In Chile, the availability of poultry manure has recently increased as a result of expanding poultry production. The application of this organic waste on agricultural land is desirable since it not only helps recycle nutrients but also solves the problem of its disposal. A two year field study was undertaken to compare the effects of poultry litter (PL) and traditional mineral fertilizer on the growth of silage maize (Zea mays L.). The effects of adding mean annual PL rates of 10, 15 and 20 Mg ha -1 , with and without mineral fertilizer, were compared with those of two rates of conventional mineral fertilizer and a control treatment (no fertilizer). Crop yield showed a positive response to the fertilized treatments and fluctuated between 26.30 and 37.13 Mg ha -1 ; values for the controls ranged between 17.12 and 23.80 Mg ha -1 . The yield averages obtained with the PL treatments were 13.85 and 9.05 Mg ha -1 higher than the controls in the first and second year respectively. Nutrient uptake was similar with the PL and conventional fertilizer treatments. The mean of apparent efficiency of N recovery (AENR) for the PL treatments was higher than that of conventional fertilizer treatments, suggesting PL to be an appropriate N supply that suffers only small N losses. The highest AENR was obtained with the lowest PL dose, indicating this to be the most appropriate rate. In conclusion, PL is an efficient alternative to conventional mineral fertilizers for silage maize production.Additional key words: N efficiency recovery, nutritional needs, soil fertilizer. ResumenEfecto de la aplicación de cama de broiler sobre la producción y absorción de nutrientes en maíz para ensilaje (Zea mays L.)La disponibilidad de estiércol o cama de broiler (CB) en Chile ha aumentado, como resultado del incremento en la producción de carne de ave. La utilización de este residuo orgánico en la actividad agrícola es beneficiosa, contribuyendo al reciclaje de nutrientes y disminuyendo su acumulación en zonas de producción. Para comparar el efecto de la aplicación de CB y fertilizantes convencionales sobre la producción de maíz para ensilaje, se realizó un experimento de campo durante dos años consecutivos. Se comparó el efecto de la aplicación de CB en dosis de 10, 15 y 20 Mg ha -1 , incluyendo en algunos casos la aplicación de nitrógeno, con la utilización de dos dosis de fertilizantes convencionales y un control sin fertilización. El rendimiento mostró una respuesta positiva a la fertilización, fluctuando entre 26,30 y 37,13 Mg ha -1 ; en tanto que en el control fluctuó entre 17,12 y 23,80 Mg ha -1 . El rendimiento medio obtenido con la CB fue 13,85 y 9,05 Mg ha -1 mayor que el control sin fertilización para el primer y segundo año, respectivamente. La absorción de nutrientes fue similar entre los tratamientos con CB o fertilizantes convencionales. La eficiencia de recuperación aparente de N (AENR) media para los tratamientos con CB fue mayor que la obtenida con fertilización convencional, lo cual sugiere un suministro adecuado y bajo ...

Nutritional management in rice (Oryza sativa L.) crops is mainly associated with N fertilization, which is difficult to adjust in field conditions due to variations in soil type and climatic conditions. Between 28 000 and 46 000 ha per year is dedicated to rice production in Chile and profits depend on fertilization. A field experiment determine the effect of N rates and split N fertilization on grain yield and its components was carried out in two locations during two consecutive seasons (2007 to 2009), where five N rates and five split N fertilizations were evaluated. The locations were in Parral (36º2' S; 72º08' W, Vertisol) and San Carlos (36º19' S; 71º59' W, Inceptisol), with N rates of 80, 100, 120, 140, and 160 kg ha -1 applied in different development stages, such as sowing, tillering, panicle initiation, and boot. Results indicate an important seasonal effect on grain yield. Yield increased with N rates higher than 120 and 140 kg ha -1 in San Carlos and Parral, respectively. Moreover, higher productivity with split N fertilization was (1) 33% of N at sowing, 33% at tillering, and 34% at panicle initiation or (2) 50% of N at sowing and 50% at panicle initiation. Yield components with the highest effect on productivity were affected by the evaluated split N. On the other hand, higher N rates increased the percentage of both stained and sterile grains per panicle.

Optimum application rates of poultry litter (PL) spread out on the farmer´s field is a valuable source of available plant nutrients. The aim of this study was to compare the effect of two rates of PL and conventional fertilization (CF) on N mineralization and P, K, Zn, and Cu availability in an Andisol from Southern Chile under controlled conditions. Aerobic incubation was carried out for a 16-wk period. N mineralization rates were higher (61.5%) with the two PL treatments than with conventional fertilizer (23%). CF was associated with high N availability prior to the start of incubation and slight immobilization during the first week, perhaps due to a more rapid conversion of urea into NH4 which was then temporarily immobilized by the microbial biomass. At the start and end of the incubation period, Olsen-extractable P content was generally higher in CF. Due to the high fixation capacity of the soil studied, extractable P values were slightly increased suggesting that PL mineralization is only associated with a low risk of P contamination in volcanic soil. In PL, K, Zn, and Cu availability were higher than in CF. However, values obtained for Cu and Zn were average in relation to referential values used in agricultural soil. The results indicated that PL could be an alternative to conventional fertilizer under the conditions of the present study.

Poultry litter (PL) is a cheap alternative to conventional fertilizers. The use of PL in this way also reduces the environmental problems normally associated with its disposal. The residual effect of PL may reduce the amount of fertilizer (especially N fertilizer) required by subsequent crops. This study examines the residual effects of PL (with and without additional mineral fertilizer) on the properties of a volcanic ash soil and on silage maize (Zea mays) yields in central Chile. Poultry litter and mineral fertilizer were applied in 2002–2003 and their residual effects were determined in 2004–2006. The dry matter (DM) yield, nutrient balance and apparent nitrogen recovery efficiency (ANRE) of the silage maize were determined for each season, and the soil properties were analyzed at three depths (0–20, 20–40 and 40–60 cm) at the end of the third season. Crop yield showed a positive response to all fertilizer treatments. The residual effect, the nutrient balance, N uptake and ANRE also improved with fertilizer treatment, especially with the PL treatments. The average DM yield for the PL treatments was higher than that observed using mineral fertilizer by 2.8 and 1.2 Mg ha−1 in the third and fourth years, respectively. The ANRE was generally higher in the PL treatments, although it decreased over time (12.4 and 1.7% for the last 2 years, respectively). The mean ANREs for the mineral fertilizer treatment were 4.1 and 1.6% for the same years. The results suggest that the PL treatments had an important positive residual effect in terms of N supply. This should be taken into account when planning the next crop. After two annual applications of PL, slight increases were observed in soil NO3‐N at a depth of 0–20 cm, and extractable P at depths of 20–40 cm and 40–60 cm. No other soil variables were significantly affected by any of the treatments. An additional source of K was found to be necessary to maintain an adequate soil K level.

There is a worldwide increase of heavy metal or potentially toxic element (PTE), contamination in agricultural soils caused mainly by human and industrial action, which leads to food contamination in crops such as in maize. Cadmium (Cd) is a PTE often found in soils and it is ingested through food. It is necessary to determine the bioabsorption, distribution, and accumulation levels in maize to reduce or prevent food chain contamination. Cadmium absorption and accumulation in three maize cultivars were evaluated in three agricultural environments in Chile by increasing CdCl2 rates (0, 1, and 2 mg·kg−1). Evaluation included Cd accumulation and distribution in different plant tissues, bioaccumulation factor (BAF), bioconcentration factor (BCF), translocation factor (TF), and tolerance index (TI). Cadmium whole-plant uptake was only affected by the CdCl2 rate; the highest uptake was obtained with 2 mg·kg−1 CdCl2 (34.4 g·ha−1) (p < 0.05). Cadmium distribution in the maize plant usually exhibited the highest accumulation in the straw (p < 0.05), independently of the environment, Cd rate, and evaluated cultivar. Given the results for TF (TF > 2) and BAF (BAF > 1), the Los Tilos and Chillán environments were classified as having a high capacity to contaminate the food chain for all evaluated cultivars.

Blueberry production under netting has increased in recent years to mitigate the adverse effects of climate change. The objective of the present study was to evaluate the effect of different radiation intensities on rabbit-eye blueberry (Vaccinium virgatum Aiton) 'Ochlockonee' photosynthetic efficiency and productive parameters. Four treatments were established: T1 (control), T2, T3, and T4 at 0%, 30%, 60%, and 90% radiation decrease (RD), respectively, with black shedding netting. The following were recorded for each treatment: environmental conditions, photosystem II (PSII) maximum quantum yield (F v /F m ), photosystem II effective quantum yield (Φ PSII ), leaf stomatal conductance (g s ), quality parameters, and fruit yield. Results showed an increase of 4.6 ºC in mean minimum temperatures for the different netting treatments, which promote development and fruit set, as well as prevent damage at temperatures near 0 ºC. The RD treatments increased Φ PSII between 175% and 325% (P < 0.05) compared to the control. It can be concluded that netting decreased soil temperature between 1 and 3 ºC and increased minimum temperatures between 1 and 6 ºC, which promoted plant development and decreased frost damage during flowering and fruit development. Current direct radiation levels over 1000 µmol m -2 s -1 in V. virgatum inhibited productivity in T1. Netting decreased the degree of photoinhibition and increased photosystem II photochemical efficiency throughout the day, and T4 and T3 exhibited the highest efficiency. K e y w o r d s : P h o t o s y s t e m I I , p h o t o i n h i b i t i o n ,photosynthetically active radiation, stomatal conductance.

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