Techniques using the critical value and sufficient range. Plant analyses are often interpreted based on “critical levels” for each nutrient for diagnostic purposes. Different people have defined the critical level in various ways. It is described as “that concentration below which yields decrease or deficiency symptoms develop” by Jones and Eck (1973). Even before obvious signs of nutrient insufficiency are noticed, many nutrients' yields start to decline. Some people define the critical level as the nutrient concentration at 90 or 95% of maximum yield because it might be challenging to pinpoint the specific concentration of a nutrient below which yields decrease.
Critical levels
Critical levels are established for a given plant part at a specific stage of maturity because the nutritional composition of a plant changes as the plant matures and depending on the part of the plant that was tested. The most often used part of the corn ear leaf is from silking through tasselling. Instead of a single point, there is an ideal concentration range for most crops across which yield will be maximized. If possible, one would like to feed nutrients at the lowest concentration that yet produces the highest yields, however because of the numerous variables impacting yields and concentrations, it is challenging to pinpoint this point. As a result, growers typically aim to operate within the range of sufficiency.
In the inadequate range, crop output is less than 75% of the maximum and there are clear signs of nutrient shortage. Although there are no overt signs of shortage in the low range, responses to the addition of the low nutrient are likely. The yield plateau is represented by the sufficiency range. Because there is no further increase in dry matter production to “dilute” the added nutrient, the nutrient concentration rises more quickly as the nutrient supply rises. Most nutrients have rather wide ranges of sufficiency. The crucial range is defined as the lower end of the sufficient range (or the upper end of the low range). The plant Bio Analytics consumes more nutrients than are necessary for maximum production when it is in the “high” range. This range is also known as the “luxury consumption zone.”
When the nutrient supply is adequately increased, yields decrease either as a result of an imbalance with other plant nutrients or directly as a result of the harmful effects of the excess nutrients. High quantities of phosphorus, for instance, can inhibit the intake of copper and zinc and throw nitrogen or potassium out of balance, but it is rarely hazardous per se. On the other hand, if boron is administered incorrectly, corn can quickly turn toxic.
Critical quantities Of Plant
Critical quantities of plant nutrients “may seldom be derived by a single carefully prepared experiment,” according to Melsted et al. (1969). More frequently, the averaged results of numerous studies conducted over a number of years and in various locations are used. Table 1 lists the critical levels and sufficient ranges that were published by Melsted et al. (1969) and Jones (1967) and Neubert et al. (1969), respectively. The sufficiency ranges used by the University of Wisconsin-Soil Madison's and Plant Bio Analytics Lab are also included. These were put together using data from many sources, including Jones (1967), Chapman (1966), and others. Considering the range of sources from which the data were gathered, agreement is extremely close. Table 2 lists the nutrient concentration ranges for maize used by the Soil & Plant Bio Analytics Lab at the University of Wisconsin-Madison to signify insufficient, low, sufficient, high, and excessive amounts.
Excessive nutritional levels for several nutrients are not well understood. However, they should not be applied dogmatically. These ranges are helpful guidelines for evaluating plant analyses. It is important to take into account any mitigating circumstances, such as hybrid requirements, peculiar soil or climate conditions, or other relevant knowledge.
The necessity for earlier sampling and Bio Analytics increases as plant analysis gains popularity as a diagnostic tool so that issues can be fixed before substantial yield loss occurs. Critical levels would need to be set for those stages in order to evaluate plant analyses at the early growth stages. Sadly, there is a dearth of information on the necessary nutrient concentrations for very early plants.
In addition to ranges for more mature maize, Lockman (personal communication) has created sufficiency values for complete corn plants 24 to 45 days after sowing (see Table 3). Early phases of growth are often characterized by high nutrient intake and dry matter buildup. As a result, it is possible to anticipate that nutrient concentrations will change significantly as plants mature, as shown by the relatively large sufficiency range for the mobile elements. At 24 to 45 days, the concentration of these elements—N, P, K, and Mg—in whole plant tissue is noticeably higher than it is in earleaf tissue. At this stage of growth, a change of a few days in sample time would be more important than at the silking stage.
technique using multiple regression. Results from contemporary analytical multiple-element Bio Analytics are amenable to multiple-regression Bio Analytics for interpretation. More complex interactions can be analyzed in terms of yields, providing more information. Even though some work has been done in this way, especially for N, P, and K, this kind of interpretation has not been incorporated into regular plant Bio Analytics tools.
Nutritional approach
Nutritional approach The Diagnosis and Recommendations Integrated System (DRIS), created by Beaufils (1971,1973) and introduced in this country by Sumner, is a recent version of the multiple regression approach (1977a, 1977b, 1979). As originally created, recommendations are given based on a diagnostic that takes into account as many yield determining factors as are capable of quantitative or qualitative expression. These variables include data on soil and plant analyses as well as details on the climate, insects, diseases, varieties, and other things.
Dris Method
The DRIS method for deciphering the outcomes of plant Bio Analytics entails the examination of hundreds of samples of a particular crop. In order to establish the criteria that can be utilized to differentiate between the high and low yielding populations, the samples are split into high and low yielding populations, and the analytical data from each population are examined. It turns out that i Testing nutrient ratios have produced superior results than just concentrations by themselves. The ratios present in the sample being tested are then contrasted with the ratios corresponding to the high yielding population (norms). However, combinations of various nutrient ratios can be computationally integrated to identify which nutrients are most likely to limit yield. Nutrient ratios alone cannot be utilized to diagnose i Testing issues. The “DRIS Indices” are the conclusions of such calculations.
DRIS indices are typically calibrated so that values between roughly -10 or -15 and +10 or +15 are regarded as normal and in balance, however finer tuning may be feasible. Between a DRIS index of -25 and -15, a deficiency is most likely present. A probable nutritional surplus may be indicated by values higher than +25. The likelihood that an element is out of balance in the i Testing increases with the magnitude of the nutrient index, whether it is positive or negative.
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