Effects of zinc fertilizer amendments on yield and grain zinc concentration under controlled environment conditions

The application of zinc (Zn) fertilizer to lentil is an agronomic strategy that has the potential to improve yield and enhance grain Zn concentration. A pot study was conducted to determine if Zn fertilizer applied to three popular Saskatchewan lentil cultivars could increase yield and concentration of Zn in the grain. The effects of soil and foliar applied Zn forms, including ZnSO₄, Zn chelated with EDTA, Zn lignosulphonate, and a control were evaluated. Forms of Zn were not found to significantly increase yield (P = 0.828) or grain Zn concentration (P = 0.708) in any of the lentil cultivars tested. Fertilization with soil applied ZnSO₄ resulted in significantly (P < 0.0001) higher amounts of residual available Zn in the soil relative to other Zn treatments. Soil fertilized with ZnSO₄ had 1.13 mg kg^?1 diethylenetriaminepentaacetic acid (DTPA)-extractable Zn compared to 0.84 mg Zn kg^?1 and 0.77 mg Zn kg^?1 in the soil and foliar applied chelated Zn, respectively.     

Availability of previous and current applications of zinc fertilizer using single superphosphate for the grain production of wheat on soils of south Western Australia

Thirty field experiments on a range of soils in different rainfall zones of South Western Australia were used to examine the effectiveness, relative to freshly applied zinc (Zn) fertilizer of previously applied Zn fertilizer for grain yield of wheat. The soils had been fertilized with Zn at 0.2 to 1.2 kg Zn ha^‐1, 9 to 24 years previous. The effect of applied nitrogen (N) fertilizer on grain yield and Zn concentrations in the youngest emerged blade (YEB) was also examined. At all sites, the current application of Zn fertilizer to soils previously treated with Zn did not increase grain yield. The highest level of N fertilizer did not reduce grain yield where Zn had been applied previously or induce Zn deficiency in wheat plants. The lowest level of Zn (0.2 kg Zn ha^‐1, Experiment 17) applied 15 years earlier was still fully effective for maximum grain production. The application of currently applied Zn increased the Zn concentration in the YEB for 23 experiments. Application of N decreased Zn concentration in YEB in the 19 experiments, had no effect on the Zn concentration in 11 experiments, and increased Zn concentrations in two experiments. This was so for recent and previously applied Zn. In experiments where N decreased the Zn concentration in YEB, the concentration declined to 10 mg kg^‐1 in seven experiments. Zn concentration in the grain was increased by the current application of Zn in 25 experiments. It had no effect in five experiments (Experiments 11–13, 21–22). The application of N fertilizer decreased the Zn concentration of the grain for both previously and currently applied Zn in 20 experiments. Nitrogen decreased the concentration of Zn in the grain to 10 mg Zn kg^‐1 in seven experiments. Zinc extracted from the soil by DTPA was correlated with the amount of previously applied Zn fertilizer. DTPA‐extractable Zn for the experimental sites were 0.3 mg kg^‐1, except for 2 experiments which were 0.2 mg/kg. The results show that where Zn fertilizer had been applied previously, applications of high levels of N fertilizer to cereal crops did not require further applications of Zn if superphosphate (400–600 mg Zn kg^‐1) was used in the cropping and pasture phase. This is because of contaminates of Zn in rock phosphate used to make superphosphate. However, the requirements for Zn for wheat grain need to be reconsidered if diammonium phosphate (DAP) is used for cropping and if superphosphate applications are less than 150 kg ha^‐1 during the legume crop or pasture species in rotation with the cereal.     

Influence of Zn nutrition on the productivity,grain quality and grain biofortification of wheat under conventional and conservation rice–wheat cropping systems

ABSTRACT

This study was conducted to evaluate influence of zinc (Zn) application on productivity, grain biofortification and grain quality of wheat planted under plough tillage (PT) and zero tillage (ZT) systems. Zn was delivered as soil application (10 kg ha^?1), foliage spray (0.025 M) and seed priming (0.5 M) in wheat planted under PT and ZT systems. ZT had higher total soil porosity, total soil organic matter, soil organic carbon and soil microbial biomass carbon than PT. Zn application, by either method, improved grain yield, grain Zn and grain quality in both tillage systems. The grain Zn concentration was 72% and 59% higher with soil-applied Zn in ZT wheat during 2016–2017 and 2017–2018, respectively, compared with no Zn. However, Zn seed priming was the most effective in improving wheat grain yield in both tillage systems. Foliage and Zn soil application were better in improving the indices of Zn use efficiency of Zn. In conclusion, Zn seed priming was the most effective method in improving the wheat grain yield, whereas soil Zn application in ZT and foliar applications in PT were the most effective for grain Zn biofortification. However, Zn soil application was the most cost-effective method of Zn application.     

Effects of phosphorus addition and energy supply on acid phosphatase production and activity in soils

To find out how acid phosphatase activity and production in some Alberta soils may be related to soil properties and past fertilizer history, soils of varying organic matter content, extractable P and P fertilization history were assayed for acid phosphatase using p-nitrophenyl phosphate as substrate. The effect of solution P concentration during the phosphatase assay was examined. The effect of P on the production of new phosphatase was examined in soils incubated with an added energy supply or orthophosphate.Phosphatase activity was influenced by P fertilization practices during the 5 yr before sampling. In a Black Chernozemic soil (Malmo SiCL) with a high organic matter content and high initial phosphatase activity, P fertilization at 27 or 54 kg P ha^?1 y^?1 for 5 yr reduced phosphatase activity by about 20%. However, in a Grey Luvisolic soil (Cooking Lake L) with low organic matter and initial phosphatase, P fertilization at 54 kg P ha^?1y^?1 for 5 yr tended to increase activity, probably by increasing plant root growth and organic matter additions.Assay solutions containing orthophosphate at 0.55 mM reduced activity by 25% and 47% in a Malmo SiCL and Maleb L (Orthic Brown Chernozem) soil respectively. Further increases of phosphate concentration to 5.5 mM reduced phosphatase activity by 50% and 76% in the Malmo and Maleb L soils respectively.Phosphatase activity was increased up to 6-fold by incubation of soil with glucose and NH₄NO₃. Addition of P to produce an added C: added P ratio of 20:1 completely prevented synthesis of phosphatase by proliferating organisms and had a slight inhibitory effect on phosphatase already present. Similarly, addition of P without C in a 6-week incubation had only a small effect on phosphatase activity and maintained P concentrations in the assay solutions slightly below 0.55 mM. It was concluded that the effect of phosphate on soil phosphatase operates more through its effect on phosphatase synthesis than on activity of existing phosphatase.     

Effects of long-term legume cover crop incorporation on soil organic carbon, microbial biomass, nutrient build-up and grain yields of sorghum/sunflower under rain-fed conditions

Low organic matter, poor fertility and erosion are common features of rain‐fed Alfisols in southern India. Build‐up of organic matter is crucial to maintain sustainable production on these soils. The possibility of on‐farm generation of legume biomass [horsegram; Macrotyloma uniflorum (Lam.) Verdc.] by using off‐season rainfall was examined in two field experiments involving sorghum and sunflower from 1994 to 2003. The effects of this incorporation were assessed on crop yields and soil properties for 10 years together with fertilizer application. Horsegram biomass ranging from 3.03–4.28 t ha^?1 year^?1 (fresh weight) was produced and incorporated in situ under different levels of fertilizer application. Annual incorporation improved the soil properties and fertility status of the soil, which resulted in improved yields of test crops. With biomass incorporation, mean organic carbon content improved by 24% over fallow. Microbial biomass carbon improved by 28% at site I. Long‐term biomass incorporation and fertilizer application resulted in the build‐up of soil nutrients compared with the fallow plots. Application of N and P alone resulted in a negative balance of soil K. A time‐scale analysis of yields showed that incorporation together with fertilizer application maintained a stable yield trend over a 10‐year period in sorghum, whereas fertilizer application alone showed a declining trend. At the end of 10 years of incorporation, the increase in grain yield because of incorporation was 28 and 18%, respectively, in sorghum and sunflower over fallow when no fertilizers were applied to rainy season crops. The incorporation effect was even larger in plots receiving fertilizer. The growing and incorporation of a post‐rainy season legume crop is a low‐cost simple practice that even small and marginal farmers can adopt in semi‐arid regions of the country. Widespread adoption of this practice, at least in alternate years, can restore the productivity of degraded soils and improve crop yields.     

EFFECT OF SOIL AMENDMENT WITH ALFALFA POWDERS AND DISTILLERS GRAINS ON NUTRITION AND GROWTH OF CANOLA

Two pot experiments were carried out under controlled environment conditions in the growth chamber to assess the potential use of alfalfa powders and distiller grains as organic fertilizers. Two types of dehydrated alfalfa powders (one with canola meal protein extraction by-product and one without) and two types of distiller grains (dried distillers grain with distillation solubles added and wet distillers grain without solubles) from wheat-based ethanol production were evaluated. Four different nitrogen (N)-based amendment application rates (0, 100, 200 and 400 kg N ha^?1) were used along with urea applications made at the same N rates to a Brown Chernozem (Aridic Haploboroll) loamy textured soil collected from south-central Saskatchewan, Canada. Canola biomass yield, N, phosphorus (P), potassium (K), zinc (Zn), and cadmium (Cd) uptake were measured along with soil properties including pH, salinity, organic carbon, total nitrogen, phosphorus and extractable nutrients and cadmium before and after canola growth in each of the treatments. Application of alfalfa powder and distiller grain amendments resulted in significant canola biomass yield increases along with increased N, P, and K uptake compared to the unfertilized control. However, only a portion of the N added (～30% to 50%) in the organic amendments was rendered available over the five week duration of the experiments. Amendments that had higher N content and lower carbon (C):N ratios such as dried distillers grain with solubles resulted in greater canola N uptake. Reduced germination and emergence of canola seedlings was observed at high rates of addition of distillers grain (400 kg N ha^?1), the reason for which is unclear but may be due to a localized salt or toxicity effect of the amendment. The amendment with alfalfa powders and distiller grains resulted in small increases in residual soil nutrients. Effects on pH, salinity, organic carbon and extractable metals tended to be small and often not significant. Alfalfa powders and distillers grains appear to be quite effective in supplying nutrients, especially N, for plant growth over the short-term.     

Short-term responses of soil nutrients and corn yield to tillage and organic amendment

Field experiments were conducted in 2010 and 2011 at the Agricultural College of Shiraz University to evaluate the effects of cattle manure and nitrogen (N) fertilizers on soil properties such as soil organic carbon (SOC), soil organic nitrogen (SON), soil electrical conductivity, soil pH and corn yield under two tillage systems. Treatments included tillage systems in two levels as conventional tillage and reduced tillage as subplots, cattle manure (0, 25 and 50 tons ha^?1) and N fertilizer (0, 125 and 250 kg N ha^?1) as sub-subplots. Results showed that SOC and SON were significantly affected by tillage system in both years of the experiment. SOC and SON were higher in reduced tillage compared to conventional tillage. Tillage system had no significant effect on grain yield, plant height and 1000 seed weight. Increased cattle manure rates at 25 and 50 tons ha^?1 increased grain yield by 27% and 38%, respectively, in 2010 and 25% and 25% in 2011. The results showed that application of cattle manure combined with N fertilizer might be an efficient management to increase soil productivity in southern Iran, in soils with poor organic content. Additionally, reduced tillage showed to be an efficient method to increase soil organic matter.     

Relative Nitrogen Fertilizer Requirements of Forage Versus Grain for Barley and Oat

Field experiments were conducted at 15 site-years with barley and 10 site-years with oat over five years to determine the relative nitrogen (N) fertilizer requirements of forage versus grain for barley and oat on Black Chernozem (Typic Agricryoll – 6 site-years on barley and 3 site-years on oat) and Gray Luvisol (Typic Haplocryalf – 9 site-years on barley and 7 site-years on oat) soils in central and north-central Alberta, Canada. Barley harvested for forage responded to higher level of applied N than when it was harvested for grain at most site-years. On average for barley, the amount of N fertilizer required to achieve maximum yield of forage was 58 kg N ha^?1 greater than that of grain, and also was somewhat greater on Black Chernozem soils than on Gray Luvisol soils. The results for oat were inconclusive, with almost equal numbers of site-years showed higher N requirements for grain as for forage.     

Long continued applications of N fertilizer to cereals on sandy loam: grain and straw response to residual N

Abstract. The residual value of mineral N fertilizer applied in the spring was investigated in a field experiment where four cereals (winter wheat, winter barley, spring barley and spring oats) had been grown at reduced (0.7N), normal (1N) or high (1.3N) N fertilizer rates for 20 to 28 years. The effect of previous N fertilizer dressing was tested in two succeeding years by replacing the original N rate with five test N rates ranging from 0 to 240 kg N ha^?1 for winter cereals and 0 to 200 kg N ha^?1 for spring cereals. In the first test year, winter wheat grown on plots previously supplied with the high rate of mineral fertilizer (202 kg N ha^?1 yr^?1) yielded more grain and straw and had a higher total N uptake than wheat on plots previously supplied with the normal (174 kg N ha^?1 yr^?1) or reduced (124 kg N ha^?1 yr^?1) rate. The grain yield response and N uptake was not significantly affected by the N supply in the test year. The winter wheat grown in the second test year was unaffected by the previous N supply. Grain and straw yield response and total N uptake for spring barley, winter barley and oats, were almost identical irrespective of the previous N rate. After 20 to 28 years there were no significant differences in soil C and N (0 to 20 cm) between soil receiving three rates of N fertilizer. Soil from differently fertilized oat plots showed no significant differences in N mineralizing capacity. Nitrate leaching losses from the soils at the three N rates were estimated and the N balances for the 20 to 28 years experimental period calculated. The data indicated a reduction in overall loss of 189 to 466 kg N ha^?1 at the normal and high N rates compared with the reduced N rate. We conclude that the N supplying capacity and soil organic matter content of this fertile sandy loam soil under continuous cereal cropping with straw removal was not significantly affected by differences in N fertilizer residues.     

RESPONSES OF COOL-SEASON GRAIN LEGUMES AND WHEAT TO SOIL-APPLIED ZINC

The yield and zinc (Zn) content response of faba bean (Vicia faba L.), chickpea (Cicer arietinum L.), lentil (Lens culinaris Medik.) and wheat (Triticum aestivum L.) to applications of Zn fertilizer was compared in a glasshouse experiment using two alkaline soils from southwestern Australia. Comparative Zn requirements were determined from yields of 46-day-old dried shoots when no Zn fertilizer was applied, the amount of Zn required to produce the same percentage of the maximum (relative) yield of dried shoots, and the Zn content of dried shoots (Zn concentration multiplied by yield of dried shoots). The concentration of Zn in youngest tissue and in dried shoots was used to determine critical concentrations for Zn in tissue. Faba bean used indigenous soil Zn more effectively than chickpea, followed by wheat and then lentil. The Zn requirement was lowest for faba bean, and increased in the order faba bean < chickpea < wheat < lentil. Zinc concentration in dried youngest tissue and in dried shoots increased with an increase in the amount of added Zn. The critical Zn concentration in the youngest tissue, associated with 90% of the relative yield, was (mg Zn kg^?1): 25 for lentil, 18 for faba bean, 17 for chickpea and 12 for wheat; corresponding values for dried whole tops (mg Zn kg^?1) were: 30 for lentil, 19 for faba bean, 17 for chickpea, and 20 for wheat. Information on comparative responses of the grain legumes to Zn additions relative to wheat, and critical tissue test values, will aid in the fertilizer management of Zn in cool-season grain legumes in the southwestern Australian farming systems.     

Response of Corn to Banded Zinc Sulfate Fertilizer in Fields with Variable Soil pH

Abstract

There are soil series that contain free calcium carbonate (CaCO₃) within fields where the surrounding pHs of the soil series are slightly acid. The objective was to study corn (Zea mays L.) grain yield response to zinc (Zn) fertilizer on different soil series within fields. The study was conducted at 12 sites between 1998 and 2000. Treatments were 0 and 5.6 kg Zn ha^?1 applied in bands to field‐length strips of corn and replicated four times. Multiple soil series were identified at each site, and treatment pairs were located within them. Grain yields, whole plant (V6 to V10 growth stage), and grain Zn content and uptake were measured. The most common result was no response to Zn application. However, significant yield decreases occurred on some soils as a result of Zn application in two situations: on soils with high soil‐test Zn or on soils with low soil‐test Zn and high pH.     

Assessment of chemical composition of plants cultivated on two different soils amended with sewage sludge compost using MANOVA

Abstract

Application of organic fertilizers may replenish soil organic matter, improve soil fertility and increase plant yield and its quality. This research deals with the effects of soil amendment with sewage sludge compost (SSC) on the chemical composition of plants (white mustard, triticale and white lupine) cultivated on two contrasting soils (light vs. medium). A 3-year pot experiment was conducted and SSC at the rate of 6?Mg ha^?1 was applied to the soils.The study clearly demonstrated that SSC as an organic fertilizer had a minor influence on the modification of the chemical composition of shoots and grain cultivated in crop rotation plants and it was more evident in medium soil. The statistically confirmed effect was mainfested in higher c ontents of N and P in grain of plants in the 2^nd and 3^rd year of the experiment.     

Response of alfalfa hay yield to phosphorus fertilization in two soils in central alberta

Abstract

Many soils in Alberta contain insufficient amount of available P and fertilizer P is needed for optimum crop yields. Fields experiments were conducted at two sites (Lacombe ‐ Black Chernozem silt loam and Botha ‐ Thin Black Chernozem loam) in central Alberta to determine the hay yield response of alfalfa (Medicago sativa leyss. cv. Rambler) to P fertilizer applied annually (0, 10, 20, 30, 40, and 60 kg P ha^‐1) or once initially (60, 120, and 180 kg P ha^‐1). In the initial application triple superphosphate was incorporated into soil prior to sowing of alfalfa in 1974 and in the annual application the P fertilizer was spread on soil surface for three years at Lacombe and for five years at Botha beginning in the spring of 1975. The hay yield increased with P application, but its magnitude of response to added P was lower at Botha than at Lacombe. The residual effect of large single P applications on hay yield lasted at least for five years.     

Evaluation of Compost for Use as a Soil Amendment in Corn and Soybean Production

The purpose of this research project was to 1) evaluate rate of compost application and 2) to compare compost with uncomposted raw material and inorganic fertilizer N application upon maize and soybean growth and productivity, and upon soil characteristics. During the first three years of the study, the source of uncomposted material and compost was food waste and ground newsprint. During years 4 to 9 of the study, the source of uncomposted material and compost was dairy cow manure and wood chips. Application rates in field site 1 were 0, 11.2, 22.4, 33.6 and 44.8 Mg ha^?1 compost, 44.8 Mg ha^?1 uncomposted material and 140 kg ha^?1 fertilizer N (as urea). Application rates in field site 2 were 0, 22.4, 44.8, 67.2 and 134.4 Mg ha^?1 compost, 134.4 Mg ha^?1 uncomposted manure and 180 kg ha^?1 fertilizer N (dry matter basis). The high rates of compost application significantly raised organic matter levels, and available P and K compared to inorganic fertilizer N. Uncomposted manure and increasing compost application rates significantly increased grain yield, number of kernels per plant and plant weight. Composting significantly reduced pathogen indicator bacteria concentrations. The data of this study suggest that on these high organic matter soils 22.4 Mg ha^?1 to 44.8 Mg ha^?1 are optimal compost application rates.     

Immobilization of Zinc Fertilizer in Flooded Soils Monitored by Adapted DTPA Soil Test

Zinc (Zn) deficiency is a persistent problem in flooded rice (Oryza sativa L.). Severe Zn deficiency causes loss of grain yield, and rice grains with low Zn content contribute to human nutritional Zn deficiencies. The objectives of this study were to evaluate the diethylenetriaminepentaacetic acid (DTPA) extraction method for use with reduced soils and to assess differences in plant availability of native and fertilizer Zn from oxidized and reduced soils. The DTPA‐extractable Zn decreased by 60% through time after flooding when the extraction was done on field‐moist soil but remained at original levels when air‐dried prior to extraction. In a pot experiment with one calcareous and one noncalcareous soil, moist‐soil DTPA‐extractable Zn and plant Zn uptake both decreased after flooding compared with the oxidized soil treatment for both soils. In the flooded treatment of the calcareous soil, both plant and soil Zn concentrations were equal to or less than critical deficiency levels even after fertilization with 50 kg Zn ha^?1. We concluded that Zn availability measurements for rice at low redox potentials should be made on reduced soil rather than air‐dry soil and that applied Zn fertilizer may become unavailable to plants after flooding.     

CUMULATIVE AND RESIDUAL EFFECTS OF ZINC SULFATE ON GRAIN YIELD,ZINC, IRON,AND COPPER CONCENTRATION IN CORN AND WHEAT

Re-application of zinc (Zn) sulfate for corn (Zea mays L.) production in rotation of wheat-corn has varied effects on yield of crops grown in Zn deficient soils. Therefore, this study was done as split plots in a complete randomized block design (CRBD) where the main plots were control with and without Zn application in wheat (Triticum aestivum L.) production. Sub-plots were of control, without Zn fertilizer, base application of 75 kg per hectare (kg Zn ha^?1), 25% and 50% less than base application and as foliar spray in combination with the 4 soil Zn treatments for corn production. Effect of previous Zn application on grain Zn concentration of corn was significant (P < 0.01). Zinc concentrations in treatments of without previous Zn (nil Zn) application and with Zn application were 28.1 and 31.8 mg kg^?1, respectively. Soil application of 75 kg ha^?1 and foliar application of Zn sulfate gave the highest yield (8853 kg ha^?1) showed an increase of 25 percent in compared with nil-Zn. Although re-application of Zn has small effect on yield, but resulted in was the highest grain concentration.     

低锌旱地土壤水分对小麦产量和锌利用的影响

【目的】西北旱地土壤有机质含量低,pH和碳酸钙含量高,导致土壤有效锌含量低,加之水分缺乏,不仅制约冬小麦生长和产量,还严重影响小麦锌的吸收利用。本研究选取西北旱地典型缺锌区,在土施锌肥的基础上,设置了2年的补充灌水田间试验,进一步研究水分对土壤锌有效性、 小麦生长、 产量以及锌和相关元素吸收利用的影响。【方法】田间试验于2010~2012年在陕西永寿县进行,采用裂区设计,锌肥为主处理,在不施锌与施锌(ZnSO4·7H2O)50 kg/hm2的基础上,设置在冬小麦关键生长期补充和不补充灌水2个副处理。在成熟期采集植株样品,测定了小麦产量、 生物量,各器官部位的锌及氮、 磷、 钾、 铁的含量; 采集0—40 cm土层土壤,测定了土壤有效性锌含量。【结果】在返青期、 孕穗期补灌20~30 mm水分对小麦产量、 土壤有效锌含量无显著影响,却有提高小麦各部位锌含量、 锌肥利用率的趋势,不施锌和施锌条件下,灌水比不灌水处理小麦籽粒锌含量分别提高3.8%~16.3%、 3.8%~13.1%,灌水使锌肥利用率提高21.2%~177.8%。灌水量和灌水时期的不同也影响锌在小麦各器官部位的分配与累积,第一季施锌和不施锌条件下,灌水比不灌水处理锌收获指数分别降低5.1%和2.0%,而第二季锌收获指数分别提高2.1%和2.7%。两季灌水对小麦籽粒中铁及大量元素氮磷钾含量的影响亦各不相同。【结论】在旱地缺锌土壤上,小麦生长关键期灌水对小麦产量、 土壤有效锌含量无显著影响,却有提高小麦各部分锌含量、 锌肥利用率的趋势,说明水肥结合对旱地石灰性土壤锌和锌肥有效性的影响应引起进一步重视,这对提高旱地缺锌地区作物和人体锌营养水平具有潜在意义。     

Total and labile soil organic nitrogen as influenced by crop rotations and tillage in Canadian prairie soils

Crop rotations and tillage practices influence the quantity and quality of soil organic N (SON). We evaluated the impact of crop rotations and tillage practices on SON and mineralizable N at a depth of 0–15 cm in six field experiments, varying in duration over 8–25 years, that were being conducted in three Chernozemic soil zones in Saskatchewan, Canada. In a Brown Chernozem, continuous wheat increased SON at 0–15 cm by 7–17 kg N ha^–1year^–1 more than fallow/wheat. In a Dark Brown Chernozem, continuous cropping increased SON by 30 kg N ha^–1year^–1, compared with cropping systems containing fallow once every 3 years; and, in a Rego Black Chernozem, the increase in SON was 29 kg N ha^–1 year^–1, compared with cropping systems containing fallow once every 4 years. The increase in SON due to increased cropping frequency was accompanied by an increase in the proportion of mineralizable SON in the Brown Chernozem, but not in the Dark Brown and Black Chernozems. In the Brown Chernozemic soil zone, no-tillage management increased SON, compared with conventional tillage, varying from 16 kg N ha^–1year^–1 to 28 kg N ha^–1year^–1. In the Dark Brown Chernozemic soil zone, it increased SON by 35 kg N ha^–1year^–1 and, in the Black Chernozemic soil zone, by about 40 kg N ha^–1year^–1. Increases in SON at a depth of 0–7.5 cm due to no-tillage management was accompanied by a greater increase in the mineralizable N for Hatton fine sandy loam, Melfort silty clay and Indian Head clay than for other soils, indicating that the material responsible for the increased SON due to no-tillage was more labile than the soil humus N. However, the increased SON under no-till in Swinton loam, Sceptre clay and Elstow clay loam was not associated with an increase in the mineralizable N, indicating that this increased SON was no more susceptible to decomposition than the soil humus N. Therefore, increases in SON under improved management practices, such as conservation tillage and extended crop rotations, do not necessarily increase the potential soil N availability.     

Enhanced Phosphorus Fertilizer (Carbond P®) Supplied to Maize in Moderate and High Organic Matter Soils

Carbond P (CBP) fertilizer often increases P uptake and crop yields in low P and organic matter soils. A glasshouse study was conducted with maize (Zea mays L.) grown in moderate or high organic matter soil with 0, 5, 15, 45, or 135 kg phosphorus pentoxide (P₂O₅) ha^?1 applied as either ammonium polyphosphate (APP) or CBP. In the high organic matter soil, both CBP and APP fertilization resulted in similar increases in biomass yield and P concentration and uptake. This was also observed in the moderate organic matter soil for maize P concentration, but biomass yield and total P uptake were significantly greater for CBP than APP at the two lowest P rates of fertilization and significantly higher for APP than CBP at the highest P application rate. The presence of high organic matter in the soil seemed to negate the effects of the organic acid bonded P found in CBP.     

Response of Hard Red Spring Wheat to Copper Fertilization

To achieve optimum production of hard red spring wheat, growers should know if use of copper (Cu) in a fertilizer program is necessary. For this study, copper was broadcast and incorporated before planting in the sulfate or chelate form to supply both 6.7 and 13.4 kg Cu ha^?1 at six sites. The soils at the majority of the sites had a loamy fine sand texture with low organic‐matter content. Application of Cu increased grain yield at one site. Grain yield response, however, could not be predicted by amount of Cu extracted from soil by the diethylenetriaminepentaacetic acid (DTPA) procedure. Concentrations of Cu in whole plant tissue did not match those reported in the literature. The results of this study do not support the addition of Cu to a fertilizer program for production of hard red spring wheat on mineral soils in the northern Great Plains.