Potential Use of Precipitated Calcium Carbonate in the High Plains.

Precipitated Calcium Carbonate (PCC) is a by-product of the sugar purification process. In sugar beet growing areas, large amounts of PCC are produced each year. PCC has the potential to improve yields by suppressing Aphanomyces. The ECC of PCC is about 42%. PCC also contains some N and P from the impurities absorbed during the juice clarification process. The objective of this research was to investigate the effect of PCC on soil chemical and physical properties and the impact of PCC on crop yield. A greenhouse study was conducted by mixing PCC with soil collected from ten sites in NE, WY, and CO. Four PCC rates of 11.2, 22.4, 33.6, 44.8 Mg ha^-1 plus an untreated check were used. There was no significant difference in plant dry weight (sugar beet Beta vulgaris L; corn Zea mays L.; and dry bean Phaseolus vulgaris L.) 7 weeks after planting in the greenhouse. There was no significant difference in soil pH before planting and after harvesting. PCC piles support a dense growth of Kochia (Kochia scoparia (L.) Roth). Seeds were collected from factory sites in CO, NE and WY and plants were grown in growth chambers and treated postemergence with glyphosate, atrazine or dicamba to develop dose response curves for each herbicide. The kochia populations collected from each site were susceptible to glyphosate, atrazine and dicamba. Ten locations were chosen from grower fields to cooperate in this study beginning in 2012. Seven fields were planted with sugar beet, two with corn, and one with dry beans. The experiment design was a Latin Square, with four replications and four PCC rates: 0, 9, 18, and 27 Mg ha^-1.These fields will be monitored during the growing season for effects of PCC on growth, diseases severity and final yield. There were no negative effects of PCC on crop growth or development early in the year at all of the experimental sites. Growing season observations for Aphanomyces expression at different PCC levels will be presented.