A dryland corn (Zea mays L.) production system that has gained popularity in Kansas involves planting as early in the spring as possible so that pollination occurs under more favorable moisture and temperature conditions. Cool soils that occur with early planting in high‐residue production systems can reduce nutrient uptake. Starter fertilizer applications have been effective in enhancing nutrient uptake even on soils high in available nutrients. Corn hybrids may differ in their response to starter fertilizer. The objective of this study was to evaluate corn hybrid response to starter fertilizer in a no‐tillage, dryland environment. This field experiment was conducted from 1993 to 1995 at the North Central Kansas Experiment Field, located near Belleville, on a Crete silt loam soil (fine, montmorillonitic, mesic Pachic Arguistoll). Treatments consisted of five corn hybrids and two starter fertilizer treatments. Fertilizer treatments were starter fertilizer (30 lb N and 30 lb P2O5/acre) or no starter fertilizer. Starter fertilizer was applied 2 in. to the side of and 2 in. below the seed at planting. In all 3 yr of the experiment, grain yield, maturity, and total P uptake (grain plus stover at maturity) were affected by a hybrid × starter fertilizer interaction. Starter fertilizer consistently increased yields, reduced the number of thermal units needed from emergence to midsilk, and increased total P uptake of Pioneer 3346, Dekalb 636, and Dekalb 591, but had no effect on ICI 8599 and Pioneer 3563. When averaged over the 3 yr of the experiment, starter fertilizer increased grain yield of responding hybrids (hybrids in which the 3‐yr average yield was increased by the use of starter fertilizer) by 13 bu/acre. Starter fertilizer increased V6 stage above ground dry matter production and N and P uptake of all hybrids evaluated. Ear leaf N and P concentrations also were increased by starter fertilizer, regardless of hybrid. Results of this work show that starter fertilizer can increase grain yield and be feasible for some hybrids, whereas yields of other hybrids are not affected. Research Question Conservation tillage production systems are being used by an increasing number of farmers in the central Great Plains. A dryland corn production system that has gained popularity in Kansas over the past few years involves planting as early in spring as possible so that pollination occurs in June when temperatures are more moderate and moisture is more favorable than in July when conditions are hot and dry. When this production system is used in high‐residue situations, the risk of cool soils interfering with root growth and nutrient uptake is greater. Corn hybrids differ in rooting characteristics that influence nutrient uptake and may differ in their response to starter fertilizer. The objective of this study was to evaluate starter fertilizer effects on yield, growth, and nutrient uptake of corn hybrids grown in a no‐tillage, dryland environment on a soil high in available P. Literature Summary No‐tillage systems have prove...

Some winter crops sown in no-tillage system can represent an important alternative to nutrient cycling. The objective of this work was to evaluate the production of dry matter (DM) and accumulation of nutrients for winter cultivation in the West of Paraná. The experimental design was a randomized block, with four treatments and six replications. The treatments were represented by four different winter crops (oat IPR 126, crambe FMS Brilhante, radish common cultivar and wheat BRS Taruma), and the DM, the contents of C, N, P, K, Ca, Mg and C/N ratio in DM and nutrients accumulation were determied The dry matter production was higher for radish with 4.929,14 kg ha-1. The different winter crops used influenced the contents of C, N and C/N ratio. The other studied characteristics were not influenced. Among the four winter cultivation the radish presented larger production of dry matter. The chemical composition was influenced by the cultivations, the contents of C, N and C/N ratio, consequently in the contribution differentiated in the area. The winter cultivation in the studied conditions influences the accumulation of magnesium.

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No‐till planting winter wheat (Triticum aestivum L.) following summer crops requires different crop management than continuous wheat. A 3‐yr study was conducted to determine if increased seeding rates and N fertilizer rates were required to maximize wheat grain yields following grain sorghum [Sorghum bicolor (L.) Moench] and soybean [Glycine max (L.) Merr.]. Wheat seeding rates of 67, 101, 134, and 168 kg ha−1 and N treatments of 0, 45, 90, and 134 kg N ha−1 were applied to areas previously planted to grain sorghum and soybean. Grain yield increased as seeding rate increased in all 3 yr, with yield optimized at seeding rates of ≥134 kg ha−1 regardless of the previous crop. Wheat response to N varied with previous crop, with wheat following grain sorghum requiring 21 kg ha−1 more N to maximize grain yields compared with wheat planted after soybean. These previous‐crop effects were attributed to grain sorghum producing higher levels of residue and this residue immobilizing a greater amount of available N than soybean residue. Leaf N content decreased as seeding rates increased and increased as N rates increased. Leaf N content had a similar response to N rates and previous crops as grain yields. Grain N content increased as applied N increased. Results of this study indicate that different seeding and N rates are required to optimize wheat yields when no‐till planted after grain sorghum and soybean.

Reduced-and no-tillage seedbed preparation methods coupled with broadcast P applications lead to an accumulation of available P in the surface 0-to 5-cm soil layer and a depletion of available P deeper in the profile. A 3-yr study determined the effects of tillage and fertilizer P management on P uptake and grain yield for P-stratified soils. Tillage practices were moldboard plow (once at the start of the study followed by reduced tillage), reduced tillage (disk followed by field cultivation), and no-tillage. Four P management methods were imposed: (i) no P; (ii) 20 kg P ha 21 applied as a surface broadcast; (iii) 20 kg ha 21 applied as a banded starter, 5 cm to the side and 5 cm below the seed; or (iv) 20 kg ha 21 applied in a deep placed band, 13 to 15 cm on 0.7-m centers. The one-time moldboard plowing produced higher early season dry matter yields for corn (Zea mays L.), wheat (Triticum aestivum L.), and soybean [Glycine max (L.) Merr.] compared with the no-tillage system, but tillage effects on final grain yield were inconsistent. Subsurface placement of P generally increased P uptake and grain yield of corn and sorghum [Sorghum bicolor (L.) Moench], but had little effect on grain yield of soybean. Results indicate that subsurface applications of P fertilizers should be considered if soil test P is highly stratified within the surface 0-to 15-cm layer and the 15-cm composite is medium or below for available P.

Zinc (Zn) deficiency is more common in corn (Zea mays L.) than in sorghum [Sorghum bicolor (L.) Moench] or wheat (Triticum sp.). The ability of wheat to withstand low soil Zn conditions is related to increased release of phytosiderophore from its roots. The reasons for sorghum's ability and corn's inability to utilize low levels of soil Zn have not been explored adequately. The objectives of this research were to 1) ascertain if Zn deficiency could be induced in sorghum, wheat, and corn grown in a chelator-buffered nutrient solution and 2) determine relative releases of phytosiderophore from roots of sorghum, wheat, and/or corn under Zn-deficiency conditions. Sorghum, wheat, and corn were grown hydroponically in the greenhouse with a chelator-buffered nutrient solution designed to induce Zn deficiency, while supplying adequate amounts of other nutrients. Root exudates were collected over time to measure phytosiderophore release. Shoot Zn concentrations and shoot and root dry 1 Kansas Agricultural Experiment Station Journal Series No. 98-212-J. 2623

due issue, but with the dominance of corn and grain sorghum in Kansas, management strategies are needed No-till planting winter wheat (Triticum aestivum L.) following that address issues impeding successful wheat producsummer crops requires different crop management than continuous wheat. A 3-yr study was conducted to determine if increased seeding tion following these summer crops in no-till systems.rates and N fertilizer rates were required to maximize wheat grain Proper management of late-planted wheat after a yields following grain sorghum [Sorghum bicolor (L.) Moench] and summer crop is complicated by factors that are influsoybean [Glycine max (L.) Merr.]. Wheat seeding rates of 67, 101, enced by the previous crop as well as the environment 134, and 168 kg ha Ϫ1 and N treatments of 0, 45, 90, and 134 kg N that the wheat crop is subjected to as a result of delayed ha Ϫ1 were applied to areas previously planted to grain sorghum and planting. Dahlke et al. (1993) reported that increasing soybean. Grain yield increased as seeding rate increased in all 3 yr, seeding rates compensates for reduced tiller growth that with yield optimized at seeding rates of Ն134 kg ha Ϫ1 regardless of typically occurs under the cooler temperatures encounthe previous crop. Wheat response to N varied with previous crop,tered at later planting dates. The recommended winter with wheat following grain sorghum requiring 21 kg ha Ϫ1 more N to wheat planting window for Manhattan, KS, is from 25 maximize grain yields compared with wheat planted after soybean. These previous-crop effects were attributed to grain sorghum produc-September through 20 October (Shroyer et al., 1996). ing higher levels of residue and this residue immobilizing a greaterWhen following a summer crop, harvest often delays amount of available N than soybean residue. Leaf N content decreased wheat planting through early November, suggesting that as seeding rates increased and increased as N rates increased. Leaf higher seeding rates are needed to maximize yields at N content had a similar response to N rates and previous crops as these later planting dates. grain yields. Grain N content increased as applied N increased. ResultsWheat yields may also be influenced by several factors of this study indicate that different seeding and N rates are required such as soil water content (Norwood et al., 1990), alleloto optimize wheat yields when no-till planted after grain sorghum pathy (Roth et al., 2000; Knowles et al., 1993), and N and soybean.availability. Previous-crop influence on N availability to the following wheat crop in a no-till system complicates N management. Increased residue levels of grain sor-253