Investigating The Impact Of Organic Matter And Soil Organisms On Rice Cultivation In Bay Of Plenty

The Bay of Plenty in New Zealand is a wetland area that is suitable for rice cultivation

Questions:

1. Experiment to investigate potential of organic farming in particular, cultivation of rice in the Bay of Plenty in the North Island of New Zealand.

2. Explain how a life-cycle assessment could be used to determine the potential environmental impacts of organic egg production.

3. Explain the options for supplying phosphorus in organic farming systems. Consider soil characteristics, climate and agricultural production system in your answer.
 

The Bay of Plenty in New Zealand is a wetland area that is suitable for rice cultivation. The area is a costal region characterized by low lying plains that enable free flowing of water for rice plantation. The area has a range of soil types from alluvial/river deposited to allophonic and Podzolic soils. The area has a sunny climate with dry spells and may experience prolonged rainfall period. The annual rainfall of the area ranges from 1000mm – 1200mm. (During, 1984)

The system of rice intensification

• Design of the experiment

The main variable under this particular experiment will be the amount of organic matter that will be added to the soil fields. The amount will be varied holding other factors constant like size of the land, amount of water allowed to the rice paddy fields, herbicides that may be added, type of seeds to be used, timings for land tilling and weeding etc and harvesting. The experiment will be conducted using five different fields of rice paddy. Although the area is expected to have similar soil conditions the soils for these five fields must be thoroughly mixed together to attain best possible soil similarity in terms of characteristics. The mixed soils will then be distributed to the five fields and spread on the surface to about 10 centimeters of dept. The fields should not be too big that pose logistical challenges in terms of creating similar conditions across the fields. About 3m² size per field should be enough. (Dabbert, Haring and Zanoli, 2003)

• Hypothesis

That the rice output per sq meter of rice field is directly proportional to the amount of organic matter added to the field. 

• Methodology

Under this experiment all the other principles associated with the system of rice intensification will be held constant. These principles are; Early, quick and healthy plant establishment, reduced plant density and reduced and controlled water application. The field should be made of the same size and be prepared at the same time. There should be five fields prepared. In the first field the amount of the organic matter to be added should be ten spades of the organic manure to the rice field. The second field should have twenty spades of organic fertilizer; the rest of the fields should have thirty, forty and fifty spades of organic fertilizers respectively. This variation is what will determine if increase in the organic matter leads to increase of the production and to what extend. Rice harvested per field is compared by the amount of the organic matter added. (Lampkin, 1990)

A graph should then be plotted using the data obtained showing level of production on the y-axis verses amount of organic matter used on the x-axis. The graph will obviously be rising until a point where it starts flattening off. This point is the maximum production or the potential of the land when using organic matter as the fertilizer.

The system of rice intensification

Figure I shows table for collection of data.

Figure 1 

Figure II shows example of graphical representation of the results

Figure 2

• Justification

The expected outcome of the experiment will resemble above curve because the amount of  as the amount of organic fertilizer increases the will be a proportional increase in output i.e. rice harvested until a certain point where by, an increase in amount of organic fertilizer added leads to a decreasing increase of the output. At this point the maximum potential of the organic fertilizer will have been reached.

Variation of level of decomposition

• Design of the experiment

In this experiment a number of soil samples from within Bay of plenty are obtained and taken to laboratory for the purpose of varying the level of decomposition. A zigzag method of soil sampling can be used.  Once one large sample (about 20 kilograms) has been obtained the sample is thoroughly mixed to obtain a uniform soil sample. Another different set of soil sample enriched with soil organisms like worms, bacteria and fungi encouraged by adding organic matter in the sample is set a side. This second sample will be used to increase soil organisms to various samples respectively. 

• Hypothesis

Soil with more soil organisms will be rich in organic matter which in turn will boost productivity of the soil. Soils with fewer organisms that aid in breaking down organic matter into components that can be absorbed by plants has low productivity compared with soils with more soil organisms.

• Methodology

The then different samples are place in a tray that can hold 2 kilograms of soil matter spread in about 2cm thick. The soil rich in soil organisms are added to the ten soils sample in increasing order with the first sample receiving 5 grams and increasing subsequently by 10 grams to the last tenth sample. Each sample must be thoroughly mixed after adding soil organism. The samples will then be left for about one week before equal numbers of seeds are planted to each sample. The researcher can use beans seeds. The sample must be occasionally exposed to sunlight for same duration of time. Every other condition must be held constant e.g. watering and weeding. All the samples must be exposed under similar conditions except for the variable under investigation. The table below is tabulated with data once the experiment is complete. i.e. When the beans are ready for harvesting.

Figure 3

The graph will then be plotted in x-y axis such that y-axis will have production verses x-axis amount of soil organisms added. See figure 4 below.

Figure 4

• Justification

Soil organisms are responsible for decomposition of organic matter to form organic fertilizers. The more the number of soil organisms the higher the rate of organic matter decomposition the productivity of the soil. Thus the graph will sharply rise during the initial stage of soil organisms’ increase but it gets to appoint where the graph will flatten off. This is the maximum production level of the land under investigation.

The life-cycle assessment can be used to find out environmental impact of organic egg production.

Variation of level of decomposition

Under the first part of the phase the raw materials here the investigation will zero in on the layers feeds. The researcher will investigate about recycling of feeds or/and product downsizing i.e. usage of less inputs to downsize on the output. (Rossberg, n.d.)

The second part of the cycle involves investigation on packaging, efficiency in distribution and use of delivery vehicles at are low in pollution.

The third part of the cycle will include investigation to determine the extent at which egg is an auxiliary product. I.e. products that require less water and other materials for consumption

The final stage will involve investigation into amounts of environmentally harmful components or substances in the egg by products e.g. shells.

The factors that will be considered are the measure of;

• Global worming potential i.e. release of greenhouse gases to the atmosphere during egg production that causes earth warming.
• Acidification potential of the process of egg production. Acidification leads to reduction of soil PH which affects many soil organisms thus affecting decomposition of organic matters which in turn leads to poor production.
• Eutrophication potential that is excessive usage of nutrients thereby finding it’s way to water systems.

The time frame of this study will be three months. The data will be analyzed using social statistical tools like SPSS and MS excel with any timescale desired by the researcher. 

In organic farming phosphorous is mainly supplied by recycling on-farm organic materials like green manures composts and animal wastes. These organic materials contain phosphorus materials which are broken down into phosphate components that can be absorbed by plants. This method works best for loam soils and climate with wet and dry spells. (Panda and Hota, 2007)

Addition of green manures to the soil also has ability to increase the rate at which phosphorus materials can be mineralized. This works best for any soil types suitable for agriculture with moderate rainfall.

During the preparation of organic fertilizers phosphorus rocks can be added to the residues so that as the phosphorus rock disintegrate it spreads across the compost which is letter used for organic farming. This method also works best for agricultural soils like loam soils with areas receiving moderate rainfall of about 600mm -1000mm per annum.

Requirements for organic farming certification are:

• A detailed description of the farm process to be certified.
• A record of farm inputs or substances added to the land for the last three years.
• The organic products that are produced from the farm.
• An organic system plan that describes the practices and materials to be used. 

Phosphorous sources available include organic and inorganic sources. Organic sources of Phosphorus are composts with animal bones and fish wastes. The solubility characteristics of this type of source is low but to enhance it more green residue is added to the compost manure in order to speed up mineralization of phosphorus.

For inorganic source like phosphate fertilizers the solubility of the mineral phosphate is higher so long as water is available enough to dissolve the phosphate.

A study titled Meeting the phosphorus requirements on organic farms explored ways in which phosphorus can be added to the soils, Namely Soil organic matter, cover crops rock phosphates and mycorrhizal fungi. The soil organic matters are broken down by soil micro organisms into particles that can be absorbed by plants. The plant covers provide some of the soil organic matter. Mycorrhizal fungi colonization improves P uptake in the soils. This is a symbiotic relation where the fungi get food and shelter from the soils. The rock phosphate are sources fro the readily available P that are easily absorbed by plants once they are dissolved. (Nelson and mikkelsen, 2016). 

References

Dabbert, S., Haring, A. and Zanoli, R. (2003). Organic farming. London: Zed Books.

During, C. (1984). Fertilisers and soils in New Zealand farming. Wellington, N.Z.: P.D. Hasselberg, Govt. Printer.

Lampkin, N. (1990). Organic farming. Ipswich, U.K.: Farming Press.

Nelson, N. and mikkelsen, r. (2016). .

Panda, H. and Hota, D. (2007). Biofertilizers & organic farming. New Delhi: Gene-Tech Books.

Rossberg, J. (n.d.). Beginning application lifecycle management.