Mixing of phosphate fertilizer with farmyard manure (FYM) is a simple technique for optimizing phosphorus (P) availability and then improving the productivity of wheat (Triticum aestivum) grown in alkaline calcareous soils. Diammonium phosphate (DAP) and phosphoric acid (PA) were applied to soil at 36 mg P kg−1, either as sole or after amending 1-g P fertilizer with 2-g FYM (1:2, w/w basis). After 45-day incubation, concentration of P ions in the soil solution (Cp) and exchangeable P present in soil solid (E-value) were determined to evaluate the amount of total plant-available pool. The FYM-amended fertilizers, i.e., PA+FYM and DAP+FYM, showed higher E-values, i.e., 114 and 97 mg kg−1 soil, respectively. Similarly, PA+FYM exhibited the highest proportion of P derived from fertilizer (Pdff = 51.5%) and induced the highest P uptake by wheat seedlings (L-value = 72.1 mg kg−1). Consequently, PA+FYM and DAP+FYM treatments caused higher grain yield and P-use efficiency. The regression analysis revealed strong and positive correlation between L-value and grain yield (r = 0.86), biomass production (r = 0.84) and P-use efficiency (r = 0.87) by wheat crop. Results suggested that FYM-amended inorganic P fertilizer can be a promising technique to optimize supply of P from soil, improve efficiency of inorganic P fertilizers, and improve wheat yield in alkaline calcareous soils.

Organic farming seems to be a solution in environmentally sensitive zones such as the protection zone of Tahtalı Dam, which supplies fresh water to Izmir, the third largest city in Turkey. Greenhouse vegetable production is the major agricultural activity in this area (Menderes Township). However, due to the pollution risk from agriculture, governmental authorities have issued a regulation discouraging the use of chemicals within the collection basin of the dam. An on-farm project was conducted in 2001 to introduce organic greenhouse vegetable production in the Tahtalı Dam preservation area and to serve as a model for other areas in Turkey facing similar ecological problems. Two irrigation levels and four organic fertilizers were tested on the growth of cucumbers (Cucumis sativus cv. Sardes). The four fertilizers were two rates of farmyard and poultry manure (30 and 50 tons ha−1) with and without two organic fertilizers based on either bacteria or algae. During the growing period, pests and diseases were monitored weekly and preparations allowed in organic agriculture were used when necessary. Plant diseases did not create any significant problem, but the pest population, in particular spidermites, increased. No significant differences in cucumber yield were found between the fertilizer and irrigation treatments tested. However, it should be noted that yields from the addition of 30 tons ha−1 of farmyard or poultry manure and organic fertilizers were the same as those for 50 tons ha−1 of manure alone. The average total yield was 13 kg m−2, within an acceptable range for short-term crop production in this region, but 55% lower than a conventional substrate culture trial nearby. However, due to reduced production costs and a price premium for organic products, the organic produce yielded a net return of US$1.12–1.79 per m2 whereas that for conventional bag culture produce was US$0.55 per m2. Our results indicate that, under present conditions, organic greenhouse cucumber production has less environmental impact and is more economic than conventional bag culture, due to reduced chemical input and reduced operating and initial investment costs.

Introduction. Information correlating leaf nutrient contents to fig tree yield is still rare in Brazil. The objective of our research was to evaluate the effect of fertilization with boron and cattle manure on fig tree productivity and the leaf and fruit nutrient contents, and to estimate the extraction of nutrients by the crop. Materials and methods. The treatments consisted of five boric acid levels [(0, 20, 40, 60 and 100) g per plant] combined with two levels of cattle manure [(0 and 10) kg per plant]. The experimental design was in randomized blocks in a split-plot scheme with four replicates. The cattle manure levels constituted the plots, and the boron levels the subplots. We studied tree productivity, macronutrient and micronutrient leaf and fruit contents, amounts of nutrients extracted per ha and per crop yield, and fig tree leaf and fruit dry matter nutrient contents as a function of sampling dates. Results. Fruit yield productivity, average fruit weight and number of fruits per tree were not affected by B fertilization but they were by cattle manure levels, which increased the fig tree productivity. The macronutrient and micronutrient leaf and fruit contents obtained are discussed in relation to Brazilian results already published. The levels of cattle manure did not significantly affect the amount of nutrients extracted from green fig yield. The Mn, Zn and B leaf contents and the fruit extraction of Mn and B increased linearly with boric acid levels. The fig tree leaf nutrient contents varied with the plant physiological stages during its production cycle. Conclusion. These results should be taken into account for the development of fig tree fertilization programs in Brazil.

Nitrogen, a vitally important plant nutrient, is subject to various losses that affect its efficiency. We tested prilled urea (PU), urea supergranules (USG), green manures (GM) and farmyard manure (FYM) in a rice-wheat cropping system to determine which were the most efficient and economical N sources. The maximum rice growth, yield and N-uptake occurred with USG and with GM (Sesbania rostrata) plus PU. Incorporation of GM saved 60 kg N/ha. On the following wheat crop, GM (S. aculeata) plus PU and FYM plus PU had the highest residual effect on the number of tillers per m2, and straw and grain yield. An increase in N recovery efficiency occurred with combined use of PUand organic Igreen manures compared with PU alone. In areas where USG is costly or unavailable and FYM is scarce, green manures can be a cheap N source that allows small-scale farmers to get sustainable yields in a rice-wheat rotation.