How much phosphorus does corn need

The use of agroecological practices such as inoculation by plant growth-promoting bacteria PGPB can represent a sustainable alternative for increase nutrient use efficiency in tropical agriculture Galindo et al. The Azospirillum spp. An analysis of field trials conducted worldwide for over 20 years, where various non-legume crops were inoculated with Azospirillum spp.

Also, positive results in corn development and yield has been reported with Azospirillum brasilense inoculation strains Ab-V5 and Ab-V6 under tropical conditions Martins et al. New research investigating Bacillus spp.

For example, under tropical conditions, Bacillus subtilis inoculation strains Pant and QST associated with Bradyrhizobium japonicum has been reported to increase soybean [ Glycine max L. Lima et al. Zarei et al.

Differently, Oliveira et al. Understanding the success or failure of inoculation requires understanding the complex interactions between the roots of inoculated plants, the specificity between hosts and PGPB, and the major microbial communities in the rhizosphere Bashan et al. This study was based on the hypothesis of positive effect between the different PGPB inoculation and P utilization, providing greater nutrient use efficiency, reflecting on corn development and yield.

The objective of this study was to evaluate the effect of A. The experimental area was cultivated with annual crops cereal and legume crops for over 30 years, with the last 12 years using a no-tillage system.

The last crop sequence prior to corn was wheat. The maximum and minimum temperatures, air relative humidity and the rainfall verified during the study are presented in Figure 1. Figure 1. Twenty soil samples were collected, mixed and a random sub-sample was used to determine soil chemical attributes before the beginning of field trial in the 0.

This samples were collected with soil core sample type cup auger 0. After samples be collected and mixed, the sub-sample was dried in the shade and soil chemical attributes were determined according to the Raij et al. The following results were verified in Table 1. Table 1. Soil chemical attributes in 0—0. Weed control was performed with herbicides application of glyphosate [ g ha —1 of the active ingredient a.

The mineral N and K fertilization was performed with 30 kg N ha —1 urea and 60 kg K 2 O ha —1 potassium chloride at seedling and for all treatments, based on the soil analysis and corn crop requirements.

Also, the application of P 2 O 5 rates was performed at seedling based on soil analysis and crop requirements. The inoculation with A. The inoculation with B. The inoculation with P.

These are commercial strains used in Brazil [for both A. Both inoculations A. The control treatment did not receive inoculations, however, the chemical seed treatment with fungicide and insecticide was performed, similarly to inoculated treatments. Seedling emergence occurred 5 days after sowing, on November 16, When necessary, the corn crop was irrigated with supplementary irrigation, using a center pivot sprinkling system water depth of 14 mm. Weed and insect control were performed according to crop demand.

Nitrogen fertilizer side dress application was spread on the soil surface without incorporation by placing the fertilizer in the middle of the rows when the plants were in the V4 stage with four leaves completely unfolded at the dose of kg N ha —1 as urea source, for all plots.

After N-fertilization, the area was irrigated 14 mm depth at night to minimize losses by ammonia volatilization. The plants were harvested manually at days after emergence DAE on March 21, The following nutritional evaluations were performed: a P foliar concentration, in g kg —1 of dry matter, was determined by collecting the middle third of 20 leaves of the main ear insertion in each experimental plot in the female flowering stage, according to the methodology described in Cantarella et al.

Also, the b P concentration in biomass and grains were determined, at harvest time, and the P uptake in biomass and grains were calculated, in kg ha —1. P determinations in tissue and grains followed the methodology that was proposed in Malavolta et al. Five soil samples depth of 0—0. The following productive components measurements were performed: d plant height at maturity, defined as being at a distance m from the ground level to the apex of the tassel; e stem diameter in the second internode at corn maturation plant using a manual caliper.

The data was analyzed by ANOVA in a 2-way factorial design with P 2 O 5 application rates and inoculation and their interactions considered fixed effects in the model.

Mean separation was done when significant factors or interactions were observed using the test Tukey. Regression analysis was used to discern whether there was a linear or non-linear response to P 2 O 5 rates in R software R Development Core Team, Phosphorus resin in soil and stem diameter were significantly affected by the main effects of P 2 O 5 rates and PGPB inoculation Table 2. Table 2. Control plots associated with low and average P 2 O 5 application rates 0, Also, control plots associated with high P 2 O 5 rates kg ha —1 resulted in greater leaf P concentration compared to A.

Leaf P concentration responded linearly to P 2 O 5 application rates when P. Differently, leaf P concentration responded non-linearly to P 2 O 5 application rates when B. Figure 2. Ctl, Azos, Pseud e Bac refers to the control treatment and inoculations with A. In the absence of P 2 O 5 application, control plots resulted in lower biomass P uptake compared to A.

Also, control plots associated with high P 2 O 5 application rates kg ha —1 resulted in lower biomass P uptake compared to P. Biomass P uptake responded non-linearly to P 2 O 5 application rates without inoculation and when A. The A. In addition, A. Grain P uptake responded linearly to P 2 O 5 application rates when B. Differently, grain P uptake responded non-linearly to P 2 O 5 application rates when control and A.

Phosphorus resin in soil responded linearly to P 2 O 5 application rates Figure 2D. In addition, control and A. Control plots associated with low P 2 O 5 application rates 0 and In addition, control plots associated with kg P 2 O 5 ha —1 resulted in greater plant height compared to P. However, B. Plant height responded non-linearly to P 2 O 5 application rates when A.

Stem diameter responded linearly to P 2 O 5 application rates Figure 3A. Figure 3. Stem diameter as a function of P 2 O 5 rates A and inoculations B , ear length C , ear diameter D , grains per row E , and grains per ear F as a function of the interaction between P 2 O 5 rates and inoculations in corn crop.

Ear length fluctuated throughout the P 2 O 5 application rates; however, in general, control plots showed reduced ear length compared to A.

Ear length responded linearly to P 2 O 5 application rates when P. Differently, ear length responded non-linearly to P 2 O 5 application rates when B. Control plots and P. Ear diameter responded non-linearly to P 2 O 5 application rates when control and P. In the absence of of P 2 O 5 application, B. Grains per row responded non-linearly to P 2 O 5 application rates when control and B.

Similarly, in the absence of of P 2 O 5 application, B. Also, A. Mass of grains responded linearly to P 2 O 5 application rates when B. Differently, mass of grains responded non-linearly to P 2 O 5 application rates when control and A. Figure 4. The B. Phosphorus use efficiency responded linearly to P 2 O 5 application rates regardless of inoculations Figure 4B. However, A.

Grain yield responded linearly to P 2 O 5 application rates when A. Differently, grain yield responded non-linearly to P 2 O 5 application rates when control and P. Phosphorus is the second nutrient that is most demanded by corn plants and directly affects crop development and yield Dhillon et al.

Thus, the higher P availability as a function of the P 2 O 5 application probably favored initial root system development, reflecting on corn grain yield. The better growth of P 2 O 5 -fertilized plants can be attributed to the P readily available for absorption after being added to the soil as verified by the linear increasing response in P content in soil to P 2 O 5 application rates.

Phosphorus plays important roles in plant nutrition and development Lollato et al. In addition, P is responsible for the storage and transport of energy for endergonic processes, such as the synthesis of organic compounds and the active uptake of nutrients Marschner, Also, P is related to root system development and plant growth Sulieman and Tran, ; Fink et al.

There are several studies reporting the P fertilization benefits in corn crop Wen et al. Therefore, P application must be rational and optimized, since the increased P 2 O 5 application rates results in increased losses and less utilization by cropping systems. We verified this behavior on lower grain P uptake associated with 35 and kg P 2 O 5 ha —1 , ear diameter with 35 and 70 kg P 2 O 5 ha —1 , mass of grains with 70 and kg P 2 O 5 ha —1 and grain yield with kg P 2 O 5 ha —1 when P.

Positive responses to B. In the absence of P 2 O 5 application rates B. With application of 70 kg P 2 O 5 ha —1 , B. In addition, when Grain yield was also positive affected by B. Similarly, positive responses to A. With application of 35 kg P 2 O 5 ha —1 , A. The study found that applying P fertilizers, like MAP or DAP, the fall or spring before planting soybeans does not increase soybean yield. As long as enough P fertilizer was applied before the previous corn crop to account for the needs of both corn and soybean, soybean yield was maximized.

For corn, results showed a four to five bushel average yield advantage when some or all of the P fertilizer was applied the fall or spring before the crop. This means that farmers could save money on application costs by only applying before corn, instead of before both corn and soybean crops.

Field trials were located near St. Applying P to high calcium soils Previous research has shown that it does not matter whether P is applied in the fall or spring ahead of corn. However, new research on high calcium soils in central and western Minnesota indicates that spring application may have an advantage. Nutrient removal by harvested portions of grain crops is an important consideration in deciding fertilizer rates. As crops are being harvested and grain is taken to the storage or elevator, it is time to recognize the amount of nutrients that are removed from your field by this grain, particularly the three major macronutrients: nitrogen N , phosphorus P and potassium K.

Nutrient removal amounts can be easily calculated by multiplying the nutrient removal rate per bushel shown in table by actual yield. For example, a bushel-per-acre corn will remove pounds per acre N, 56 pounds per acre P 2 O 5 and 41 pounds per acre K 2 0.

Likewise, a bushel-per-acre soybean crop will remove pounds per acre N, 32 pounds per acre P 2 O 5 and 56 pounds per acre K 2 0. Nutrient removal rates indicate the variations in N, P and K needs among different crops. As crops yields increase, more and more nutrients are removed from the soil. As a result of this removal, the soil test P and K levels will gradually decrease over the years if no fertilizers are added.

Information on nutrient removal alone is not adequate for making fertility recommendations because it does not take into account the ability of the soils to retain and supply nutrients.

Another important aspect is the current soil test level.