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Copyright of World Food Policy is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The distribution and availability of phosphorus (P) fractions in restored cut slope soil aggregates, along altitude gradients, were analyzed. Samples were collected at 3009, 3347, 3654 and 3980 m of altitude. We examined soil aggregates total phosphorus (TP), available phosphorus (AP) and phosphorus activation coefficient (PAC), and discovered that there was no significant difference in TP levels between all four altitudes samples (p > 0.05). However, there was a significant difference in AP at 3009, 3347 and 3980 m of altitude (p < 0.05). At the altitudes of 3009, 3347 and 3654 m, the AP accumulation in small size aggregates was more advantageous. Overall, PAC dropped steadily as soil aggregates sizes increased, as shown: PAC (3654 m) > PAC (3347 m) > PAC (3009 m) > PAC (3980 m). In all particle size soil aggregates, the distribution of the P fractions was as follows: total inorganic phosphorus (TPi) > total organic phosphorus (TPo) > residual phosphorus (R-P), at 3009, 3347 and 3654 m, but a different registry was observed at 3980 m of altitude: TPo> TPi> R-P. Through correlation and multiple stepwise regression analysis, it was concluded that active NaHCO3-Pi was the main AP source. It was also suggested that more attention should be given to the ratio of small particle size aggregates to increase soil AP storage. In order to improve the activation capacity and supply of soil P, along with promotion of the healthy development of soil ecosystem on slope land, it was suggest that inorganic P fertilizer and P activator could be added to soil at both low (3009 m) and high altitudes (3980 m). [ABSTRACT FROM AUTHOR]

Without fertilization, harvest of perennial bioenergy cropping systems diminishes soil nutrient stocks, yet the time course of nutrient drawdown has not often been investigated. We analyzed phosphorus (P) inputs (fertilization and atmospheric deposition) and outputs (harvest and leaching losses) over 7 years in three representative biomass crops—switchgrass (Panicum virgatum L.), miscanthus (Miscanthus × giganteus) and hybrid poplar trees (Populus nigra × P. maximowiczii)—as well as in no‐till corn (maize; Zea mays L.) for comparison, all planted on former cropland in SW Michigan, USA. Only corn received P fertilizer. Corn (grain and stover), switchgrass, and miscanthus were harvested annually, while poplar was harvested after 6 years. Soil test P (STP; Bray‐1 method) was measured in the upper 25 cm of soil annually. Harvest P removal was calculated from tissue P concentration and harvest yield (or annual woody biomass accrual in poplar). Leaching was estimated as total dissolved P concentration in soil solutions sampled beneath the rooting depth (1.25 m), combined with hydrological modeling. Fertilization and harvest were by far the dominant P budget terms for corn, and harvest P removal dominated the P budgets in switchgrass, miscanthus, and poplar, while atmospheric deposition and leaching losses were comparatively insignificant. Because of significant P removal by harvest, the P balances of switchgrass, miscanthus, and poplar were negative and corresponded with decreasing STP, whereas P fertilization compensated for the harvest P removal in corn, resulting in a positive P balance. Results indicate that perennial crop harvest without P fertilization removed legacy P from soils, and continued harvest will soon draw P down to limiting levels, even in soils once heavily P‐fertilized. Widespread cultivation of bioenergy crops may, therefore, alter P balances in agricultural landscapes, eventually requiring P fertilization, which could be supplied by P recovery from harvested biomass. [ABSTRACT FROM AUTHOR]

Copyright of Revista Colombiana de Entomología is the property of Universidad del Valle and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Sustainable farming systems provide food for humans while balancing nutrient management. Inclusion or exclusion of livestock has nutrient management implications, as livestock produce food from otherwise inedible crops and their manure is a valuable soil conditioner. However, plant‐based diets are becoming more widespread due to perceived environmental benefits. We measure both food production in terms of nourishment to humans (in this study measured by protein, fat, starch and sugar production) and nutrient sustainability in terms of fertiliser use of six rotational farming systems with differences in nutrient management approaches. The arable practices included were the application of synthetic fertilisers, a range of organic amendments, incorporation of crop residues and legume cultivation. Livestock and associated products were included in some systems but excluded in others. The production of protein, fat, starch and sugar was combined with the balance of nitrogen (N), phosphorus (P) and potassium (K) into an overall measure of nutrient use efficiency of human macronutrient production. Across all systems considered, N use efficiency (5–13 kg protein/kg applied N) was lower than P (84–772 kg protein/kg applied P) or K (63–2060 kg protein/kg applied K), and combining synthetic fertiliser use with organic amendment applications raised production significantly while balancing P and K management, regardless of which organic amendment was used. Legume‐supported rotations without livestock produced more protein, starch and sugar per unit area than those with livestock. Nutrient balances and nutrient use efficiencies were more sensitive to management changes than purely food production. Using this approach allowed us to identify areas for improvement in food production based on the specific nutritional value of offtakes as opposed to yield overall. [ABSTRACT FROM AUTHOR]

Soil available P for crops, derived from P inputs and regulated by soil chemical, physical and biological factors, represents a small fraction of the total P content. Soil P balance (P input minus P output) is potentially a good descriptor of fluctuations in the available P pool, making it possible to compare experiments that differ in management and duration. Using a data set compiled from three long‐term experiments in NW Italy that tested different P fertilization types (nil, mineral, organic and manures), cropping systems and P balances in different soils, this paper focused on (a) proposing an empirical exponential model to describe the relationship between variables and (b) providing an agronomical interpretation of optimized parameter values, to set the basis for a unified interpretation of long‐term dynamics of soil plant‐available P. The pooled data fit well in an exponential model that identified three factors supportive of an agronomic interpretation, two linked to soil attributes and one that differentiated fertilizer types. Soil characteristics were found to affect minimum soil Olsen P values in depletion and response rates with additions, while fertilizer type had a multiplier effect on cumulative P balance. Farmyard manure was shown to build the available P pool better than other organic sources (bovine slurry, commercial organic fertilizers, green manure) and inorganic fertilizers, owing to a high C/P. The exponential model provided a good theoretical basis, but further studies are needed to correlate parameter values to soil (e.g., carbonates, Al and Fe oxide content) and fertilizer (e.g., C:P, lignin:P) characteristics and to verify the model applicability to different conditions. [ABSTRACT FROM AUTHOR]

More and more attention is being paid to assessing the effect of long-term fertilization considering global warming to ensure sustainable soil fertility management. The aim of this study is to evaluate the soil properties under mineral fertilization in long-term experimental fields. These experiments were carried out in the experimental fields of SCDA Livada. In order to evaluate the effect of fertilization, with progressive doses of nitrogen and phosphorus, with 5 graduations, there were taken and analysed 75 soil samples. Following the statistical processing of the data obtained, it was observed that nitrogen and phosphorus fertilization significantly influenced soil properties. Based on these results it could be established the optimal doses of fertilizers that should be applied on soil in order to improve the quality of soil in terms of environmental protection. Also, these results contribute to contemporary knowledge regarding sustainable land use. [ABSTRACT FROM AUTHOR]