Effects of Water Deficit and Supplemental Irrigation on Winter Wheat Growth, Grain Yield and Quality, Nutrient Uptake, and Residual Mineral Nitrogen in Soil
Notice bibliographique
Résumé
Water deficit (WD) is a primary factor that limits winter wheat (Triticum aestivum L.) production in the Loess Plateau of China, as rainfall during the growing season is usually low and erratic in this region. Supplemental irrigation (SI) in early winter and/or early spring has been widely practiced to mitigate this problem. However, the timing at which WD and SI occur can influence grain yield and quality. A simulation pot experiment was conducted from October 1999 to June 2000 to determine the effects of WD and SI applied at different stages on winter wheat growth, grain yield and quality, nutrient uptake, and residual mineral nitrogen (N) in soil. The results showed that wheat at tillering, stem elongation, and grain‐filling growth stages was more sensitive to WD than at dormant stage. Water deficit at stem elongation or grain‐filling stage not only decreased biomass, but it also appeared to have inhibited the translocation of assimilates from the vegetative plant parts to the heads, especially when WD occurred during grain‐filling stage. Water deficit at dormant stage had no significant effect on biomass production, but it may have hindered the allocation of assimilates to the heads. Water deficit at tillering tended to increase grain harvest index but decreased biomass. Grain yield was significantly decreased (15–91%) by WD at all four growth stages. Translocation of N, phosphorus (P), and potassium (K) also appeared to have been pronouncedly impeded by WD. This inhibitory effect was more apparent at the advanced growth stages of winter wheat. Supplemental irrigation applied at dormant or grain‐filling stage increased grain yield (12% and 35%, respectively). Of the nutrients uptake, only N uptake in grain was increased (21%) when SI occurred at grain‐filling stage. Application of SI at tillering stage significantly decreased grain yield and N and P uptake in the grain, possibly due to decreased biomass and nutrient uptake in the whole plant. Supplemental irrigation at elongation stage increased biomass and N, P, and K uptake in the whole plant, but it appeared to have decreased translocation of assimilates and nutrients to the heads. Supplemental irrigation decreased or had no effect on N, P, and K concentration in grain. The main form of residual mineral N in soil was nitrate‐N, and it was markedly increased when WD was applied at all growth stages or when SI was applied at tillering stage. Supplemental irrigation at elongation or grain‐filling stage significantly decreased residual soil nitrate‐N.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».