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Abstract:
In 2005, few would have predicted the current revolution in global agriculture that is being driven by a sudden rise in the price of petroleum and a rapid expansion of global biofuel production from grain, sugar, and oilseed crops. The result has been a convergence of valuation between petroleum and agricultural commodities such that food prices are likely to rise substantially. While countries with adequate resources to support an expansion of biofuel crop production will benefit from this convergence, developing countries and regions that consistently experience food shortages or rely on food imports will face greater food insecurity. To avoid an excessive rise in food prices and increased numbers of undernourished will require a rapid response to improve global targeting of research and development funds to assure an acceleration in food production capacity while protecting natural resources and environmental quality.

Abstract:
The shortage of fresh water (FW) in Israel and other semiarid regions has forced farmers to significantly expand the use of treated wastewater (TWW). Recently, farmers utilizing reclaimed wastewater (TWW) reported a unique type of water distribution regime in drip-irrigated soils, as follows: (i) limited wetted area on the soil surface; and (ii) small saturated areas around and below the dripper, in TWW irrigated soil as opposed to an even, onion-like wet profile, formed under fresh water (FW) irrigation. Following this observation in the field and after conducting preliminary tests in the laboratory, we hypothesized that TWW irrigation introduces water-repellent organic constituents into the soil. Tests characterizing the water distribution showed the diameter of the saturated area on the soil surface and its water content (at a depth of 0-10 cm) was smaller with TWW than with FW irrigation. The TWW accumulated on the soil surface in small lenses and then flowed rapidly into the ground. The repellency of soils irrigated with FW and TWW was measured with the water drop penetration time test. Soils irrigated with FW were hydrophilic, whereas those irrigated with TWW exhibited hydrophobicity. Fourier transform infrared spectroscopy (FTIR) and 13C-NMR analyses of organic components extracted from the soils with organic solvents indicated differences in composition only at a depth of 0-2 cm. Extracting soils with a methanol + chloroform (1:1, by volume) mixture was found to be very effective in the removal and extraction of hydrophobic aliphatic components from soils irrigated with TWW.

Abstract:
A trial was conducted during two years (2000/01 and 2001/02) on two sites using 'Shambar' grapefruit trees grafted to five rootstocks. The sites were located on the Greek island of Kos to evaluate the effect of rootstock and location on fruit production and leaf mineral composition of 'Shambar' grapefruit. Results indicated that yields were higher in 2001/02 than in 2000/01 and these differences were greater at site 2. Leaf nitrogen (N), potassium (K), zinc (Zn), and to some degree phosphorus (P) content was slightly deficient to deficient for the majority of the samples taken. Calcium (Ca) and magnesium (Mg) levels ranged from normal to high. The copper (Cu) and iron (Fe) leaf contents and the manganese (Mn) content of most samples were in the optimum range. The interactions between rootstock, site, and year upon yield and nutrient content were statistically significant. There were also significant correlation coefficients between yield and nutrient content as well as among the nutrients.

Abstract:
Plant nutrients such as potassium (K), phosphorus (P), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) mostly remain fixed in soils and their bio-availability to plant roots is diffusion-limited. Hence, superior root traits, that can enhance their dissolution and capture from the soils, can play a central role in its productivity. Root morphological (root length and root hairs) and physiological traits (root exudation of protons and phosphatase enzymes) often selected varieties/breeding lines of chickpea (Bari-chhola-3, Bari-chhola-4, Bari-chhola-5, Bari-chhola-6, Bari-chhola-7, Bari-chhola-8, BGM-E7, ICCV-98926, ICCV-94924, and ICCV-98916) were studied and related them to the uptake of the nutrients in a pot experiment. There were significant (P < 0.05) genotypic differences in root length (RL) and root hair length (RHL). The RL ranged between 70 m plant-1 and 140 m plant-1. The variation in RHL was significant (P < 0.05) and it ranged between 0.58 ± 0.09 mm (Bari-chhola-5) and 0.26 ± 0.09 mm. The root hair density (RHD, number mm-1root) varied between 13 ± 2 and 21 ± 3 among the genotypes. The presence of root hairs increased the effective root surface area (e.g., Bari-chhola-5) up to twelve times. The genotypes differed in their ability to acidify the rooting media in laboratory agar studies, with Bari-chhola-5 inducing most acidification followed by Bari-chhola-3. The ability of Bari-chhola-5 to acidify the rhizosphere was also confirmed by embedding in situ roots in the field in an agar-agar solution containing pH indicator dye Bromocresol purple. The genotypes did not differ for induction of acid phosphatase activity (Aptase) in the rooting media. The genotypes inducing greater acidification and possessing prolific root hairs (Bari-chhola-3 and Bari-chhola-5) absorbed significantly higher amounts of the nutrients K, P, Fe, Mn, and Zn, whose availability in soils is usually low. The results suggest that a collective effect of superior morphological and physiological root traits confers better nutrition of chickpea genotypes in low-nutrient soils.

Abstract:
Bacillus thuringensis (Bt) transgenic (insect-resistant) cotton cultivars senesce prematurely under potassium (K+) deficiency, more often than conventional cultivars, in the North China Plain. To verify if Bt-transgenic cotton was more susceptible to K+ deficit, two transgenic cultivars, 'CCRI 41' and 'DP 99B', and two conventional cultivars, 'CCRI 35' and 'CCRI 36', selected from widely used cultivars in China, were used in a seedling hydroponic study. The culture solution K+ concentration was 0.5 mM for high K+ and 0.02 mM for low K+ conditions. Seedlings of all four cultivars accumulated more dry matter and K+ when grown at high K+ than low K+ conditions. However, under low K+ condition, the dry weight and K+ content of Bt-transgenic cultivars CCRI 41 and DP 99B were lower than those of the conventional cultivars CCRI 36 and CCRI 35. The results indicated that Bt-transgenic cultivars CCRI 41 and DP 99B were more sensitive to K+ deficiency than conventional cultivars CCRI 36 and CCRI 35, which could be the reason for premature senescence symptoms observed from fields of Bt-transgenic cotton under K+ deficiency. Seedlings of all four cultivars had a higher K+ use efficiency (KUE) under low K+ than high K+ conditions, but the KUE did not account for the differential responses between Bt-transgenic and conventional cultivars at the low K+ concentration. The K+ depletion results did not reveal the mechanism for the above differential responses in Vmax and Km of the seedlings either. Further experiments with more cultivars are needed to clarify the differential mechanisms in these genotypes.

Abstract:
Potassium nutrition requirements may differ in cotton (Gossypium hirsutum L.) cultivars that contrast in maturity and growth habit. Our objectives were to determine the effects of K fertility on carbohydrate and biomass partitioning, earliness, and lint yields of two contrasting cultivars. Fertilizer rates of 56 and 112 kg K ha-1 yr-1, representing 1x and 2x recommended K rates, were applied to long-term K fertility plots on a no-tilled Loring silt loam (thermic Oxyaquic Fragiudalf) in Jackson, TN. Plant samples were harvested at early bloom and cutout, to evaluate carbohydrate and dry matter partitioning during boll filling. Earliness was determined as the percentage of total yield at the first of two harvests. The more determinate cultivar, 'Paymaster PM1218 BG/RR', had higher aboveground dry weight, main stem starch concentrations and percentage first harvest, representing earlier maturity than the more indeterminate 'Deltapine DP555 BG/RR'. The 2x K rate delayed maturity relative to the 1x rate, reflected in biomass partitioning and lint yield distribution. Lint yields were lower at the 1x than at the 2x K in the more determinate cultivar, but K did not affect the indeterminate yields. The two cultivars had equivalent lint yields at the 2x K rate, but the indeterminate cultivar produced more vegetative biomass, further delaying its maturity. Results suggest that an earlier, more determinate cultivar may require more K fertilization for optimal yield response with no tillage.

Abstract (full paper in French or German):
Close customer relationships and customer satisfaction are important aspects of attaining the efficiency targets of research stations. In order to be able to better meet these targets, the Swiss Federal Office for Agriculture carried out a written consultation in 2006. A total of 1712 farmers gave their opinion of the comprehensibility of information and the practical benefit, which they derive from the information from Agroscope and downstream communicators of knowledge. Comprehensibility and benefit were for the most part assessed as being good to very good; crop farmers and among them horticulturalists in particular assessing Agroscope's services more positively than livestock farmers. It showed especially the importance of communicators of knowledge as providers of information in areas in which Agroscope is no longer active due to cuts in funding. Overall, farmers were very interested in new findings. They are therefore also convinced in the main that research is important for the future of Swiss agriculture. However, they want research to be more practice-based. These findings from the customer consultation provide valuable information for the formation of Agroscope's work programmes and communication plan, in order to foster the exchange of knowledge between the research stations and their customers.

Read on:

  • Carbon mitigation by biofuels or by saving and restoring forests? Righelato & Spracklen, 2007. Published in Science, 17 August 2007, Vol. 317; pp 902.
  • The other greenhouse effect; Rising carbon dioxide levels should increase crop yields. But what about if their effect on the nutritional value of our food is less benign? Stafford, 2007. Published in Nature, 2 August, Vol. 448; pp526-528. http://www.nature.com/nature/index.html.
  • Fertile progress. The past 20 years have seen an evolution in researchers' understanding of how to best apply nitrogen fertilizer to rice. That knowledge is now being passed on to farmers. Buresh, R.J., 2007. Rice Today July-September 2007. http://www.irri.org/publications/today/today.asp.
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September 2007

English