International Journal of Plant Production
Volume:10 Issue: 2, Apr 2016

A field experiment was conducted to study the effects of N fertilization on uptake, accumulation/remobilization, use efficiency and yield of sunflower grown in alluvial plains of northwestern India comprising four hybrids (PSH 996, PAC 3789, PSH 569 and SH 3322) and five N levels (Control, 40, 80, 100 and 120 kg N ha-1) in split-plot design with three replications. Increased N fertilizer rates significantly prompted sunflower yield only up to 100 kg N ha-1. Every additional kilogram of N taken up increased sunflower yield by 26 kg ha-1. Significant genetic variation for seed yield and NUE traits explicated PSH 569 as the efficient one at sub-optimal N application while PSH 996 outperformed others at N80, N100 and 120. Dry matter accumulation pattern revealed average harvest index of 30% with 29% of the biomass as stalk, 19% as leaf and 22% as thalamus. Temporal changes in N acquisition indicated most of the total N uptake upto 50% flowering while maximum remobilization takes place during reproductive phase. Significant correlation between N uptake and N use efficiency parameters with yield indicate the importance of N nutrition in sunflower; LAI (r=0.841 **), N uptake (r=0.956**), NUpE (r= -0.814**), NUtE (r= -0.787**), NUE (r=-0.802**). Variation in NUE was more closely associated with NUpE (r=0.996**) than NUtE (r=0.812**) and linearly decreased with increasing leaf greenness (R2=0.70) and total leaf area (R2=0.81). This work will complement other studies to establish a baseline for breeding N efficient sunflower genotypes be grown under semi-arid tropical conditions in India and similar environments.

The objective of the present study is to investigate the effects of irrigation water salinity, cow manure levels and different planting methods on saffron quality compounds including crocin (coloring strength), picrocrocin (bitterness) and safranal (aromatic strength). A split-split plot arrangement was conducted in complete randomized block design with irrigation water salinity levels (0.45 (fresh water, S1), 1.0 (S2), 2.0 (S3) and 3.0 (S4) dS m-1) as the main plot, cow manure levels (30 (F1) and 60 (F2) Mg ha-1) as the sub plot and planting method (basin (P1) and in-furrow (P2)) as the sub-sub plot in three replications. Results showed that the saffron coloring strength, bitterness and aromatic strength in higher salinity level decreased by 9, 1 3 and 18% in comparison with the lowest salinity level, respectively. However, saffron (stile/stigmas) yield declined significantly as about 42% by increasing water salinity to highest level. The saffron crocin and picrocrocin concentration for the in-furrow planting method were significantly higher than the basin planting method by about 4 and 8%, respectively. Higher application rate of cow manure (60 Mg ha-1) did not promote the saffron quality compounds. Furthermore, planting methods showed no significant effect on saffron aromatic strength. Correlation analysis indicated that saffron quality compounds showed negative relationship with leaf calcium, sodium and chloride and positive relationship with leaf phosphorus, nitrogen and potassium at 0.01 and 0.05 significant levels, Furthermore, a positive correlation between crocin and picrocrocin and saffron yield components (leaf dry matter, corm, flower and saffron yields) was observed; however, there was no significant correlation between safranal and yield components. Generally, the saffron quality compounds variations were concurrent with the saffron quantity variations.

In Ardabil region potato crop needs several irrigation, however ground water supplies are being exhausted due to reduced precipitation and intensive irrigation. In this research drought tolerance of 10 commercial potato cultivars was studied at three irrigation treatments 100%, 80% and 60% of required irrigation water) in Ardabil in a two years field study, 2013 2014. At harvest, marketable tuber yield, tuber weight per plant, mean tuber weight, tuber number per plant, percent tuber dry matter, plant height and the main stem diameter were measured. Also the stress indices such as water stress susceptibility (SSI), tolerance (TOL), mean productivity (MP), geometric mean productivity (GMP) and stress tolerance (STI) were determined and used to select the tolerant cultivars to water deficit. There were significant differences among irrigation treatments, cultivars and cultivars × irrigation treatments for all studied traits; between years and interaction of years × cultivars for marketable tuber yield, tuber weight per plant, mean tuber weight and tuber numbers per plant. The cultivar Satina produced the highest marketable tuber yield, tuber weight per plant, mean tuber weight and plant height and also had higher MP, GMP and STI indices in all three irrigation treatments, therefore, it can be recommended for cultivation under water deficit condition. Cultivar Caesar showed the lowest SSI and TOL indices under both mild and severe water deficit conditions, therefore it can be used in breeding programs for developing drought–tolerant potato cultivars. Under both mild and severe stress conditions a high correlation was found between marketable tuber yield and plant height, but a negative correlation existed between mean tuber weight and tuber number per plant. Cultivar Savalan showed the highest tuber dry matter content.

Himalayas, are among the areas most vulnerable to global warming, however, little is known about warming impacts on the crops. Therefore, the actual affects of anticipated warming on winter wheat were tested in Tibet, China. During the period 1988-2012, Tibet region has experienced a large increase in daily mean, minimum and maximum temperatures during wheat growing seasons by 0.50, 0.67 and 0.51 oC every ten years, respectively. The de trended wheat yield increased by 34.4 kg ha-1 year-1 during this period. According to the historical data, 1 oC increase in daily mean temperature could get 370.6 kg ha−1 gain in wheat yield. Similar gains in wheat yield were found in a field warming experiment with an increase of 1.1 oC in daily mean temperature. The field warming caused a significant reduction in the pre-anthesis phase and entire growth period by 14 and 13 days, respectively. The green leaf areas and spike number in the warmed plots were significantly higher than that in non-warmed plots, while the grain number per spike was significantly lower in the former than the later (P

The Saffron Yield Estimation Model (SYEM) was modified for salinity conditions, cow manure application and planting methods using two-year experiments data in Badjgah region of Iran. A split-split plot arrangement was conducted in complete randomized block design during two years with irrigation water salinity levels (0.45 (fresh water, S1), 1.0 (S2), 2.0 (S3) and 3.0 (S4) dS m-1) as the main plot, cow manure levels (30 (F1) and 60 (F2) Mg ha-1) as the sub plot and planting method (basin (P1) and in-furrow (P2)) as the sub-sub plot in threereplications. Data of the second and first growing season were used to calibrate and validate the modified model, respectively. In the modified SYEM model, the soil salinity was estimated. Based on the NRMSE and d indices, the modified SYEM model presented a very good to fair estimation of actual evapotranspiration, evaporation, transpiration, soil water content and salinity, leaf drymatter, corm and saffron yields. The advantage of this model is its simplicity and easy calibration in other climate conditions for saffron crop. Prediction of saffron yield by this model can be used for better irrigation salinity management under different manure application levels and planting methods.

The objective of the present study is to investigate the effects of irrigation water salinity, cow manure levels and different planting methods on ions variation in soil and their uptake by saffron. A split-split plot arrangement was conducted in a randomized complete block design with irrigation water salinity levels (0.45 (fresh water, S1), 1.0 (S2), 2.0 (S3) and 3.0 ( 4) dS m-1) as the main plot, cow manure levels (30 (F1) and 60 (F2) Mg ha-1) as the subplot and planting method (basin (P1) and in-furrow (P2)) as the sub-subplot with three replications. Results showed that the concentration of sodium (Na), calcium (Ca2), chloride (Cl-), potassium (K), sulphate (SO42-) ions in soil was increased significantly with increasing water salinity levels. These variations were in accordance with EC e variations that were 2.6 times in S4 compared with S1 treatment. However, the soil nitrate (NO3-N) decreased in the highest irrigation salinity level by about 30% compared with the lowest salinity level in two growing seasons. These element concentrations were significantly higher in F2 treatment in comparison with F1 due to addition of these ions by higher application rate of cow manure to soil. There was no significant difference between element concentrations in soil for two planting methods. Increasing salinity to the highest level significantly increased the saffron leaf concentration of Na, Ca2 and Cl- by about 4.0, 1.4 and 1.5 times, respectively. Increasing salinity resulted in decrease in K, nitrogen (N) and phosphorus (P) concentration in saffron leaf by about 30, 20 and 39% under the highest water salinity level, respectively. The in-furrow planting method significantly led to increase in K, N and P concentration in plant by about 10, 3 and 8% in comparison with the basinplanting, respectively. Also, higher manure application rate as 60 Mg ha-1 significantly increased plant N and P concentration by about 12 and 20% in two growing seasons, respectively.

Understanding the physiological processes associated with high yield traits in modern crop varieties is essential to further increase grain yield and improve nutrient management strategies. Field trials were conducted to study the effects of fertilization and variety on the grain yield of rice (Oryza sativa L.) with two fertilizer levels and 18 modern varieties. The objectives were to evaluate yield components, time courses of dry matter production and time courses of N, P2O5 and K2O accumulation among different yield categories and to determine physiological processes associated with yield-trait relationships. Variation among varieties had a considerable impact on rice grain yield, regardless of fertilization. Close correlations were observed between grain yield and effective panicles, dry matter production and N, P2O5 and K2O accumulation. Differences in dry matter production and P2O5 accumulation among different yield categories began at anthesis; differences in N and K2O accumulation emerged earlier. It can be concluded that consistent increases in dry matter production (especially post-anthesis) and N, P2O5 and K2O accumulation are crucial for further improvements in rice yield-trait relationships.

Comprehensive agricultural models are crucial for assisting several decision making processes due to their capability for use under different conditions. SALTMED is a holistic generic model, which simulates yield, dry matter and soil water content under different irrigation managements and systems. The aim of this study was to calibrate the SALTMED model to simulate wheat yield, dry matter and soil water content of two different field experiments using different irrigation amounts and systems, namely sprinkler and basin irrigation systems. For both irrigation systems, experimentation was conducted for two consecutive years. For the sprinkler irrigation system, three irrigation treatments (wet, medium and dry) were considered. For the basin irrigation system, 50, 75 and 100% of the irrigation requirement were applied as irrigation treatments. The SALTMED model reasonably predicted the wheat yield and dry matter for both irrigation methods by small tuning of crop coefficients and some growth parameters. Besides, a good agreement between observed and simulated soil moisture content was obtained for both experiments with different irrigation treatments and systems. Comparison of the soil moisture prediction for the two different irrigation methods revealed that the SALTMED model simulated the soil moisture content better under the sprinkler system. It is concluded that SALTMED model performed better under sprinkler system rather than basin irrigation system.

Water shortage worldwide mandates minimum use of irrigation water with maximum efficiency and productivity in all agricultural crops, landscape plants and turf. The objective in this experiment was to study the effect of two levels of evapotranspiration-based (ETc) drought in combination with two levels of nanosilicon dioxide (SiO2; NanSi1=1 mM and NanSi=2 mM), two levels of digoxin (Dig1=0.25 mg.l-1 and Dig2=0.5 mg.l-1) and Dig1 plus NanSi1 on mineral nutrient concentration, chlorophyll index, visual performance of perennial ryegrass (loliumperenne) under climatic conditions of the southwest Idaho in the Intermountain West Regions of the United States. Clippings with 50% ETc had higher percentage dry weight but lower chlorophyll index and visual rating than those with 75%. Clippings of 75% ETc treatment had significantly higher concentrations of nitrogen (N), potassium (K), zinc (Zn) and copper (Cu) but lower sodium (Na), than those of 50% ETc treatment. Considering all mineral nutrient values, chlorophyll indices and visual performance ratings, we conclude that application of 75% ET c is sufficient for maintaining a healthy lawn with satisfactory appearance while we can save25% water as compared to application of water at 100%. Root growth was not affected by any of these treatments. Based on the results of this study, applications of NanSi1 or Dig1, either individually or simultaneously, can slow the process of quality decline in perennial ryegrass turf under extremely severe drought conditions.