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Fluid Journal : Winter 2016
Subsuñace Fertigation In Highly Productive Soils Increases nutrient use and grain yield of corn and soybeans. . Drs. Ross R. Bender and Fred E. Below T DOWNLOAD The Fluid Journal · Official Journal of the Fluid Fertilizer Foundation · Winter 2016 · Vol. 24, No.1, Issue #91 ;:::::; I '1--. .. ..... \. . . ..,. 'I. .:\ . . \, , , ," ., ... ... . .. . I 1\ I , . , I, t' l' . I ..,. . ,.. I. . I · , I J .; , , "1 I' l · r , j i. . - , , . ' \ t . .... . Summary: Precision ferlilizer application technologies may help producers sustain improvement of crop productivity to feed a growing world population. Subsutface ferligation (through subsutface drip irrigation, or SOl) was investigated as a possible strategy to improve the efficiency of nutrient uptake when applied at key growth stages across a range of corn (n = 3) and soybean (n = 15) genotypes. Across all corn hybrids, marked yield improvements (20 to 22 bu/A) occurred due to season-long ferlilization of N, K, and S along with higher populations. Nutrients (N, K, and S) were also ferligated in soybeans and improved grain yield by as much as 6.1 bu/A. Six soybean varieties measured significant yield increases due to ferligation (average of +4.8 bu/A) classified as yield 'responsive' with the remaining nine varieties exhibiting more variation (classified as yield 'non-responsive). Responsive varieties measured significantly greater plant biomass, improving the recovery efficiency of N, K, and S by as much as three-fold over 'non-responsive' varieties. Varietal differences in response to ferligation suggest that the tool may be used to classify soybean varieties for their responsiveness to agronomic management which, to our knowledge, has never been demonstrated. These findings highlight significant corn and soybean yield increases associated with in-season nutrient ferligation, and how agronomic management and cultivar selection can be used to complement improvements in nutrient recovery. S ub-surface drip irrigation (SOl) has traditionally been used for high- value vegetable and fruit crops such as the tomato. More recently, it has been adopted for commodity row crops such as corn, soybeans, and cotton as an alternative to center-pivot or flood irrigation. The benefits of a SOl system relative to other traditional irrigation forms include reduced water use brought about by up to a 50 0 /0 reduction in evaporation losses (Lamm and Trooien, 2003) and the ability to adapt to any field size, geometry, or topography (Netafim, Winter 2016 2010). Additionally, SOl provides the opportunity to increase the efficiency of nutrient application through the practice of fertigation (Le., fluid fertilizer supplied with irrigation water). Fertigation of nutrients directly into the root microenvironment, particularly during periods of rapid uptake, can minimize nutrient losses associated with immobilization, volatilization, or surface runoff (Hartz and Hochmuth, 1996). Currently, fertigated corn and soybean acreage in Illinois is limited in scope (90,000 acres or less than 1 0 /0 of total crop acres as of a 2013 survey, The Fluid Journal USOA-NASS, 2015a & 2015b). However, factors may accelerate fertigation and SOl system adoption in traditionally non- irrigated parts of the Corn Belt, including: 1) high commodity and input prices, 2) catastrophic weather events such as the 2012 drought, and 3) the demand for increased agricultural productivity in response to world population growth. The season-long nutritional needs for modern corn and soybean cultivars have recently been quantified by Bender et al. (2013, 2015). Macronutrient accumulation varies considerably between crops 10