Bahan kajian MK. PEMUPUKAN

EKONOMI PUPUK

Oleh: Prof.Dr.Ir.Soemarno, M.S.

Jur. Tanah FPUB Oktober 2011

EFISIENSI HARA

Nutrient efficiency is a measure of how much crop is produced per unit of nutrient supplied. The higher the efficiency, the more product is produced per unit of nutrient. The quality of soil affects nutrient use efficiency. Soil quality is measured or evaluated by a number of indicators.

ADA SEBANYAK 13 indikator yang berklaitan dengan efisiensi unsur hara tanaman.

SUMBER: http://soils.usda.gov/sqi/management/files/sq_atn_4.pdf

KUALITAS TANAH DAN KETERSEDIAAN HARA

A healthy soil functioning at nearly full capacity stores and cycles nutrients and allows crops to grow and use nutrients efficiently. In a healthy soil, nutrients become available when the plants need them. There is little risk for crop nutrients to move below the root zone through leaching, off the edge of field by runoff and erosion, or above the crop canopy by volatilization. Crop nutrients that move beyond the crop’s zone of uptake could potentially contaminate the environment.

EROSI DAN KEHILANGAN HARA

Erosion and runoff are both detrimental to nutrient management. Nutrients contained in the topsoil, along with soil organic matter, can be carried away by erosion or washed out with runoff water. The organic matter is the first to be transported by water or wind because of its lower specific gravity. Additional nutrients are required to maintain productivity lost when topsoil is carried away by erosion.

SEDIMENTASI DAN KESUBURAN

Sediment additions in the field can be good or bad. Some sediment, especially the finer clay particles and organic matter, bring in nutrients. The coarser sediments, like sands, do not have a high nutrient content and tend to cover the topsoil that is in place. Coarser textured soils also lack moisture holding and pesticide-retention capacity.

PEMADATAN TANAH DAN KETERSEDIAAN HARA

Compact soils restrict the movement of roots. Less root volume in the soil prevents nutrient uptake. Compaction also restricts the diffusion and flow of nutrients in the soil. Few roots and limited nutrient movement can result in stunted growth because the plant is unable to take up the nutrients in the soil. Compacted soils retard air movement and gas exchange in the root zone. This can lead to nutrient losses, like denitrification or toxic gas build-up near the roots.

AGREGASI TANAH DI LAPISAN PERMUKAAN

Good soil aggregation means better water and nutrient movement through the soil. More aggregation means more of the surface area of the soil particles have capacity for adsorbed nutrients. Surface aggregation allows pore space for water infiltration and gas exchanges. Good soil aggregation is closely tied to the amount of active organic matter and to biological activity.

Agregasi tanah berhubungan erat dengan siklus hara-tersedia.

INFILTRASI DAN PERGERAKAN HARA

Plants require water. Nutrients move with the water through the soil pores and are absorbed into the plant. When nutrients are applied to the soil surface, as in no-till systems, water is required to move the nutrients down into the root zone. Good soil infiltration permits this to happen. Nutrients that are not carried into the root zone are susceptible to runoff.

Percolating water carries the nutrients deeper into the root zone and also removes harmful salts that may accumulate there.

KERAK TANAH

Crusting seals the soil surface and restricts water infiltration and gas exchange. If not allowed to infiltrate, surface applied nutrients on crusted soils are susceptible to runoff and wind transport. Crusting also reduces seed germination and seedling survival which directly has an effect on the plant population and the amount of nutrients necessary for the crop.

NUTRIENT LOSS atau IMBALANCE

Nutrients need to be applied according to the crop and soil requirements. Soil and plant analyses are a good way to determine the amount of nutrients needed. Over-application of nutrients can lead to plant toxicity, poor pH reaction, and excess nutrients susceptible to runoff, leaching, and volatilization. A deficiency in nutrients will not sustain optimum plant growth.

RESIDU PESTISIDA

Pesticides with residual soil activity can stunt growth of subsequent crops. If roots are affected, their ability to absorb nutrients will be lessened. Any effect on plant photosynthesis will reduce nutrient uptake and metabolism.

Without pesticide or weed control, weeds can utilize nutrients in competition of the crop. The weed residue may not decompose and recycle plant nutrients for the subsequent crops.

BAHAN ORGANIK TANAH

Soil organic matter is a very valuable component of the topsoil. Organic matter stores nutrients, feeds soil organisms that decompose organic material, and return the basic nutrients to the soil. Organic matter holds soil moisture for plant use. Soil organic matter is developed by combining of carbon, oxygen, and nitrogen plus other nutrients in the soil. Nitrogen and other nutrients must be available to soil microorganisms for development of organic matter.

AKTIVITAS BIOLOGI TANAH A healthy soil has a diverse set of macro and micro organisms that assure a well functioning soil food web. Microorganisms decompose organic material, store nutrients in their bodies, and as they decay or become food for other organisms, they release nutrients.

Some small animals like insects and crustacea carry organic material and related nutrients into the soil and aid in its decomposition. Some microorganisms have a symbiotic relationship with plants such as mycorrhiza. Mycorrhiza live in plant roots and help the plants assimilate water and nutrients.

SIKLUS NITROGEN

SUMBER: soilcarboncenter.k-state.edu

GULMA & PATOGEN

Nutrients can be used by crops or by weeds. Weeds utilize nutrients, but fail to produce a marketable commodity. So, the nutrients are not efficiently used to grow crops.

The same is true for crops that are attacked by disease and insects. Efficient utilization means nutrients are converted to a harvestable product.

LENGAS TANAH DAN KETERSEDIAAN HARA

The amount of soil moisture impacts nutrient cycling. A dry soil does not promote root extension in the root zone. And, since nutrients are carried by water, plants are unable to obtain adequate nutrition. Waterlogged soils affect the transformation of nutrients. Phosphorus becomes more mobile and less attached to minerals in waterlogged conditions.

Nitrate nitrogen is denitrified by changing form from a liquid to a gas which can be lost to the atmosphere. Roots consume oxygen and respire carbon dioxide. Because gases are transported much more slowly through water (about one ten thousanth slower) than air, some gases such as carbon dioxide can accumulate in the soil and be toxic to roots.

RESPON TANAMAN TERHADAP PEMUPUKAN Sumber: smart-fertilizer.com

KURVA RESPON HASIL

The curve describes the crop response to fertilizers application : 1. Zone A - Too low fertilizers application which results in nutrient deficiencies and lower yields 2. Zone B - Adequate fertilizers application results in maximum efficiency and the highest profitability.

3. Zone C - Over fertilization where yield is not affected but fertilizers are wasted.

4. Zone D - Excessive fertilizers application which results in decreased yields, toxicities and salinity damages

FUNGSI PRODUKSI Fungsi Produksi = Hubungan teknis antara faktor produksi (input) dengan hasil produksinya (output).

Metode Produksi = Proses Produksi = Aktivitas = kombinasi faktor-faktor produksi yang dibutuhkan untuk memproduksi satu satuan produk

Modal (dianggap tetap)

M2 M1 P2 P1 M3 Fungsi Produksi yg sebanding (

fixed proportion

) P3 Tk2 Tk1 Tk3

Tenaga kerja (dianggap variabel)

ISOKUAN : ISO QUANTITIES Fungsi produksi tidak sebanding (variable proportions).

ISOKUAN = Kurva yang menggambarkan berbagai kombinasi faktor produksi yang menghasilkan volume produksi yang sama Pupuk P A A P B TK A C Q = Q1: Kuantitas Prod.

B TK B Q = Qo Tenaga Kerja

FUNGSI PRODUKSI: Q = f (TK, P) Q B Q D A

Fase ekonomis

C

Fase ekonomis

TK A TK B TK variabel, Ptetap P C Pd Pvariabel, TK tetap Titik-titik A, B, C dan D = inflection points Produk Marjinal = dQ / dTK atau dQ/dM

Law of deminishing returns

Titik B = batas ekstensif penggunaan tenaga kerja

PRODUKSI RATA-RATA Produktivitas faktor produksi: Produksi rata-rata per satuan faktor produksi.

Q/TK = f (1, M/TK) ….. produksi rata-rata per satuan TK Q/M = f (1, TK/M) ….. produksi rata-rata per satuan M Q B Q R R P O TKP TK R TKB TK/M

HUBUNGAN PRODUKSI TOTAL, PROD. MARJINAL & PROD. RATA-RATA Fungsi produksi : Q = f (TK, Pk) Produksi rata-rata: Q/TK = f (TK, Pk) / TK Produksi marjinal:



Q/



TK Q B Q = f (TK, Pk) R 0 TK A TK R PM PRTK TK

ISOKUAN Kurva indiferensi ……….… Lereng ISOKUAN mencerminkan laju substitusi teknis marjinal, hubungan antara faktor produksi TK dan Pk bersifat teknis Pk Fungsi produksi: Q = f(TK 1 Pk) Pk A A



Pk



TK Isokuan: Q o = f(TK 1 Pk) Q = Q o 0 TK A TK

TEKNOLOGI, MODAL & FUNGSI PRODUKSI Q

Kenaikan produktivitas karena penambahan modal

Q = F(TK, M 1 ) Q = F(TK, M 0 ) M1 > Mo 0 TK

EKONOMI PUPUK Petani melakukan usahataninya bertujuan mendapatkan keuntungan yang sebesar besarnya per satuan luas lahan yang digarapnya ……….. Profit maximizing The farmer realize that : “he must spend money to make money” This is certainly true of expenditures for: “lime, fertilizer, and manure” 3.

4.

5.

6.

7.

8.

9.

Use of fertilizers is an index of the use of modern agricultural methods Faktor lain yg berpengaruh: 1.

2.

Water control Seedbed Cultivar Date and rate of seeding Stand of population Fertilizer placement Cultivation Weed, insect and disease Harvesting practices

EKONOMI PUPUK DAN KAPUR YIELD LEVEL & UNIT COST OF PRODUCTION Biaya produksi: 1.

Biaya tetap (fixed cost): jumlah biaya yang harus dikeluarkan tidak tergantung pada tinggi-rendahnya hasil tanaman 2.

Biaya tidak tetap (variable cost): biaya yang dikeluarkan tergantung pada tinggi-rendahnya hasil, misalnya biaya pupuk, pestisida, dan panen hasil Pengaruh pupuk dapat dilihat dari: 1.

2.

Meningkatkan total hasil tanaman Menurunkan biaya per unit produksi, per ton hasil tanaman

EKONOMI PUPUK DAN KAPUR .

Pengaruh pupuk N-P-K terhadap hasil jagung dan keuntungan usahatani jagung Usahatani Jagung 0-0-0 67-22-22 134-45-45 270-90-90 ……………………. Kg/ha ……………………….

Hasil jagung (kw/ha) Gross income per ha Operating cost Othe cash cost Fixed cost Interest cost of land Total cost Cost per q Return to land, labor Source: 48 $188 56 25 88 82 251 5.3

-63 70 274 69 25 88 82 264 3.8

+10 85 98 336 390 82 25 88 111 25 88 82 277 3.3

+59 82 306 3.4

+84

EKONOMI PUPUK DAN KAPUR Level of Farm-Management: Bgm kemampuan petani dalam mengelola usahataninya: Merencanakan, menjadwal, melaksanakan dan mengendalikan kegiatannya Peningkatan hasil atau nilai hasil Superior management Average management Fertilizer cost A B Dosis pupuk With superior farm management, ………… ……………higher rates of fertilizer can be profitably used

EKONOMI PUPUK DAN KAPUR Level of Farm-Management: Bgm kemampuan petani dalam mengelola usahataninya: Merencanakan, menjadwal, melaksanakan dan mengendalikan kegiatannya Peningkatan hasil atau nilai hasil all controllable growth factors adequate R1 Q1, R2 Q2 Some controllable growth factors inadequate Q R Dosis pupuk A higher yield is obtained when all controllable growth factors are adequate ………

EKONOMI PUPUK DAN KAPUR Unit Production Cost: Biaya Produksi Satuan Yield, q per ha Fertilizer cost Irrigation cost Total cost Cost per q Profit per ha Profit per q Usahatani jagung irigasi Average Superior Farm Management FM 90 8.30

8.00

76.80

0.85

13.20

0.15

150 23.20

8.00

102.20

0.68

47.80

0.32

EKONOMI PUPUK DAN KAPUR Level of management on returns from farming Level of Management: Current Good Superior Yield, bu per acre Price per unit Value per acre Cost per acre Cost per unit Return over cash 20.0

2.00

40.00

41.98

2.10

-1.98

Usahatani kedelai 34.0

2.00

68.00

53.72

1.56

14.28

50.0

2.00

100.00

55.75

1.11

44.25

RETURNS PER RUPIAH SPENT ON FERTILIZER.

Effect of rate of nitrogen on net return per added Rp invested Nitrogen rate kg/ha Added input kg N/ha Net return per added Rp invested 20 40 60 80 100 120 140 160 180 200 20 20 20 20 20 20 20 20 20 20 7.25

5.75

5.00

3.87

2.38

1.63

0.88

0.50

0.12

-0.62

PROFIT per LAND-AREA.

Petani umumnya akan berupaya melakukan pemupukan untuk mencapai keuntungan (profit) yang setinggi-tingginya per hektar lahannya.

Maximum profit tercapai kalau tambahan hasil sama dengan biaya tambahan terakhir dosis pupuk yang diberikan ( Δ hasil / Δ pupuk).

Aspek ekonomi dari respon hasil jagung terhadap dosis pupuk nitrogen Dosis N Yield kg/ha kw/ha 20 40 60 80 100 120 8 15 21 26 30 32 Marginal Yield 8 7 6 5 4 2 Marginal Cost 2.4

2.4

2.4

2.4

2.4

2.4

Catatan: Harga pupuk N sebesar Rp 0.12 per kg Marginal Return Gross profit per ha ……. (harga jagung Rp 1/ ku) ………..

3.33

2.92

2.50

2.08

1.67

0.83

5.60

10.20

13.80

16.40

18.00

17.60

What are the most profitable rates of plant nutrients?.

Beberapa faktor yang berpengaruh: 1. The expected increase in yield from each increment 2. The level of management 3. The price of fertilizer 4. The price the farmer expects to receive for his crops 5. Additional harvesting and marketing costs 6. Residual effects 7. Levels of other nutrients in the soil or fertilizer

Expected increase in yield from each incement of fertilizer.

Hasil per ha HA HB HE HC Lokasi A Lokasi B Lokasi E Lokasi C HD Lokasi D N Dosis pupuk N

Respon tanaman terhadap pemupukan dipengaruhi oleh kesuburan tanah.

Hasil tanaman H K Tanah kaya P dan K H M Tanah miskin P dan K Profit P K P M ’ P M P K ’ N Dosis pupuk N Tanah kaya P dan K

profit difference Max profit

N M N K Tanah Miskin P dan K Dosis pupuk N

Weather effects on the fertilizer response.

Hasil tanaman H G good weather H D dry weather N Dosis pupuk

Hasil tanaman per ha

Price of fertilizer vs. Value of crop

kurva hasil tanaman

Y C garis

biaya pupuk

C Y NC N N’

Dosis pupuk per ha

PRIORITY IN USE OF FUNDS Kontribusi berbagai komponen usahatani terhadap hasil tanaman: Yield increase (ton/ha) 1. Weed and pest control 2. Improved cultivar 3. Planting rates 4. Rotations 5. Fertilizer and lime Total 3.7

4.4

4.4

7.2

12.8

32.5

Kontribusi (%) 11.4

13.5

13.5

22.2

39.4

100.0

Fertilizing good cropland according to soil test recommendations should have a high priority for operating funds.

EKONOMI PEMUPUKAN.

Hasil tanaman yang lebih tinggi akan menyediakan peluang yang lebih besar untuk mencapai maximum net-profit per luasan lahan dan memperkecil biaya produksi per satuan hasil. Kesuburan tanah yang baik menjadi faktor utama untuk mendapatkan hasil yang tinggi. Biaya tetap dalam usahatani adalah biaya yang dikeluarkan oleh petani, tidak tergantung pada besarnya hasil tanaman. Dengan demikian praktek usahatani yang meningkatkan hasil tanaman biasanya akan memperendah biaya produksi per satuan hasil .

Kurva respon hasil tanaman terhadap pemupukan biasanya mengikuti The Law of Diminishing Return (Kurva Asimtotis).

Pendapatan per biaya produksi akan semakin menurun, hal ini menjadi pertimbangan utama bagi petani yang modal kerjanya terbatas.

Petani yang progresif biasanya menyadari bahwa profit per hektar lahan lebih penting daripada penghasilan per satuan biaya produksi Maximum profit dari pemupukan akan tercapai kalau tambahan hasil tanaman sama dengan tambahan biaya pemupukan (dY/dX = dC/dX)

EKONOMI PEMUPUKAN.

Dosis pupuk yang apling menguntungkan dipengatruhi oleh: 1. Peningkatan hasil akibat tambahan pupuk 2. Level of farm management 3. Harga pupuk 4. Harga hasil tanaman 5. Tambahan biaya panen 6. Biaya pemasaran 7. Residual effects 8. Soil fertility level.

Level of farm management: derajat sampai dimana semua faktor produksi tanaman dapat berhasil dikendalikan.

Pada dosis pupuk yang tinggi, diperlukan kemampuan manajerial yg lebih tinggi Harga per satuan hara tanaman, beragam dengan bahan pupuk.

Pupuk yang kandungan haramya lebih tinggi dianggap lebih murah biaya aplikasinya Prioritas penggunaan modal kerja sangat penting bagi petani.

Umumnya lebih menguntungkan untuk melakukan pemupukan sesuai dengan ahsil uji tanah.

.

EKONOMI PEMUPUKAN.

Residual effects pupuk menjadi bagian penting dari ekonomi pemupukan. Semakin banyak jumlah pupuk yang diaplikasikan dalam jangka panjang, maka nilai residual pupuk harus dipertimbangkan.

1.

2.

3.

Why high yields are a necessity in periods of low prices ?

What are fixed cost? Variable costs? In relation to the fertilizer application Discuss the factors that determine the most profitable rate of plant nutrients.

4. How would you evaluate the residual nutrients in your area?

EKONOMI PEMUPUKAN Prof.Dr.Ir.Soemarno,M.S.

JURS TANAH FP-UB, Oktober 2011