Evaluasi Pertumbuhan dan Perkembangan Arachis Pintoi sebagai Biomulsa pada Budidaya Tanaman di Lahan Kering Tropis

Cover crops is widely used as biomulch because of its advantages for land conservation, weed control and increasing soil nutrients, especially in upland agriculture. The objective of the research was to study the growth and development of Arachis pintoi as biomulch in upland agriculture. The experiment was carried out at IPB Experimental Field from February until May 2014. Observation was done everyweek up to 12 weeks with 10 plants were used for each observation. One stolon of A. pintoi with 4 internodes was planted in each 0.25 m2 plot. The results showed that root initiation of A. pintoi was occured at 3 weeks after planting (wap) and produced 42.4 roots with average root length of 17.10 cm on 12 wap.A. pintoi had nett assimilation rate of 0.0023 g cm-2 per day and relative growth rate of 0.052 g per day. With this growth rate, A. pintoi covered 58% of 0.25 m2 plot and produced biomass 10.08 g per plant within 12 wap. A. pintoi produced flowers on 4 wap and pods on 7 wap. A. pintoi produced root nodules through mutualism symbiosis with local Rhizobium. The equation for rate of coverage is Coverage (%) = 5.273 Time (wap)-16.512; 100% land coverage can be reached on 22 wap. Based on the results of this study, A. pintoi is potential to be used as biomulch; however, a denser spacing must be applied for faster land coverage

Potensi Gangguan Gulma pada Tiga Sistem Budidaya Padi Sawah

Weeds has become a big problem in system of rice intensification (SRI), integrated crop management (ICM) and conventional cultivation systems. The objective of the research was to study the dominancy and potential of harmful effect of weed in these three cultivation systems. The research was conducted at Sukamandi research station of Indonesian Center for Rice Research, Subang, from November 2013 to April 2014 during rainy season. The experiment was arranged in a split plot design with four replications. The cultivation systems was main plot consisted of system of rice intensification (SRI), integrated crop management (ICM) and conventional system. The weeding techniques as subplot consisted of no weeding, manual weeding, mechanical weeding and chemical weeding. The result showed that based on dry mass of weeds the highest risk of weed was exhibited at SRI with total dry mass of weed 51.53 g m-2 (0.5 ton ha-1) and the lowest was at conventional system with 32.45 g m-2 (0.3 ton ha-1). Proper weed control increased rice production by 28.9% for SRI, by 29.4% for ICM and by 14.6% for conventional cultivation systems

Identifikasi Senyawa Fenol Beberapa Aksesi Teki (Cyperus Rotundus L.) Serta Pengaruhnya terhadap Perkecambahan Biji Borreria Alata (Aubl.) DC.

Purple nutsedge (Cyperus rotundus L.) is one of the important weeds in the world because of its ability to suppress the production of crops and difficult to control. C. rotundus residues can suppress the growth of others weeds. The experiments were conducted to identify the phenolic compound of C. rotundus from six different accessions and to determine the allelopathic effects of C. rotundus extracts on germination of Borreria alata (Aubl.) DC. The identification of phenolic compound was done using extract from all part of mature C. rotundus taken from different accessions and was analyzed using GC-MS. Analysis of C. rotundus extracts on germination of B. alata was designed using completely randomized design with three replications. The treatments were extract of C. rotundus from different accessions (from Cikarawang-Darmaga, Babakan-Darmaga, Ciawi, Megamendung, Cisarua, and Cianjur) with different concentration, 0.75 kg L-1 and 1.5 kg L-1. The result showed that C. rotundus from six accession had phenolic compond with different amounts. Cianjur accesion contained the most phenol content such as 2-furanmethanol; 1,4-benzenediol; 2-methoxy-4-vinylphenol; phenol, 2,6-dimethoxy; syringic acid; and 3-hydroxybenzoic acid. Germination test showed that C. rotundus extracts from different accessions and concentration had the same inhibitory effect on germination of B. alata

Toleransi Galur Harapan Padi Sawah (Oryza Sativa L.) pada Persaingan dengan Gulma Echinochloa Crus-galli

Barnyard grass (Echinochloa crus-galli (L.) P. Beauv.) is a major weed competitor to rice production in Indonesia. In order to develop integrated weed management program, a research to select competitive rice lines to E. crus-galli was conducted in a green house of Indonesian Centre of Agricultural Biotechnology and Genetic Resource Research and Development Bogor. The research design was split plot with four replications, E. crus-galli was designed as the main plot (rice without E. crus-galli compared rice with four E. crus-galli per pot), and the sub-plots were 25 genotypes (23 lines, 1 tolerant variety and 1 sensitive variety). Level of tolerance was determined by the reduction percentage of grains weight, the number of productive tillers and dry matter weight. The results showed that rice competition with E. crus-galli reduced plant height, productive tiller numbers, filled spikelet numbers per panicle, dry matter weight and dry grain weight. Three lines, i.e., IR10L-155, IR10L-133 and BIO-R84-1 were classified as tolerant, 19 lines were moderate and 3 lines were sensitive to E. crus-galli competition

Senyawa Fenol dari Tajuk dan Umbi Teki (Cyperus rotundus L.) pada Berbagai Umur Pertumbuhan serta Pengaruhnya terhadap Perkecambahan Gulma Berdaun Lebar

Purple nutsedge (Cyperus rotundus L.) is noxious weed that contains allelochemicals which inhibit other plants germination, thereby it can be potentially used as bioherbicide. Laboratorium experiments were conducted to identify phenol compound in purple nutsedge's shoot and tuber from three plant ages, and to study its effect on germination of Asystasia gangetica and Borreria alata. First experiment was single factor using descriptive method and the second experiment was arranged in completely randomized design with single factor. The first experiment treatments were shoot and tuber extracts of purple nutsedge from 1, 2, and 3 months after planting. The second experiment treatments were control, shoot, tuber, and all parts extracts of purple nutsedge from 1, 2, and 3 months after planting, with 3 replications. Data from the second experiment was analyzed using F test and followed by Tukey test 5%. Result showed that shoot extracts from 2 months after planting had the highest type of phenol compound namely 2-methoxy-4-vinylphenol; phenol,2,6-dimethoxy; 2-furanmethanol; and α-tocopherol. Tuber extract from 3 months after planting suppressed germination rate of A. gangetica about 54.72%. All parts extracts from 2 months after planting suppressed germination rate of B. alata about 60.98%. Purple nutsedge's extracts inhibited growth of plumule and radicle of B. alata at 2 days after sowing. This showed that purple nutsedge's extract gave different effects on different weed species