant samples of beans and 
sweet corn and potato stems, leaflets, and petioles were sampled for 
chemical analyses during the growing season. All bean plants were 
Zn deficient when grown after fallow or sugarbeets but not after 
corn or where Zn fertilized. Potatoes and sweet corn did not show 
any Zn deficiency symptoms or any growth responses to Zn fertilization. 
The average zinc concentration in beans (vegetative development 
stage, V3) following Corn was 20.5 mg kg-1 compared with 
12.5 mg kg-1 following fallow or sugarbeets without Zn fertilization. 
The average Zn uptake by beans (V3) following corn was 1.3 g ha-1 
compared with 0.6 g ha-1 after fallow or suprbeets without Zn 
fertilization. The Zn uptake after corn was even greater than where 
11.2 kg Zn ha-1 was applied to fallow or sugarbeets (1.3 vs. 0.9 g 
Zn ha-1). Enhanced Zn availability following corn persisted 
throughout the growing season and into a second bean crop, although 
at a decreased level. Similar trends occurred with potatoes 
and sweet corn. Soil DTPA-extractable Zn was not significantly 
different after fallow, sugarbeets, or corn. These results indicate that 
Zn deficiency in sensitive crops may be alleviated or prevented depending 
upon the preceding crop grown, and that factors not measured 
by DTPA can significantly influence Zn availability.
Soil Fertility and Bean Production
Beans require adequate amounts of all essential plant nutrients for optimum growth but only a few nutrients are documented to be needed for southern Idaho soils. These nutrients include phosphorus (P), nitrogen (N), zinc (Zn), potassium (K), sulfur (S), and to a much less extent B, Cu, Mn and Fe. University of Idaho Agricultural Experiment Station research as well as research from throughout the Pacific Northwest (PNW) is the basis for current fertilizer recommendations for Idaho dry beans. This article is not intended to be a complete review of the extensive plant nutrition literature on dry beans. The intent is to acknowledge the PNW research that has contributed significantly to Idaho recommendations.
An automated procedure for the determination of boron in plant tissue
A routine procedure in which the Technicon Auto Analyzer is used for the determination of boron in plant tissue with azomethine H is described. The preparation of the reagent as the condensation product of H-acid and salicylaldehyde is given. The reagent is highly sensitive to boron, and only copper, iron and aluminium interfere. These interference effects are eliminated with an EDTA solution. The procedure is performed in aqueous medium thus simplifying its adaptation to an automated system and its use for routine determination.