Cover Crop Seeding Rate Effects on Forage Yields of Oat and Barley and Underseeded Bromegrass–Alfalfa Mixture

Annual cover crops compete with underseeded perennial forages for light, moisture, and nutrients and may suppress their establishment and growth. Field experiments were established in 2000 and 2001 at Nipawin and in 2002 and 2003 at Melfort in northeastern Saskatchewan to determine the effects of seeding rates of cover crops of oat (19, 38, and 112 kg ha^?1) and barley (31, 62, and 124 kg ha^?1) on forage dry-matter yield (DMY) of the cover crop cut as greenfeed in the seeding year, DMY of the underseeded meadow bromegrass–alfalfa mixture in the following 1 or 2 years after establishment, and forage quality [concentration of crude protein (CP), acid detergent fiber (ADF) and neutral detergent fiber (NDF)]. In the first establishment year, the no cover crop treatment produced considerably less DMY than the treatments with cover crops. Oat seeded at 112 kg ha^?1 produced greater DMY than when it was seeded at 19 or 38 kg ha^?1 in all four site-years, but DMY differences between the 19 or 38 kg ha^?1 seeding rates were not significant in any site-year. For barley, there was no significant difference in DMY among the three seeding rates in 2000, 2001, and 2002. In 2003, barley seeded at 62 or 124 kg ha^?1 produced greater DMY than when it was seeded at 31 kg ha^?1, but DMYs were not significantly different between the 62 and 124 kg ha^?1 seeding rates. The use of a cover crop did reduce DMY in 2003 of bromegrass–alfalfa mixture underseeded in 2002, but the type of cover crop and its seeding rate did not appear to affect DMY in any site-year. Forage quality in the seeding year was consistently superior in no cover crop treatment compared to that in treatments with cover crops, especially related to CP concentration. There was no consistent trend of forage quality in the cover crop treatments, indicating cover crops and their seeding rates had little effect on forage quality. In conclusion, oat appeared to be more sensitive to seeding rate than barley for forage DMY in the establishment year, but in the subsequent 1 or 2 years after establishment there was little effect of cover crop type and its seeding rate on DMY of bromegrass–alfalfa mixture, although DMY was considerably greater in the no cover treatment than that in treatments with cover crops in 1 site-year.     

Effect of 13 Years Long Minimum Tillage Cum Conjunctive Nutrient Management Practices on Soil Fertility and Nitrogen Chemical Fractions under Sorghum (Sorghum bicolour (L.) Moench)–Mungbean (Vigna radiata (L.) Wilczek) System in Semi-Arid Tropical Alfisol (SAT) in Southern India

A long-term experiment was conducted at the Central Research Institute for Dryland Agriculture for 13 years to evaluate the effect of low tillage cum cheaper conjunctive nutrient management practices in terms of productivity, soil fertility, and nitrogen chemical pools of soil under sorghum–mung bean system in Alfisol soils. The results of the study clearly revealed that sorghum and mung bean grain yield as influenced by low tillage and conjunctive nutrient management practices varied from 764 to 1792 and 603 to 1008 kg ha^?1 with an average yield of 1458 and 805 kg ha^?1 over a period of 13 years, respectively. Of the tillage practices, conventional tillage (CT) maintained 11.0% higher yields (1534 kg ha^?1) over the minimum tillage (MT) (1382 kg ha^?1) practice. Among the conjunctive nutrient management treatments, the application of 2 t Gliricidia loppings + 20 kg nitrogen (N) through urea to sorghum crop recorded significantly highest grain yield of 1712 kg ha^?1 followed by application of 4 t compost + 20 kg N through urea (1650 kg ha^?1) as well as 40 kg N through urea alone (1594 kg ha^?1). Similar to sorghum, in case of mung bean also, CT exhibited a significant influence on mung bean grain yields (888 kg ha^?1) which was 6.7% higher compared to MT (832 kg ha^?1). Among all the conjunctive nutrient management treatments, 2 t compost + 10 kg N through urea and 2 t compost + 1 t Gliricidia loppings performed significantly well and recorded similar mung bean grain yields of 960 kg ha^?1 followed by 1 t Gliricidia loppings + 10 kg N through urea (930 kg ha^?1). The soil nitrogen chemical fractions (SNCFs) were also found to be significantly influenced by tillage and conjunctive nutrient management treatments. Further, a significant correlation of SNCF with total soil nitrogen was observed. In the correlation study, it was also observed that N fraction dynamically played an important role in enhancing the availability pool of N in soil and significantly influenced the yield of sorghum grain and mung bean.     

Compost and Nitrogen Management Influence Productivity of Spring Maize (Zea mays L.) under Deep and Conventional Tillage Systems in Semi-arid Regions

On-farm research was conducted to investigate the effects of nitrogen (N) and compost (C) on yield and yield components of spring maize (Zea mays L.) under conventional and deep tillage system (T) at the research farm of the University of Agriculture, Peshawar, Pakistan, during spring 2013. The experiment was laid out in a randomized complete block design with split-plot arrangement, using three replications. Three compost levels (0, 1, and 2 t ha^?1) and two tillage systems (conventional and deep tillage) were allotted to the main plot, whereas N levels (60, 90, 120, and 150 kg N ha^?1) were allotted to subplots in the form of urea. Nitrogen and compost levels had significantly affected all the parameters. Plots treated with 150 kg N ha^?1 increased ear length (31 cm), grains ear^?1 (413), thousand-grain weight (240.2 g), grain yield (3097 kg ha^?1), straw yield (9294 kg ha^?1), harvest index (24.7 percent), and shelling percentage (81.7 percent). Compost applied at 2 t ha^?1 increased ear length (32 cm), grains ear^?1 (430), thousand-grain weight (242.3 g), grain yield (2974 kg ha^?1), straw yield (8984 kg ha^?1), harvest index (24.6 percent), and shelling percentage (83.2 percent). Tillage system had significant effect on all parameters except ear length and harvest index. Deep tillage system produced more grains ear^?1 (365), thousand-grain weight (233.3 g), grain yield (2630 kg ha^?1), straw yield (8549 kg ha^?1), and shelling percentage (79.6 percent). It was concluded from the results that application of 120 kg N ha^?1 + 2 C t ha^?1 under a deep tillage system could improve spring maize yield and yield-contributing traits under semi-arid conditions.     

Impact of tillage and intra-row spacing on cotton yield and quality in wheat–cotton system

Farmers normally practice conventional tillage ((CT), disk plowing, cultivator, rotavator, and leveling) in cotton (Gossypium hirsutum L.) with 15 cm intra-row spacing to avoid risks of poor plant stand and obtain higher yield. However, CT is costly besides it has adverse effects on soil and crop when sown after wheat. Conservation tillage [zero tillage (ZT) or reduced tillage (RT)] with suitable spacing can reduce production cost, increase cotton yield and quality, and it has favorable effects on soil properties. Field experiments were conducted to evaluate cotton response to tillage (ZT, RT, and CT) and intra-row spacing (15.0, 22.5, 30.0, 37.5 cm). Results revealed that RT produced higher bolls plant^?1, boll weight, seed cotton yield, ginning out turn, fiber length and strength than ZT and CT. Mean boll weight, seed cotton yield, earliness, and fiber qualities were optimum at 22.5 cm spacing. Tillage × spacing interaction showed optimum boll weight, earliness, and fiber strength with 15.0–22.5 cm spacing under RT. CT with 22.5 cm spacing also performed better in terms of boll weight and fiber strength; however, 15.0 cm spacing resulted in earlier maturity. RT with 22.5 cm spacing is an alternative to CT for higher yield, earliness, and quality of cotton besides environmental safety.     

Impact of tillage and nitrogen on cotton yield and quality in a wheat-cotton system,Pakistan

Growing cotton (Gossypium hirsutum L.) after wheat (Triticum aestivum L.) is an important cropping system in Pakistan. However, numerous tillage practices commonly applied for cotton production are not productive. Conservation tillage may optimize cotton yield and quality if nitrogen (N) is not a limiting factor. Field experiments were conducted on silty clay soil (Hyperthermic, and Typic Torrifluvents) of Dera Ismail Khan, Pakistan to study the impact of tillage techniques (zero (ZT), reduced (RT), and conventional tillage (CT)) and nitrogen, namely 0, 50, 100, 150, and 200 kg ha^–1 on cotton yield and quality. Mean values for N revealed that bolls plant^–1, boll weight, seed cotton yield, ginning out turn (GOT), fiber length, strength, and micronaire were highest at 150–200 kg N ha^–1. Averaged over years, tillage × nitrogen revealed that RT had higher bolls plant^–1, boll weight, GOT, fiber length, and strength at 150–200 kg N ha^–1 compared to other tillage system. The micronaire revealed that RT had no adverse effect on fiber fineness compared to ZT/CT. RT had accumulated higher soil organic matter and total soil N compared to CT. RT with 150–200 kg N ha^–1 may be a sustainable and environmentally safe strategy to enhance cotton yield and quality.     

Short-term responses of soil nutrients and corn yield to tillage and organic amendment

Field experiments were conducted in 2010 and 2011 at the Agricultural College of Shiraz University to evaluate the effects of cattle manure and nitrogen (N) fertilizers on soil properties such as soil organic carbon (SOC), soil organic nitrogen (SON), soil electrical conductivity, soil pH and corn yield under two tillage systems. Treatments included tillage systems in two levels as conventional tillage and reduced tillage as subplots, cattle manure (0, 25 and 50 tons ha^?1) and N fertilizer (0, 125 and 250 kg N ha^?1) as sub-subplots. Results showed that SOC and SON were significantly affected by tillage system in both years of the experiment. SOC and SON were higher in reduced tillage compared to conventional tillage. Tillage system had no significant effect on grain yield, plant height and 1000 seed weight. Increased cattle manure rates at 25 and 50 tons ha^?1 increased grain yield by 27% and 38%, respectively, in 2010 and 25% and 25% in 2011. The results showed that application of cattle manure combined with N fertilizer might be an efficient management to increase soil productivity in southern Iran, in soils with poor organic content. Additionally, reduced tillage showed to be an efficient method to increase soil organic matter.     

The Relationship Between Yield and Fructan Exo-Hydrolases Activity in Two Drought Resistant Wheat Cultivars Grown Under Different Fertilizer and Tillage Treatments

Using two drought resistant wheat (Triticum aestivum L.) cultivars, ‘Changwu134’ and ‘Changhan58,’ a field experiment was conducted in ChangWu Agro-ecological Experiment Station on China's Loess Plateau during 2008 and 2009 to compare the effects of different fertilizer and tillage treatments on the fructan contents as well as fructan exo-hydrolase (FEH) activity in relation to wheat yield. We found that ‘Changhan58’ had greater yield and fructan content in the penultimate internode and higher FEH activity than did ‘Changwu134.’ For ‘Changhan58.’ applying 195 kg·ha^?1(120 +75) N plus 45000 kg·ha^?1 of pig manure and 120 kg·ha^?1 phosphate under conservation tillage produced the highest yield (6769 ka/ha), fructan content in penultimate internode, water use efficiency (WUE), as well as FEH activity among the fertilizer and tillage treatments. Therefore, routine soil management for wheat should focus on combined use of manures and inorganic fertilizer to enhance the amount and transportation efficiency of WSC and ultimately ensure greater yield.     

Influence of Long-term Tillage,Straw, and N Fertilizer Management on Crop Yield,N Uptake,and N Balance Sheet in Two Contrasting Soil Types

Field experiments (established in autumn 1979, with monoculture barley from 1980 to 1990 and barley/wheat–canola–triticale–pea rotation from 1991 to 2008) were conducted on two contrasting soil types (Gray Luvisol [Typic Haplocryalf] loam soil at Breton; Black Chernozem [Albic Agricryoll] silty clay loam soil at Ellerslie) in north-central Alberta, Canada, to determine the influence of tillage (zero tillage and conventional tillage), straw management (straw removed [S_Rem] and straw retained [S_Ret]), and N fertilizer rate (0, 50 and 100 kg N ha^?1in S_Ret, and only 0 kg N ha^?1in S_Rem plots) on seed yield, straw yield, total N uptake in seed + straw (1991–2008), and N balance sheet (1980–2008). The N fertilizer urea was midrow-banded under both tillage systems in the 1991 to 2008 period. There was a considerable increase in seed yield, straw yield, and total N uptake in seed + straw with increasing N rate up to 100 kg N ha^?1 under both tillage systems. On the average, conventional tillage produced greater seed yield (by 279 kg ha^?1), straw yield (by 252 kg ha^?1), and total N uptake in seed + straw (by 6.0 kg N ha^?1) than zero tillage, but the differences were greater at Breton than Ellerslie. Compared to straw removal treatment, seed yield, straw yield, and total N uptake in seed + straw tended to be greater with straw retained at the zero-N rate used in the study. The amounts of applied N unaccounted for over the 1980 to 2008 period ranged from 1114 to 1846 kg N ha^?1 at Breton and 845 to 1665 kg N ha^?1 at Ellerslie, suggesting a great potential for N loss from the soil-plant system through denitrification, and N immobilization from the soil mineral N pool. In conclusion, crop yield and N uptake were lower under zero tillage than conventional, and long-term retention of straw suggests some gradual improvement in soil productivity.     

Long-term conservation agriculture and intensified cropping systems: Effects on growth, yield, water, and energy-use efficiency of maize in northwestern India

Conservation agriculture(CA)-based best-bet crop management practices may increase crop and water productivity, while conserving and sustaining natural resources. We evaluated the performance of rainy season maize during 2014 under an ongoing long-term trial(established in 2008) with three tillage practices, i.e., permanent bed(PB), zero tillage(ZT), and conventional tillage(CT) as main plots, and four intensified maize-based cropping systems, i.e., maize-wheat-mungbean, maize-chickpea-Sesbania(MCS), maizemustard-mungbean, and maize-maize-Sesbania) as subplot treatments. In the seventh rainy season of the experiment, maize growth parameters, yield attributes, yield, and water-and energy-use efficiency were highest at fixed plots under ZT. Maize growth parameters were significantly(P 0.05) superior under ZT and PB compared with CT. Maize yield attributes, including cobs per m~2(7.8), cob length(0.183 m), grain rows per cob(13.8), and grains per row(35.6), were significantly higher under ZT than CT; however, no significant effect of cropping systems was found on maize growth and yield attributes. Zero tillage exhibited the highest maize productivity(4 589 kg ha~(-1)). However, among the cropping systems, MCS exhibited the highest maize productivity(4 582 kg ha~(-1)). In maize, water use was reduced by 80.2–120.9 mm ha-1under ZT and PB compared with CT, which ultimately enhanced the economic water-use efficiency by 42.0% and 36.6%, respectively. The ZT and PB showed a 3.5%–31.8% increase in soil organic carbon(SOC) at different soil depths(0–0.45 m), and a 32.3%–39.9% increase in energy productivity compared with CT. Overall, our results showed that CA-based ZT and PB practices coupled with diversified maize-based cropping systems effectively enhanced maize yield and SOC,as well as water-and energy-use efficiency, in northwestern India.     

Soil properties,crop productivity and energetics under different tillage practices in fodder sorghum + cowpea – wheat cropping system

Tillage is an important agricultural operation which influences soil properties, crop yield and environment. Nine combinations of three tillage practices including conventional tillage (CT), minimum tillage (MT) and zero tillage (ZT) were evaluated in fodder sorghum (Sorghum bicolor) + cowpea (Vigna unguiculata) – wheat (Triticum durum) cropping system for 5 years (2009–2014) on clay loam soil under limited irrigation. Continuous ZT practices significantly improved surface soil organic carbon, bulk density, infiltration rate and maximum water holding capacity. Carbon sequestration rate, soil organic carbon stock and soil enzymatic activities were relatively more under ZT than CT-CT practice. Higher fodder yield of sorghum + cowpea was recorded with CT (kharif) while wheat grain yield with ZT (rabi). However, the system productivity was statistically similar in all the tillage treatments on pooled data basis. The economic benefits were also maximum under ZT-ZT practice. The ZT-ZT practice recorded significantly lowest energy input (17.1 GJ ha^?1) which resulted in highest energy use efficiency (13.6) and energy productivity (518 kg GJ^?1). Thus, adoption of ZT significantly improved soil health, stabilized crop yield, increased profitability and energy use efficiency in the semi-arid agro-ecosystem.     

Response of Chickpea Cultivars to Application of Boron in Boron‐Deficient Calcareous Soils

Abstract

This study was conducted to investigate the effects of four boron (B) doses (control, 0 kg B ha^?1; B₁, 1 kg B ha^?1; B₂, 3 kg B ha^?1; and B₃, 6 kg B ha^?1) in soils deficient in available B (0.19 mg B kg^?1) and lime (CaCO₃) content (20.7%) on yield and some yield components of five chickpea (Cicer arietinum L.) genotypes, namely Akçin‐91, Population, Gökçe, ?zmir‐92, and Menemen‐92 in central Anatolian Turkey in the 2002 and 2003 growing seasons. Plant height, pods per plant, grain yield, protein content, protein yield, thousand seed weight, and leaf B concentration were measured. Grain yields in all genotypes (except for Gökçe) were significantly increased by 1 kg ha^?1 B application. Application of 1 kg ha^?1 B increased the yield by an average of 5%. Genotypes studied showed significant variations with respect to their responses to additional B. Akçin‐91 gave the highest grain yield (1704.8 kg ha^?1) at 3 kg B ha^?1, whereas Population, ?zmir‐92, and Menemen‐92 yielded best (1468.2 kg ha^?1, 1483.0 kg ha^?1, and 1484.7 kg ha^?1, respectively) at 1 kg B ha^?1. Interestingly, Gökçe reached to the highest level of grain yield (1827.1 kg ha^?1) at the control. Gökçe was a B deficiency B tolerance genotype. The other genotypes appeared to have high sensitivity to B deficiency. This study showed that B deficiency could result in significant yield losses in chickpea under the experimental conditions tested. Thus, B contents of soils for the cultivation of chickpea should be analyzed in advance to avoid yield losses.     

Greenhouse gases emission,soil organic carbon and wheat yield as affected by tillage systems and nitrogen management practices

Agricultural activities are responsible for greenhouse gases (GHGs) emission in the environment. Strategies are required to enhance the soil organic carbon (SOC) and nitrogen (N) sequestration to adapt and mitigate the climate change. We investigated GHGs emission, SOC and N enhancement under conventional tillage (CT) and zero tillage (ZT) with N management in wheat (Triticum aestivum L.). Seasonal carbon dioxide (CO₂) emission and global warming potential (GWP) reduced for ZT treatments over CT without residues and 100% of required N with a blanket split application (CT – R + 100N). The ZT with 5 t ha^?1 maize (Zea mays L.) residues retention and 75% of required N and GreenSeeker^TM (GS)-aided N management (ZT + R + 75N + GS) reduced yield-scaled GHGs emission and increased total organic carbon (C) stock over CT – R + 100N. However, nitrous oxide (N₂O) emission was lower in CT. The GS-based N management saved 26–35 kg N ha^?1 in different tillage systems in both years over blanket application with higher N uptake and associated reduction in N₂O emission. The study recommends that ZT with residues retention and GS-based N management can minimize the GHGs emission and improve the SOC.     

Response of Sunflower to Sulfur Rate and Time of Application under Two Tillage Systems in a Silty Clay Soil of Dera Ismail Khan Pakistan

ABSTRACT

Sulfur (S) availability is a characteristic of conservation tillage. We studied the effects of S on sunflower yield and fatty acid profile under conventional and conservation tillage in silty clay soil of D.I. Khan, Pakistan. Conventional tillage consisted of disk plowing followed by tiller and rotavator, while conservation tillage comprises tiller and disc harrowing. Treatments comprise six sulfur levels (S₁ = 0, S₂ = 20 kg S ha^?1 at sowing, S₃ = 10 kg S ha^?1 at sowing +10 kg S ha^?1 25 days after sowing (DAS), S₄ = 40 kg S ha^?1 at sowing, S₅ = 20 kg S ha^?1 at sowing + 20 kg S ha^?1 25 DAS, and S₆ = 20 kg S ha^?1 at sowing + 10 kg S ha^?1 25 DAS + 10 kg S ha^?1 50 DAS) replicated thrice. After 2 years of experimentation, soil samples were collected (from 0 to 0.30 m depth) for organic matter (OM), total soil N (TSN), and available sulfur analysis. Conservation tillage significantly increased OM, TSN, and S contents in 0–0.30 m soil compared to conventional tillage. Likewise, sunflower plants showed higher achene yield, better fatty acid profile, and net economic returns in conservation tillage than in conventional tillage. Application of 20 kg S ha^?1 at sowing and 10 kg S ha^?1 at each 25 and 50 DAS recorded significantly higher achene yield, higher oil, and linoleic acid contents; however, oleic and oleic/linoleic ratio did not increase with higher S rates. Conservation tillage was effective in increasing OM, TSN, and available S besides increasing yield and economics in silty clay soil.     

Changes in soil chemical characteristics with different tillage practices in a semi-arid environment

We examined the effects of various tillage intensities: no-tillage (NT), minimum tillage with chisel plow (MT), conventional tillage with mouldboard plow (CT), and zone-tillage subsoiling with a paraplow (ZT) applied in alternate years in rotation with NT, on the topsoil profile distribution (0–30 cm) of pH, soil organic carbon (SOC), organic N and available nutrients on a semi-arid soil from Central Spain. The equivalent depth approach was used to compare SOC, N and nutrient stocks in the various tillage treatments. Measurements made at the end of 5 years showed that in the 0–30 cm depth, SOC and N had increased under NT and ZT compared with MT and CT. Most dramatic changes occurred within the 0–5 cm depth where plots under NT and ZT had respectively 7.0 Mg ha⁻¹ and 6.2 Mg ha⁻¹ more SOC and 0.5 Mg ha⁻¹ and 0.3 Mg ha⁻¹ more N than under MT or CT. No-tillage and ZT plots, however, exhibited strong vertical gradients of SOC and N with concentrations decreasing from 0–5 to 20–30 cm. In the 0–20 cm layer, higher concentrations of P and K under NT and ZT than under MT or CT were also found. Soil pH under NT and ZT was 0.3 units lower than under MT or CT at a depth of 0–5 cm. This acidifying effect was restricted at the surface layer and in the 20–30 cm interval, pH values under NT and ZT were higher than in MT and CT plots. These results suggest that in the soil studied, ZT in rotation with NT maintain most advantages associated with NT, and present a definite potential for use as a partial-width rotational tillage practice.     

<Emphasis Type="Italic">Lotus ornithopodioides</Emphasis> L. a potential annual pasture legume species for Mediterranean dryland farming systems

Twenty-three populations of Lotus ornithopodioides L., collected from different regions of the Mediterranean basin, were investigated for their ecological and agronomic traits in Western Australia. Great variability was found between and within populations for flowering time, forage and seed yield. Flowering time ranged between 75 and 120 days, dry matter production from 2.8 to 4.3 t ha^?1 and seed yield from 284 to 684 kg ha^?1. Other important traits such as non-shattering pods and hard seed were taken into account during the selection to assure an easy seed harvesting and legume persistence in the targeted environments. The high level of hard seed recorded in early winter, associated to the low seedling regeneration, indicates that L. ornithopodioides is best suited to ley cropping systems. Elite lines of L. ornithopodioides characterized by early flowering time, high seed yield and non-shattering pods were selected. Two of them, LOR02.1 and LOR03.2, showed dry matter higher than 4.0 t ha^?1 and seed yield around 700 kg ha^?1 resulting the lines with most potential for Mediterranean farming systems. The results encourage the exploitation of L. ornithopodioides germplasm to develop a new annual self-reseeding legume resource for Mediterranean farming systems for both forage production and crop rotation uses.     

RESPONSE OF ALFALFA SEED YIELD AND YIELD COMPONENTS TO PHOSPHORUS FERTILIZING SYSTEMS AND SEEDING RATE AT SEMI-SALINE SOIL CONDITIONS

To study the effects of phosphorus (P) fertilizer (cow manure, phosphorus solublizing bacteria) and sowing density on seed production of alfalfa, an experiment was laid out in a three-replicated split-split plot design with four phosphorus fertilizer rates (0, 30, 60 and 90 kg ha^?1) in main plots, three phosphorus-solublizing bacteria (9, 41strains, and no bacteria) in sub-plots and three sowing densities (2, 6 and 10 kg ha^?1) in sub-sub plots. The highest seed yield resulted from 60 and 90 kg P ha^?1. Application of bacteria strain 41 was more efficient than bacteria strain 9 in seed yield and 1000-seed weight. Seed yield at 6 seed kg ha^?1 treatment was higher than 10 kg ha^?1, although there was no significant difference between them. Based on the results of this experiment the triple application of P60, B41 and SD6 could be recommended as the best treatment for seed production of alfalfa (Cultivar ‘Nikshahri’) under the semi-saline condition.     

Effects of zone-tillage in rotation with no-tillage on soil properties and crop yields in a semi-arid soil from central Spain

A limiting factor to the no-tillage system in arid and semi-arid regions is the possibility of soil densification from lack of tillage. This research examines the extent and duration of the effects of periodic (rotational) zone-tillage over 2 years, on selected soil physical and chemical properties and crop yields. In the first year four tillage treatments were applied: conventional tillage with mouldboard plow (CT), minimum tillage with chisel plow (MT), no-tillage (NT) and zone-tillage subsoiling with a paraplow (ZT). In the second year, the ZT plots were returned to NT to follow the residual effects of ZT. The soil was a loamy sand (Calcic Haploxeralf) from semi-arid Central Spain and the crop rotation was grey pea (Pisum sativum L.)–barley (Hordeum vulgare L.). Crop residues on the soil surface after sowing grey pea were 85% in NT plots, 55% in ZT plots and 15% in MT plots. When comparing NT and ZT, the immediate effects of subsoiling on soil physical properties were significant (P < 0.05). Soil strength as measured by cone index approached 3.0 MPa in NT and was reduced to <1.0 MPa by ZT over 300 mm sampling depth. Soil moisture content and bulk density were improved by ZT. No-till and ZT favoured surface accumulation of soil organic carbon (SOC), total N and available P and K. Stratification ratio of SOC was not different among tillage systems, but soil N stratification ratio followed the order NT > ZT > MT > CT. Grey pea yields were reduced by 3 Mg ha⁻¹ in the NT and MT compared with ZT. Crop residues on the soil surface after barley sowing were 80% in NT, 56% in ZT, and 12% in MT. At the end of the second year, soil strength, soil moisture and bulk density in ZT declined to NT levels at all soil depths. The positive effect of ZT in increasing SOC in the top layer had also disappeared. However, total N, and available P and K concentrations under NT and ZT were still significantly higher than in MT and CT. Stratification ratios of SOC under NT and ZT were >2 and more than two-fold those under MT and CT. Nitrogen stratification ratio under ZT increased and no significant differences between NT and ZT could be reported. Barley yield was 0.6 Mg ha⁻¹ higher in ZT compared with NT. Our results suggest that ZT improved the physical and chemical condition of the soil studied in months following subsoiling. These positive effects, however, diminished with time and only some residual effects on total N and available P and K content in the top-layer were still evident after 2 years.     

Boron Nutrition Studies with Cotton and Sunflower in Southern Turkey

Wide variations in boron (B) contents are typical of Turkish soils and plants, and most of the variation, 84% of the plant-soil B values are within the “normal.” Boron application on low B soils can make a contribution to yield in cotton and sunflower crops. Field experiments were carried out on clayey and medium-textured soils, which are Chromoxererts, Haploxererts, Xerochrepts, and Xerofluvents in Southern Turkey to study the effects of boron fertilization on irrigated cotton and rainfed sunflower growth, yield, and yield components. Four levels of boron—0, 1, 2, and 3 kg ha^?1—were applied at planting and the experimental design was completely randomized block design with four replications. There was a 31% and 31.9% increase in seedcotton yield at 3 kg and 2 kg ha^?1 of B, compared to the control only two out of four sites. There was an average increase of 61.4% in boll weight with 2 kg B ha^?1 application compared to the control. Effect of different application rates of B was not significant for fiber length, fiber strength, and fiber length uniformity. All levels of boron produced higher head diameters over control only one out of four sites. Boron applied at the level of 3 kg ha^?1 produced the highest 1000 seed weight of 47.5 g representing an 18% increase over the control. Boron applied at the level of 1 kg ha^?1 produced the highest seed yield, representing a 25% increase over the control only at one out of four sites. Boron was no value as a fertilizer for sunflower under given experimental conditions even though some uptake of boron was occurred. Boron fertilization may be regarded as effective in improving cotton yields.     

Performance and behaviour of Bt cotton hybrids under sub-optimal rainfall situation

Growth behaviour and yield performance of Bt cotton hybrids under sub-optimal rainfall situation is of practical significance, because more than 60% of the cotton area is under rainfed condition in India. A field trial conducted in a sandy clay loam soil during the seasons 2006–2007, 2007–2008, and 2008–2009 to study the growth behaviour and yield performance under scanty rainfall situation revealed that growth in both Bt and non-Bt cotton hybrids significantly differed under these parameters. The crop experienced moisture stress at the early stages of growth and again during boll development phase in 2006–2007 and 2008–2009. However, Bt hybrids (1691 kg ha^?1) produced higher seed cotton yield than non-Bt hybrids (1092 kg ha^?1), while the controlled variety (LRA 5166) performed the average of these two (1399 kg ha^?1). Similar trend was evident in respect of bolls per plant (at 90 DAP) and the final harvested bolls in both Bt and non-Bt cotton. Because of Bt gene, the early formed bolls were protected from the boll worms which led to less damage and higher yield with Bt hybrids. Amongst the hybrids, RCHB 708 Bt (1917 kg ha^?1) performed better over the others.     

Soil-Plant-Fertilizer Relationships in Turmeric Assessment of Soil-Plant-Fertilizer-Nutrient Relationships for Sustainable Productivity of Turmeric under Alfisols and Inceptisols in Southern India

Field experiments were conducted during 2005–2007 to test effects of nineteen treatments on turmeric rhizome yield in Alfisol at Utukur and Inceptisol at Jagtial in India. The treatments were comprised of nitrogen (N) at 0, 60, 120 and 180 kg ha^?1; phosphorus (P) at 0, 40, 80, and 120 kg ha^?1; and potassium (K) at 0, 50, 100, and 150 kg ha^?1. Application of 180-120-100 kg ha^?1 NPK gave maximum yield of 4302 kg ha^?1 in Alfisols, whereas application of 120-80-100 kg ha^?1 gave 4817 kg ha^?1 in Inceptisols. Regression and principal component (PC) models were calibrated through soil-plant-fertilizer variables. The regression model gave significant R² of 0.75 in Alfisols compared to 0.88 in Inceptisols, whereas the PC model explained variance of 66.5 percent in Alfisols and 76.3 percent in Inceptisols. Regression model through PC scores gave R² of 0.54 in Alfisols and 0.47 in Inceptisols. Maximum sustainability yield indexes of 58.8 and 55.5 percent by 180-120-120 kg ha^?1 (Alfisol) and 67.1 and 60.6 percent by 120-80-100 kg ha^?1 (Inceptisol) were attained based on regression and PC models respectively.