MK. Manajemen Kesuburan Tanah BEST MANAGEMENT PRACTICES Oleh : Prof.Dr.Ir.Soemarno,M.S .

1. MK. ManajemenKesuburan Tanah BEST MANAGEMENT PRACTICES Oleh: Prof.Dr.Ir.Soemarno,M.S. FP-UB, Okt2013

2. BMPs BEST MANAGHEMENT PRACTICES

3. NITROGEN BMPs FOR SMALL FARMS Kebutuhan N manusia Nitrogen (N) is an element essential for all plant and animal life. Humans have a nutritional requirement of 55 pounds of protein per year. Nitrogen is a component of protein. There are 8.8 pounds of nitrogen in 55 pounds of protein. In the USA a typical person obtains half their protein from animal sources, and the other half from vegetable matter. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

4. NITROGEN BMPs FOR SMALL FARMS EFISIENSI PENGGUNAAN N Kebutuhan manusia secara teoritis hanya 8.8 lbs N protein setahun, namun inefisiensi ekosistem harus diperhitungkan. Sehingga diperlukan lebih dari 8.8 lbs N , karena tumbuhan dan hewan tidak efisien dalam menangkap N dari ekosistem. Tanaman dianggap 50% efisien – sehingga hanya mampu mengubah sekitar 50% N menjadi protein. Sedangkan hewan lebih kurang efisien, hanya sekitar 15% N yang dikonversi menjadi protein. Kalau diasumsikan manusia mendapatkan suplai protein nabati sekitar 50%, maka ia memerlukan 38 lbs N per tahun untuk memenuhi kebutuhan proteinnya; bukan 8.8 lbs N. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

5. NITROGEN BMPs FOR SMALL FARMS SIKLUS NITROGEN This diagram represents a simplified nitrogen cycle. Agriculture affects both N additions and subtractions to the soil. Additions include N fertilizers, crop residues, N fixation by legumes, and manures. Subtractions attributed to agriculture include crop removal (harvesting), plant uptake, and N leaching. Plants can use two forms of N -- ammonium and nitrate. Nitrate is the plant available form of N that can leak or leach from the system and have a detrimental effect on the environment. Another important aspect of the N cycle is the process called mineralization. In this process organic matter (OM) breaks down and forms plant available ammonium and eventually nitrate. Crops residues, animal and plant manures, and composts when added to the soil become part of the soil OM which when mineralized will form ammonium and nitrate. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

6. NITROGEN BMPs FOR SMALL FARMS KEHILANGAN NITROGEN Anytime we have leaks in the nitrogen cycle there are some environmental concerns. The two biggest problems which can impact water quality are leaching and erosion. Nitrates are mobile in soils and can leach into our groundwater supplies. On the other hand soil erosion has a negative impact on surface water quality -- our streams, rivers, and lakes. Organic matter is concentrated on the soil surface. Consequently, if soil erosion occurs, this nitrogen containing organic matter washes off the land into our surface water sources. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

7. NITROGEN BMPs FOR SMALL FARMS SUMBER Nada beberapa sumber N yang digunaklan dalam ekosistem pertanian. Common N sources include the decomposition of soil organic matter, commercial N fertilizers, animal manures, plant residues, and composts. The decomposition of soil organic matter -- called mineralization is a natural process that occurs in all soils. Dalam ekosistem non-pertanian, mineralisasi BOT menjadi sumber utama N bagi tanaman. N dalam Pertanian N adalah hara esensial makro yang dibutuhkan tanaman. Tanaman menyerap N lebih banyak dibandingkan dnegan unsur lainnya. Plants contain anywhere from 1 to 5% nitrogen on a dry weight basis. The importance of nitrogen to all agricultural systems is unquestionable. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

8. NITROGEN BMPs FOR SMALL FARMS Bentuk N Semua sumber N yang diberikan ke tanah pada akhirnya menghasilkan amonium dan nitrat. Nitrate paling panyak diserap tanaman dalam ekosistem pertanian. Nitrate is nitrate -- it does not matter to the plant whether it came from commercial nitrogen fertilizer or if it mineralized from a compost pile. Nitrates dalam Groundwater Nitrates dalam tanah sangat mobil. Berlebihannya air ke lahan dapat mencuci nitrat ke luar tanah, dan mencemari groundwater. Baku mutu air minum maksimum mengandung 10 ppm N-nitrate. Recent surveys have shown that about 2% of the rural wells in the PNW currently exceed this 10 ppm nitrate-nitrogen drinking water standard. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

9. NITROGEN BMPs FOR SMALL FARMS N-Manajemen Proper nitrogen management on small farms is important for three reasons. Pengelolaan N yang tepat dapat memperbaiki kualitas tanaman. Pengelolaan N yang tepat sangat menguntungkan. Pengelolaan N yang tepat dapat melindungi lingkungan. N-MANAJEMEN When we talk about proper nitrogen management to prevent water pollution there are two key concepts one needs to become familiar with. Konsep pertama adalah efisiensi nitrogen atau disingkat NUE. Konsep ke dua adalah best- management-practices, disingkat BMP. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

10. NITROGEN BMPs FOR SMALL FARMS KONSEP NITROGEN Efisiensi Nitrogen (NUE) didefinisikan sebagai persentase N-tersedia dalam tanah yang diserap tanaman, nilainya berkisar 0 - 100 %. Ideally, we would like to see an NUE value of 100%. The greater the NUE value -- the less plant available nitrogen is left in the soil. Plant available nitrogen left in the soil could leach and contaminate our groundwater supplies. Nilai NUE yang tinggi sangat penting karena -- (1) perlindungan lingkungan, dan (2) profitabilitas usahatani. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

11. NITROGEN BMPs FOR SMALL FARMS KONSEP NITROGEN Apakah N dalam NUE? The nitrogen is plant-available nitrogen in the soil. It includes both nitrate and ammonium. This would be the sum total of ammonium and nitrate that got into the soil by the following means: Ammonium Dan nitrate dimineralisasidari BOT, Nitrogen ditambahkansebagaipupuk N, Residu ammonium dan nitrates yang tertinggaldalamtanah yang tidakdiserapolehtanaman yang terakhir. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

12. NITROGEN BMPs FOR SMALL FARMS KONSEP NITROGEN Across the country, nitrogen use efficiency averages about 50% for most crops. Intensive management using best management practices can result in NUE values approaching 70% in production agriculture. On the other hand, poor or careless management often results in NUE values less than 30%. Small farms lend themselves to intensive management. Consequently, a NUE goal of 75% is realistic when nitrogen best management practices are employed. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

13. NITROGEN BMPs FOR SMALL FARMS KONSEP NITROGEN APA artinya efisiensi nitrogen (NUE) 45%? It simply means that 45% of the plant-available nitrogen -- ammonium and nitrate -- in the soil was taken up by the plant. What happened to the other nitrogen that constitutes the 55% not taken up by plants? Well, a portion of it remained in the soil, a portion may have leached, and a portion was utilized by soil microbes or taken up by weeds. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

14. NITROGEN BMPs FOR SMALL FARMS KONSEP NITROGEN The other concept of importance is best management practice, or BMP. Best management practices can be defined as implemented strategies which eliminate or minimize non-point source agricultural pollution. There has been extensive research to design best management practices for nitrogen management. BMP dirancang sesuai dengan kondisi dan karakteristik ekosistem pertanian. Penerapan BMP diharapkan dapat melindungi lingkungan tanpa mengorbankan profitabilitas usaha pertanian. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

15. NITROGEN BMPs FOR SMALL FARMS Ada tujuh BMP Nitrogen yang harus diadopsi oleh usahatani sekala kecil. BMP Nitrogen yang pertama adalah aplikasi dosis pupuk optimum pada setiap bidang lahan usaha. To do this correctly, you must consider the following: soil testing, setting realistic yield goals for the crops in each field, providing nitrogen credits from soil organic matter, providing nitrogen credits for manures and legumes incorporated into your fields, and you need to consider the overall vulnerability of groundwater to contamination. Semakin besar ancaman yang ada – semakin penting segera menerapkan BMP. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

16. NITROGEN BMPs FOR SMALL FARMS You must test your soil to determine its organic matter content and the amount of plant-available nitrogen -- ammonium and nitrate present. This is a necessary best management practice. Dosis pupuk Nitrogen harus didasarkan pada hasil analiosis sampel tanah dan target hasil tanaman yang realistis. A realistic yield goal will allow accurate determination of optimum nitrogen rates for crop production. Yield goals that are too low will under estimate nitrogen needs and result in both reduced yields and profits. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

17. NITROGEN BMPs FOR SMALL FARMS Pengambilan sampel tanah dari lahan usaha harus mengukuti prosedur baku yang berlaku. Soil samples for OM content should be taken to a depth of 12 inches. For ammonium and nitrate the soil sample should be taken to the effective rooting depth of the crop that will be planted. Your local extension office can help here also. The soil samples should be taken 3 to 4 weeks prior to planting. The soil sample should be analyzed by a reputable laboratory. The numbers provided by the soil testing laboratory can be interpreted by your county agent. Dosis pupuk N berdasarkan hasil analisis tanah, sesuai dengan rekomendasi pemupukan bagi tanaman yang ditanam. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

18. NITROGEN BMPs FOR SMALL FARMS TARGET HASIL TANAMAN Yield goals that are too high will over estimate nitrogen needs. This will result in excess plant available nitrogen in the soil profile. This increases the potential for groundwater contamination with nitrates. In addition to accounting for the nitrogen in a soil test one must consider giving credit to nitrogen obtained from other sources. You should take into account the nitrogen in soil organic matter, legumes, animal manures, composts plus other soil additives, and sludge. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

19. NITROGEN BMPs FOR SMALL FARMS KREDIT NITROGEN Nitrogen credits should be given for the amount of organic matter in the soil. BOT mengalami dekomposisi dengan kecepatan sekitar 1.5% per tahun. Dekomposisi BOT akan menghasilkan -- ammonium dan nitrate – yang tersedia bagi tanaman. Secara umum, untuk tanaman yang ditanam pada tanah-tanah yang mengandung BOT 1% , harus dikredit dengan 15 pound N-tersedia. Sekitar 15 pound N-tersedia harus dikredit untuk setiap satu persen BOT dalam tanah. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

20. NITROGEN BMPs FOR SMALL FARMS Tabel ini menunjukkan kredit N-tersedia untuk lahan-lahan yang mengandung BOT 1 - 10%. Konstante sebesar 15 pound dibagi persen BOT dapat digunakan untuk menduga jumlah BOT yang mengalami dekomposisi menjadi N-tersedia dalam tanah. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

21. NITROGEN BMPs FOR SMALL FARMS KREDIT NITROGEN Kredit Nitrogen juga harus diberikan kalau legum ditanam pada musim tanam yang lalu. Residue from these legumes will provide some nitrogen for the next crop. Peas, beans, alfalfa, birdsfoot trefoil, and clovers are legumes which can provide a nitrogen credit. Kacang Peas dan beans menyediakan kredit nitrogen 10 - 20 pounds per acre. Alfalfa, birdsfoot trefoil, dan clovers memberikan kredit 30 - 50 pounds N per acre. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

22. NITROGEN BMPs FOR SMALL FARMS Pupuk kandang dalam tanah dapat menyediakan kredit N cukup besar. Only a portion of the nitrogen in the manure would be mineralized during the first growing season after application. This table provides information on nitrogen credits for manure for the first season after application. For example, if one ton of solid beef manure had been appplied over an acre the nitrogen credit would be 4 pounds nitrogen per acre. Kalau 6,000 gallons pupuk kandang babi diberikan ke satu acre lahan, maka kredit N sebesar 66 pounds (11 X 6 = 66). "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

23. NITROGEN BMPs FOR SMALL FARMS Another material which can provide nitrogen credits to a field is sludge. Sludge does contain some nitrogen -- however, the nitrogen content varies from batch to batch. Annual sewage sludge applications should be limited by the amount of nitrogen required for crop growth. You should test sludge for its nutrient content. An important best management practice for nitrogen is to make sure that the fertilizer rate applied is sound -- based on research. Dosis pupuk N harus ditentukan berdasarkan kajian dan informasi ilmiah. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

24. NITROGEN BMPs FOR SMALL FARMS These fertilizer guides take into account the residual plant-available nitrogen in the soil profile, the amount of nitrogen that is mineralized from organic matter during the growing season, the crop yield potential, and plant residue from the previous crop. The appropriate fertilizer guide for your crop of interest can be obtained from your local county extension office. BMP lainnya adalah waktu yang tepat aplikasi pupuk N. Waktu aplikasi yang tepat merupakan faktor penting yang menentukan efisiensi serapan N – Efisiensi Nitrogen. Strategi terbaik adalah aplikasi sebaghian besar N sebelum tanaman memerlukannya – bukan beberapa minggu berikutnya. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

25. NITROGEN BMPs FOR SMALL FARMS Waktuaplikasipupuk N harusmemperhatikan: Aplikasi N musimhujandanmusimkemarau, Aplikasi N sebelumtanam, Aplikasi N secaragandaatau split, Aplikasi N disisitanaman. Strategiwaktuaplikasi N tergantungpadapolapertumbuhantanaman. Correct nitrogen fertilizer placement is another best management practice that can help protect water quality. The strategy is very simple -- put nitrogen in the vicinity of plant roots to maximize nitrogen uptake and nitrogen use efficiency (NUE). The two most often employed placement strategies are banding and broadcast placement. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

26. NITROGEN BMPs FOR SMALL FARMS Tugal (Banding) dan Sebar. “Banding” adalah penempatan pupuk pada area yang sempit (band), liang tugal. The fertilizer is usually placed 2 to 5 inches below and to the side of the seed at planting. In contrast, broadcast refers to a uniform placement of fertilizer. Broadcast can occur either before or after planting. If before planting, it is uniformly applied to the soil surface and then mixed into the soil with an implement. If applied after planting -- it is uniformly applied to the soil surface -- water is required to move the fertilizer into the root zone. Tanaman yang dipupuk dengan cara “banding” ternyata mempunyai akses yang lebih baik terhadap pupuk. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

27. NITROGEN BMPs FOR SMALL FARMS Some advantages of banding fertilizer nitrogen compared to broadcast placement include: An improvement in nitrogen use efficiency; you fertilize the crop to be grown -- not the weeds; the nitrogen is close to the roots -- better chance of uptake; and the close proximity of the nitrogen often improves early season crop growth. Water management is a very important best management practice. Water management is a key to groundwater protection. Nitrogen dalam tanah bersifat mobil – ia bergerak dalam larutan tanah -- nitrogen dalam air irigasi juga harus dianggap sebagai Kredit. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

28. NITROGEN BMPs FOR SMALL FARMS JADWAL IRIGASINitrogen is mobile in soils -- nitrate moves with water in the soil. Over-irrigation or excess precipitation results in nitrate leaching. Nitrogen management alone will not effectively reduce nitrate leaching. You must couple it with irrigation/water management. To protect groundwater, never over-irrigate. Kredit NO3-N dalam Air Irigasi Your irrigation water source may contain some nitrogen. Nitrogen present in irrigation water can be used by plants. Get your irrigation water source tested for its nitrogen content. If it contains nitrogen it has some fertilizer value. The nitrogen value of irrigation water can be calculated as follows: multiply the nitrogen concentration in the water by 1.35 by the number of acre feet of water applied. This gives you your nitrogen credit value. Many surface water sources have some nitrogen content. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

29. NITROGEN BMPs FOR SMALL FARMS KREDIT NO3-N DALAM AIR IRIGASI Your irrigation water source may contain some nitrogen. Nitrogen present in irrigation water can be used by plants. Get your irrigation water source tested for its nitrogen content. If it contains nitrogen it has some fertilizer value. The nitrogen value of irrigation water can be calculated as follows: multiply the nitrogen concentration in the water by 1.35 by the number of acre feet of water applied. This gives you your nitrogen credit value. Many surface water sources have some nitrogen content. Keunggulanpupuk N lambattersedia (slow-release) : Mereduksipencucian nitrogen, Mereduksikerusakangangguangarampadakecambah, Dapatmemupuk N sekaligus – tidakaplikasiganda Nitrogen tersediapadasaatdibutuhkantanaman. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

30. NITROGEN BMPs FOR SMALL FARMS Nitrogen BMPs If slow-release fertilizers have all these advantages -- then why doesn't everyone use them? Probably because slow-release fertilizers also have one big disadvantage! Cost! On a pound of nitrogen basis, slow-release materials cost between 35 and 40% more than traditional nitrogen sources. However, if nitrogen use efficiency (NUE) is substantially improved with a slow-release material -- its cost may be competitive. To show you how a slow-release fertilizer can be competitive let's look at an example: Let's say that under normal management -- 50% NUE -- you need to apply 90 lbs of N. With a conventional N fertilizer -- let's say ammonium nitrate which costs $.30 per lb N. Using 90 lbs at $.30 per lb would cost $27.00 per acre. A slow-release material would cost more -- $.41 per lb N -- but it would also result in high NUE -- 75% vs 50%. At 90 lbs per acre at $.41 per lb the cost would be $36.90 per acre. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012

31. NITROGEN BMPs FOR SMALL FARMS NITROGEN BMPs Bagian akhir dari BMP Nitrogen adalah pemilihan pergiliran tanaman dan pemilihan tanaman. Pemilihan jenis tanaman dalam sistem rotasi mempengaruhi dinamika N dalam tanah. Penggunaan tanaman penutup tanah juga sangat penting. Tanaman penutup tanah di antara tanaman pokok juga berfungsi menangkap kelebihan N dalam profil tanah. Memilih kultivar terbaik untuk dapat memanfaatkan N-tanah secara efektif. "Nitrogen best management practices for small farms in the Pacific Northwest." Diunduh dari: http://www.uiweb.uidaho.edu/wq/wqbr/wqbr20.html ……….. 6/10/2012