Integrated nutrient management strategies involving chemical and biologic fertilizer is a real challenge to stop using the high rates of agrochemicals and to enhance sustainability of crop production. In order to study the effects of livestock manure, chemical nitrogen, and biologic (Azotobacter) fertilizers on yield and yield components of wheat, an agricultural experiment in the form of split factorial design with three replications was conducted in Elam region, Iran. The aim of this research was assessment of the effects of these fertilizers separately and in integrated forms; and setting out the best fertilizer mixture. The results showed that treatment with livestock manure, Azotobacter and chemical nitrogen increased plant height, biological and grain yield. Using livestock manure and Azotobacter increased biologic yield through increase in plant height which cause to increase in grain yield without any significant changes in harvest index and other yield components, but the use of chemical nitrogen caused an increase in plant height, No. of spikelete/spike, No. of grain/spike, one thousand grain weight and harvest index, biologic and grain yield. In the light of the results achieved, we may conclude that using livestock manure and chemical nitrogen fertilizer together with the Azotobacter had the maximum impact on yield; and that we can decrease use of chemical fertilizers through using livestock manure and biologic fertilizers and to reach to the same yield when we use only chemical fertilizers.

ABSTRACT. Cumin (Cuminum cyminum L.) is one of the most important pharmaceutical plants. As a considerable portion of existing agricultural lands in arid regions is exposed to aridity and finally to salinity, we need to study the effects of salinity on the growth and production of agronomical products. For this purpose, an agricultural experiment in the form of split plots with three replications was conducted in 2011 at the Islamic Azad University, Gonabad Branch, Iran, in the longitude of 58°, 50', latitude of 34°, 54', and altitude of 940 m from the sea level. At the main plot, four salinity levels (2,5,8 and 11ds/m) and at the sub plot, the growth stages of stress implementation (including stress in establishment, flowering, and seed filling stage), were located at random. The results showed that the salinity rate had significant impact on fresh weight, dry weight, height , percentage of essence, seed and biological yield. With the increase in salinity from 2 to 11ds/m, a significant decrease in all vegetative and reproductive characteristics were observed. The most sensitive growth stages of plant to salt stress, during vegetative and reproductive period were the stage of establishment and flowering, respectively. There was no interaction between the growth stage of plant and salinity rate, except for seed yield and harvest index.

In hot and arid regions, drought stress is considered as one of the main reasons for yield reduction. To study the effect of drought stress, iron and zinc spray on the yield and yield components of wheat, an experiment was carried out during the crop seasons of 2010 and 2011 on Shahid Salemi Farm in Ahwaz as a split factorial within randomized complete block design with three replications. The main plots with irrigation factor and three levels were considered: Level A) full irrigation, Level B) stopping irrigation at pollination step, and Level C) stopping irrigation at the seed filling stage. Subsidiary plots were considered with and without iron and zinc spray. Influencing the seed filling process, in interaction with iron, wich is an important leaf's chlorophyll cation, zinc increased the seed yield. The drought stress reduced the thousand kernels weight (TKW) and the number of seeds per spike increased about 24% and 8.5% more than the one of control treatment, respectively. Using iron, as compared with control treatment, causes the increase of thousand kernels weight from 45.71 to 46.83 grams and the increase of spike from 49.51 to 51.73. Zinc spray increased seed yield and thousand kernels weight. The results obtained from the present research showed that iron and zinc spray has fairly improved the effects caused by drought stress.

Water stress is known as the major threat to reduced growth and yield of plants in arid and semi-arid regions. Potassium is one of the indicators of plant responses to water stress. To evaluate the impact of water stress and levels of potassium on yield and yield components of two varieties of mung bean (Vigna radiata) (promising lines VC6172 and Indian), an experiment in the form of split factorial, based on randomized complete block design with three replicates was conducted in 2011, at the research farm of Safi-Abad Dezfool, Iran (latitude 32°16’ N, longitude 48°26’ E and altitude 82.9 m above sea level) .Water stress in three levels: irrigation at 120 (no stress), 180 (moderate stress) and 240 (severe stress) mm evaporation from pan, were allocated to the main plots and potassium fertilizer at three levels (0, 90, 180 kg /ha) and two varieties of mung bean (promising line VC6172 and Indian) were allotted to the sub-plots. Results showed that water stress and potassium fertilizer significantly affect all traits. The highest grain yield (2093 kg /ha) was obtained from no stress treatment in the case of 180 kg /ha potassium. Total dry matter, number of pods and grain yield, were significantly different between the two varieties. The interaction between fertilizer and variety, on dry matter and grain yield and the interaction between irrigation and variety, on dry matter were significant. We conclude that use of potassium fertilizer can reduce the adverse effects of water stress.

In hot and arid regions, drought stress is considered as one of the main reasons for yield reduction. To study the effect of drought stress, Iron and potassium spray on the yield and yield components of corn, an experiment was carried out during the crop seasons of 2010 and 2011 on Abosaeid research field of Mahvellat as a split factorial within randomized complete block design with three replicates. The main plots with irrigation factor and three levels were considered: irrigation per 6, 9 and 12 days. Subplots were considered with and without Iron and potassium spray. The irrigation reduced the grain yield in irrigation per 12 more than other stages. Irrigation effects significantly on chlorophyll value, leaf relative water content, stem, ear and leaves dry weight, number grain in ear and row, number row in ear, unfilled seed percentage and thousand grains weight. Iron increased the seed yield and yield component, except unfilled seed percentage and SPAD. Using K, as compared with control treatment, causes the increase of grain yield, 1000 grains weight and number grain in ear 16.5, 9 and 5.5% respectively. Potassium could somewhat reduce the impact drought stress on corn.