International Journal of Plant Production
Volume:11 Issue: 3, Jul 2017

The effects of two water regimes (well-watered condition or drought stress) on root length, root surface area and root volume were tested on two peanut genotypes (the drought resistant variety HuaYu 22 (HY22) and the drought-sensitive variety HuaYu 23 (HY23)), measured 101 days after sowing. The roots were sampled from the upper (0–40 cm) and deeper (40 100 cm) soil layers. Root diameter was measured to the nearest 0.5 mm in describing its distribution. Total dry weight and pod yield were measured at harvest. The drought tolerance index of pod yield and the harvest index in HY22 were higher than those in HY23. The total root length density (RLD), total root surface area and volume were significantly higher for HY22 than HY23. The RLD in the deeper soil layer was lower for HY23 than HY22. Under drought stress, the percent RLD in the deeper layers increased in both genotypes. Compared to well watered condition, the total root surface area and root volume in the upper soil layer were lower under drought stress and root traits in deeper soil layers were higher. Drought stress had no impact on very fine roots (diameter

The water resource shortage in North China Plain is an increasing threat to the sustainability of wheat (Triticum aestivum L.) production. A two-year field experiment was conducted to examine the effects of two supplemental irrigation (SI) methods on wheat flag leaf senescence, chlorophyll fluorescence and grain yield. The following field treatments were conducted: no irrigation (W0); SI with 60 mm of water at jointing and anthesis stages (local quota SI, Wck); SI based on the relative soil water content (SWC) of 0–40 cm soil layers with 65% field capacity (FC) at jointing stage and 70% FC at anthesis stage (W1); SI based on SWC of same soil layers with 70% FC at the jointing and anthesis stage (W2); and SI based on the SWC of same soil layers with 75% FC at jointing stage and 70% FC at anthesis stage (W3). Results showed that W0 accelerated flag leaf senescence and had reduced grain yield. Among irrigation treatments, W2 (and W3 in 2013-2014) significantly increased flag leaf water potential from 7 to 28 days after anthesis (DAA) compared with Wck and W1. Superoxide dismutase activity, catalase activity of W2 increased by 15.41% and 14.96% compared with those in Wck, resulting in the significantly decreased concentration of malondialdehyde and increased concentration of soluble protein at 14–28 DAA. The Fv/Fm at 21–28 DAA and the ΦPSII, qP and NPQ at 14–28 DAA for W2 (and W3 in 2013–2014) were also significantly higher than those of Wck and W1. Eventually, grain yield, water use efficiency and irrigation benefit of W2 were 8704.54 kg ha-1, 20.86 kg ha-1 mm-1 and 31.44 kg ha-1 mm-1, respectively, which were the highest among those of all the treatments. These values increased by 5.82%, 9.65% and 6.00%, respectively, relative to those of Wck. In conclusion, the SI based on 0–40 cm soil layer and use of an appropriate relative SWC (both 70% FC at the jointing and anthesis stages) can reduce irrigation amount, delay leaf senescence and improve grain yield and water use efficiency.

Although the nitrogen nutrition index (NNI) is a widely used indicator of plant nitrogen status, no model of NNI calculation for spring barley (Hordeum vulgare) reflecting also specific malting requirements on grain has been published. The aim of this study was to determine an optimal range of the nitrogen nutrition index (ratio of nitrogen concentration in shoot biomass to critical nitrogen concentration) with respect to optimal grain protein content (N × 6.25 = 9.0 – 11.5 %), plump grain (grain > 2.5 mm) yield and lodging of spring malting barley during 7-year (2007 – 2013) strict field experiments realized under the conditions of three experimental sites in the Czech Republic. A dose of 80 kg N/ha and 130 kg N/ha, respectively, was applied in mineral fertilizers. The nitrogen nutrition index was determined at the BBCH 30 (beginning of stem elongation) and BBCH 45 (late boot stage) growth stages. The most suitable indicators for evaluation of the nitrogen concentration in shoot biomass of the spring malting barley in our experiments proved to be Justes et al.´s model Nc = 5.35 DM(-0.442) designated for winter wheat and Zhao´s model Nc = 4.76 DM(-0.39) designated for winter barley, where DM is shoot dry matter in t/ha. The nitrogen nutrition index for spring malting barley should not exceed a value of NNI = 0.80 and NNI = 0.90 using the Justes et al.´s model and the Zhao´s one during the BBCH 30 – 45 growth stages.

Poor irrigation water management is one of the major factors limiting crop production in Ethiopia. This study was, therefore, conducted at three different locations in the southeastern Ethiopia for 2 consecutive years to investigate the effects of different irrigation depths and intervals with furrow irrigation system on tuber yield, biomass yield and water use efficiency of potato. The treatments consisted of four irrigation regimes. Three of them were determined using FAO-Cropwat 4 Windows 4.3 computer model based on maximum irrigation efficiency and minimum yield loss. The fourth treatment was farmer's practices for each location. The irrigation treatments were laid out in randomized complete block design with 3 replications. Results showed that irrigation regimes determined using FAO-Cropwat 4 Windows 4.3 computer model gave superior tuber and biomass yields and water use efficiencies of potato compared to farmers’ practices at all locations. Higher values of crop and water productivity were obtained when scheduled at application of 20 mm irrigation water every 6 days, 15 mm irrigation water every 7 days and 15 mm irrigation water every 9 days for Sheled, Golja and Lemu areas, respectively. It could be conclude that farmers were over irrigating their farms without equivalent returns. The water saved through optimized irrigation can be used more profitably to irrigate supplemental lands, thus achieving a more efficient and rational use of land and water resources.

Intercropping often results in increasing production than sole per unit land area, but the underlying mechanisms are poorly understood. Plants showed different physiological characteristics in intercropping and sole. However, less information was shown the relationships between plant aboveground biomass (AB), phosphorus accumulation (PB) and remobilization and the yield advantage. Here, field experiments were designed as split plot and carried out in 2012 and 2013 with three P levels (0, 40 and 80 kg P ha-1) in wheat (Triticum aestivum L.)/ maize (Zea mays L.) relay intercropping and sole. The study measured grain yield, AB and P accumulation and remobilization of wheat. Averaged grain yield of intercropping wheat increased 3.9 Mg ha-1 in 2012 and 2.7 Mg ha-1 in 2013 compared with that of the corresponding sole and the grain yield of intercropping wheat changed with the border row (BR) > the inner row (IR) > the sole wheat (SR), the grain yield in BR was contributed by 58.2% to intercropping wheat. The PA was consistent with AB accumulation, which in intercropping was higher than that in sole over the entire growing season. Close correlations between yield and AB remobilization and P remobilization were observed. The yield of BR was higher from 39.3 to 88.0% than that of SR wheat, as mainly attributed to more AB and P accumulation across the whole growing season and more remobilization from pre-anthesis to grain filling stage. More than 40 kg P ha-1 did not result in any further increasing in yield and did not enhanced the physiological processes associated with AB and P remobilization, indicating that P fertilizer and agronomic management should be intensified synchronously in field to achieve high yield and sustainability.

This research was carried out in 2014 and 2015 to assess the effects of salicylic acid (SA) (0 and 1 mM) and abscisic acid (ABA) (0 and 50 µM) on essential oil content and yield of ajowan (Carum copticum L.) organs under different irrigation intervals (I1, I2, I3, I4: irrigation after 70, 100, 130 and 160 mm evaporation, respectively). Plants were sprayed by SA and ABA at vegetative and reproductive stages. In both years, the biomass of vegetative organs (leaves and stem), flower production and seed yield per unit area of ajowan decreased with decreasing water availability. All organs mass improved by application of ABA and particularly SA. Essential oil percentage of all organs increased, but essence yield decreased as a result of water limitation. Reduction in essential oil yield of ajowan organs due to water stress strongly related with the reduction of individual organ mass under stress. Foliar spray of ABA and especially SA improved the medicinal and commercial value of ajowan under different irrigation intervals by enhancing plant organs biomass and accumulation of more essential oil.

Increase in rice yield under excessive nitrogen (N) supply is negligible, hence it is necessary to analyze the limiting factors via yield components. The present study was carried out during 2014 and 2015 growing seasons in order to quantify the yield componenents of different types of tiller at various N levels. Tillers were divided into three different types (superior, medium and inferior) based on their productivity. The results indicated that the quantitative proportions and yield contributions were decreased in superior tillers, increased in the inferior tillers, while remained stable in the medium tillers with increasing supply of N fertilizer. The increased rate of spikelets per panicle in the superior tillers was higher under all N application levels; however, a high quantitative proportion and the lower number of spikelets per panicle of the inferior tillers might have resulted in the reduced population of spikelets per panicle. The rates of grain filling percentage and grain weight in medium and inferior tillers were decreased with increasing N applications, which led to a decrease in population grain filling and grain weight. The present study suggested that the enhancement of grain filling and weight of the inferior tillers would be an effective approach to further improve the per acre yields of rice. The acquisition of more accurate yield component data, in the perspective of tiller, might be helpful for researches regarding the development of augmented rice breeding architectures.

Weed infestation of durum wheat was determined in the systems of conventional tillage (CT), reduced tillage (RT) and herbicide tillage (HT). Cultivations measures performed after the harvest of the previous crop included shallow ploughing (at a depth of 10-12 cm) and pre-winter ploughing (25-30 cm) in the CT system; only field cultivation (10-15 cm) in the RT system; and spraying with glyphosate (Roundup 360 SL) in the HT system. In the springtime, a tillage set consisting of a cultivator, a string roller and a harrow (10-12 cm) was applied on all plots. It was demonstrated that wheat cultivation in the RT and HT systems was increasing the number and weight of weeds, compared to the CT system. The highest number of weeds occurred at the middle level of wheat crop, whereas the highest air-dry weight was produced by the weeds at the upper and middle crop levels. In the HT system, weed community was constituted exclusively by short-term species, whereas in CT and RT systems – by short-term and perennial species.