بررسی عملکرد بوته و اجزای عملکرد نخود زراعی (cicer arietinum l.) و وزن و ارتفاع بوته کاهو (lactuca sativa l.) تحت تاثیر نیتروژن و نسبت‎های مختلف کشت مخلوط

به‌منظور بررسی تاثیر کود نیتروژن و نسبت‎های مختلف کشت مخلوط بر عملکرد بوته و اجزای عملکرد نخود زراعی(cicer arietinum l.)  و وزن و ارتفاع بوته کاهو (lactuca sativa l.)، آزمایشی به‌صورت فاکتوریل در قالب طرح بلوک‌های کامل تصادفی با سه تکرار در سال زراعی 97-1396 در مزرعه دانشگاه گنبدکاووس اجرا گردید. عامل‌ الگوی کاشت در نه سطح شامل کشت خالص نخود زراعی و کاهو، کشت مخلوط جایگزین 33، 50 و 67 درصد کاهو به‌جای نخود زراعی و کشت مخلوط افزایش 33، 50، 67 و 100 درصد کاهو به نخود زراعی و عامل نیتروژن در سه سطح شامل عدم مصرف و مصرف 50 و 100 کیلوگرم نیتروژن خالص در هکتار بودند. نتایج نشان داد که بیش‌ترین وزن خشک بوته، تعداد غلاف در بوته، تعداد دانه در بوته، وزن هزار دانه، وزن دانه در بوته و شاخص برداشت نخود زراعی مربوط به تیمار کشت مخلوط جایگزین 33 درصد نخود زراعی و 67 درصد کاهو و کم‌ترین آن مربوط به تیمار کشت مخلوط افزایشی 100 درصد کاهو + 100 درصد نخود زراعی بود. با افزایش مصرف نیتروژن، وزن بوته، تعداد غلاف در بوته، تعداد دانه در بوته، وزن دانه در بوته، وزن 1000 دانه و شاخص برداشت نخود زراعی افزایش یافت. اگرچه در تیمارهای افزایشی ارتفاع بوته کاهو بیشتر بود، امّا وزن بوته در تیمارهای جایگزین بیش از سایر تیمارها بود. در مجموع، افزایش تراکم بوته وزن بوته نخود زراعی و کاهو را کاهش داد، امّا مصرف نیتروژن تا 100 کیلوگرم در هکتار وزن بوته را افزایش داد.

The Investigation of Plant Yield and Yield Components of Chickpea (Cicer arietinum L.) and Weight and Length of Lettuce (Lactuca sativa L.) as Affected by Application of Nitrogen Levels and Row Intercropping Ratios

IntroductionThe main goal of conventional agriculture is to maximize both production and income. Intercropping, the agricultural practice of cultivating two or more crops in the same space at the same time, is an old and commonly used cropping practice that aims to match efficiently crop demands to the available growth resources and labor. The most common advantage of intercropping is the production of greater yield on a given piece of land by making more efficient use of the available growth resources using a mixture of crops of different rooting ability, canopy structure, height, and nutrient requirements based on the complementary utilization of growth resources by the component crops. Mixed cropping of cereals with noncereal plants, in addition to the optimal and fair use of resources such as land and labor, increased productivity per unit area and strengthened total productivity per unit area and time. In mixed cropping of bean and sesame, treatments including 25:75, 50:50 and 75:25 had 1000seed weight, number of capsules or pods per plant, number of seeds per pod and harvest index were higher than other treatments. Materials and MethodsAn experiment was carried out as factorial based on a randomized complete block design with three replications in Gonbad Kavous University farm from 2017to 2018. The intercropping ratios were in nine levels, including sole crop of chickpea and lettuce, replacement intercropping of 33, 50, and 66% lettuce instead of chickpea, and additive intercropping of 100% cicer + 33, 50, 67, and 100% lettuce and pure nitrogen consumption in three levels of 0, 50 and 100 Kgha. Row distance was 30cm, and row lengths were 3m. The distance between plants in rows was 20 cm for lettuce and 10 cm for chickpeas. The number of rows in sole cropping of chickpea and lettuce was four, 50% lettuce + 50% chickpeas 4 (chickpealettucechickpealettuce), 33% lettuce + 67% chickpea 5 (chickpealettucechickpeachickpea–lettuce), 33% chickpea + 67% lettuce 5 (lettucechickpeachickpea lettucechickpea) and in additive treatments was 8 (lettucelettucelettucelettucelettucelettucelettucelettuce) with 15 cm from together. In additive treatments distance of plants was 60, 40, 30, and 20 cm for 33, 50, 67, and 100% increase, respectively. SAS Ver. 9.4 was performed for statistical analysis of data, and the least significant difference test (LSD) at the 5% probability level was employed for mean comparisons.   Results and DiscussionThe results showed that the highest dry weight, number of pods per plant, number of seeds per plant, 1000seed weight, seed weight per plant, and chickpea harvest index were obtained from replacement series of 33% chickpea and 67% lettuce. This was due to reduced external competition, which provided more space for the plant and produced more photosynthetic material. Also, the lowest dry weight, number of pods per plant, number of seeds per plant, seed weight per plant, and 1000seed weight of chickpea were obtained from an increase of 100% lettuce to chickpea. With increasing nitrogen consumption, plant weight, the number of pods per plant, number of seeds per plant, seed weight per plant, 1000seed weight and chickpea harvest index, and lettuce plant height and weight were increased. By increasing of nitrogen, plant growth, yield components, and consequently, chickpea seed yield increased. ConclusionAmong the two pea and lettuce plants, lettuce plant weight was higher. The higher weight of lettuce can be attributed to the genetic characteristic of the plant (harvest of the whole plant and high level of water content of the plant). The weight of both species increased with increasing nitrogen consumption. The highest harvest index resulted from the treatment of 50 kg nitrogen per hectare, and the lowest harvest index was obtained from the treatment of nonconsumption of nitrogen. Chickpea plant dry weight was reduced due to increasing density which in turn resulted in high competition between plants. Seed weight and yield components of chickpea decreased with increasing density.