PRODUKSI BAHAN KERING, SERAPAN N DAN P HIJAUAN PADA PERTANAMAN GANDA SETARIA DAN PUERO ATAU CENTRO DENGAN PEMUPUKAN FOSFAT DART SUMBER YANG BERBEDA

Abstract

Legumes are sensitive to P deficiency at tropical soil, therefore, P fertilization is required for instance by using superphosphate (SP-36) or alternative by using rock phosphate (BP). The purpose of this study was to know the effects of mixed cultures of either setaria + puero or setaria + centro that were fertilized with SP-36 or BP on dry matter production, N and P uptake of their forages. The study was conducted during 180 days, initiated in November 2002 and ended in April 2003, at The Experimental Farm, The Faculty of Animal Science, UNSOED., Purwokerto. Split plot in time, Randomized Complete Block Design was used in this study, with three replicates for each treatment. The main plots were mixed cultures (T1 = setaria + puero, T2 = setaria + centro), the sub plots were P fertilization (PO = without P fertilizer, P1 = SP-36, P2 = BP). The level of P fertilization was 200 kg P205/ha. There were two defoliations (Dl = first defoliation, D2 = second defoliation) that were used as time. The observed parameters were dry matter production (DM), N uptake, and P uptake (setaria, puero or centro and setaria + puero or centro). The SAS 6.12 packet program was used to analyze the analysis of variance of the data. The differences among treatments were tested using Duncan Multiple Range Test (DMRT). The results of this study showed that DM production of setaria at the second defoliation was highly significant compared to that of the first defoliation and it was highly significant affected by TxP interaction. The DM production of puero or centro was significantly affected by TxD interaction. The DM production of mixed cultures (setaria + puero or centro) at the second defoliation was highly significant compared to the first defoliation, and it was highly significant affected by TxPxD interaction. The N uptake by setaria tended to be affected by TxP interaction. All of treatments were not significant effect on the N uptake of puero or centro. The N uptake by mixed cultures (setaria + puero or centro) tended to be affected by defoliation periods, PxD, and TxPxD interactions. The P uptake by setaria at the second defoliation was highly significant compared to the fi•st defoliation, and tended to be affected by Tx P interaction. The P uptake by puero or centro was tended to be affected by PxD interaction. The P uptake by mixed cultures (setaiia + puero or centro) was highly significant affected by defoliation periods, the second defoliation being highly significant compared to that of the first defoliation. It can be concluded that fertilized SP-36 and BP not different on the production and nutritive value of mixed cultures. Legum pada tanah tropika umumnya peka terhadap lcekurangan unsur hara fosfor (P). Oleh karena itu perlu dilakukan pemupukan P, umunmya digunakan pupuk superfosfat (SP-36), tetapi ada alternatif menggunakan batuan fosfat (BP). Penelitian ini bertujuan untuk mengetahui pengaruh penggantian SP-36 dengan BP pada pertanaman ganda setaria + puero/centro terhadap produksi bahan kering, serapan N dan P hijauannya. Penelitian dilaksanakan selama 180 hari, mulai November 2002 sampai dengan April 2003, di Sub Stasiun Percobaan Fakultas Peternakan Unsoed., Purwokerto. Split Plot in Time dengan Rancangan Acak Kelompok (RAK) diulang 3 kali (kelompok) digunakan pada penelitian ini. Petal• utama pertamanan ganda T(T1= setaria + puero, T2= setaria + centro), anak petak pemupukan P (PO = tanpa pupuk P, P1= SP-36, P2 = BP). Dosis pupuk P = 200 kg P203 kg/ha. Periode defoliasi liijauan D (D1= defoliasi pertama, D2 = defoliasi kedua) sebagai time. Parameter yang diteliti meliputi produksi bahan kering, serapan N, dan serapan P (setaria, puero atau centro dan setaria+puero atau centro). • Data yang didapat diolah dengan analisis keraganian dengan paket program SAS. 6.12. Perbedaan antar perlakuan dilakukan uji lanjut dengan Uji Jarak Berganda Duncan (UJBD). Hasil penelitian menunjukkan bahwa produksi bahan kering hijauan setaria defoliasi kedua sangat nyata lebih tinggi dibanding defoliasi pertama dan sangat nyata dipengaruhi interaksi perlakuan TxP. Produksi bahan kering hijauan puero atau centro nyata dipengaruhi interaksi perlakuan TxD. Produksi bahan kering hijauan pertanaman ganda (setaria+puero atau centro) defoliasi kedua sangat nyata lebih tinggi dibanding defoliasi pertama dan sangat nyata dipengaruhi interaksi perlaktian TxPxD. Serapan N hijauan setaria cendenmg dipengaruhi interaksi perlakuan TxP. Semua perlakuan tidak berpengaruh nyata pada serapan N hijauan puero atau centro. Serapan N hijauan pertanaman ganda (setaria+puero atau centro) cenderung dipengaruhi periode defoliasi, interaksi perlakuan PxD dan interaksi perlakuan TxPxD. Serapan P hijauan setaria defoliasi kedua lebih tinggi dan sangat nyata beda dengan defoliasi pertama, dan cendenmg dipengaruhi interaksi perlakuan TxP. Serapan hijauan puero atau centro cenderung dipengaruhi interaksi perlakuan PxD. Serapan P hijauan pertanaman ganda (setaria+puero atau centro) sangat nyata dipengaruhi periode defoliasi hijauan, dimana defoliasi kedua sangat nyata lebih tinggi dibanding defoliasi pertama.