Depth Of Fertilizer Placement Research Articles

Suitable Fertilizer Application Depth Enhances the Efficient Utilization of Key Resources and Improves Crop Productivity in Rainfed Farmland on the Loess Plateau, China.

Appropriate fertilizer application methods can help to improve crop yields. However, limited information is available regarding how different fertilizer application depths might affect crop production in dryland winter wheat-summer maize cropping in the Loess Plateau region of China. Therefore, we conducted field experiments in 2019–2020 and 2020–2021 to evaluate the effects of changing the fertilizer placement depth on summer maize (current crop) and winter wheat (succeeding crop) productivity, as well as the resource use efficiency and soil nitrate-nitrogen residue (SNR) level. Four fertilizer placement depths were tested comprising 5 cm (FD5), 15 cm (FD15), 25 cm (FD25), and 35 cm (FD35). The nitrogen uptake by summer maize in the two seasons was 10.0, 6.5, and 11.8% higher under FD15 compared with those under FD5, FD25, and FD35, respectively, because FD15 effectively increased the root length density, root surface area density, and rate of root bleeding sap. Due to the increased nitrogen uptake, the leaf area index, plant height, stem diameter, and accumulated dry matter were improved in summer maize. The interception of photosynthetically active radiation was 3.6, 3.7, and 5.9% higher under FD15 compared with those under FD5, FD25, and FD35, respectively. The summer maize grain yield increased by 13.9–22.4% under FD15 compared with the other treatments. In addition, the SNR in the deep soil (200–300 cm) was significantly lower under FD15 during the summer maize harvest (17.9–30.7%) compared with the other treatments. Moreover, FD15 increased the winter wheat (succeeding crop) grain yield (2.6–11.2%) and reduced the SNR in the 200–300 cm soil layer (8.8–16.8%) at the winter wheat harvest. The highest radiation use efficiency, precipitation use efficiency, and nitrogen use efficiency were obtained under FD15 in both summer maize and winter wheat. These results clearly suggest that depth fertilization of 15 cm enhanced the productivity and resource use efficiency for the current and subsequent crops in rainfed farmland in the Loess Plateau of China, as well as reducing the SNR in the deep soil to promote sustainable agricultural development. These findings provide a practical reference for optimizing fertilizer application management.

Root physiological adaptations that enhance the grain yield and nutrient use efficiency of maize (Zea mays L) and their dependency on phosphorus placement depth

Root growth demonstrates a high degree of plasticity in response to spatial variations in the availability of vital nutrients, and P fertilizer placement depth affects the development and distribution of plant roots. Optimizing the spatial matching between soil nutrients and the roots of maize plants in order to improve their N and P uptake and utilization capacity is a potential measure for improving the grain yield from summer maize. The spatial distribution profile of N, P and roots in the soil, as well as the roots’ absorption and utilization characteristics with respect to N and P and how these relate to the dry matter accumulation and grain yield formation were evaluated under four different placement depths of 5, 10, 15 and 20 cm (labeled P5, P10, P15, and P20, respectively). Compared with the P5 treatment, the P15 treatment induced a larger root length density, as well as a larger rooting depth. That happened because a higher number of root cortical aerenchyma, combined with a larger cortical cell size, reduces the metabolic cost required to establish them, which drives regulation processes that result in the allocation of more biomass to root proliferation. It also helped plants to maintain a higher level of biomass and N and P accumulation during the later growth period, which in turn increased the N and P assimilation of grain and enhanced the grain yield by 22%, the P recovery efficiency by 74%, the P agronomic efficiency by 150%, and both the partial factor productivity of P and the partial factor productivity of N by 21%. In conclusion, this study demonstrates that placing P fertilizer at a depth of 15 cm promotes root growth by reducing the metabolic cost of having a higher number of root cortical aerenchyma and a larger cortical cell size, and also that it improves the N and P absorption and utilization of roots and synergistically increases the grain yield and nutrient utilization efficiency of the whole plant.

Effects of NP Fertilizer Placement Depth by Year Interaction on the Number of Maize (Zea mays L.) Plants after Emergence Using the Additive Main Effects and Multiplicative Interaction Model

Field experiments were carried out at the Department of Agronomy of the Poznań University of Life Sciences to determine the effect of the depth of NP fertilization placement in maize cultivation on the number of plants after emergence. The adopted assumptions were verified based on a six-year field experiment involving four depths of NP fertilizer application (A1—0 cm (broadcast), A2—5 cm (in rows), A3—10 cm (in rows), A4—15 cm (in rows)). The objective of this study was to assess NP fertilizer placement depth, in conjunction with the year, on the number of maize (Zea mays L.) plants after emergence using the additive main effects and multiplicative interaction model. The number of plants after emergence decreased with the depth of NP fertilization in the soil profile, confirming the high dependence of maize on phosphorus and nitrogen availability, as well as greater subsoil loosening during placement. The number of plants after emergence for the experimental NP fertilizer placement depths varied from 7.237 to 8.201 plant m−2 during six years, with an average of 7.687 plant m−2. The 61.51% of variation in the total number of plants after emergence was explained by years differences, 23.21% by differences between NP fertilizer placement depths and 4.68% by NP fertilizer placement depths by years interaction. NP fertilizer placement depth 10 cm (A3) was the most stable (ASV = 1.361) in terms of the number of plants after emergence among the studied NP fertilizer placement depths. Assuming that the maize kernels are placed in the soil at a depth of approx. 5 cm, the fertilizer during starter fertilization should be placed 5 cm to the side and below the kernel. Deeper NP fertilizer application in maize cultivation is not recommended. The condition for the use of agriculture progress, represented by localized fertilization, is the simultaneous recognition of the aspects of yielding physiology of new maize varieties and the assessment of their reaction to deeper seed placement during sowing.

Dry Matter Yield of Maize (Zea mays L.) as an Indicator of Mineral Fertilizer Efficiency.

This study presents the results of 3-year field trials, whose purpose was to assess the dynamics of dry matter accumulation by maize depending on the placement depth of a two-component (NP) mineral fertilizer in the soil layer, type of nitrogen fertilizer and date of its application. Weather conditions, mainly thermal in the early growing season, had a significant effect on maize responses to placement depth of phosphorus starting dose in the soil profile. In the initial stage of maize development, the temperature determined plant growth to a significantly higher extent than the sum of rainfall. The dry matter yield of ears and whole plants showed a clear reaction to starter phosphorus fertilization, but the effect of the depth of fertilizer placement varied over the years, indicating a depth of 5 cm and 10 cm as advisable and recommended for agricultural practice. The PFPFN (partial factor productivity of fertilizer nitrogen) and PFPFP (partial factor productivity of fertilizer phosphorus) indices confirmed the significant effect of fertilizer (NP) placement in the soil profile, indicating row fertilizer application (regardless of the depth) as recommended to improve the efficiency of maize fertilization. The SPAD (soil plant analysis development) leaf greenness index turned out to be a sensitive indicator of maize response to fertilizer (NP) placement depth in the soil profile.

Layered application of mineral fertilizers with the coulter ripper of a combined unit

The applied methods of fertilizing cotton in Uzbekistan have a number of significant disadvantages. They do not provide available nutrients to the plant’s root system. With the distribution of fertilizers in the zone of root development in layers in the required ratio, the coefficient of their use and the yield of cotton increases. (Purpose of the study) To substantiate the design parameters of a subsoiler’s distribution pipeline for three-tier fertilization. (Materials and methods) The design of a developed pipeline distributor for three-tiered fertilization is presented. The subsoiler is equipped with a fertilizer distribution pipe, which consists of a cylindrical and inclined funnel-shaped part, a high-flow channel and a lower fertilizer distributor. In the conductive channel, two branch pipes with reflective plates are installed, which cut the moving fertilizers and direct them to the appropriate soil horizon. (Results and discussion) We investigated the movement of mineral fertilizer granules along the fertilizer channel, on the basis of which the length of the pipes of the upper and middle tiers was determined.Experiments were carried out to study the influence of the length of the protruding part of the baffle plates of the branch pipe and the angle of inclination of the pipeline-distributor funnel on the distribution of fertilizers and on the unevenness of the flow of fertilizers into the upper, middle and lower tiers. The parameters of the loading funnel of the vertical pipeline, branch pipes and movable plates of the upper and middle tiers, in addition to the fertilizer diffuser of the lower tier, were substantiated.We theoretically and experimentallysubstantiated the parameters of the nozzles of the upper and lower tiers. With optimal lengths of the branch pipe and baffle plates, a given fertilizer placement depth is provided in three tiers with the required amount of fertilizer. The influence of the parameters of the distribution pipeline on the uniformity of fertilizer distribution in the upper, middle and lower tiers was established. The rational parameters of the lower fertilizer spreader were substantiated, which ensures uniform distribution of fertilizers over the working width of the working body.

Energy demand of a mechanized unit for the implementation of common bean crops

ABSTRACT Adequate soil managements and use of agricultural machinery are essential for the economic viability of these practices and for the environmental preservation. In this context, sowing and fertilizer application practices are the most important activities, since they affect crop development and present high energy demand. Therefore, the objective of this study was to evaluate the energy demand of a tractor-planter-fertilizer unit for the sowing of common bean seeds in no-tillage system as a function of three soil water contents (28.7, 36.4, and 47.6%) and three soil fertilizer placement depths (0.06; 0.11 and 0.15 m). The final common bean grain yield was also evaluated. The lowest energy demand was found for the highest soil water content combined with the lowest soil fertilizer placement depth. The highest common bean grain yield was found for plants under soil water content of 36.4% and fertilizer placement depth of 0.11 m, reaching 4,186 kg ha-1.

Deep N fertilizer placement mitigated N2O emissions in a Swedish field trial with cereals

Deep fertilizer placement is a proposed strategy to increase crop yield and nitrogen (N) use efficiency while decreasing nitrous oxide (N2O) emissions from soil to atmosphere. Our objective was to test three fertilization depth orientations to compare overall N use efficiency, based on a 2-year field trial on a mineral soil cropped with cereals in Uppsala, Sweden. The field was fertilized with ammonium nitrate at a rate of 120 kg ha−1 (2016) and 105 kg ha−1 (2017) and a deep fertilizer placement (DP) at 0.20 m was compared to a shallow placement (SP) at 0.07 m and a mixed-depth placement (MP) where fertilizer was halved between the depths of 0.07 and 0.20 m, and a non-fertilized control (NF). In 2016, compared to SP, MP and DP increased N content in harvested grain by 3.6% and 2.5% respectively, and DP increased grain yield by 11% (P < 0.05). In both years, N2O emissions were similar in DP and NF, whereas SP and MP emissions were similar but generally higher than those in DP and NF. Fertilizer-induced emission factors (EF) for the growing season of 2017 decreased with fertilizer placement depth and were 0.77 ± 0.07, 0.58 ± 0.03, and 0.10 ± 0.02 for SP, MP, and DP, repectively. Although deep N placement benefits are likely dependent on weather conditions and soil type, this strategy has a clear potential for mitigating N2O emissions without adversely affecting yield.

Wheat grain yield and nitrogen uptake as influenced by fertilizer placement depth

AbstractGlobal nitrogen use efficiency (NUE) for cereal production is estimated to be only 33%. Providing producers with efficient methods to increase the effectiveness of their N applications is integral to agricultural sustainability and environmental quality. This study was conducted to evaluate the effect of urea ammonium nitrate (UAN) injected at different depths on grain yield and uptake of N in grain. Liquid UAN (28–0–0) was applied in bands at depths of 5 and 10 cm, along with surface applications, all at various N rates around Feekes growth stage 5. Placement depth had the most significant impact on yield at low N rates. Subsurface application at 10 cm was most beneficial in low N no‐till (NT) soils, whereas surface treatments produced higher yields in low N environments of conventional till (CT) systems. Three of the four locations experienced higher rates of N uptake from subsurface applications when compared with surface treatments. No difference in grain N uptake was apparent between application depths of 5 and 10 cm. Subsurface N applications were beneficial in reducing rates of ammonia volatilization from urea‐based fertilizers. While there was no clear separation between 5 and 10 cm application depths, subsurface depths of 10 cm provide the most significant promise in benefiting yield in low N environments of NT soils and increasing grain N across CT and NT systems.

Multilevel modelling of the draft force required by seeder-fertilizers

The high production costs in agriculture have guiding the adoption of farming systems and new management techniques as well as the sizing of agricultural machinery. In this regard, planning entails knowledge on the efficiency according to the energy requirements parameters, so the farmer shall consider the characteristics of the soil on which the implement operates. The performance assessment of sowing-fertilize machines shows the effect of some variables on the draft requirement, so the experimental conditions, which might lead to different outcomes of implement operation, must be regarded. Therefore, it is necessary obtain metanalytical estimates to integrate the results available in the literature. Grounded on systematic review, this study aimed to model the draft imposed by sowing-fertilizing machines considering fixed effects, mainly soil characteristics, and random effects associated to the selected experiments. It was found that the best models according to information criteria may not always meet the assumptions as normality of the distribution of residuals and homoscedasticity. The variables such as bulk density of soil, stubble conditions, depth of fertilizer placement, and speed could accurately explain the draft requirement with mean squared deviation of 2.93 whereas the referred evaluator for the ASABE standard was 63.51. Forthcoming works may analyze the repeatability of the models considering different seeders under diverse configurations and operation conditions

Effect of soil compaction and fertilizer placement depth on growth, yield, nutrient uptake of maize (Zea mays L.) and soil properties in tarai soils of Uttarakhand

Soil compaction and placing of fertilizer in undesirable depth in soil are the most serious threat under intensive cultivation system in poorly drained heavy textured soil. In view of this, a field experiment was conducted during kharif season of 2014–15 to understand the effect of soil compaction and fertilizer placement depth on performance of maize crop, nutrient uptake and soil properties. The soil was heavy textured i.e. silty clay loam with poor drainage and receiving about >1400 mm rainfall annually. Root length and root length density of plants in compacted plots (1.54 and 1.63 Mg/m3) decreased remarkably from 1.50–4.60 cm and 0.06–0.11 cm/cm3, respectively, compared with non-compacted soil (1.34 Mg/m3) however root dry weight did not exhibit response against soil compaction. Maximum grain yield of 5613.4 and 5593.0 kg/ha was recorded with non-compacted soil (1.34 Mg/m3) and 0–10 cm fertilizer placement depth, respectively, however at par yields were obtained between 1.54 and 1.63 Mg/m3 compaction levels. Compaction and fertilizer placement depth showed highest adverse effect on Zn uptake (14.70–20.42%) whereas least on P uptake (6.23–11.0%). Non compacted soil (1.34 Mg/m3) and placing fertilizer at 0–10 cm depth maintained favourable oxidizable organic carbon and hydraulic conductivity but reduced with increase in compaction and placement depth. In general, strong negative and non-significant relationships of the compaction and fertilizer placement depth with growth and yield parameters, yields, nutrient uptake and soil properties were estimated.

Effect of depth of fertilizer banded-placement on growth, nutrient uptake and yield of oilseed rape (Brassica napus L.)

A better understanding of crop growth and nutrient uptake responses to the depth of fertilizer banded-placement in the soil is needed if growth and nutrient uptake responses are to be maximized. A two-year field study covering two rape seasons (2010–2011 and 2011–2012) was conducted to examine the effect of banded-placement of N–P–K fertilizer at various depths on growth, nutrient uptake and yield of oilseed rape (Brassica napus L.). The results showed that fertilization at 10cm and 15cm soil depth produced greater taproot length and dry weight than fertilization at 0cm and 5cm. 0 cm and 5cm deep fertilization significantly increased the lateral root distribution at 0–5cm soil depth, while 10cm and 15cm deep fertilization induced more lateral root proliferation at 5–15cm soil depth. At 36 days after sowing (DAS), 5cm deep fertilization produced better aboveground growth and nutrient uptake than 10cm and 15cm deep fertilization. However, reversed results were observed after 36 DAS. 10 cm and 15cm deep fertilization produced more rapeseed than 0cm and 5cm deep fertilization, moreover, the yield difference was more significant in drought season (2010–2011) than in relatively normal season (2011–2012). In summary, these results preliminarily suggest that both 10cm and 15cm are relatively proper fertilizer placement depth when the practice of banding fertilizer is used in oilseed rape production. But from the viewpoint of diminishing the production cost, 10cm deep fertilization should be recommended in actual farming. Because 15cm deep fertilization may require higher mechanical power input, and thus resulting in higher cost of production.

Lime Effects on Soil Acidity, Crop Yield, and Aluminum Chemistry in Direct‐Seeded Cropping Systems

Soil acidification threatens dryland crop production in the inland Pacific Northwest (IPNW). Our objective was to assess the efficacy of lime to lower soil acidity, alter Al chemistry, and increase crop yield in a direct‐seeded system. Treatments of subsurface banded fertilizer (120–168 kg N ha−1 yr−1) alone or with subsurface banded lime (224 kg ha−1 yr−1), or a one‐time broadcast application of lime (7000 kg ha−1) or elemental S (1000 kg ha−1) were initiated in spring 2002. Grain yield was measured annually from 2002 to 2005 in a spring barley (Hordeum vulgare L.)–spring wheat (Triticum aestivum L.)–winter wheat rotation. Soil was sampled in spring 2004 to assess pH and model Al speciation. Low pH was evident at the depth of fertilizer placement (5–10 cm). Broadcast lime increased pH in the surface 15 cm, although reductions in Al3+ activity [(Al3+)] occurred only in the 0‐ to 5‐cm layer. Relative to banded N, there was no increase in pH at the 5‐ to 10‐cm depth where banded lime was placed. At the 0‐ to 5‐cm depth, lower pHs were observed with broadcast S (4.6) compared with the banded N control (5.1) or banded lime (5.0). There was no effect of treatment on yield. Modeling suggests that soluble Al is dominated by organic matter–Al complexes (fulvic acid, FA; FA2Al+ and FA2AlOH0). Solid‐ and solution‐phase organic complexes may control (Al3+) at pH &lt;5.5. Although acidification is a concern in the IPNW, the high organic matter content in direct‐seeded soils may buffer against Al phytotoxicity.

Emissions of Nitrous Oxide and Carbon Dioxide

Innovative management practices are required to increase the efficiency of N fertilizer usage and to reduce nitrous oxide (N2O) and carbon dioxide (CO2) emissions from agricultural soils. The objectives of this study were to evaluate the feasibility of using conservation tillage and N fertilizer placement depth to reduce N2O and CO2 emissions associated with corn (Zea mays L.) production on clay loam soils in Eastern Canada. A 3‐yr field study was established on a wheat (Triticum aestivum L.)‐corn–soybean [Glycine max (L.) Merr.] rotation with each phase of the rotation present every year. Investigations were focused on the corn phase of the rotation. The tillage treatments following winter wheat included fall moldboard plow tillage (15 cm depth), fall zone‐tillage (21 cm width, 15 cm depth), and no‐tillage. The N placement treatments were “shallow” placement of sidedress N (2‐cm depth) and “deep” placement of sidedress N (10‐cm depth). Nitrous oxide emissions were measured 53 times and CO2 emissions were measured 43 times over three growing seasons using field‐based sampling chambers. There was a significant tillage and N placement interaction on N2O emissions. Averaged over all three tillage systems and site‐years, N2O emissions from shallow N placement (2.83 kg N ha−1 yr−1) were 26% lower than deep N placement (3.83 kg N ha−1 yr−1). The N2O emissions were similar among the tillage treatments when N was placed in the soil at a shallow depth. However, when N was placed deeper in the soil (10 cm), the 3‐yr average N2O emissions from zone‐tillage (2.98 kg N ha−1 yr−1) were 20% lower than from no‐tillage (3.71 kg N ha−1 yr−1) and 38% lower than those from moldboard plow tillage (4.81 kg N ha−1 yr−1). Tillage type and N placement depth did not affect CO2 emissions (overall average = 5.80 Mg C ha−1 yr−1). Hence, zone‐tillage and shallow N placement depth reduced N2O emissions without affecting CO2 emissions.

Characteristics of P supply from polyolefin-coated P fertilizers in soil

Improvement of the availability of phosphorus (P) fertilizers in soil has been one of the major topics in the field of soil science and plant nutrition. We evaluated the P supplying characteristics of the polyolefin-coated (POC)-P fertilizers, POC double superphosphate (POC-DSP). POC multi-phosphate (POC-MP) and POC high-analysis compound fertilizer (POC-HACF) to improve the P recovery rate by crops in comparison with those of uncoated DSP, MP and fused magnesium phosphate (Fused P) in two soils (A horizon soils of Alic Pachic Melanudand and Oxyaquic Udorthent) with different P fixing capacity. The P supply from these fertilizers was examined using anion exchange resin and barley seedlings.P recovery from POC-DSP and POC-MP was maximal after 2 to 5 weeks while P recovery from uncoated DSP and MP markedly decreased with time. P recovery from POC-DSP and POC-MP was 3–5 times that from uncoated DSP and MP. P recovery from Fused P was very low because of its low solubility rather than fixation by soil. The P recovery markedly decreased with increasing depth of fertilizer placement, especially in Alic Pachic Melanudand. These findings suggest that close contact between crop root and POC-phosphorus fertilizers (POC-Ps) is important to improve P recovery. Findings obtained by using barley seedlings were in agreement with those obtained by using the resin.

Phosphorus and nitrogen rate and placement for winter wheat grown on chemical fallow in a Brown soil

The most assured method of producing winter wheat (Triticum aestivum L.) in the semiarid Brown soil zone of the Canadian prairies is by seeding it directly into chemical fallow. This provides adequate soil moisture at seeding, protection from low winter temperatures and results in some build-up of available soil N. However, there is usually a need for additional P. Further, to ensure that adequate levels of grain protein are attained, winter wheat may require added N fertilizer. There is also some question regarding the most effective method and depth of fertilizer placement. Two 3-yr experiments, one during a relatively dry period and the other in a moist period, were conducted on a silt loam at Swift Current, Saskatchewan, to determine grain yield and protein response of winter wheat to rates of N, P and K and to P placement. Yield response to P rates occurred when available moisture was favourable and soil-test P was low to moderate Yield response to N rates occurred in 2 of the 3 yr tested. Here too, high moisture and low to moderate levels of soil-test N resulted in a positive yield and protein response. Seed-placed P and P banded mid-row at 5- and 10-cm depth increased yields, compared with broadcast P, in one moist year but not in two dry years (exp. 1). In three moist years (exp. 2), P placement (seed-placed and mid-row-banded at 2.5- and 5-cm depths) had no effect on yield. Rate of K (0 vs. 100 kg K2O ha−1) did not influence grain yield or protein in three moist years because soil-test K was high. In three moist years (exp. 2), grain protein concentration was positively influenced by N rate, but neither P rate nor method of placement affected protein. We recommend that producers who choose to grow winter wheat on chemical fallow in the Brown soil zone apply N and P fertilizer based on a soil test. Further, they should either seed-place the P or band it at a shallow depth (about 5 cm). Key words: Grain yields, protein, fertilizer response, potassium

Shoot and Root Growth Response of Perennial Ryegrass to Fertilizer Placement Depth

AbstractA better understanding of turfgrass growth responses to the vertical placement of nutrients in the soil is needed if growth responses are to be maximized. This greenhouse work examined the shoot and root growth responses of perennial ryegrass (Lolium perenne L.) to placement of N‐P‐K fertilizer at various depths in a sandy clay loam and in a sandpeat mixture. Fertilization at the 5‐, 10‐, and 15‐cm soil depths produced greater verdure and total root mass than fertilization at 0 cm in both the sandy clay loam and sand‐peat. Root mass increases occurred within the 5‐ to 35‐cm zone of the sandy clay loam and the 10‐ to 35‐cm zone of the sand‐peat with subsurface fertilization. Water use efficiency was increased 11% in the sandy clay loam with 10 and 15 cm deep fertilization and 21% in the sand‐peat with 5 cm deep fertilization compared with surface fertilization. Except for P, nutrient accumulation with subsurface fertilization matched or exceeded that achieved with surface fertilization. Management practices that position nutrients below the soil surface and as deep as 15 cm can improve turfgrass growth responses to fertilizer. Further research needs to relate irrigation, fertilization, cultivation, and soil modification practices to fertilizer placement, and subsequently shoot and root growth responses.

Response of wheat to deep placement of nitrogen and phosphorus fertilizers on a soil high in phosphorus in the surface layer

Wheat was grown in a series of field experimenls on a sandy red-brown earth that was well supplied with phosphorus in the top 10 cm, and deficient in nitrogen. Nitrogen (0-60 kg ha-') as ammonium sulfate or urea, and/or phosphorus (0-100 kg ha-1) as triple superphosphate were applied at various depths down to 30 cm. In one experiment the response to fertilizer placement was examined under dryland and irrigated conditions. The dry weights and the concentrations of nitrogen and phosphorus in the plants were determined, and in one experiment root lengths were also measured. In none of the experiments did placement of fertilizers at depth increase grain yields to a greater extent than placement at 5 cm. While the concentrations of nitrogen and phosphorus in the plants were increased by the application of nitrogen and phosphorus fertilizers respectively, the depth at which the fertilizers were placed was immaterial. Application of phosphorus fertilizer increased root length, but only at the site of placement. Irrigation increased yields, but there was no interaction with depth of fertilizer placement. The soil disturbance (ripping) associated with deep placement of the fertilizers affected shoot growth in all experiments, but the effects were not consistent. Ripping had no effect on root length. Residual effects of the fertilizer treatments on growth and composition of the wheat were small. Deep placement of fertilizer is not recommended for wheat where the nutrient content of the topsoil is high and the topsoil remains wet during the early part of the season.

Effects of depth of fertilizer placement on wheat grown under three water regimes

Wheat was grown in reconstructed profiles of a sandy red-brown earth in pots 120 cm deep. Ammonium sulphate (40 mg nitrogen per pot) and/or monocalcium phosphate (75 mg phosphorus per pot) were placed either in the topsoil at 5 cm depth or in the subsoil at 25 cm. When the wheat reached ear emergence, water treatments were introduced to provide (a) dry topsoil and water shortage; (b) dry topsoil but ample water supply in the subsoil; or (c) an ample water supply with both topsoil and subsoil wet. The yield and concentrations of nitrogen and phosphorus in the wheat and the distribution of roots in the soil were measured at maturity. Water use by the plants was calculated. Drying of the topsoil decreased grain yield and uptake of nitrogen and phosphorus by the wheat, but the effects were small compared with those of water shortage per se. Placement of nitrogen and phosphorus at 25 cm produced higher grain yields than placement at 5 cm. There was no interaction between placement depth and the water treatments: this indicated that reduced availability of nutrients because of dry topsoil after ear emergence was not a major factor limiting yield. The fertilizer treatments affected the distribution of roots more than total root length. Root growth increased at the site of placement where nitrogen and phosphorus, and to a lesser extent nitrogen alone, were applied in the subsoil; there was little effect in other parts of the profile. Efficiency of water use was increased by the application of nitrogen.

Effect of Rate and Placement of Superphosphate on the Yield and Phosphorus Absorption of Legume Hay

AbstractA study was undertaken to determine the effect of superphosphate topdressing on the yield and phosphorus content of legume and legume‐grass hay. Radioactive superphosphate containing 20% P2O5 was broadcast in the early spring on established meadows at five locations in central Michigan.A significant yield response of first cutting hay was obtained on all fields as a result of topdressed applications of 80 and 120 pounds of P2O5per acre. The hay which was thus treated contained appreciably more phosphorus than did that which was grown on untreated plots or where only 40 pounds of P2O5 was applied.The absorption of fertilizer phosphorus was low in hay grown on two soils and relatively high in hay from the remaining locations. As the rate of broadcast superphosphate increased, the percentage of plant phosphorus derived from fertilizer in forage plants also increased. The recovery of fertilizer phosphorus by first‐cutting hay from two locations was low, but was as high as 15% in hay from the other areas. As the rate of broadcast superphosphate increased, the percentage of recovery of applied phosphorus decreased.The percentage of phosphorus in hay derived from superphosphate placed at various depths in two soils was related to depth of fertilizer placement. Absorption of fertilizer phosphorus was highest at the surface or 3‐inch depth; intermediate at the 6‐inch depth; and low for the 12‐, 24‐, and 36‐inch placement. In an alfalfa‐bromegrass meadow where the fertilizer was applied broadcast, the bromegrass obtained a greater percentage of its phosphorus from the fertilizer than did alfalfa. However, at the 3‐ and 6‐inch depths, the alfalfa absorbed two to three times as much phosphorus as did the bromegrass.