June Guelph Service Bulletin
This spring has been unseasonably cool through April and May, and spring soil samples from wheat fields were testing low for sulphate-sulphur. By mid-May, deficiency symptoms in winter wheat were evident. With the late and slow start to microbial activity, it is expected that soil nitrate-nitrogen levels may also test lower than expected. Pre-Sidedress Nitrate Testing (PSNT) will provide an indication of how much NO3-N is currently present, so that additional N rates can be better determined.
Large rates of N can lead to sulphur deficiency, especially where sulphur is in lower concentrations than typical for the time of year. With this in mind, and the fact that sulphate –sulphur is soluble and mobile, we’re offering to add SO4-S as an option to the standard PSNT test, as well as showing the N to S ratio for informative purposes.
PLANT TISSUE ANALYSIS
Wet chemistry analysis of plant tissue provides accurate reporting of essential nutrient concentrations. Although soil testing is essential for nutrient management and fertilizer planning, it cannot predict plant nutrient uptake. Since physical and environmental conditions can influence the utilization of nutrients, only a tissue test can reveal if it is adequate.
While testing symptomatic tissue can verify a deficiency, such as the wheat pictured, yield has already been lost. Using tissue analysis as a monitoring tool may reveal ‘hidden hunger’, the deficiency of one or more nutrients before symptoms are visual. Early detection can lead to appropriate remedial action to minimize losses of yield and improve plant quality.
Samples should be packaged in paper bags, so that they dry naturally and do not decompose during shipment.
LIVESTOCK WATER TESTING
Checking background levels of minerals in drinking water is important for overall livestock health. For example, higher levels of sulphur in drinking water can be tolerated by poultry and swine, but relatively low levels can be detrimental to the health and performance of cattle and sheep. It is suggested that 1000 ppm is a maximum sulphate concentration for livestock, and greater than 250 ppm may have a laxative effect.
High sulphates can lead to trace mineral deficiencies, as well as thiamine deficiency. Symptoms include poor hair coat, reduced growth rate or weight loss, and reduced fertility in cattle and sheep.
While individual sources of sulphur are usually not of concern, the combination of multiple sources, such as water, alfalfa, and other feed sources, can contribute to elevated total dietary sulphur.
FERTILITY MANAGEMENT - FORAGE FIELDS
Once first-cut hay is harvested, there is a good opportunity to apply manure and fertilize if fertility is lacking. Soil sampling the hay fields will provide the data for nutrient requirements, which can then be credited if nutrient is applied with manure. The soil tests may also reveal the fields, or sections of fields, that are most in need of supplemental nutrient and/or organic matter additions.
For more information, please contact: