Perencanaan Usaha Tani Lahan Kering Berkelanjutan Berbasis Tembakaudi Sub-DAS Progo Hulu (Kabupaten Temanggung, Provinsi Jawa Tengah) - Suyana, Jaka (Buletin Tanaman Tembakau, Serat & Minyak Industri, 2014)
Akibat dari teknik budi daya yang kurang mengindahkan kaidah konservasi tanah dan air, pada kemiringan berbukit dan curam, serta curah hujan yang tinggi pada usaha tani lahan kering berbasis tembakau di Sub-DAS Progo Hulu telah menyebabkan terjadinya erosi yang parah dan degradasi lahan. Penelitian ini bertuju-an: (1) mengkaji kondisi biofisik lahan dan karakteristik usaha tani lahan kering berbasis tembakau di Sub-DAS Progo hulu; (2) mengkaji pengaruh teknologi konservasi tanah dan air (KTA) spesifik lokasi terhadap limpasan permukaan dan erosi; dan (3) merumuskan perencanaan sistem pertanian konservasi untuk mewu-judkan sistem usaha tani lahan kering berkelanjutan berbasis tembakau di Sub-DAS Progo Hulu. Penelitian dilakukan menggunakan metode survei, percobaan lapangan, dan analisis di laboratorium. Data karakteristik lahan, karakteristik usaha tani, serta data limpasan permukaan dan erosi dianalisis secara deskriptif dan dilan-jutkan dengan analisis ragam (uji F) dan uji HSD 5%. Selanjutnya pengembangan rekomendasi agroteknolo-gi diformulasikan melalui teknik simulasi dengan program Powersim Versi 2.5d. Hasil penelitian menunjukan bahwa penggunaan lahan pada usaha tani lahan kering berbasis tembakau di Sub-DAS Progo Hulu pada umumnya (58,4%) sesuai dengan kelas kemampuan lahan dan sisanya 41,6% tidak sesuai dengan kelas ke-mampuan lahan. Terdapat 77,2% lahan memiliki nilai prediksi erosi lebih besar dari nilai erosi yang dapat di-toleransikan (ETol) dan perlu penyempurnaan dalam teknologi KTA. Usaha tani lahan kering berbasis usaha tani tembakau di Sub-DAS Progo Hulu didominasi pola tanam jagung-tembakau (51,0%) dan cabai-temba-au (29,2%), dengan pendapatan usaha tani masih di atas nilai kebutuhan hidup layak (KHL). Perlakuan pem-berian mulsa batang tembakau dikombinasikan rumput penguat teras (Setaria spacelata) dapat menekan erosi 15â19% pada dosis 7 ton/ha dan 31â43% pada dosis 14 ton/ha batang tembakau, sedangkan tumpang sari koro merah dengan tembakau dikombinasikan penggunaan mulsa batang tembakau 7 ton/ha dapat menekan erosi 13â20%. Pengembangan usaha tani lahan kering berkelanjutan berbasis tembakau di Sub-DAS Progo Hulu dapat diwujudkan dengan penyempurnaan teknologi KTA yang meliputi: (a) perlakuan rumput setaria sebagai penguat teras + mulsa batang tembakau 7 ton/ha atau perlakuan tumpang sari koro merah dengan tembakau + mulsa batang tembakau 7 ton/ha pada kemiringan lereng 8â15%; (b) teras miring + perlakuan rorak pada kemiringan lereng 15â30%; dan (c) perlakuan rumput setaria sebagai penguat teras miring + mulsa batang tembakau 14 ton/ha + rorak pada kemiringan lereng >30%. Â Due to inadequate soil and water conservation practices in farming activity at tobacco based farming sys-tems, severe erosion and land degradation had been occuring in almost all upland agriculture in Progo Hulu Sub-watershed. This research was conducted: (1) to study landâs biophysic conditions and the characteris-tics of tobacco based farming systems, (2) to study and analyze the impact of various soil and water conser-vation practices on erosion, (3) to study and design sustainable conservation farming systems in tobacco based farming systems. This research by using a survey method, field experiments, and laboratory analysis.Data characteristics of land, farm characteristics, surface run off and erosion by using descriptive analyzed and followed by analysis of variance (F test) and 5% HSD test. The development of agrotechnology recom-mendations formulated by simulation techniques using program Powersim Version 2.5 d. The results showed that land use in tobacco-based farming systems at Progo-Hulu sub-watershed was generally (58.4%) suitable to its land capability and 41.6% were not suitable. The predicted erosion on approximately 77.2% of lands were higher than local tollerable soil loss which need improvement of soil and water conservation techniques. Tobacco based farming systems was dominated by maize-tobacco (51.0%) and chili-tobacco (29.2%) cropping patterns; farmers income on this farming systems were higher than the income that can support worthed life living standard. The application of crop residue (tobacco stems) as mulch with rate of 7 tones/ha and 14 tones/ha combined with grassed bench terraces ((Setaria spacelata) reduced erosion as much as 15â19% and 31â43%, respectively. Meanwhile, red bean-tobacco intercropping combined with crop residue mulch of 7 tones/ ha had suppressed erosion 13â20%. Sustainable tobacco-based farming systems could be developed in this area by practicing improved soil and water conservation technologies with: (a) setaria grass to strengthen terraces + 7 tones/ha of crop residue mulch or red bean and tobacco intercropping + 7 tones/ha of crop residue mulch on 8â15% slope; (b) broad base terraces + adequate slit pit on 15â30% slope; and (c) setaria grass to strengthen broadbase terraces + 14 ton/ha of crop residue mulch + adequate slit pit on >30% slope.