INDEKS PRODUKTIVITAS LAHAN

INDEKS PRODUKTIVITAS

LAHAN

BAHAN KAJIAN. MK.STELA.SMNO.FPUB.MEI2013

PRODUKTIVITAS

Sumber:http://en.wikipedia.org/wiki/Production_%28economics%29

PRODUKSI adalah aktivitas menghasilkan output, barang atau jasa, yang mempunyai nilai dan memberikan utilitas

bagi individu.

The act may or may not include factors of production other than labor. Any effort directed toward the realization of a desired product or service is a "productive" effort and the

performance of such act is production.

Hubungan antara jumlah input yg digunakan dalam produksi dnegan jumlah output yg dihasilkan disebut FUNGSI-

PRODUKSI.

PRODUKTIVITAS

Sumber: http://en.wikipedia.org/wiki/Production_theory_basics

TEORI PRODUKSI merupakan kajian ttg produksi, atau proses ekonomi yg mengkonversi input menjadi output.

Production uses resources to create a good or service that is suitable for use, gift-giving in a gift economy, or exchange in a market economy. This can include manufacturing, storing, shipping, and packaging. Some economists define

production broadly as all economic activity other than consumption. They see every commercial activity other than the final purchase as some form of production.

Production is a process, and as such it occurs through time and space. Because it is a flow concept, production is measured as a “rate of output per period of time”.

Ada tiga aspek penting dalam proses produksi:1. Kuantitas barang atau jasa yg dihasilkan,2. Bentuk barang atau jasa yg dihasilkan,3. Distribusi temporer dan spatial barang atau jasa yg dihasilkan.

A production process can be defined as any activity that increases the similarity between the pattern of demand for goods and services, and the quantity, form, shape, size, length and distribution of these goods and services available to the

market place.

INDEKS PRODUKTIVITAS LAHAN

Sumber:

Faktor ProduksiInput atau sumberdaya yg digunakan dalam proses produksi disebut “faktor

produksi”. Faktor produksi ini biasanya dikelompokkan menjadi lima kategori:1. Bahan mnetah2. Mesin/peralatan produksi3. Tenaga kerja4. Barang kapital5. Lahan.

Dalam jangka panjang “long run”, semua faktor produksi ini dikendalikan oleh manajemen. Akan tetapi dalam jangka pendek “short run”, didefinisikan sebagai periode dimana salah satu

faktor produksi dianggap tetap (fixed).A fixed factor of production is one whose quantity cannot readily be changed. Examples

include major pieces of equipment, suitable factory space, and key managerial personnel.A variable factor of production is one whose usage rate can be changed easily. Examples

include electrical power consumption, transportation services, and most raw material inputs. In the short run, a firm’s “scale of operations” determines the maximum number of outputs

that can be produced. In the long run, there are no scale limitations.

FUNGSI PRODUKSI

Sumber:http://en.wikipedia.org/wiki/Production_function

Fungsi Produksi menghubungkan output-fisik proses produksi dnegan

input-fisik atau faktor produksi. Fungsi produksi merupakan salah satu

konsep kunci dari teori neoklasik mainstream, yg dipakai untuk

mendefinisikan “marginal product” dan membedakan “allocative efficiency” yg

mendefinisikan fokus ekonomi. The primary purpose of the production

function is to address allocative efficiency in the use of factor inputs in

production and the resulting distribution of income to those factors, while

abstracting away from the technological problems of achieving technical

efficiency, as an engineer or professional manager might understand it.

http://upload.wikimedia.org/wikipedia/en/d/df/Total,_Average,_and_Marginal_Product.gif


Sumber:http://en.wikipedia.org/wiki/Production_function

Spesifikasi Fungsi ProduksiFungsi produksi dapat dinyatakan dalam bentuk fungsional sebagai

sisi kanan, dimana: Kuantitas output = F(Kuantitas input),

(kapital, tenagakerja, lahan atau bahan mentah).

If Q is not a matrix (i.e. a scalar, a vector, or even a diagonal matrix), then this form does not encompass joint production, which is a production process

that has multiple co-products. On the other hand, if f maps from Rn to Rk then it is a joint production function expressing the determination of k different types of output based on the joint usage of the specified quantities of the n

inputs.

One formulation, unlikely to be relevant in practice, is as a linear function:where and are parameters that are determined empirically.


Sumber:

Fungsi kuadratik yang khas ditunjukkan dalam diagram berikut ini mengambil asumsi input tunggal (atau ratio input yang tetap sehingga

dapat dianggap sebagai input tunggal).

All points above the production function are unobtainable with current technology, all points below are technically feasible, and all

points on the function show the maximum quantity of output obtainable at the specified level of usage of the input.

From the origin, through points A, B, and C, the production function is rising beyond point X.

Dari titik A ke titik C, perusahaan mengalami keuntungan marjinal positif yg semakin menurun atas variabel input.


Sumber:

Stages of production

To simplify the interpretation of a production function, it is common to divide its range into 3 stages. In Stage 1 (from the origin to point B)

the variable input is being used with increasing output per unit, the latter reaching a maximum at point

B (since the average physical product is at its maximum at that

point). Because the output per unit of the variable input is improving throughout stage 1, a price-taking firm will always operate beyond

this stage.

http://upload.wikimedia.org/wikipedia/commons/e/e8/Stages_of_production_small.png


Foto.smno.saradan.okt2012

‘Economics is the science which studies human behaviour as a relationship

between ends (wants and needs) and scarce means (resources) which have

alternative uses.’Lionel Robbins 1930’s

Faktor-faktor Produksi

11

The ‘scarce means’ in Robbins

definition are the limited resources

available for satisfying ends.

Faktor-faktor ProduksiProposed Minimum Data Set (MDS) of Physical, Chemical, and Biological Indicators for

Screening the Condition, Quality, and Health of Soils

Sumber: http://www.agnet.org/library.php?func=view&id=20110808172707&type_id=4

Resources are said to be scarce or limited relative to the extent

of our wants and

needs.

Faktor-faktor ProduksiSoil Physical Indicators Selected for Assessing the Quality of Taiwan Soils


13

SUMBERDAYA

1. Sumberdaya ekonomi dapat dikelompmokkan menjadi lahan, tenagakerja, kapital dan enterprise.

2. Keempat faktor produksi tersebut seringkali disebut “sumberdaya produksi’.

Lahan didefinisikan sebagai semua

sumberdaya ciptaan Tuhan yang

terlibat dalam proses produksi.

SUMBERDAYA - LAHAN


Tanah untuk tanaman,

mineral dalam perut bumi,

pohon-pohon, air untuk ikan, transport atau energi, bahkan ikan itu sendiri.

SUMBERDAYA - LAHANAtribut utama penggunaan lahan yg lestari:

1. Menggunakan lahan dengan orientasi jangka panjang;

2. Meeting present needs without jeopardizing future potential;

3. Enhancing per capita productivity;4. Maintaining/enhancing environmental

quality; and5. Restoring productivity and the

environmental regulatory capacity of degraded and impoverished ecosystems.

Sumber: http://archive.unu.edu/unupress/unupbooks/uu27se/uu27se03.htm

Empat kategori sumberdaya ekonomi atau faktor produksi:

1. Land2. Labor3. Capital4. Entrepreneurship


Sumber: http://www.agecon.purdue.edu/commercialag/progevents/LandValuesWebinar/Farmland_Values_Choices_Web.pdf

Pendekatan Valuasi Lahan PertanianThe traditional income capitalization model provides a straightforward approach with which to view the economic fundamentals of farmland

values. This model simplifies the farmland valuation problem and expresses current farmland values as a function of current income

produced by farmland, the opportunity cost of capital or discount rate, and the constant rate at which income is expected to grow in the

future, as shown below:

Model ini beralasan bahwa peningkatan nilai lahan-pertanian karena ekspektasi peningkatan pendapatan, penurunan suku-bunga, atau

peningkatan laju pertumbuhan pendapatan dari lahan.

Nilah lahan pertanian ditentukan oleh::

1. Produktivitas (supply of crops)

2. Biaya produksi

3. Harga jual hasil tanaman (demand)

4. Interest rates5. Inflation6. Alternative

investments

Soil quality in relation to soil properties, soil processes, and environmental quality

Sumber: http://archive.unu.edu/unupress/unupbooks/uu27se/uu27se03.htm

KUALITASTANAH

Produktivitas tanah


Penjualan KomparatifFaktor-faktor untuk membandingkan:

1. Produktivitas +2. Lokasion + or -3. Other uses/income + or -4. Family sales -5. Sales contract +6. Akses jalan + or -

Components of a Sustainable Soil Management System.


Changes in Soil Organic Matter Content (MT/Ha) Calculated in Taiwan under Different Soil Management Systems with Long-Term Application of Composts or

Fertilizers.


Karakteristik Lahan Pertanian

1. Tidak mengalami depresiasi or wear out2. Suplainya tertentu (fixed)3. Setiap bidang lahan bersifat unik4. Nilainya tgt pada profit dari pertanuan,

penggunaan lainnya5. Kepemilikan menyediakan keamanan ,

pride (kebanggaan, kepuasan)

PRODUKTIVITAS LAHAN

Sumber: http://tax.illinois.gov/publications/pubs/pub-122.pdf

Lahan tanaman termasuk :1. all land from which crops were harvested or hay was cut; 2. all land in orchards, citrus groves, vineyards, and nursery

greenhouse crops; 3. land in rotational pasture, and grazing land that could have been

used for crops without additional improvements; 4. land used for cover crops, legumes, and soil improvement grasses,

but not harvested and not pastured; 5. land on which crops failed; 6. land in cultivated summer fallow; 7. idle cropland.

Cropland is assessed according to the equalized assessed value (EAV) of its adjusted soil productivity index (PI)

PRODUKTIVITAS LAHAN

TINGKAT PENGELOLAAN YANG OPTIMUM

Hasil tanaman yg dihasilkan oleh suatu tanah pd kondisi iklim tertentu tergantung pada input teknologi yg digunakan dan kapasitas tanah

dan tanaman untuk meresponnya. Manajemen merupakan pemilihan dan penerapan teknologi produksi tanaman.

Continuing increases in average crop yields result from improved management. Because the impact of management on crop yields is so

great, the optimum level of management should be defined for measures of soil productivity to have any meaning.

Tingkat optimum pengelolaan termasuk input-input yg dibutuhkan untuk menghasilkan keuntungan-maksimum pada tingkat teknologi

tertentu.

Sumber: http://soilproductivity.nres.illinois.edu/Bulletin811ALL.pdf

Sasarean tingkat pengelolaan optimum

Sumber: http://soilproductivity.nres.illinois.edu/Bulletin811ALL.pdf

Faktor Pengelolaan (faktor Manajemen)

Pengelolaan Optimum

Drainage Parallel or herringbone pattern with closer-than-recommended spacing and adequate outlets

pH tanah at or above 6.2 for grain; at or above 6.9 for alfalfa and clover

P-tersedia (P soil test) based on soil test and depending on phosphorus yield goal, at or above 50 pounds per acre

K-tersedia based on soil test and depending on potassium yield goal, at or above 300 pounds per acre

Dosis pupuk N per tahun untuk tanaman jagung (atau lainnya)

based on soil test and depending on per year for yield goal, at or above 175 pounds per acre.

Populasi jagung 30,000 tanaman per acre, atau lebih

Residu tanaman returned to soil with additional organic materials added as needed

Kontril hama-penyakit-gulma timely using an integrated control pest management approach

Pengolahan tanah dan penanaman

moldboard plow or conservation tillage <2% slopes;conservation tillage including no-tillage for 2% to 10% slopes

Erosi tanah reduced to below soil tolerances using conservation practices as required

PRODUKTIVITAS LAHAN

Sumber:

Indeks Produktivitas Tanaman untuk tanah-tanah pada tingkat pengelolaan yg optimum

Produktivitas tanah snagat dipengaruhi oleh kapasitas tanah untuk mensuplai hara dan air-tersedia yg dibutuhkan tanaman dalam

kondisi iklim tertentu. Productivity also depends in part on the adaptation of a particular crop to specific growing conditions and level of management. It is

often necessary to compare soils that differ in suitability for particular crops or in response to management. Estimated crop yields are not

suitable for these comparisons because yields fluctuate from year to year, and absolute yields mean little when comparing different crops. Indeks produktivitas merupakan sekala tunggal untuk menilai tanah-

tanah berdasarkan kesesuaiannya bagi tanaman pada kondisi pengelolaan tertentu.

KUALITAS TANAH DAN PRODUKTIVITAS

TANAH merupakan suatu entitas fisik dan hidup, tersusun atar batuan-lapuk, senyawa kimia anorganik, biomasa residu tumbuhan dan

binatang, dan beribu organisme hidup. Soil quality has been defined as the sustained capability of a soil to

accept, store, and recycle water, nutrients and energy (Gregorich et al., 1994). In addition, soil quality is the capacity of a soil to sustain

ecological productivity, maintain environmental quality, and promote plant and animal health (Doran & Parkin, 1994).

Selama periode waktu tertentu, tanah mampu menjaga kemampuannya untuk berfungsi sbg komponen hidup dari suatu

ekosistem, tanah dapat mengalami degradasi, atau dapat diperbaiki kualitasnya (Gregorich et al., 1994).

1. Doran, J. & T. Parkin. (1994). “Defining and assessing soil quality.” In: Doran, J., D. Coleman, D. Bezdicek, B. Stewart, (eds) Defining Soil Quality for a Sustainable Environment. SSSA Special Publication 35. Madison WI: Soil Science Society of America: 3-21.

2. Gregorich, E.G., Carter, M.R., Angers, D.A., Monreal, C.M. & Ellert, B.H. (1994). “Towards a minimum data set to assess soil organic matter quality in agricultural soils.” Can. J. Soil Sci. 74, 367-385.Sumber: GPI AGRICULTURE ACCOUNTS, PART TWO: RESOURCE CAPACITY AND USE: SOIL QUALITY AND PRODUCTIVITY. Jennifer Scott and Julia

Cooper. September, 2002. gpi aTLANTIC


While production is measured in terms of the yields of crops a particular soil can produce, productivity is its yield per unit of

input, in a given unit of time. Inputs in this case include energy, costs, time, labour, area, nutrients, etc.

Produktivitas seringkali diukur berdasarkan faktor yg paling membatasi atau input yang mahal. Input yg dipilih untuk

menentukan produktivitas harus dilakukan secara eksplisit, karena ia akan berubah menurut pembatas yg ada di lokasi.

Produktivitas ekologis meminimumkan input non-renewable dan output yg mencemari lingkungan, sambil berupaya menjamin

produksi optimum jangka panjang.

Sumber: GPI AGRICULTURE ACCOUNTS, PART TWO: RESOURCE CAPACITY AND USE: SOIL QUALITY AND PRODUCTIVITY. Jennifer Scott and Julia Cooper. September, 2002. gpi aTLANTIC


Produktivitas tanah merupakan suatu fungsi, bukan hanya kualitas tanahnya, tetapi juga beragam faktor lingkungan, seperti iklim dan

topografi. Two soils may have equivalent quality, in terms of the indicators listed in this section, yet one may be less productive than the other. This may

be due to climate. For example, one soil may be located in a cooler location with a shorter growing season. Topography may also limit

productivity.

Tanah-tanah yang kualitasnya sangat baik, mungkin tidak sesuai untuk usahatani karena lerengnya snagat curam. Hal yang sama juga dapat

terjadi untuk tanah-tanah yg kualitasnya bagus dengan pembatasnya berbatu-batuan, drainage, atau bahan induk.



Kualitas tanah dan indikator produktivitas tanah :1. Bahan Organik Tanah (BOT) (or soil organic

carbon); 2. Struktur Tanah; 3. Konservasi Tanah4. Jaring-jaring Makanan yang sehat dalam tanah.

Each of these indicators can be tracked over time using a number of different methods.



NILAI TANAH

Tanah merupakan aset kapital alami tempat berlangsungnya sistem pertanian. Oleh karena itu untuk menjaga kelestarian

sistem pertanian yg optimal maka TANAH harus dijaga kesehatan dan produktivitasnya.

TANAH dalam sistem produksi pangan biasanya mengalami “undervalued”.

Methods of agriculture that degrade the soil are profitable in the short term under our current system of accounting. This is because the losses of natural capital due to soil erosion or

degradation are invisible in conventional economic accounts, and not included directly in the costs of food production.



Degradasi tanah akibat pemadatan-tanah dan kemerosotan kesuburan tanah dapat diimbangi dnegan epeningkatan aplikasi

input produksi seperti pupuk dan bahan bakar.

These inputs can mask the degradation of our soils by allowing crop yields to be sustained and profitable in the short term, at

the expense of long-term productivity.

Ironically, these additional fuel and fertilizer inputs are counted in our conventional measures as contributions to economic growth and ‘prosperity’ even though they may potentially

represent a decline in ecological productivity, and additional costs to the farmer and society.



Banyak upaya dilakukan untuk memberikan nilai moneter pada jasa-jasa ekosistem yang dihasilkan oleh tanah-tanah pertanian.

Costanza et al. (1997) menetapkan nilai-nilai untuk lahan pertanian tanaman berdasarkan pada jasa-jasa ekosistem yang dihasilkan oleh

lahan-lahan ini. A higher value was placed on agricultural land that is under grass or

forage, because of the importance of grass and forage in maintaining and protecting soil as a natural capital asset, as emphasized below.

Table 1 shows the ecosystem services provided by these two classes of agricultural land, and the value assigned by Costanza and his

international team of scientists to these lands.

Costanza, R., d’Arge, R., de Groot, R., Farber, S., Grasso, M., Hannon, B., Limburg, K., Naeem, S., O’Neill, R.V., Paruelo, J., Raskin, R.G., Sutton, P., & van den Belt, M. (1997). “The value of the world’s ecosystem services and natural capital.” Nature 387, 253-260.


KUALITAS TANAH DAN PRODUKTIVITASTable 1: Nilai Jasa Ekosistem yg dihasilkan oleh Lahan Pertanian

($1997/ha/yr)


Costanza, R., d’Arge, R., de Groot, R., Farber, S., Grasso, M., Hannon, B., Limburg, K., Naeem, S., O’Neill, R.V., Paruelo, J., Raskin, R.G., Sutton, P., & van den Belt, M. (1997). “The value of the world’s ecosystem services and natural capital.” Nature 387, 253-260.

KUALITAS TANAH DAN PRODUKTIVITAS: BOT

BOT merupakan biomasa bangkai tumbuhan dan binatang dalam tanah – seperti residu tumbuhan, rabuk kandanh ternak, dan bangka

serangga – yang tersusun atas unsur karbon.

Most scientific studies report soil organic matter as soil organic carbon (SOC); a factor of 1.7 is used to convert SOC to SOM. Organic matter is

critical for maintaining soil productivity because of the beneficial effects it has on soil moisture, fertility and structure.

It is the most important indicator of soil health and productivity in agricultural systems (Glover et al., 2000).

Glover, J., J. Reganold, & P. Andrews. (2000). “Systematic method for rating soil quality of conventional, organic, and integrated apple orchards in Washington State.” Agriculture Ecosystems and Environment 80, 29-45.



Memelihara BOT merupakan proses dinamik yg tergantung pada berapa banyak BO ditambahkan ke tanah (sebagai residu tanaman

atau rabuk kandang) dan berapa banyak kehilangan BO (melalui dekomposisi BO atau erosi).

Thus trends are based on net organic matter losses or gains over time. Soil organic matter is decomposed by soil micro-organisms and

provides a source of nutrients for plants. Laju dekomposisi BOT dipengaruhi oleh lengas-tanah, temperature,

tekstur, dan aerasi tanah. Tanah-tanah pertanian dapat mengandung 1 - 10% BO berdasarkan beratnya (Acton and Gregorich, 1995)

tergantung pada lokasi geografisnya dan pengelolaan tanahnya.

Acton, D. & Gregorich, L. eds. (1995). The Health of Our Soils -- Toward sustainable agriculture in Canada. Centre for Land and Biological Resources Research Research Branch Agriculture and Agri-Food Canada Publication 1906/E. Ottawa, Ontario.Sumber: GPI AGRICULTURE ACCOUNTS, PART TWO: RESOURCE CAPACITY AND USE: SOIL QUALITY AND PRODUCTIVITY. Jennifer Scott and Julia



Tanah-tanah Podsolik dan tanah-0tanah hutan virgin di Nova Scotia , kandungan BOT nya sekitar 2.8% - 5.8% dalam

lapisan topsoilnya setebal 30 cm.

Cultivation of these soils results in the breakdown of organic matter with declines of 35% of initial soil organic matter reported (Carter et

al. 1998). In some cases growing forage crops on these soils can restore soil

organic matter to levels equivalent to forested sites, or even greater (Carter et al. 1998).

Carter, M.R., Gregorich, E.G., Angers, D.A., Donald, R.G. & Bolinder, M.A. (1998). “Organic C and N storage, and organic fractions, in adjacent cultivated and forested soils of eastern Canada.” Soil Till. Res. 47,253-261.



Maintenance of at least 3.8% organic matter (2.2% carbon) has been suggested as a minimum level required for

“moderate structural stability” (Greenland et al., 1975). This level will serve as a goal for sustainable agricultural

production.Humus merupakan BO yang telah diproses oleh organisme

tanah menjadi bentuk yg lebih stabil. Humus berawarna hitam, dan sumber orisinil bahan organik ini tidak mungkin

dapat dikenali kembali secara visual.

1. Greenland, D.J., Rimmer, D. & Payne, D. (1975). “Determination of the structural stability class of English and Welsh soils, using a water coherence test.” J. of Soil Sci. 26, 294-303.



Pemeliharaan BOT sangat vital bagi produktivitas sistem pertanian jangka panjang karena alasan berikut ini:

1. It is necessary for the formation of stable soil aggregates (see section on Soil Structure) which provide the soil with good aeration, drainage and resistance to erosion and degradation

2. It provides the soil with a negatively charged exchange complex (see box) which prevents leaching of positively charged nutrients into groundwater and holds them in the soil, available for plant use.

3. Organic matter itself is a reservoir of nutrients, particularly nitrogen, phosphorous and sulphur, which become slowly available to crops through processes of biological decomposition (see section on Soil Foodweb).

4. It functions like a sponge to hold water in the soil and release it as needed by crops. This reduces drought-related problems in crops.

5. It is essential as a food source for the many soil microorganisms that provide vital ecosystem services (including pesticide degradation, nutrient cycling, pathogen control, see Soil Foodweb section)

6. It sequesters carbon and can be used to counteract greenhouse gas emissions.



BOT dibentuk dengan mengembalikan BO ke tanah. Hal ini dapat dilakukan dengan aplikasi rabuk kandang (terutama yang telah masak)

ke lahan, atau mengembalikan residu tanaman ke tanah.

Plants with fibrous root systems, for example ryegrass, hay, or pasture, have immense potential to increase soil organic matter. These crops

are considered soil building because each year their roots produce far more organic matter than is lost through normal SOM decomposition.

Table 2 menyajikan kontribusi residu akar ke tanah setiap tahun, yang secara langsung berhubungan dengan sifat jenis-jenis tanaman ini

dalam membangun karakteristik tanah.


KUALITAS TANAH DAN PRODUKTIVITAS: BOTTable 2: Estimasi residu biomasa akar yg dihasilkan oleh

jenis-jenis tanaman, PEI



BOT dapat rusak dan hilang. Tillage, crop growth, crop harvest, and erosion are several of the loss pathways for organic matter. The cultivation of some

types of crops can have a negative effect on soil quality, by causing net losses of soil organic matter. These potentially soil degrading crops include cultivated row crops such as

corn, beans, potatoes and other vegetables.

The between-row area in row crops is open and cultivated for the first part of the growing season accelerating the

microbial breakdown of soil organic matter.



BOT didekomposisi oleh Mikroba tanah.

Dekomposisi BOT merupakan bagian dari siklus hara yang menstransfer hara dari bahan organik kepada tanaman (proses ini

disebut MINERALISASI). Akan tetapi, kalau perombakan BO melampaui akumulasinya dalam jangka panjang, maka kandungan

BOT akan menurun.

The process of organic matter breakdown speeds up when air is mixed with the soil during cultivation.

The tillage associated with growing annual crops is generally depleting to soil organic matter.

Growing hay crops for several years in a row without tillage will help to re-build soil organic matter levels.


KUALITAS TANAH DAN PRODUKTIVITAS: BOTTable 4: BOT: Measures, Objectives, Results



NILAI BOTEstimasi total nilai semua jasa-jasa ekosistem yg dihasilkan oleh BOT tidak mudah diestimasi, tetapi dapat diestimasi kontribusi tahunan

(musiman) hara-tersedia bagi tanaman. Carter et al. (1998) report an average soil nitrogen (N) content of 5,800 kg/ha for

cultivated Podzols (the predominant soil type in Nova Scotia). Although some of that nitrogen exists in the inorganic (nitrate, ammonium, and amino acid) form, the

majority of soil N is tied up in soil organic matter. This nitrogen is released to the growing crop through the process of mineralization.

Moncayo (1992) estimated the annual contribution of organic N mineralization in Nova Scotia to be 1.5% of the total soil N content. Using this factor, we can estimate

an annual contribution of N from soil organic matter of 87 kg N/ha. Fertilizer N is currently worth almost $1/kg.

Therefore organic matter is contributing $82/ha/yr worth of nitrogen. The reservoir (stock) of soil organic N on farmed land is worth more than $5,400/ha ($945 million

provincially).



NILAI BOT

BOT juga mensuplai sejumlah hara P bagi tanaman. Kandungan P BOT diperkirakan sepersepuluh (0.10) kandungan N nya (Tisdale et al.

1985). Maka dapat dihitung kontribusi musiman P ke lahan pertanian sebesar 21 kg P2O5 /ha.

Fertilizer P is worth about $1/kg P2O5, so the value of phosphorus supplied by organic matter is approximately $20/ha annually or $3.5 million province-wide. Because this remarkable contribution is provided ‘freely’ by nature, it appears

nowhere in standard accounting systems.

And when farmland is managed so that soil organic matter is lost, this loss of value also remains invisible. Ironically, the cost to the farmer of replacing this lost asset through synthetic fertilizer is then counted as a contribution to general economic

prosperity, simply because the exchange of money now enters the economy.



KEHILANGAN BOT

Farmers on the monoculture potato fields will be spending approximately $10/ha/yr more than the farmers using potato-grass rotations to supply the N and P that could

have been provided by the lost soil organic matter. If the farmers using rotations switched to a leguminous forage crop (which ‘fixes’

atmospheric nitrogen and adds it to the soil), they could expect to spend up to $114/ha/yr less than the monoculture potato farmers in the year after plowdown, to

meet their potato crop’s N needs.This 0.5% loss of soil organic matter represents a decrease in stock value (based only

on N and P fertilizer value) of $650/ha.Kehilangan kapital alam ini dapat dipulihkan kembali kalau pertanian monokultur diubah menjadi sistem rotasi tanaman , misalnya forage-

potato. We can expect a new, higher soil organic matter equilibrium level to be reached after about twenty years, the amount of time it would take to

increase soil organic matter by 0.5%.Sumber: GPI AGRICULTURE ACCOUNTS, PART TWO: RESOURCE CAPACITY AND USE: SOIL QUALITY AND PRODUCTIVITY. Jennifer Scott and Julia


KUALITAS TANAH DAN PRODUKTIVITAS: BOTTable 5: A comparison of revenues and expenses, continuous corn vs. corn/hay rotation




KUALITAS TANAH DAN PRODUKTIVITAS: STRUKTUR TANAH

Soil structure is defined as the physical properties of a soil relating to the arrangement and stability of soil particles and pores (McBride et al., 2000). Structure is a qualitative characteristic of soil. We can describe a soil with ‘good’ structure as being friable, light, and workable, with good tilth. Soil

aggregation is a component of soil structure. This is the arrangement of soil particles in granules or crumbs which are held together by organic

compounds known as polysaccharides (complex sugars). Suatu tanah yang struktur dan agregasinya baik mempunyai :

1. Ruang porinya banyak2. Aerasi dan drainagenya bagus3. Daya simpan airnya bagus4. Penetrasi akarnya lebih baik5. Sedikit energi untuk pengolahan tanah6. Tahan terhadap gaya-gaya erosi.

1. McBride, R.A., Joosse, P.J. & Wall, G. (2000). Risk of Soil Compaction in Agriculture and Agri-Food Canada. Environmental Sustainability of Canadian Agriculture: Report of the Agri-Environmental Indicator Project. T. McRae, C.A.S. Smith, & L.J. Gregorich (eds). Agriculture and Agri-Food Canada, Ottawa.



Compaction can be defined as a process by which external forces compress the soil, making it more dense, less porous, and less capable

of performing the functions just listed (Moerman, 1994).

Soil compaction caused by wheel traffic and tillage is one form of soil degradation. This process leaves the soil denser, less permeable to air and water, slower to warm up in the spring, more difficult to till, and

more resistant to the penetration of plant roots. Reduced efficiency of nutrient uptake results in impeded plant growth.

Pemadatan tanah merupakan masalah serius pada tanah-tanah yang teksturnya halus.

Moerman, D. (1994). “Soil compaction: avoiding and fixing a widespread problem,” in Proceedings Nutrient Management on the Farm: A Conference for Maritime Farmers. Kentville, Nova Scotia, February 8-9, 1994, NSDAM and Agriculture Canada.Sumber: GPI AGRICULTURE ACCOUNTS, PART TWO: RESOURCE CAPACITY AND USE: SOIL QUALITY AND PRODUCTIVITY. Jennifer Scott and Julia



Mengukur Struktur Tanah

Struktur tanah dievaluasi dengan jalan menilai derajat pemadatan (diukur dnegan bobot isi tanah), kandungan BOT, tipe tanaman, dan

tipe/jumlah pengolahan tanah. Umumnya, tanah-tanah yang BI nya rendah mempunyai struktur yang

lebih baik. Bobot isi yang tinggi dan resistensi penetrometer merupakan indikasi dari strultur tanah yang jelek, dan pemadatan

tanah yang tinggi (McBride et al., 2000). Fine- textured soils are most prone to soil compaction. The structure of these soils is easily destroyed by excessive tillage, especially when

the soil is cultivated during wet periods.

McBride, R.A., Joosse, P.J. & Wall, G. (2000). Risk of Soil Compaction in Agriculture and Agri-Food Canada. Environmental Sustainability of Canadian Agriculture: Report of the Agri-Environmental Indicator Project. T. McRae, C.A.S. Smith, & L.J. Gregorich (eds). Agriculture and Agri-Food Canada, Ottawa.Sumber: GPI AGRICULTURE ACCOUNTS, PART TWO: RESOURCE CAPACITY AND USE: SOIL QUALITY AND PRODUCTIVITY. Jennifer Scott and Julia



BOBOT ISI (BI) TAMAH

BI merupakan ukuran fisik yg dipakai untuk mendeskripsikan tanah-tanah. BI tanah dapat dihitung dengan jalan membagi berat-kering-oven tanah dengan

volumenya. Biasanya BI tanah dinyatakan dnegan satuan g/cm3 atau kg/m3.

Typical bulk densities in agricultural soils range from 1.1 to 1.7 g/cm3 depending on various factors including texture, organic matter content, and soil management practices.



Strabilitas agregat tanah dan bobot isi tanah merupakan dua indikator penting bagi struktur tanah (Glover et al., 2000). Aggregat adalah struktur,

atau gumpalan, yang dibentuk kalau mineral tanah dan bahan organik berikatan (bergabung) bersama dengan bantuan (sebagai perekatnya)

molekul organik , akar tanaman, fungi, dan liat (Magdoff & van Es, 2000). The strength of the soil aggregates (granules or crumbs) will determine the soil’s resistance to compaction. This ‘aggregate stability’ has been strongly

correlated with soil organic matter content (Glover et al., 2000).Bobot isi tanah dan stabilitas agregat tidak diukur untuk keseluruhan lahan

usahatani, sehingga diperlukan cara lain untuk menduga struktur tanah.

1. Glover, J., J. Reganold, & P. Andrews. (2000). “Systematic method for rating soil quality of conventional, organic, and integrated apple orchards in Washington State.” Agriculture Ecosystems and Environment 80, 29-45.

2. Magdoff, F., & van Es, H. (2000). Building Soils for Better Crops. Second Edition. Beltsville MD: Sustainable Agriculture Network.



Compaction can be reduced by certain soil management practices. Methods that return organic matter to the soil will improve soil structure, result in better soil aggregate formation, and reduce

compaction. Metode-metode ini meliputi:

1. Penambahan rabuk kandang dan kompos ke tganah2. Pergiliran tanaman yg melibatkan tanaman berakar-dalam, yang

residu biomasanya meningkatkan BOT, akarnya dapat memecah lapisan-tanah subsoil padat. Angers et al. (1987) melaporkan perbaikan kekuatan agregat tanah dan porositas antar agregat setelah dua tahun penanaman “bromegrass” mengikuti 12 tahun penanaman jagung monokultur.

Angers, D.A., Kay, B.D., & Groenvelt, P.H. (1987). “Compaction characteristics of a soil cropped to corn and bromegrass.” Soil Sci. Soc. Amer. J. 51,779-783.



Since excessive wheel traffic contributes to soil compaction, farming practices which minimize the number of trips the farmer must make

around the field should also reduce soil compaction.Metode-metode ini meliputi:

1. Olah tanah minimum; misalnya memakai “bajak chisel” yg memecahkan cadas-cadas keras dan meninggalkan residu biomasa tanaman di permukaan tanah

2. Meminimumkan olah tanah sebelum tanam, untuk mengurangi efek langsung peralatan olah-tanah thd pemadatan tanah dan meminimumkan kerusakan struktur tanah akibat pengolahan tanah

3. Integrated pest management (IPM) strategies for pest control so that trips over the field with spray equipment are kept to a minimum.



Large loads and high surface pressure from wheel traffic in the field also contribute to compaction.

Petani dapat mereduksi efek pemadatan tanah oleh alat-mesin pengolahan tanahnya dengan menggunakan sistem yg

efek tekanan-tanahnya minimum.

Hal ini melibatkan pemilihan peralatan yang :1. uses dual or flotation tires which spread the load, thereby reducing

the pressure per square inch of soil;2. has more axles, thereby distributing the load over more wheels;

and3. Bobotnya ringan, sehingga mereduksi “tekanan” terhadap tanah.



Table 7: Metode-metode untuk Menduga Struktur Tanah



Table 9: Nilai Struktur Tanah


KUALITAS TANAH DAN PRODUKTIVITAS: EROSI TANAH

Techniques of soil management that minimize the risk of soil loss due to wind and water erosion are known as soil conservation practices. Erosion rates in excess of the natural rate of regeneration (1 cm in 120 to 400 years) reflect a gradual loss of value in farmland.30 This loss can be expressed conservatively as 1 tonne per ha per year.

Erosion has serious implications for soil quality and productivity. Nutrients and organic matter are lost when soil is eroded from a field. The soil’s structure is

weakened and general soil degradation results, producing losses in crop productivity. Tillage operations can be impeded by erosional gullies, and energy

expended can increase due to exposure of compact subsoil.

Off-site damage also results from soil erosion. In streams and rivers, water turbidity and sedimentation increase. The nutrients, pesticides, and bacteria that can be

bound to the eroded soil particles can have a detrimental effect on fish and wildlife health. And the recreational value of fresh and salt water can be reduced due to a

decline in aesthetic quality.



Strategi mengurangi erosi tanah:

Memelihara dan Memperbaiki Kandungan BOT

Soil organic matter is vital for the formation of stable soil aggregates (see discussions of soil organic matter and structure above).

Plant roots and microbes produce mucilage, which in effect ‘glues’ together soil mineral and organic particles. The resulting improvement in soil structure decreases

the soil’s erodibility. Erodibility is the soil’s susceptibility to detachment and transport by erosive agents

(ECSWCC, 1993). Pergiliran tanaman dan aplkikasi pupuk kandang dapat meningkatkan

kandungan BOT.

1. Eastern Canada Soil and Water Conservation Centre. (1993). “Crop Rotation Systems for Potato Production in Atlantic Canada.”




Pengelolaan Residu sisa panenManagement practices which leave 30% of crop residue or more on

the soil surface reduce soil erosion by obstructing overland flow, reducing the velocity of the runoff, and increasing water infiltration

into the soil.

Strip-cropping dan Terrasering. Penanaman lahan menurut garus kontur di lapangan, dan bukan tegak lurus garis kontur, dapat mengurangi erosi tanah sebesar 75% (DeHaan

1994).




Vegetasi Penutup Muka Lahan.

Penanaman jenis-jenis tanaman yang secara khusus untuk menutup muka tanah selama periode risiko erosi tinggi – (misalnya di lokasi

Prince Edward Island 85% erosi terjadi selama periode antara October dan akhir April) – dapat mereduksi kehilangan tanah secara signifikan.

Edwards and Barney (1987) report a reduction in soil loss of 1.8 t/ha (0.36 t/ha versus 2.16 t/ha) when soil loss from a

cover crop of winter rye was compared to bare soil.



MENGUKUR KEHILANGAN TANAH & KONSERVASI

The Universal Soil Loss Equation (USLE)

If annual soil loss could be measured, it would be a direct way to assess the status of soil conservation in the province:

As soil losses from agricultural land decrease, soil conservation, as a component of soil quality, would improve.

Soil losses on agricultural land can be estimated using the Revised Universal Soil Loss Equation (RUSLE) (see box).

VegetaSI PENUTUP TANAH (C) and soil management (P) are the two components of the RUSLE over which the farmer has control.



The Universal Soil Loss Equation (USLE), A=RKLSCP, computes annual soil loss as a function of rainfall (R), soil erodibility

(K), slope length (L), slope gradient (S), vegetative cover (C), and soil management (P).

It can be used to estimate soil losses for a given piece of land under different management systems.

The Revised USLE was released in 1992 with refined factor values generated from improved data and computer

modeling.


KUALITAS TANAH DAN PRODUKTIVITAS: EROSI TANAHTable 13: Metode untuk menilai erosi tanah dan konservasi


KUALITAS TANAH DAN PRODUKTIVITAS: EROSI TANAHTable 14: Produktivitas relatif (%) tanaman yang dipengaruhi oleh kehilangan tanah

akibat erosi, Nova Scotia


KUALITAS TANAH DAN PRODUKTIVITAS: EROSI TANAHTable 18: Nilai Konservasi Tanah


KUALITAS TANAH DAN PRODUKTIVITAS: Soil Foodweb Health

Soil foodweb analysis has been proposed as an indicator of soil quality. The soil foodweb is the complex mixture of bacteria, fungi, protozoa,

nematodes and microarthropods, which control the cycling of nutrients within an ecosystem.

Bacteria convert easily decomposable organic matter additions into humus. Fungi convert more recalcitrant organic matter, such as lignin,

into humus. Protozoa feed on bacteria and release nutrients to the soil solution as a by-product of this activity.

Nematodes dan micro-arthropods memangsa bakteri dan fungi, serta melepaskan sejumlah hara ke dalam larutan tanah.



“The numbers, biomass, activity and community structure of the organisms which comprise the soil foodweb can be used as indicators of ecosystem health because these organisms perform critical processes and functions” (Ingham, 2000).

Dalam ekosistem yang sehat, biasanya siklus hara dan produktivitasnya meningkat, kehilangan hara minimum.

Hal ini dapat dicapai dengan jalan meningkatkan kompleksitas “foodweb” tanah .



Kalau BOT ditambahkan, organisme tanah memakan BO itu dan men-dekomposisi senyawa organik kompleks menjadi

senyawa mineral (anorganik).

The living soil is a central part of soil fertility, because the activity of soil organisms renders available the elements in

plant residues and organic debris entering the soil.

Sebagian dari bahan organik ini tetap berada dalam tanah (humus) dan membantu stabilitas tanah (Fleissbach et al.,

2000).



A healthy soil foodweb has adequate populations of soil decomposers (bacteria and fungi) to retain nutrients within the soil.

In agricultural systems it is in our best interest :1. to promote a healthy soil foodweb so that we can make the most

efficient use of plant nutrients. 2. When we minimize nutrient losses from the soil, we are saving dollars

spent on purchased fertilizers. 3. We also minimize off-site damage from lost nutrients, which can end up

in groundwater. 4. That, in turn, can produce health-related costs including nitrate toxicity,

which particularly affects young children and livestock. Nutrients that do not leach to the groundwater can be lost in surface waters.

Preventing nutrient loss through a healthy soil foodweb enhances productivity and avoids both fertilizer costs and water quality

deterioration.Sumber: GPI AGRICULTURE ACCOUNTS, PART TWO: RESOURCE CAPACITY AND USE: SOIL QUALITY AND PRODUCTIVITY. Jennifer Scott and Julia



Mengukur Kesehatan Foodweb Tanah

Ada banyak cara mengkaji organisme tanah dan menghubungkan hasil-hasilnya dengan kesehatan ekosistem. Biomasa dan aktivitas fungi dan

bakteri dapat diukur. The ratio of fungal to bacterial biomass is a useful indicator of foodweb

structure. Forest soils are typically dominated by fungi and have a fungal:bacterial biomass ratio (F:B) of greater than one. Fungi effectively decompose recalcitrant organic matter producing secondary metabolites

which make the soil more acidic. Sebagian terbesar N dalam fungi-tanah berbentuk ammonium, yang sangat disenangi oleh pertumbuhan belukar dan pohon-pohon.. Prairie grasslands tend to be dominated by bacteria (F:B<1). These soils are characterized by

alkaline conditions and nitrate/nitrite as the dominant form of soil N. These conditions are beneficial for grasses and row crops.




Infertile agricultural soils in Nova Scotia are probably characterized by an excess of fungi relative to bacteria (F:B>1). Fungi tend to dominate

in acidic soil conditions, typical of the Podzolic soils of this region.Soil acidity also becomes a problem when synthetic nitrogen fertilizers

are used on crop land. The ammonium contained in commercial fertilizers is converted to nitrate (nitrification) in the soil and hydrogen

ions are released, contributing to acidification. This acidification results in the constant need to lime agricultural soils.

Kondisi masam menurunkan produktivitas tanah-tanah pertanian karena problematik seperti toksisitas hara dan reduksi ketersediaan

hara tertentu, terutama fosfat.




In the soil quality index developed by Glover et al. (2000), several measures of soil foodweb health (biological activity) are used.

Dalam lapisan topsoil 15 cm, mereka menilai (urut kepentingannya)1. C-organik tanah (t/ha);2. Banyaknya cacing tanah per m2;3. C biomasa mikroba (kg/ha); 4. N biomasa mikroba (kg/ha).

Glover, J., J. Reganold, & P. Andrews. (2000). “Systematic method for rating soil quality of conventional, organic, and integrated apple orchards in Washington State.” Agriculture Ecosystems and Environment

80, 29-45.Sumber: GPI AGRICULTURE ACCOUNTS, PART TWO: RESOURCE CAPACITY AND USE: SOIL QUALITY AND PRODUCTIVITY. Jennifer Scott and Julia



Soils amended with composted manure or grass/legume residues have shown higher levels of microbial biomass carbon than conventionally

managed soils (Glover et al., 2000). In Switzerland, researchers assessed microbial biomass carbon in treatments using composted manure and no synthetic fertilizer or pesticides. These treatments had 20-40% higher microbial biomass compared to treatments fertilized with manure

plus synthetic fertilizer and pesticides, and 60-85% higher microbial biomass compared to treatments with synthetic fertilizer and pesticides (Fleissbach et al.,

2000). Earthworm density and biomass followed a similar trend, where treatments

receiving composted manure and no synthetic pesticides had 30 to 80% higher earthworm density and biomass compared to treatments using

synthetic fertilizer and pesticides (Fleissbach et al., 2000).

1. Fliessbach, A., P.Mäder, D.Dubois, & L.Gunst. (2000). Results from a 21 year old field trial. FiBL Dossier 1:1-15.2. Glover, J., J. Reganold, & P. Andrews. (2000). “Systematic method for rating soil quality of conventional, organic, and

integrated apple orchards in Washington State.” Agriculture Ecosystems and Environment 80, 29-45.



Very little research has been done on soil foodweb analysis in Nova Scotia. Research into microbial activity (a component of soil foodweb analysis) is also scarce. In the early nineties, Cooper and Warman (1997) conducted an experiment in which they added either fresh or composted manure, or synthetic (NPK) fertilizer, to hayfields near Truro, every year for three years. Microbial activity was measured using the

dehydrogenase enzyme activity assay.Of the two sites they used, the one with the lower soil organic carbon levels showed a biological response to organic matter additions; plots that had been amended with

either manure or compost always had higher dehydrogenase enzyme activity (microbial activity) than synthetically fertilized plots.

Mikroba tanah di-stimulir oleh penambahan kompos atau pupuk kandang. Kandungan hara-tersedia dalam tanah dan pH tanah juga meningkat setelah

penambahan kompos atau pupuk kandang. Dosis aplikasi pupuk kandang digunakan sebagai cara tidak langsung untuk menduga

kesehatan foodweb tanah.

1. Cooper, J.M. & Warman, P.R. (1997). “Effects of three fertility amendments on soil dehydrogenase activity, organic C and pH.” Canadian J. Soil Sci. 77,281-283.



Table 21: Metode Pendugaan Foodweb Tanah yang Sehat



Kuantitas Mikroba TanahMikroba tanah menghasilkan beragam jasa-jasa ekosistem yg penting

bagi masyarakat, di antaranya adalah:1. SIKLUS HARA – conversion of nutrients from organic residues into plant available

forms ready for plant uptake.2. DEGRADASI PESTISIDA – conversion of active ingredients in pesticides into less

harmful products, and their eventual conversion into CO2 and water3. KONTROL PENCEMARAN – conversion of labile plant nutrients such as nitrate

and phosphate, into more stable organic forms4. SIMPANAN KARBON – formation of stable humus from organic residues.5. FIKSASI NITROGEN – fixation of 140 to 170 million tonnes of N each year in

agricultural and natural systems by free-living and symbiotic microorganisms6. KONTROL PATOGEN – neutralization of disease organisms that could attack

crops; control of disease organisms found in animal wastes applied to agricultural land.



Table 22: Nilai-nilai Foodweb yang Sehat



Nilai foodweb tanah yang sehat sulit dikuantifikasikan. Mikroba tanah memainkan beragam fungsi dan jasa ekosistem, seperti siklus

hara, fixation dan retention, purifikasi limbah, dan detoksifikasi pesticides dan bahan kimia.

The rotation effect is one benefit attributed to a healthy soil foodweb.

We can estimate that crop yields on land with a healthy soil microbial population are 10% higher than yields on land with poor soil health because of the competitive interactions between a diversity of soil

microorganisms which prevent the proliferation of deleterious rhizobacteria.


KUALITAS TANAH DAN PRODUKTIVITASTable 23: Kualitas Tanah dan Indikator Produktivitas



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