Corn Yield and Residual Soil Nitrate as Affected by Time and Rate of Nitrogen Application

Abstract

Efficient use of N fertilizer for corn (Zea mays L.) production is important for increasing economic return to the grower and for minimizing the potential impact on water quality. Time and rate of application are important management tools for improving N efficiency. This experiment was conducted for 3 yr on two nonirrigated southern Minnesota soils-a Mt. Carroll silt loam (fine-silty, mixed, mesic Mollie Hapludalf) and a Webster clay loam (fine-loamy, mixed, mesic Typic Haplaquoll)-to evaluate the effect of time and rate of N application on corn yield, N uptake, and residual soil N03-N. Nitrogen as (NH 4 hS0 4 was applied in a factorial arrangement of N rate (low and high) and time of application (at planting (PL), eight-leaf stage (SL), or split evenly between the two times (SP)). A zero N control and a very high N rate at PL were also included. Nitrogen rates were 75, 150, and 225 kg ha-• on the Mt. Carroll, and 100, 200, and 300 kg ha-• on the Webster. Grain and total dry matter (DM) yield, and plant uptake of N were increased by N application in five of six site years, in most cases up to the high N rate. Delayed N application (SL or SP vs. PL) resulted in either no effect or a slight decrease in DM and in variable effects on N uptake, depending on the year and location. Residual NO:;-N in the 1.5 m profile ranged from 150 to 400 kg ha-• for most treatments in the fall but was 50 to 70o/o lower the following spring. Residual NO:; in the fall was consistently increased by delayed application of the high N rate from the PL to SL stage, with most of the increase occurring in the upper 0.6 m of the profile. The decrease in residual NO:; from fall to spring, attributed in part to leaching beyond the sampled zone, minimized the potential carryover effect for the next year's production and indicated a potential for greater environmental impact where N application was delayed. Dry matter production, N uptake, and residual N03-N were affected by unusually dry periods in midsummer of all3 yr, especially at the Webster site.

Use of a pre-sidedress soil nitrate test (PSNT) to determine nitrogen fertilizer requirements for irrigated corn

“…2.5 to 4.1 kg N·ha -1 ·day -1 for the highest N fertilizer treatments. These rates were in accordance with values reported by Magdoff [18], Jokela and Randall [14] and Karlen et al [15], who found maximum uptake rates 2 to 3 weeks prior to silking. For the highest N fertilizer treatments, 64 to 81% of total N uptake was accumulated by silking.…”

Growth and nitrogen use efficiency of irrigated maize in a semiarid region as affected by nitrogen fertilization

“…However, in 2001, a delayed N application up to 130 kg ha -1 affected both growth parameters to a limited extent. Jokela and Randall (1989) reported an increase in yield when N rate was increased from 0 to 150 and 225 kg ha -1 , depending on the environment. Cerrato and Blackmer (1990) reported a linear increase in corn grain yield with N applications ranging from 0 to 100 kg ha -1 .…”

Dose optimale économique d’azote et nitrates du sol après la récolte du canola

“…Ces variations des diffe´rentes quantite´s de nitrates re´siduels ont pu eˆtre associe´es a`l'historique des champs, aux proprie´te´s chimiques et physiques du sol (Roth et Fox 1990), aux re´gimes hydriques du sol (Jokela et Randall 1989) et aux conditions climatiques. Par exemple, il est mentionne´que les saisons de ve´ge´tation se`ches ont tendance a`favoriser l'accumulation des nitrates dans le sol tandis que les saisons de croissance humides favorisent le lessivage des nitrates (Campbell et al 1983;Tran et Giroux 1998).…”

“…Par exemple, il est mentionne´que les saisons de ve´ge´tation se`ches ont tendance a`favoriser l'accumulation des nitrates dans le sol tandis que les saisons de croissance humides favorisent le lessivage des nitrates (Campbell et al 1983;Tran et Giroux 1998). D'autre part, les saisons de croissance ayant des pe´riodes alterne´es se`ches et humides peuvent accroıˆtre la mine´ralisation de l'azote et favoriser l'accumulation des nitrates dans le sol a`la re´colte (Campbell et al 1983;Jokela et Randall 1989 (Be´langer et al 2003;Hong et al 2007). Des diffe´rences e´leve´es entre la dose applique´e et la dose optimale e´conomique d'azote ont indique´des risques accrus de lessivage par une accumulation excessive de la quantite´de nitrates dans le sol (Fig.…”

“…Cependant, dans une autre e´tude, aucun accroissement de la quantite´de nitrates re´siduels n'a e´te´mesure´avec l'utilisation des engrais mine´raux dans la culture de canola quoique avec la fertilisation a`base de lisier de porc, des augmentations des teneurs en nitrates aient e´te´mesure´es dans la couche de sol 0Á40 cm (Lafond 2004). Les nitrates qui sont demeure´s dans le sol apre`s la re´colte sont susceptibles d'eˆtre lessive´s et de contaminer les eaux souterraines (Campbell et al 1983;Jokela et Randall 1989;Roth et Fox 1990;Tran et Giroux 1998). Par conse´-quent, la quantite´de nitrates dans la zone exploite´e par les racines devrait eˆtre re´duite le plus possible a`la fin de la saison de croissance.…”