Changes in soil organic matter under different land management in misiones province (Argentina)

Dang

et al. 2015

Global Change Biology

114

Knowledge of soil organic matter (SOM) dynamics following deforestation or reforestation is essential for evaluating carbon (C) budgets and cycle at regional or global scales. Worldwide land-use changes involving conversion of vegetation with different photosynthetic pathways (e.g. C and C ) offer a unique opportunity to quantify SOM decomposition rate and its response to climatic conditions using stable isotope techniques. We synthesized the results from 131 sites (including 87 deforestation observations and 44 reforestation observations) which were compiled from 36 published papers in the literatures as well as our observations in China's Qinling Mountains. Based on the C natural abundance analysis, we evaluated the dynamics of new and old C in top soil (0-20 cm) following land-use change and analyzed the relationships between soil organic C (SOC) decomposition rates and climatic factors. We found that SOC decomposition rates increased significantly with mean annual temperature and precipitation in the reforestation sites, and they were not related to any climatic factor in deforestation sites. The mean annual temperature explained 56% of variation in SOC decomposition rates by exponential model (y = 0.0014e ) in the reforestation sites. The proportion of new soil C increased following deforestation and reforestation, whereas the old soil C showed an opposite trend. The proportion of new soil C exceeded the proportion of old soil C after 45.4 years' reforestation and 43.4 years' deforestation, respectively. The rates of new soil C accumulation increased significantly with mean annual precipitation and temperature in the reforestation sites, yet only significantly increased with mean annual precipitation in the deforestation sites. Overall, our study provides evidence that SOC decomposition rates vary with temperature and precipitation, and thereby implies that global warming may accelerate SOM decomposition.

Section: Climatic Controls Over Soil C Accumulationmentioning

confidence: 99%

Soil carbon dynamics following land‐use change varied with temperature and precipitation gradients: evidence from stable isotopes

Dang

et al. 2015

Global Change Biology

114

Applied and Environmental Soil Science

“…As stated previously, the data set obtained from two long-term experiments (sites A and B) was used to calibrate the AMG model. The second and third terms of (2) were determined separately by using the 13 C natural abundance technique which allows obtaining a unique evaluation of the parameters , 1 , and C s in longterm experiments [43,58].…”

mentioning

confidence: 99%

Effect of Continuous Agriculture of Grassland Soils of the Argentine Rolling Pampa on Soil Organic Carbon and Nitrogen

Delaye¹,

Irizar²,

Andriulo³

et al. 2013

Self Cite

Long-term soil organic carbon (SOC) and soil organic nitrogen (SON) following cultivation of grassland soils (100/120-year tillage (T) + 20/30-year no tillage (NT)) of the Rolling Pampa were studied calibrating the simple AMG model coupled with the natural13C abundance measurements issued from long-term experiments and validating it on a data set obtained by a farmer survey and by long-term NT experiments. The multisite survey and NT trials permitted coverage of the history of the 140 years with agriculture. The decrease in SOC and SON storage that occurred during the first twenty years by a loss through biological activity was 27% for SOC and 32% for SON. The calibrated model described the SOC storage evolution very well and permitted an accurate simultaneous estimation of their three parameters. The validated model simulated well SOC and SON evolution. Overall, the results analyzed separately for the T and NT period indicated that the active pool has a rapid turnover (MRT ~9 and 13 years, resp.) which represents 50% of SOC in the native prairie soil and 20% of SOC at equilibrium after NT period. NT implementation on soils with the highest soil organic matter reserves will continue to decrease (17%) for three decades later under current annual addition.

J. Ilmiah Aplikasi Isotop dan Radiasi

“…Secara umum lahan kering memiliki tingkat kesuburan yang rendah, terutama pada tanah-tanah dengan lapisan olah tipis dan kadar bahan organik rendah atau sangat rendah. Secara alami kadar bahan organik di daerah tropis cepat menurun, mungkin diakibatkan oleh erosi air dan pemadatan tanah [15]. Bahan organik sangat penting karena mendukung karakteristik lahan kering, berkaitan dengan sifat fisik, kimia, dan biologi tanah [16].…”

Section: Karakteristik Lahan Kering DI Indonesiaunclassified

Potensi Kombinasi Teknologi Mutan Padi Toleran Kekeringan dan Polimer Superabsorben: Peran IPTEK Nuklir dalam Peningkatan Produksi Padi Lahan Kering

Herwibawa

Kusmiyati

2017

ABSTRAKPadi merupakan sumber bahan pangan pokok, yang dikonsumsi lebih dari 95% penduduk Indonesia. Kebutuhannya terus meningkat tiap tahun, namun belum berhasil dicukupi dari produksi sendiri, sehingga masih bergantung impor hingga 1.347.856 ton per tahun. Upaya yang dapat dilakukan selain impor, adalah peningkatan produksi padi melalui ekstensifikasi dan intensifikasi pertanian. Namun 72,98% daratan Indonesia yang sesuai untuk pertanian merupakan lahan kering, tentu akan menghambat peningkatan produksi padi. IPTEK Nuklir dapat berperan dalam optimalisasi pemanfaatan lahan kering, dimana keterbatasan keragaman alami dalam pemuliaan tanaman padi toleran kekeringan, dan polimerasi serta grafting polimer superabsorben, keduanya dapat diperbaiki melalui radiasi pengion. Kombinasi teknologi mutan padi toleran kekeringan dan polimer superabsorben sangat potensial sebagai satu diantara upaya-upaya untuk meningkatkan produksi padi. Namun, upaya penerapan teknologi tersebut tentu akan menimbukan masalah karena lemahnya diseminasi teknologi inovatif, dan lambatnya adopsi teknologi. Diperlukan perhatian yang lebih besar dari peneliti, pengambil kebijakan, dan masyarakat pengguna.Kata kunci : iradiasi, kekeringan, mutasi, padi, superabsorben ABSTRACTRice is the main source of staple food, which is consumed by more than 95% of Indonesia's population. Its needs continue to increase each year, but has not been successfully fulfilled from its own production, so it still depends on imports up to 1347785 tonnes per year. Efforts can be made other than imports are the increase of rice production through agricultural extensification and intensification . However, 72.98% of Indonesia's land suitable for agriculture is dry land, it will inevitably increase rice production. Nuclear science and technology can play a role in optimizing the use of dryland, where the limitations of natural diversity in drought tolerant rice breeding, and polymeration and grafting of superabsorbent polymers, both can be improved through ionizing radiation. Technologies combination of drought tolerant rice mutant and superabsorbent polymer are great potential as one of the efforts to increase rice production. However, the application of such technologies will certainly lead to problems due to weak dissemination of innovation technologies, and slow the adoption of technologies. Greater attention is required from researchers, policy makers, and user communities. Keywords