The Effect of EM on Growth and Nitrogen Uptake by Wheat in the Green
A.C.S. Rao1, J.L.Smith2, R.I.Papendick2 AND J.F. Parr3
l Washington University,
2 USDA Agricultural Research Service, and
3The International Nature Farming Research Center, USA
An experiment was conducted under greenhouse conditions to study the efficacy of Effective Microorganisms (EM) on growth and N uptake by wheat. Thus solutions of EM were applied alone, with organic matter or with chemical fertilizers. Application of EM increased dry matter production of wheat, although the magnitude was less than that observed with chemical fertilizers. EM did not enhance N uptake by wheat. However, a basal application of EM increased dry matter yield of wheat when there was no top dressing after plant emergence.
Effective Microorganisms (EM) consist of mixed cultures of beneficial and naturally occurring microorganisms including lactic acid bacteria, photosynthetic bacteria, yeasts, and actinomycetes. EM has been reported to increase the microbial diversity of soils and plants; to improve soil quality; and to enhance the growth, yield and quality of crops (Kyusei Nature Farming, 1991: Kyusei Nature Farming, 1 994; Higa and Parr, 1994). However, most of this research was conducted in warmer climates, often under tropical conditions. Research with EM has been extremely limited in the USA, especially with major crops such wheat (Triticum
aestivum ) and corn (Zea mays ). Of particular interest is crop response in low fertility or poor quality soils.
A greenhouse experiment was conducted during late spring 1995 at Pullman, Washington with spring wheat grown for 55 days in soil obtained from the Nature farm near Lompoc, California. The objectives of the study were to determine the effect of:
The treatments included 1. three N sources, i.e. bokashi, compost, and ammonium sulfate, 2. EM basal application and 3. EM top-dressed once, twice or three times at 10-day intervals after wheat emergence. The control for the N sources did not receive N and the control for EM received molasses solution (the carrier for EM) The bokashi was obtained as a standard
- EM applied alone or with compost, bokashi or ammonium sulfate on growth and N uptake by wheat.
- Top dressing of EM on dry matter production and N uptake by wheat.
- EM applications superimposed over treatments of the previous wheat crop on the growth of a succeeding corn crop .
product from EM Technologies, Inc., Tucson, Arizona but without the EM inoculant. The compost was obtained from a local nursery and was a commercial grade derived from a vegetative-manure mix. ,The N sources were applied to supply 100 mg N per greenhouse pot, each pot containing 2.5 Kg of soil on an oven-dry basis. There was an additional treatment of chemical fertilizer (ammonium sulfate) applied at a rate of 200 mg per pot. Besides N, the P, K, and S nutrient levels were balanced among the treatments by supplying them through appropriate inorganic sources .
The soil from the Nature farm was obtained from the surface 15 cm. It is classified as a Metz fine sandy loam and is considered to be a low fertility soil. Other soil properties are presented in Table 1.
Table 1. Some properties of Metz fine sandy loam soil obtained from the Nature farm and used in the greenhouse pot experiment.
|Water content, firstname.lastname@example.org mg Pa ||7.50%|
|Water content, email@example.com mg Pa|| 14.70%|
The bokashi and compost materials were pre-inoculated with EM or molasses solution at a rate of 1 ml/kg of the original solution. The concentration of molasses in the N sources with and without EM was also kept uniform. The EM (or molasses) inoculate bokashi or compost was applied to the soil in the pots two weeks prior to planting the wheat. In the case of ammonium sulfate, the fertilizer and the EM or molasses solution were individually mixed into the pot. The N sources were mixed in a layer about 5-7 cm thick and two cm below the soil surface. The pots were then watered to 90 % of field capacity and incubated until planting of wheat. Spring wheat seeds treated with EM or molasses solution ( 1 : 1000 dilution of EM/molasses with water) were sown in EM or control pots, respectively, After emergence, plant stands were adjusted to 5 seedlings per pot. During plant growth the pots were weighed at intervals of one to three days and watered as necessary to restore the soil to 90% of field capacity . The soil water content was never allowed to fall below 60 % of field capacity. Pots
were randomized completely on alternate days to minimize shade and positional effects. The above-ground biomass of wheat was harvested at 55 days after emergence. Dry weights of biomass were recorded after drying at 49 oC and plant samples were analyzed for their N content. The data were statistically analyzed using SAS and applying the General Linear
Plant stand counts made during the emergence stage indicated that EM increased germination up to about the 5th and 6th day after the beginning of emergence. However, there: was no effect of EM after emergence was complete.
The dry matter yield data shown in Figure 1 indicates that the N sources differed significantly in their effect on wheat dry matter production . The "full " " half" designations for the fertilizer treatments refer to the 200 and 100 mg N application rates, respectively. As shown, the dry matter yields of wheat followed the order: ammonium sulfate (200 mg) > ammonium
sulfate (100 mg) > bokashi > compost > control . The statistical analysis revealed that there was a significant difference between the EM top-dressing and no top-dressing. There was also a strong interaction between the EM basal and EM top dressing treatments as well as between N source, EM basal and EM top- dressing. The effect of the EM basal treatment alone was not significant because of these interactions. When analyzed separately the EM basal treatment in the absence of EM top-dressing significantly increased dry matter production across all N sources over the control (P = 0.0008) . Figure 2 shows that the effect of the EM basal treatment without EM top-dressing in increasing wheat yields is consistent across all N
With EM top-dressed 10,20 and 30 days after wheat emergence, the effect of the basal application of EM was not consistent. This effect of EM was generally not significant and occasionally had negative or positive effects on dry matter production . Top-dressing of wheat with EM which received a basal EM treatment tended to decrease dry matter production compared with the control . Top-dressing of pots with EM which had received no basal EM treatment showed no consistent effects on dry matter production . Dry matter yields with EM top-dressing were decreased (compared with the control) for the bokashi and ammonium sulfate (100 mg) treatments. The effect of EM basal or EM top-dressing on N uptake by wheat was not significant.
Figure 1. Effect of N Sources on Spring Wheat Yield in a Greenhouse Pot Study. Different Letters Indicate Significant Differences in Yield at P=0.0001
Figure 2. Effect of EM and Different N Sources on Dry Matter Yield of Spring Wheat in a Greenhouse Pot Study.
Wheat dry matter production in the greenhouse was highest with ammonium sulfate(200 mg applied per pot) compared with bokashi or compost which followed the order of ammonium sulfate (200 mg) > ammonium sulfate(100 mg) > bokashi > compost > control. Basal application of EM significantly increased the dry matter yield of wheat when there was no top-dressing of EM after plant emergence. The beneficial effects of EM top-dressing were inconsistent for wheat dry matter production , although there may be benefits when there is no basal application of EM. In other words, there was no apparent advantage of EM; top-dressing when a basal application of EM was made. Moreover, there was no significant effect of EM
on N uptake by wheat.
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