بالنسبة للنبات، لا يهم المقدار فحسب، بل أيضًا التوقيت

كيف أُجريت دراستنا

نما كل نبات قمح في حاويته الخاصة بمحلول ينقصه عنصر غذائي واحد. يتيح ذلك رؤية ما يحدث للنبات بالضبط عند نقص ذلك العنصر بعينه – وإلى متى يمكنه الانتظار.

ليس القمح فقط

تجربة الذرة 2026

في عام 2026 تُزرع الذرة بالمبدأ نفسه في البيت المحمي لجامعة VMU: ينمو كل نبات في حاوية مستقلة ينقصها عنصر واحد. ويُدرس أيضًا نقص الكالسيوم (Ca).

لماذا تستحق مراحل النمو BBCH 30–37 الاهتمام؟

في دراستنا زُرع القمح الربيعي زراعةً مائية. بدأ نقص عنصر كبير واحد عند BBCH 23 واستمر 21 أو 28 أو 35 يومًا؛ وقد وافقت هذه الفترات تقريبًا المراحل BBCH 30 و32 و37. واعتمد الأثر على العنصر والمدة: فعلى سبيل المثال خفّض نقص البوتاسيوم لمدة 28 يومًا عدد الإشطاءات المنتجة، بينما ازدادت خسائر الكتلة الحيوية كلما طال نقص النيتروجين أو الفوسفور أو الكالسيوم.

مهم: لا ينبغي نقل هذه الأعداد من الأيام مباشرة إلى التربة. في التربة يتطور النقص أسرع بـ 3 إلى 5 مرات. ففي التربة كثيرًا ما تعاني النباتات أيضًا من نقص الماء، بينما في الزراعة المائية حيث لا ينقص الماء أبدًا يمكن للنبات أن يبقى مدة أطول في حالة حماية – فهو أكثر صبرًا.

من الخبرة الحقلية

في الحقل يمضي الوقت أسرع بعدة مرات

في الزراعة المائية يتوفر الماء للنبات دائمًا، لذا يتطور الجوع الغذائي ببطء. أما في التربة، وفق ملاحظات مهندسينا الزراعيين، فيتطور نقص مماثل خلال 5–10 أيام، وفي الجفاف خلال 1–3 أيام فقط. وقد تعادل ثلاثة أسابيع من الجوع في الزراعة المائية أسبوعًا في الحقل، وبضعة أيام فقط في فترة جفاف.

لهذا قد يكون تأخير بضعة أيام في الحقل متأخرًا جدًا بالفعل: إذ يشغّل النبات عمليات أخرى وقد يحتاج حينها إلى عناصر مختلفة. يجب قياس النقص، لا انتظار أن يصبح مرئيًا.

تستند المدد الحقلية إلى ملاحظات المهندسين الزراعيين في UAB „Žemdirbių konsultacijos“؛ وهي ليست نتيجة للدراسة المائية.

استنتاجات ممارس

ماذا تفعل عندما يُظهر SmartAgrometer نقصًا

ليس كل نقص يستحق الإنقاذ بالطريقة نفسها. فأحيانًا يكون القرار الصحيح هو التوقف عن الاستثمار في حقل وإعطاء تلك الأسمدة لحقل آخر أفضل. فيما يلي استنتاجات مهندس زراعي ممارس من أبحاثنا وعملنا في الحقل.

استنتاجات إرنستاس بيتراوسكاس، المهندس الزراعي الممارس وطالب الدكتوراه في جامعة VMU، من أبحاث UAB „Žemdirbių konsultacijos“ وعملها الحقلي. الأساس العلمي: Petrauskas et al., 2026, Plants 15(7), 1094.

صور التجربة

12 حالة نقص. هل تستطيع تمييزها بالعين؟

التجربة نفسها على القمح الشتوي: كان كل نبات ينقصه عنصر غذائي واحد. بعض الفروق واضحة، لكن معظمها شبه خفي عن العين – خاصة في الحقل حيث تتشابه النباتات كلها. أما SmartAgrometer فيُظهر النقص بالأرقام.

12 عنصرًا غذائيًا

ما يقدمه كل عنصر للقمح، وكيف قد يبدو نقصه، ومتى يكون أخطر، وهل يمكن تصحيحه لاحقًا.

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