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Fertilizer Dose (fertilizer + dose)

Distribution by Scientific Domains

Earth and Environmental Science	50%

Selected Abstracts

Mulberry nutrient management for silk production in Hubei Province of China

JOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 2 2009
Fang Chen
Abstract The silk industry is important for south China's rural economy. Leaves of mulberry (Morus spp.) are used for silkworm production. Hubei province is one of the main silk-producing provinces in China. The objectives of this research were to survey the fertilization practices in the mulberry-producing regions in the province and to determine the best nutrition-management practice for mulberry plantations. A survey and a series of field experiments with N, P, K, and micronutrients were conducted from 2001 to 2002. In addition, a silkworm-growth experiment was also conducted by feeding leaves harvested from various fertilization treatments. The results indicate that poor soil fertility and unbalanced fertilization were the main factors limiting mulberry-leaf yield and quality in Hubei province. Nitrogen fertilization of mulberry has reached a high level (454,kg ha,1 y,1) in Hubei province, but P- and K-fertilization rates have not been matched with N-fertilization rates as farmers are not aware of the significance of P and K. Balanced fertilization showed positive nutrient interactions with respect to mulberry yield and quality. Potassium application increased yield and quality (protein and sugar concentration) of mulberry leaves. Silkworm growth and cocoon quality were improved when silkworms were fed with the leaves derived from K-fertilized plants in comparison with those taken from control plots. Application of Mg, S, and B also significantly improved leaf sugar, essential and total amino acid concentrations, but did not increase leaf yield significantly. It is concluded that a fertilizer dose of 375,kg N ha,1, 66,kg P ha,1, and 125,kg K ha,1 is suitable for the cultivation of mulberry in the Hubei province along with Mg, S, and B, wherever necessary, for the improvement of yield and quality of mulberry leaves. [source]

The Bayesian choice of crop variety and fertilizer dose

JOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES C (APPLIED STATISTICS), Issue 1 2002
Chris M Theobald
Recent contributions to the theory of optimizing fertilizer doses in agricultural crop production have introduced Bayesian ideas to incorporate information on crop yield from several environments and on soil nutrients from a soil test, but they have not used a fully Bayesian formulation. We present such a formulation and demonstrate how the resulting Bayes decision procedure can be evaluated in practice by using Markov chain Monte Carlo methods. The approach incorporates expert knowledge of the crop and of regional and local soil conditions and allows a choice of crop variety as well as of fertilizer level. Alternative dose,response functions are expressed in terms of a common interpretable set of parameters to facilitate model comparisons and the specification of prior distributions. The approach is illustrated with a set of yield data from spring barley nitrogen,response trials and is found to be robust to changes in the dose,response function and the prior distribution for indigenous soil nitrogen. [source]

Using farmer knowledge to combat low productive spots in rice fields of a Sahelian irrigation scheme

LAND DEGRADATION AND DEVELOPMENT, Issue 4 2004
P. J. A. van Asten
Abstract In the oldest sections of Burkina Faso's largest irrigation scheme in the Sourou Valley (13°,10,,N, 03°,30,W) rice (Oryza sativa L.) yields dropped from about 5 to 6,t,ha,1 in the early 1990s, shortly after establishment of the scheme, to 2 to 4,t,ha,1 from 1995 onwards. Farmers blamed this yield decline on the appearance of 2 to 20,m diameter low productive spots. According to farmers and field measurements, the low productive spots decreased yields by 25,50 per cent. The low productive spots are caused by Zn deficiency. Low Zn availability is related to the very low DTPA-extractable Zn content of the soil (0·08,0·46,mg,kg,1), the alkaline-calcareous character of the soil, the non-application of Zn fertilizers, and a relatively large P fertilizer dose (21,kg,P,ha,1). Farmers were correct in relating the calcareous nature of the soil to the presence of the low productive spots. They were instrumental in identifying application of decomposed organic resources (e.g. rice straw at 5,t,ha,1) as a short-term solution that increases yields by 1·5 to 2·0,t,ha,1. Application of Zn fertilizer (10,kg,Zn,ha,1) in 29 farmer fields in the 2001 dry season eradicated the low productive spots and increased yields from 3·4 to 6·0,t,ha,1. Although application of Zn fertilizer is strongly recommended, it is not yet available in Burkina Faso. Based on a comparison of fertilizer prices on the world market and the local market, we expect that the use of Zn fertilizers will be highly profitable (cost/value ratio,,,2). Despite the relatively recent introduction of irrigated rice cropping, most farmers showed a good understanding of cropping constraints and possible solutions. Both farmers and researchers mutually benefited from each other's knowledge and observations. Copyright © 2004 John Wiley & Sons, Ltd. [source]